Arctic Sea Ice : Forum

AGW in general => Consequences => Topic started by: jai mitchell on May 20, 2014, 09:51:45 PM

Title: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 20, 2014, 09:51:45 PM
Now that we have determined that the likely contribution to sea level rise from WAIS will be 1 meter or so:  http://news.sciencemag.org/climate/2014/05/west-antarctic-ice-sheet-collapsing (http://news.sciencemag.org/climate/2014/05/west-antarctic-ice-sheet-collapsing)

and the previous AR5 projection says that the Antarctic contribution was supposed to be about 5 cm

 (https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.realclimate.org%2Fimages%2F%2FIPCC_AR5_13.11.png&hash=707e1d75e083a0e772f7e22f26eb53e4)

What will be the real sea level rise by 2100 under RCP 6.0 now?

1 meter?
2 meters?
3 meters?

Since the DICE model used to determine the costs of climate change only projects 1 meter of sea level rise

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fobject.cato.org%2Fsites%2Fcato.org%2Ffiles%2Fwp-content%2Fuploads%2Fgsr_040914_fig1.jpg&hash=270335f13fa94f3af917a4bf0d3ef568)

and it now looks like we will have 2.5 to 3.5 meters of sea level rise.  What is the new social cost of carbon?  is it now double what it would be without this new information?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: crandles on May 21, 2014, 12:34:35 AM
AR5 says
Quote
For the period 2081–2100, compared to 1986–2005, global mean sea level
rise is likely (medium confidence) to be in the 5–95% range of process-based models, which give ... 0.33–0.62 m for RCP6.0

(Edit that is all sources not just Antarctica.)


Hmm 1.2m over 500 years instead of 5cm by 2100 could be an increase of 20cm or perhaps more likely less if some acceleration is assumed.

or we could take the 200 of the 200-500 years and then there is up to a 55cm increase as a result of the item linked.

So my calcs come to almost anything up to 55cm which leaves me a bit puzzled as to where your increase from 0.33–0.62 m to 3.5 m comes from.

Of course your "What will be the real sea level rise by 2100 under RCP 6.0 now?" requires finding all the other errors and updates to research since AR5 deadline.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 21, 2014, 01:49:51 AM
Sorry I should have updated:

the current WAIS projections are 1 meter by 2100 and 3 meters by 2200  just from the WAIS.

all of the levels reported in the first calculation was 2100.

Another thing to consider regarding the social cost of carbon is the discounting mechanism.  Since sea level rise was previously expected in the latter half of the century for any real impact, the (very large) impacts were discounted by almost 45% in real dollars.

now that increase is supposed to happen in 20 years.  which should increase the effect on the social cost of carbon by 300% for the sea level component of the costs of climate change (per ton of co2)

It is likely now that the current SCC is already underestimated by at least 30%
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 21, 2014, 04:32:58 PM
jai,

As we are currently following, and have been following for at least 30-yrs, RCP 8.5, I am not sure why you present RCP 6 as your basis for discussion.  RCP 6 assumes relatively low levels of methane emissions, and with Barrow and Mauna Loa (and every other monitoring station in the world) indicating accelerating methane emissions into the atmosphere, it seems to me that RCP 8.5 is much more justified as a basis for discussion, and at a minimum, should not be ignored in any meaningful discussion about SLR to the end of the century, and beyond.  I know that you are aware of the discussions on this topic in the Antarctic folder, but I am citing it here for those who have not yet looked at that folder.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 21, 2014, 05:34:45 PM
Thanks SLR

Yes, I am aware.  I also am aware that for the purposes of realistic projections, the RCP 8.5 will not possibly be maintained.  If we want to understand real potential sea level rise, then the RCP 6.0 is the most likely candidate for actual emissions.

this is because we will experience a catastrophic global economic collapse sometime around 2050 if we attempt to maintain the RCP 8.5 scenario.

I believe that, with aggressive mitigation, the carbon-cycle feedbacks will mimic the RCP 6.0 (but it may be closer to RCP 8.5 as you say, depending on clathrates)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 21, 2014, 06:04:03 PM
jai,

Thanks for your response, and I guess that we will both need to wait to see what anthropogenic greenhouse gases are (or are not) emitted in the coming years.  But that said, we should not forget the following factors that have little to do with anthropogenic GHG emissions after 2050: (a) RCP 6.0 also assumes an ESS (Earth System Sensitivity) of about 3.0 degrees C this century; which may well be too low; (b) The most likely sources of accelerated methane emissions this century are from northern/tropical wetlands and from fracking, not from clathrates; and (c) as SLR is most closely related to the temperature of the ocean, and as the most significant changes in ocean temperature take about 50-years to manifest after the GHG emissions (due to thermal inertia), even if societal GHG emissions drop dramatically by 2050, the SLR to 2100 will still follow the RCP8.5 scenario for at least 50-yrs after your postulated drop in societal GHG emissions.

Obviously, I do not have a crystal ball, but I prefer to follow the Precautionary Principle rather than to make overly optimistic assumptions.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on May 21, 2014, 06:26:19 PM
I agree that none of us has a perfect crystal ball, except that we can be pretty damn sure that the future will be hotter, no matter what the pathway.

I know of a number of people who have been counting on peak oil, global economic collapse, or other bottlenecks to suddenly stop the juggernaut of global industrial civilization and its predations. Those predictions have so far not come to fruition, and so I find I no longer count on them to slow down global warming.

Even if/when collapse comes, there is no guarantee that it will greatly slow down un-sequestering of buried carbon. Power struggles will surely ever more fiercely center around control over whatever source of such carbon are left, no matter how dirty or expensive to exploit. And the emphasis will be on exploiting them as quickly as possible before the other side(s) have a chance to do so, no matter how inefficient or bad for GW those methods are.

Modern wars are waged and won with massive use of energy, and the wars will (and mostly have been) about getting control of those ff sources. You don't really need an economy beyond a war economy to keep extracting enormous quantities of ffs. And the ability to wage war will take priority more and more over every other part of the economy.

Anyway, that is (part of) my dark vision of how things are likely to play out in the last days of the naked ape/ homo necans--no salvation in collapse, just increasingly nasty, universally destructive and globally polluting wars. 

Have a nice day. :o
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 22, 2014, 05:53:48 PM
The following linked article by Forbes encourages more fracking in Europe due to both the Ukrainian situation and the new $400 Billion gas deal diverting more Siberian gas to China:

http://www.forbes.com/sites/christopherhelman/2014/05/21/china-russia-gas-deal-should-unleash-a-euro-fracking-revolution/ (http://www.forbes.com/sites/christopherhelman/2014/05/21/china-russia-gas-deal-should-unleash-a-euro-fracking-revolution/)

This shows how political tension may drive more fossil fuel consumption.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on May 24, 2014, 12:06:49 AM
An other problem with Sea level rise but because of Dams this time...Ouuffff it is not AGW....

Life-Giving Deltas Starved by Dams
http://www.huffingtonpost.com/peter-bosshard/lifegiving-deltas-starved_b_5380336.html?utm_hp_ref=green&ir=Green (http://www.huffingtonpost.com/peter-bosshard/lifegiving-deltas-starved_b_5380336.html?utm_hp_ref=green&ir=Green)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 02:52:27 AM
OK, maybe I missed something obvious, but I don't see what Jai is basing this on:

Quote
the current WAIS projections are 1 meter by 2100 and 3 meters by 2200  just from the WAIS.

The new paper by Joughin, Smith, and Medley says that SLR from Thwaites -- one of the largest sources in WAIS -- will be "moderate (<0.25 mm per year at sea level) over the 21st century".  That is expected to rise to 1mm/year sometime between 2200 and 2900. 

So Thwaites would produce something like 2.2cm of sea level rise by 2100.  And, again, Thwaites is among the larger sources in WAIS.

I understand that Eric Rignot and others may think that Joughin's model is underestimating the rate of ice loss.  But even if you double or triple that 2.2cm to account for this alleged underestimation, it's less than 10cm SLR from Thwaites.  Of course there is more from PIG and other sources.  But that much more?

I am seeing a lot of very large numbers for SLR being tossed around the forums.  But I don't see what they're based on.  Is this "1 meter from WAIS by 2100" coming from an actual study, or is it just speculation?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 26, 2014, 03:48:19 AM
Ned W,

I do not know where jai's numbers for WAIS SLR contribution by 2100 came from; however the linked NRC study on Abrupt Climate Change (with a free pdf), contains the following quotes clearly indicating that a collapse of WAIS this century is plausible:


http://serppas.org/Files/Climate/NAS.Abrupt%20Impacts%20of%20Climate%20Change.Anticipating%20Suprises.pdf (http://serppas.org/Files/Climate/NAS.Abrupt%20Impacts%20of%20Climate%20Change.Anticipating%20Suprises.pdf)

"An abrupt slide of the vast West Antarctic Ice Sheet into the ocean would suddenly sink coasts worldwide under 10 to 13 feet (3 to 4 meters) of water. The report rates the risk of this calamity as "unknown" although probably low for this century.
"Unknown means we should be studying this question intently, not pretending it isn't there," White says."
…..
"However, a large part of the West Antarctic Ice Sheet (WAIS), representing 3-4 m of potential sea-level rise, is capable of flowing rapidly into deep ocean basins. Because the full suite of physical processes occurring where ice meets ocean is not included in comprehensive icesheet models, it remains possible that future rates of sea-level rise from the WAIS are underestimated, perhaps substantially. Improved understanding of key physical processes and inclusion of them in models, together with improved projections of changes in the surrounding ocean, are required to notably reduce uncertainties and to better quantify worst-case scenarios. Because large uncertainties remain, the Committee judges an abrupt change in the WAIS within this century to be plausible, with an unknown although probably low probability."

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 03:59:13 AM
Thanks.  I've read that report already.  It is pretty vague on the timeframe, magnitude, mechanisms, and likelihood for sea level rise from WAIS, not surprisingly I guess since it's more than a decade old now. 

I guess I will wait to see if Jai has a source for the "1m by 2100" figure, and if not, I guess I'll have to look into it myself.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 26, 2014, 04:09:54 AM
Ned W,

I do not know if you bothered to click on the link that I provided, but it leads to a 2013 report (not one that is more than a decade old).

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 04:49:38 AM
I'm temporarily dealing with a slow connection here, and wasn't able to open the link iin anything resembling a timely fashion.  From glancing at the link I mistakenly thought it was pointing at the 2002 NAS report ("inevitable surprises") rather than the 2013 report ("anticipating surprises").  Sorry about the confusion.

In any case, I'm looking for something along the lines of what Jai was referring to (and others here who have made similar statements).  That is, what is currently considered the *best estimate* for SLR from WAIS by 2100?  Worst-case scenarios are interesting too, but it's important to be clear about the distinction between the two.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 05:06:13 AM
I wonder if some people are  being confused by the press coverage of the new paper by Rignot et al.  For example, this:

http://www.nasa.gov/jpl/news/antarctic-ice-sheet-20140512/ (http://www.nasa.gov/jpl/news/antarctic-ice-sheet-20140512/)

Quote
Rignot said this new study suggests sea level rise projections for this century should lean toward the high-end of the IPCC range.
which is described as 98 cm, very close to Jai's "1 meter".

But that's total SLR by 2100, not just the portion from WAIS.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: crandles on May 26, 2014, 05:12:17 AM
http://www.bbc.co.uk/news/science-environment-27381010 (http://www.bbc.co.uk/news/science-environment-27381010)

seems to be suggesting 1.2m from 6 big ice streams in West Antarctic in 200-500 years.

That links to
http://onlinelibrary.wiley.com/doi/10.1002/2014GL060140/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2014GL060140/abstract)

and the 7mb pdf seems freely available:
http://onlinelibrary.wiley.com/doi/10.1002/2014GL060140/pdf (http://onlinelibrary.wiley.com/doi/10.1002/2014GL060140/pdf)

but I don't think the 1.2m and 200-500 years figures are in that paper. Don't know if this 'background information' may have been provided in press briefing.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 26, 2014, 05:21:30 AM
In the press briefing Rignot confirmed that the 6 WAIS glaciers studied will yield an IPCC maximum projection value of 98cm  BASED ON CURRENT LOSS RATE PROJECTIONS.

this does not include the increases in total west AND east Antarctic mass loss in the warming scenarios produced by RCP 8.5 emissions.

When the Filcher-Ronne gives way it will produce an additional 4.5 mm per year of sea level rise.

http://www.awi.de/en/news/press_releases/detail/item/climate_scientists_discover_new_weak_point_of_the_antarctic_ice_sheet/?cHash=9308ad709f71d96e875d5c332f9b5078 (http://www.awi.de/en/news/press_releases/detail/item/climate_scientists_discover_new_weak_point_of_the_antarctic_ice_sheet/?cHash=9308ad709f71d96e875d5c332f9b5078)

In addition, when the arctic sea ice is gone (in the next 10 years or so) the regional summer temperatures are going to experience a non-linear increase, jumping by over 5C

this will greatly exacerbate Greenland's ablation, leading to rapidly lower altitudes of ice sheets and exponential warming.

I expect that the 2100 sea level rise will be closer to 2M  Based on these factors.

And in the event of a more catastrophic collapse scenario?

well, we know that 24 feet in less than 1,000 years is possible, under NORMAL MILANKOVICH DRIVEN INTERGLACIALS.



Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 05:47:05 AM
Rignot's comment about SLR being near the IPCC's upper range (98cm) includes all sources of SLR, not just WAIS.  If you believe that other non-WAIS sources of SLR (Greenland, etc.)will be greater, that still doesn't turn Rignot's 98cm into an appropriate number to cite for the WAIS-specific SLR.  WAIS is only a fraction of that 98cm.  Not the whole thing.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: crandles on May 26, 2014, 05:50:06 AM
In the press briefing Rignot confirmed that the 6 WAIS glaciers studied will yield an IPCC maximum projection value of 98cm  BASED ON CURRENT LOSS RATE PROJECTIONS.

Is anyone able to rule out this taking 200 or more years?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 06:08:48 AM
If you mean 98cm from WAIS alone, then it's almost certainly post 2100.  If you mean 98cm from all sources, then it seems to me you can't rule out either "by 2100" OR "well after 2100" ... Either one is possible.  (Edit:  but even for all sources 98cm by 2100 is on the high side of likely).

For the past 20 years, SLR has been quite linear at approx. 3.5 mm/yr.  By 2100 that would yield 30cm of SLR total.  So 98cm by 2100 would require a fairly rapid acceleration of current trend (more than tripling).  Possible?  Sure.  Probable?  I don't think so, but YMMV..
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on May 26, 2014, 06:47:29 AM
I seem to have posted this on the wrong thread. Apologies to mods. Please delete which ever seems more inappropriate:

Quote
The Intergovernmental Panel on Climate Change in August warned of a three-foot sea level rise by 2100. But with new insight into melting glaciers in West Antarctica, that increase must be revised to at least seven feet

http://america.aljazeera.com/articles/2014/5/18/greenland-ice-melt.html (http://america.aljazeera.com/articles/2014/5/18/greenland-ice-melt.html)

And that's not counting the increase in Greenland ice melt over previous projections discussed in the article--so add another couple feet, at least, from that source, and you get...


at least 9 feet (3+ meters) of sea level rise by the end of the century.


Most of that will come in the second half of the century, but I would think we could expect a meter by mid-century, 2050, and a half meter well before that, in about 20 years, say 2035.

On that last point, keep in mind that a half meter sea level rise increases probability of coastal flooding be 100 to 1000 times.

http://www.huffingtonpost.com/2014/05/12/west-antarctic-ice-sheet-melting_n_5310679.html (http://www.huffingtonpost.com/2014/05/12/west-antarctic-ice-sheet-melting_n_5310679.html)
(toward the end of the video)

If you have ocean side property, sell it soon. In spite of recent legislative shenanigans, it will not be possible to get any kind of insurance on those properties, government or otherwise, in a very few months to years. And after that, they will be washing away at record rates.

...

Similarly:

http://www.climatecentral.org/news/antarctic-ice-collapse-food-supply-17481 (http://www.climatecentral.org/news/antarctic-ice-collapse-food-supply-17481)


Antarctic Ice Collapse Could Devastate Global Food Supply


Quote
The report, due to be released at a high-level conference in Washington, DC on Thursday, is the first to factor in the effects of the slow-motion collapse of the Western Antarctica ice sheet on future food security.

Two independent studies last week warned the retreat of the Western Antarctica ice sheet was unstoppable – and could lead to sea-level rise of up to 4 meters (13 feet) over the coming centuries.

Those rising seas would displace millions of people from low-lying coastal areas - and wipe out rice-growing areas across Asia, Gerald Nelson, a University of Illinois economist and author of Thurday's report, said.

"That sea-level rise would take out half of Bangladesh and mostly wipe out productive rice regions in Vietnam," Nelson told The Guardian. "It would have a major effect on Egyptian agricultural areas."

The projected levels of sea-level rise, due to the retreat of ice in West Antarctica, pose a far greater threat to future food supply even than that envisaged in the United Nations' IPCC report in March, Nelson said.

"A sea level rise of 3 meters (10 feet) over the next 100 years is much more likely than the IPCC thought possible," the report said.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 26, 2014, 09:06:39 AM
If you mean 98cm from WAIS alone, then it's almost certainly post 2100.  If you mean 98cm from all sources, then it seems to me you can't rule out either "by 2100" OR "well after 2100" ... Either one is possible.  (Edit:  but even for all sources 98cm by 2100 is on the high side of likely).

For the past 20 years, SLR has been quite linear at approx. 3.5 mm/yr.  By 2100 that would yield 30cm of SLR total.  So 98cm by 2100 would require a fairly rapid acceleration of current trend (more than tripling).  Possible?  Sure.  Probable?  I don't think so, but YMMV..


We are experiencing a doubling of WAIS contribution rates every 4-7 years.  This will continue through 2040.

current contributions are .45mm per year Antarctica Total.

by 2040 under RCP 8.5 emissions this will become 4mm per year for a total contribution of 4.5cm from WAIS

between 2040 and 2070 the average WAIS contribution will be 5.5mm/year for a total contribution overt this period of 16.5cm.

In 2070 the filcher-ronne will collapse, leading to an additional 4.5 mm/year average contribution from 2070-2100.  This yields the last 3 decades average WAIS contribution of 30cm

for a total WAIS contribution of 50 cm by 2100. 

notice I did not include PIG?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: crandles on May 26, 2014, 01:08:57 PM
Table 13.5 of AR5 for SLR by 2100 in m says Antarctic Ice Sheet SMB is negative for all scenarios. For RCP 6 –0.02 [–0.05 to –0.01]

Quote
SRES A1B RCP2.6 RCP4.5 RCP6.0 RCP8.5
Antarctic ice-sheet SMBc –0.03 [–0.06 to –0.01] –0.02 [–0.04 to –0.00] –0.02 [–0.05 to –0.01] –0.02 [–0.05 to –0.01] –0.04 [–0.07 to –0.01]

Rapid dynamics are +0.07 regardless of scenario:

Quote
Antarctic ice-sheet
rapid dynamics
0.07 [–0.01 to 0.16] 0.07 [–0.01 to 0.16] 0.07 [–0.01 to 0.16] 0.07 [–0.01 to 0.16] 0.07 [–0.01 to 0.16]

Only the collapse of the marine-based sectors of the Antarctic ice sheet, if initiated, could cause GMSL to rise substantially above the likely range during the 21st century. This potential
additional contribution cannot be precisely quantified but there is medium confidence that it would not exceed several tenths of a meter of sea level rise.

In the multicentennial projections, Antarctic becomes more negative as you go further into the future.

-.02+.07=+.05 as Jai gave earlier. There may be other changes since AR5 but...

Jai, are you sure you expect this negative SMB contribution to double every 4-7 years? (That would have quite a different effect to what you are saying.)

(Edits: TBH I think data out since AR5 may have changed the negative SMB contribution from -.02 to possibly positive. Jai also said "doubling of WAIS contribution rates every 4-7 years" not doubling SMB contribution but I couldn't resist and there was a hint of SMB rather than rapid dynamics in the "notice I did not include PIG".)

I think the chances of initiating a collapse of marine based sectors has been increased substantially (if not already started) by Rignot et al. Excited media may not have realised that from initiation of collapse to a 1m rise in SL is quite likely a 200+ year process. I don't see any reason to think that there is much if any change to

"This potential additional contribution cannot be precisely quantified but there is medium confidence that it would not exceed several tenths of a meter of sea level rise" [by 2100]

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 02:06:01 PM
Quote
The Intergovernmental Panel on Climate Change in August warned of a three-foot sea level rise by 2100. But with new insight into melting glaciers in West Antarctica, that increase must be revised to at least seven feet

http://america.aljazeera.com/articles/2014/5/18/greenland-ice-melt.html (http://america.aljazeera.com/articles/2014/5/18/greenland-ice-melt.html)
That sentence appears to be speculation by the Al Jazeera reporter, not anything from the Rignot or Joughin papers that the reporter is citing as the source of the "new insight".  It looks like a case of the reporter misunderstanding the time-frame involved.

Again, let's look at the two new papers about WAIS that sparked all this attention this month:

* Rignot's paper doesn't attempt to quantify expected melt by 2100, but in his explanatory remarks he has made it clear that he expects total SLR from all sources by 2100 to be near the upper end of the IPCC AR5 range, i.e. around 98cm.  Of that, WAIS's contribution would presumably be a few tenths of a meter.

* Joughin's paper predicts a total of 2.2cm SLR from Thwaites, one of the largest sources of ice in West Antarctica.  I haven't seen Joughin extrapolate that to WAIS as a whole, but I do not think there's much likelihood of WAIS's total being more than a few tenths of a meter if Thwaites's contribution is 2.2cm.

For comparison, Little et al 2013 suggested an upper bound of around 20cm SLR from all of WAIS by 2100 (99th percentile). 

Back to wili...

Quote
And that's not counting the increase in Greenland ice melt over previous projections discussed in the article--so add another couple feet, at least, from that source, and you get...


at least 9 feet (3+ meters) of sea level rise by the end of the century.

Most of that will come in the second half of the century, but I would think we could expect a meter by mid-century, 2050, and a half meter well before that, in about 20 years, say 2035.
That also seems to be pure speculation.  The new paper by Morlighem does not actually quantify how much SLR is likely from Greenland at any particular timeframe in the future.  Other recent papers give estimates by 2100 of a couple tenths of a meter (e.g. Pfeffer et al. 2008) or less (e.g., Howard et al. 2014). 

Once more back to wili:

Quote
Similarly:

http://www.climatecentral.org/news/antarctic-ice-collapse-food-supply-17481 (http://www.climatecentral.org/news/antarctic-ice-collapse-food-supply-17481)


Antarctic Ice Collapse Could Devastate Global Food Supply


Quote
The report, due to be released at a high-level conference in Washington, DC on Thursday, is the first to factor in the effects of the slow-motion collapse of the Western Antarctica ice sheet on future food security.

Two independent studies last week warned the retreat of the Western Antarctica ice sheet was unstoppable – and could lead to sea-level rise of up to 4 meters (13 feet) over the coming centuries.

Those rising seas would displace millions of people from low-lying coastal areas - and wipe out rice-growing areas across Asia, Gerald Nelson, a University of Illinois economist and author of Thurday's report, said.

"That sea-level rise would take out half of Bangladesh and mostly wipe out productive rice regions in Vietnam," Nelson told The Guardian. "It would have a major effect on Egyptian agricultural areas."

The projected levels of sea-level rise, due to the retreat of ice in West Antarctica, pose a far greater threat to future food supply even than that envisaged in the United Nations' IPCC report in March, Nelson said.

"A sea level rise of 3 meters (10 feet) over the next 100 years is much more likely than the IPCC thought possible," the report said.
That's a bit of a mess, and the key part of it appears to be wrong.  (This is why it's important to go to the actual scientific literature, not rely on the general media....)

First, "up to 4 meters (13 feet)" refers to a multi-century time frame, not by 2100.

Second, the phrase you quote in bold ("A sea level rise of 3 meters (10 feet) over the next 100 years is much more likely than the IPCC thought possible") does not actually appear anywhere in the report itself.  I don't know if it's a mistake by ClimateCentral, or what.  But the report they are referring to (available online here (http://www.thechicagocouncil.org/UserFiles/File/EMBARGO_ClimateChangeFoodSecurity.pdf)) doesn't say that.  It only cites the IPCC range of 28 to 98cm total SLR by 2100.  There is no mention of "3 meters" over the next 100 years anywhere ... unsurprisingly, since that is well outside the range of what is supported by the scientific literature.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 02:15:21 PM
We are experiencing a doubling of WAIS contribution rates every 4-7 years.  This will continue through 2040.

current contributions are .45mm per year Antarctica Total.

by 2040 under RCP 8.5 emissions this will become 4mm per year for a total contribution of 4.5cm from WAIS

between 2040 and 2070 the average WAIS contribution will be 5.5mm/year for a total contribution overt this period of 16.5cm.

In 2070 the filcher-ronne will collapse, leading to an additional 4.5 mm/year average contribution from 2070-2100.  This yields the last 3 decades average WAIS contribution of 30cm

for a total WAIS contribution of 50 cm by 2100. 

notice I did not include PIG?
I asked if you had a source for the "1 meter from WAIS" claim.  Your reply is to list a bunch of other numbers with no sources either.  How is that helpful?

Also, I'm not sure what you mean by this:

Quote
the average WAIS contribution will be 5.5mm/year for a total contribution overt this period of 16.5cm.   [...]

notice I did not include PIG?

PIG drains the WAIS.  If you quote a number for the total contribution from WAIS then you are including PIG.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 02:23:13 PM
I think the chances of initiating a collapse of marine based sectors has been increased substantially (if not already started) by Rignot et al. Excited media may not have realised that from initiation of collapse to a 1m rise in SL is quite likely a 200+ year process. I don't see any reason to think that there is much if any change to

"This potential additional contribution cannot be precisely quantified but there is medium confidence that it would not exceed several tenths of a meter of sea level rise" [by 2100]
That is my understanding as well. 

I do think the long-term (multi-century to millennium) outcome is likely to include several meters of SLR from WAIS and Greenland.  But the 21st century forecast is quite different.  For now, it seems to be less than 2 m total SLR, of which a few tenths of a meter are from WAIS.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 26, 2014, 03:33:00 PM
About 2m by 2100 and 9m by 2300 seems to be the worst-case in the peer-reviewed literature, as illustrated by the attached figure 3b from Rohling et al. 2013:
http://www.nature.com/srep/2013/131212/srep03461/full/srep03461.html (http://www.nature.com/srep/2013/131212/srep03461/full/srep03461.html)

The expert elicitation by Horton et al. 2013 shows that about 33% of the experts think the worst-case could be 2m or more by 2100 and 5m or more by 2300, as shown in their figure 2:
https://marine.rutgers.edu/pubs/private/HortonQSR_2013.pdf (https://marine.rutgers.edu/pubs/private/HortonQSR_2013.pdf)

Rohling et al also say that at 400 ppm less than 9m in the long run is unlikely, 24m the best estimate, and more than 31m still a 17% probability.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 04:05:54 PM
Quote from: Jai
In 2070 the filcher-ronne will collapse, leading to an additional 4.5 mm/year average contribution from 2070-2100.  This yields the last 3 decades average WAIS contribution of 30cm
Melting of the ice shelf doesn't directly raise sea level since it's already floating.  Instead, it reduces the backpressure on the glaciers feeding the shelf (not all of which come from WAIS, by the way -- much of the ice flowing into the shelf is from East Antarctica).  Those glaciers may then increase their velocity, which does raise sea level as more ice crosses the grounding line.

The figure from Hellmer at AWI, of "4.4 mm/year" sea level rise, is not instantaneous.  It's what you would get once the glaciers flowing into the Weddell Sea had time to fully respond to the change in pressure.  Would that take decades, or centuries?  Hellmer et al. don't try to speculate, at least not anywhere that I've seen.  Their actual paper is about basal melt of the shelf itself, not quantifying the resulting change in velocity above the grounding line.

Reducing this to "the ice shelf disappears in 2070 and sea level begins rising by 4.4 mm/year immediately" does not seem accurate, in my understanding (I could be wrong).
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 26, 2014, 04:21:18 PM
About 2m by 2100 and 9m by 2300 seems to be the worst-case in the peer-reviewed literature, as illustrated by the attached figure 3b from Rohling et al. 2013:
http://www.nature.com/srep/2013/131212/srep03461/full/srep03461.html (http://www.nature.com/srep/2013/131212/srep03461/full/srep03461.html)

The expert elicitation by Horton et al. 2013 shows that about 33% of the experts think the worst-case could be 2m or more by 2100 and 5m or more by 2300, as shown in their figure 2:
https://marine.rutgers.edu/pubs/private/HortonQSR_2013.pdf (https://marine.rutgers.edu/pubs/private/HortonQSR_2013.pdf)

Rohling et al also say that at 400 ppm less than 9m in the long run is unlikely, 24m the best estimate, and more than 31m still a 17% probability.

I am not as informed as most here and would normally post this in the stupid questions thread but since it is relevant.......

Given that current level of atmospheric CO2 is 400ppm....

http://www.esrl.noaa.gov/gmd/ccgg/trends/ (http://www.esrl.noaa.gov/gmd/ccgg/trends/)

........and the long term growth trends in CO2 emissions (see CO2 graph) which is a direct result of our industrial economy which shows no signs of reducing, anytime soon, its consumption of fossil fuels (see growth in coal consumption graph) does anyone here actually believe that 400ppm is likely?

Given that this level is ridiculously low (my opinion), what impact should an exponentially accelerating level of atmospheric CO2 mean for these sea level rise projections?

And please don't answer based on IPCC proposals regarding acceptable levels of CO2. Any significant reductions in the accelerated use of fossil fuels before 2050 is a fantasy.

I do not want to derail this thread so, if you want to review forum discussions of coal use and trends, you can find it here.......

http://forum.arctic-sea-ice.net/index.php/topic,347.0.html (http://forum.arctic-sea-ice.net/index.php/topic,347.0.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 04:38:02 PM
Quote
what impact should an exponentially accelerating level of atmospheric CO2 mean for these sea level rise projections?
It increases the likelihood that much of the land ice will end up in the ocean, though that process will still take a long time. 

And it increases the amount of SLR from thermal expansion of the oceans.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on May 26, 2014, 04:54:38 PM
I do not see any confort using the models that we have now for sea level rise purpose. In the past we had around 4 cm of sea level rise per year around 14.000 years ago...so we have to expect that minimum very soon and certainly much more since what we have done never existed before. And please do not mention the CO2 level since it is the combined green house gazes that are important...so around 480 ppm of CO2 eq right now...(http://www.esrl.noaa.gov/gmd/aggi/aggi.html (http://www.esrl.noaa.gov/gmd/aggi/aggi.html))
In the recent past (holocene) the relationship between CO2 temp and SLR was linear why don't use that linear relationship to calculate the SLR knowing it is the CO2 that is leading nowadays ?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 26, 2014, 04:55:55 PM
SH,
I think Rohling et al., and also Jim Hansen, strongly suggest that we will be melting all the ice on the planet, unless we manage to stay or return below 500 ppm in time. See for example the attached fgure 1 from Rohling et al, also linked here:
http://www.nature.com/srep/2013/131212/srep03461/fig_tab/srep03461_F1.html (http://www.nature.com/srep/2013/131212/srep03461/fig_tab/srep03461_F1.html)

If we go above 500 ppm for too long, slow carbon and albedo feedbacks will probably take over and bring us to 800 ppm and more, which would melt all the remaing ice. Hansen seems to be even more pessimistic on this point than Rohling.

Only very strong mitigation will probably prevent all the ice from melting, since otherwise the momentum of anthropogenic climate forcing will grow so strong that slower feedbacks will finish the job no matter what we would try to stop it.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: crandles on May 26, 2014, 05:06:04 PM
Since the title mentions "social cost of carbon",

http://www.forbes.com/sites/timworstall/2014/05/13/if-antarctic-melting-has-passed-the-point-of-no-return-we-should-do-less-about-climate-change-not-more/ (http://www.forbes.com/sites/timworstall/2014/05/13/if-antarctic-melting-has-passed-the-point-of-no-return-we-should-do-less-about-climate-change-not-more/)

was heavily criticised for not taking timing into account. (eg see Daniel Nazar comment on page 3)

However, if you look at the numbers I quoted from AR5

SRES A1B RCP2.6 RCP4.5 RCP6.0 RCP8.5
Antarctic ice-sheet SMBc –0.03 [–0.06 to –0.01] –0.02 [–0.04 to –0.00] –0.02 [–0.05 to –0.01] –0.02 [–0.05 to –0.01] –0.04 [–0.07 to –0.01]
Antarctic ice-sheet
rapid dynamics
0.07 [–0.01 to 0.16] 0.07 [–0.01 to 0.16] 0.07 [–0.01 to 0.16] 0.07 [–0.01 to 0.16] 0.07 [–0.01 to 0.16]

the rapid dynamics in particular do not change much or at all with scenario!

So perhaps that scuppers that heavy criticism?

If so, then the concluding paragraph
Quote
It is only if continuing emissions are going to lead to something more, something else possibly worse, happening that there’s any economic case at all for limiting them. As it happens I think that there are worse things that might happen and that there is a very good case indeed for limiting future emissions. But this finding, that West Antarctica is going to melt no matter what just isn’t a valid reason to limit future emissions. The damage is already done, see?

becomes a lot harder to criticise.

So the effect of the Rignot et al study is to reduce the social cost of carbon! this is because the main effect is to move costs from possible consequences with possible changes of timing bucket into an already incurred with no chance of changing the timing bucket. The bucket it is moved to is one which should be ignored for calculating relevant social costs of carbon.

I doubt this is perfectly true, I suspect we might be able to have a tiny effect on the timing of this event unfolding but I cannot see much difference between tiny effect and no effect on timing.

That is not a conclusion I want to come to but if that is the way it is then it should be reported as it is.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 05:44:37 PM
So by that reasoning, the SLR from the loss of WAIS (and presumably Greenland as well?), and the resulting sinking coasts ... would be seen as a ... (ghastly pun coming) ... sunk cost?

Of course, it would be nice to not lose all the ice on EAIS too.  And thermal expansion keeps going in lockstep with temperature.  And there are all the non-SLR impacts of climate change.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 26, 2014, 06:08:17 PM
That is not how the Integrated Assessment Models operate.  They have damage-loss functions that are determined using regional value computations under sea level rise scenarios.  They run multiple iterations to get an average result.

The damage loss functions are heavily discounted so that damages that occur in the next 3 decades, while being identical in physical effect, are 3X the value of the same type of damage that occurs at the end of 2080.  This is the effect of discounting.

Now that we know that the rate of mass loss will continue to double, over the next several decades, radically increasing the timing of the sea level rise, moving the models from damage-loss values typically expected in 2100 to damage loss values occurring in 2050.

This will easily double the social cost of carbon in the Integrated Assessment model runs.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: crandles on May 26, 2014, 06:11:31 PM
So by that reasoning, the SLR from the loss of WAIS (and presumably Greenland as well?), and the resulting sinking coasts ... would be seen as a ... (ghastly pun coming) ... sunk cost?

Of course, it would be nice to not lose all the ice on EAIS too.  And thermal expansion keeps going in lockstep with temperature.  And there are all the non-SLR impacts of climate change.

groan.

Absolutely, lots of other things will happen and they do make a case for more action. The article does throw in that sentence:

Quote
As it happens I think that there are worse things that might happen and that there is a very good case indeed for limiting future emissions.

but only at the end which I think is a bit wrong, people with denier leanings will see the article as confirming their opinions and stop reading before they get there or think too much about it. So I think that should have been stated much more prominently much earlier.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on May 26, 2014, 06:23:15 PM
Thanks all for discussions about slr figures.

LvvL wrote:
Quote
About 2m by 2100 and 9m by 2300 seems to be the worst-case in the peer-reviewed literature, as illustrated by the attached figure 3b from Rohling et al. 2013:
http://www.nature.com/srep/2013/131212/srep03461/full/srep03461.html (http://www.nature.com/srep/2013/131212/srep03461/full/srep03461.html)

The expert elicitation by Horton et al. 2013 shows that about 33% of the experts think the worst-case could be 2m or more by 2100 and 5m or more by 2300, as shown in their figure 2:
https://marine.rutgers.edu/pubs/private/HortonQSR_2013.pdf (https://marine.rutgers.edu/pubs/private/HortonQSR_2013.pdf)

Rohling et al also say that at 400 ppm less than 9m in the long run is unlikely, 24m the best estimate, and more than 31m still a 17% probability.

(My bold.)

But the "2m or more by 2100" was before the recent news about WAIS and GIS. I understand that the main point of the papers is that they show that long term significant sea level rise now seems to be locked in. But they also seem to indicate some increase in our estimation of slr from these sources in the coming decades. It is unfortunate that they are not clearer about how much additional slr that might be. But whatever addition we have to "2m or more by 2100" pushes us ever closer to about 3 meters, which would sink considerably more cities and land than 2 meters.

It seems at this point that we only have speculation, though, at this point on these crucial issues...speculation all too easily colored by wishful thinking on the one hand and sensationalism on the other. (I'm sure people may see me as at the latter end of that spectrum, but it does seem important to know what the worst case possible scenarios are, even if their possibility may be remote, as Richard Alley has stressed repeatedly.)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 26, 2014, 06:39:56 PM
has anyone here seen a contour map of expected average summer temperatures of Antarctica, in 2080 under RCP 6.0 scenario and an ECS of 4.5 C per 2XCO2?

It would look similar to this one:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F0%2F0c%2FAntarctic_surface_temperature.png&hash=d921707a0e807b2e442cfb56753bd3ba)

except all of the dark red would be turned to orange.

This means that in the summer there are melt ponds in low-lying Antarctic regions.  This would be a late 2080-2090 effect. 

However, the summer weddell sea ice will be long (long) gone by then.

Yes, I understand the ronne shelf/buttress won't be instantaneous, The 4.5mm is an average value over a period of time.  by 2090, combining the loss of sea ice and shelf-grounding with surface warming and increased plasticity these shelves will experience rapid and catastrophic collapse.

I believe that the Eemian analogy recorded by Blachon et. al here: ftp://ftp.soest.hawaii.edu/coastal/Coastal%20Geology%20Class%20GG420/Blanchon%205e%20reef%202009.pdf (http://ftp://ftp.soest.hawaii.edu/coastal/Coastal%20Geology%20Class%20GG420/Blanchon%205e%20reef%202009.pdf)

is the only real analogy we have in the paleo record. 

The author states that, under the correct conditions, a 5cm per year SLR for 50 years is feasible.

From Joe Romm
http://thinkprogress.org/climate/2009/04/15/203960/nature-sea-level-rise-global-warming-reefs/ (http://thinkprogress.org/climate/2009/04/15/203960/nature-sea-level-rise-global-warming-reefs/)

Quote
In other words, the Nature study says that during the last interglacial (the Eemian) evidence now suggests sea levels rose 20 inches per decade for five straight decades — a roughly 8-foot rise in a half century.

Now, this means that under normal Milankovtich-driven warming cycles, we will reach a tipping point on those glaciers.  We understand now what that will look like. 

A long-drawn slow melting of the region until grounding lines retreat to the point of no return (now observed).  Except, this time we will see the 1 mile high glacier cliffs buttressing up against a warm water shoreline within only about 100 years.

-----------
late edit question:  what feedback response scenario is potentially able to cause a "sudden and catastrophic" warming of the  West Antarctic Sea Surface temperatures  in 2050?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 26, 2014, 07:10:41 PM
http://eesc.ldeo.columbia.edu/courses/w4937/Readings/Kennet.Stott.1991.pdf (http://eesc.ldeo.columbia.edu/courses/w4937/Readings/Kennet.Stott.1991.pdf)

Abrupt deep sea warming, Palaeoceanographic Changes and Benthic Extinctions at the end of the Paleocene

Kennett & Stott

Quote
The oceanographic changes associated with the excursion were clearly broad and complex, and seem to reflect a transient state between fundamentally different modes of ocean circulation.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 26, 2014, 07:17:17 PM
On the SLR-cost of carbon: I would think that while the WAIS is disintegrating the EAIS will also start losing more and more ice, and (much) earlier than previously thought probable. So the costs would indeed rise along with faster and higher SLR.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 26, 2014, 08:38:25 PM
As most people posting on this topic have already reviewed the Antarctic folder, which has extensively discussed the possible SLR contribution of both the WAIS, and the EAIS, by 2100; I will not bother to repeat those discussions here.  Nevertheless, I would like to note that the Antarctic folder cites a considerable amount of evidence that a significant portion of the WAIS became ungrounded/collapsed during the Eemian, and my favorite paper on this topic is the following by O'Leary et al (2013), which shows that around 119 to 120 kya RSLR in Western Australia jump up over 6m in less than 1,000 years (see linked and attached figure/caption):

O'Leary, M.J., Hearty, P.J., Thompson, W.G., Raymo, M.E., Mitrovica, J.X., and Webster, J.M., (2013), "Ice sheet collapse following a prolonged period of stable sea level during the last interglacial", Nature Geoscience;  doi:10.1038/ngeo1890.

http://www.nature.com/ngeo/journal/v6/n9/fig_tab/ngeo1890_F3.html (http://www.nature.com/ngeo/journal/v6/n9/fig_tab/ngeo1890_F3.html)

Caption for the linked and attached figure is: "A geomorphically defined palaeoMSL datum of +2.5 m 120 kyr ago (Fig. 1c) anchors a predicted relative sea-level curve at Red Bluff, which includes a GIA signal based on the test calculation (see Methods) plus the following ESL history: ESL jumps from 0 to 3.4 m between 127.5 kyr and 127 kyr ago and remains at this level until 120 kyr ago; and 120 kyr ago, ESL jumps ~ 6 m over 1 kyr. Dashed green line is an inferred sea-level curve based on a minimum coral palaeodepth (solid bar above circle) of 0.4 m below palaeoMSL. This palaeodepth calculation is applicable only to highest in situ corals, as corals of the same age found at lower elevations will have a known water depth of at least up to the height of the coral above it. Arrows indicate potential for greater palaeodepth range."

While this paper does not make it clear how much of this RSLR came from the WAIS, and how much faster than 1,000 yrs did it occur over; the researchers are working hard to address these questions and are making progress as indicated in the following recent paper:

Rovere, A., M. E. Raymo, J. X. Mitrovica, P. J. Hearty, M. J. O'Leary, and J. D. Inglis. 2014. “The Mid-Pliocene sea-level conundrum: Glacial isostasy, eustasy and dynamic topography.” Earth and Planetary Science Letters 387: 27-33

My general point is that paleo-evidence indicates that marine ice sheets and marine terminating glaciers appear to be less stable than commonly assumed by most researchers, so no one reading this thread should be too surprised when AR6 has higher SLR projections than AR5; not because this risk of SLR is increasing that fast, but because the more we learn the more we acknowledge the risks that are already dialed into the Earth systems.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: crandles on May 26, 2014, 08:58:09 PM
That is not how the Integrated Assessment Models operate.  They have damage-loss functions that are determined using regional value computations under sea level rise scenarios.  They run multiple iterations to get an average result.

The damage loss functions are heavily discounted so that damages that occur in the next 3 decades, while being identical in physical effect, are 3X the value of the same type of damage that occurs at the end of 2080.  This is the effect of discounting.

...

This will easily double the social cost of carbon in the Integrated Assessment model runs.


If you discount then the discount rate to use is often the dominant variable that needs to be tied down to reduce the uncertainty.


"not how the Integrated Assessment Models operate" might depend on how you interpret the results. The damage loss functions don't take account of what are sunk costs. However I suggest the appropriate way for politicians to view the results is not to look at how high the damage loss function arrives at but to look at the difference between the damage loss result for one scenario against another to see how much effort should be put into ensuring we head for one scenario vs another. If politicians do that then they are effectively treating the sunk costs as not relevant.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 26, 2014, 09:01:45 PM
As a follow-up to my last post, while crandles cites that as many marine ice sheets and marine terminating are already past their tipping point that responsibility for the trillions of dollars of damaged caused by this SLR (whether sooner or later) has moved from the fossil fuel industry to either the insurance companies, or to any owners who cannot get insurance, because even though there were numerous warnings by researchers over 30-years ago that we were nearing this tipping point, that the group/tribal consensus had not yet acknowledged the tipping point, this observation ignores several points including:
(1) As Super Storm Sandy demonstrated, just a few inches of storm surge over-topping can cause hundreds of billions of dollars of losses to one major port city for one event alone.  As all the major port cities around the world are partly at sea level, and as climate change will increase the frequency and magnitude of storm surge events which are added on top of RSLR; cutting back now on fossil fuel emissions will clearly reduce inundation damage no matter what eustic sea level does.
(2) Due to the non-linear nature of the rate of SLR a little bit of prevention now will likely buy a lot of time in the future to implement adaptive flood defense systems.
(3) As others have noted some tidewater glaciers have not yet passed their tipping points yet, so cutting back on fossil fuel emissions sooner rather than later will help everybody.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 26, 2014, 09:08:00 PM
Reading above comments, it would seem there is a near consensus that increasing levels of CO2 in this century will definitely increase long term slr but have little impact in this century due to lags in the response of the ice.

NOAA currently shows a 2 ppm average increase in atmospheric CO2 per year in the last 15 years. If we are to assume this rate of increase continues into the future, then we will be at 500 ppm by 2065 and 570 ppm by the end of the century. Most likely 500 ppm for 2065 is a low estimate as the annual contribution to atmospheric CO2 has actually been growing. Between 1980 and 2000 CO2 grew 1.5 ppm per year. I would expect this increase will continue at least until 2050 as the developing nations continue along a fairly rapid growth trajectory. I would think we shall hit 500 ppm closer to mid century.

This is where I get lost. Can these increases in atmospheric CO2 actually have no impact this century on ice melting and slr?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: crandles on May 26, 2014, 09:35:41 PM
Reading above comments, it would seem there is a near consensus that increasing levels of CO2 in this century will definitely increase long term slr but have little impact in this century due to lags in the response of the ice.

I wouldn't put it like that. Much of the discussion above is about Rignot et al saying 6 West Antartic ice streams are irreversibly collapsing. That in isolation does not respond much to rising GHG levels per IPCC AR5.

However looking at other lines in that table:

Thermal expansion varies from 0.14 [0.10 to 0.18] to 0.27 [0.21 to 0.33]
Glaciersa vary from  0.10 [0.04 to 0.16]  to 0.16 [0.09 to 0.23]
Greenland ice-sheet SMBb 0.03 [0.01 to 0.07] to 0.07 [0.03 to 0.16]
Greenland ice-sheet rapid dynamics 0.04 [0.01 to 0.06] to 0.05 [0.02 to 0.07]
Land water storage doesn't vary per scenario 0.04 [–0.01 to 0.09]

gives totals (inc Antarctica) from 0.40 [0.26 to 0.55] to 0.63 [0.45 to 0.82]

63cm is more than a 50% increase over 40cm. That is not a negligible difference though RCP 8.5 to RCP 2.6 is a big difference in scenario. Most of the difference is going to be after the end of the century with only a small part of the difference towards the end of this century.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 09:52:56 PM
This is where I get lost. Can these increases in atmospheric CO2 actually have no impact this century on ice melting and slr?

It does have an impact, mainly on the fraction of SLR from thermal expansion and ice sheet surface melt, because those have a shorter response time.  Discharge of ice from marine glaciers is slower to respond so changes in CO2 at the decadal time scale don't show up as much.

Edit:  crandles has the numbers.  Going from a low-co2 to high-co2 scenario increases SLR by a couple of tenths of a meter in 2100, which is exactly what I would have guessed.

The likelihood of SLR much greater than 1 meter by 2100 is small, IMHO.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 10:10:46 PM
Wili in #36:

What you're doing is taking (a) the worst case scenario, from (b) the individuals at the uppermost end of the range, and then (c) adding in a bunch of additional increase on speculation.

One could do the same in the opposite direction -- taking the best case scenario, from only the most optimistic individuals, and then subtract off a bit more on the assumption that they're still over-estimating reality. 

Neither of those is a good way to think about likely outcomes.

Now, you may be just doing this as a thought-experiment to see what the real worst-case scenario would be.  But the danger is that you, and others here, will begin to internalize that worst-case scenario as if it were the expected outcome ... And thus the estimate creeps upward, from under 1 m to 1 m, then 2 m, and then 3 m ... And people gradually lose touch with what most scientists think is likely. 
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: crandles on May 26, 2014, 10:46:55 PM
It does have an impact, mainly on the fraction of SLR from thermal expansion and ice sheet surface melt, because those have a shorter response time.  Discharge of ice from marine glaciers is slower to respond so changes in CO2 at the decadal time scale don't show up as much.

Temperatures don't change in response to current GHG emissions for ~3 decades SMB can begin to take effect from then though if main effect on Antarctica is not from surface melting but from warm water on underside of ice then the heat has to mix into the oceans. I would have thought it would take quite a while for heat to mix down into oceans to cause much thermal expansion so I am a little surprised you put that first.

My previous post said "[Ice streams collapsing] in isolation does not respond much to rising GHG levels"

But of course it isn't in isolation!

GHG levels will cause further SMB and thermal expansion. This SLR will presumably affect rate of collapse by changing what ice is below sea level hence more buoyancy reducing friction and more ice volume underwater. I guess that has a relatively short response timescale to get some of the effect but the full effect takes as long as the longest response timescale.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 26, 2014, 11:54:12 PM
Gotta put something first, right?  SMB is small, and ice discharge is slow.  What else is there?

Also, Both thermal expansion of oceans and marine ice sheet instability need heating of the ocean.  But as the ocean warms TE happens more or less instantaneously while MISI follows some unknown time scale that probably isn't instantaneous.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on May 27, 2014, 12:01:43 AM
Antarctica's ice collapse threatens metres of sea level rise within decades

   
Quote
Scientists know that if Antarctica's ice sheets and glaciers collapse, sea levels could rise 5 metres. But the idea that it will take 200 years to happen is based on a linear model, writes Dady Cherry. In fact, the process is exponential - and could take place 'within decades'.

    The acceleration is driven, among other things, by an accelerated warming of the atmosphere and sea surface, continued expansion of the ozone hole, strengthening of currents that bring greater masses of warm waters from the tropics to Antarctica, weakening of the ice shelves due to accelerated melting of the surface ice, weakening of the attachment of the ice below sea level due to an accelerated erosion, and decreasing reflectivity of the Earth.

West Antarctic ice sheet could raise sea levels 5m 'within decades'


Rignot blames carbon emissions, which have tripled since the Kyoto Protocol, for the current state of affairs, and he categorically says that the collapse of the ice cover from "the Amundsen sea sector of West Antarctica [is] unstoppable, with major consequences - it will mean that sea levels will rise one metre [more than 3 feet] worldwide.

"What's more, its disappearance will likely trigger the collapse of the rest of the West Antarctic ice sheet, which comes with a sea level rise of between three and five metres [10 to more than 16 feet]. Such an event will displace millions of people worldwide."

The sea-level rise of 10 to 16 feet will come in decades, rather than 200 years. It will submerge essentially every port city in the world, including Guangzhou, Mumbai, Shanghai, Ho Chi Minh City, Kolkata, Osaka-Kobe, Alexandria, New York, New Orleans, Miami, and indeed all of South Florida.

This will likely displace over 300 million people, many of them in countries that have equated development with movement of the majority of their populations to low-elevation coastal zones in port cities.

Again, most of the rapid slr seems to be speculation of the author. But he doesn't seem to be the only one making these speculations.

http://www.theecologist.org/News/news_analysis/2404476/antarcticas_ice_collapse_threatens_metres_of_sea_level_rise_within_decades.html (http://www.theecologist.org/News/news_analysis/2404476/antarcticas_ice_collapse_threatens_metres_of_sea_level_rise_within_decades.html)

Thanks to Graeme at POForums for this link.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 27, 2014, 12:42:13 AM
Quote from: wili
Reply #49 on: Today at 12:01:43 AM

Oh, good grief.

That is an opinion piece by some journalist or blogger named "Dady Cherry" or "Chery" (the byline is inconsistent).  His or her qualifications are listed as "co-editor in chief of News Junkie Post", whatever that is.

The article is entirely based on the work of Eric Rignot but completely ignores his own comments about the likely magnitude of 21st century sea level rise.  Instead, it paints a lurid picture of a global catastrophe following 3 to 5 meters of sea level rise in the next "decades".

Can you seriously not understand how non-credible a source that is?  This isn't WUWT.  Can't we leave that kind of "motivated reasoning" for the other side?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 27, 2014, 12:45:19 AM
With regard to best case/worst case scenarios.

Yes, this analysis does not include the potential for a radical global break from fossil fuel use.  Nor does it include the potential for widescale geoengineering as a world-ending moral hazard.

My analysis considers the following:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Foi57.tinypic.com%2Fb4gwn8.jpg&hash=ef33f799448ab44dd4a6555f0c29d964)

full image here:
http://oi57.tinypic.com/b4gwn8.jpg (http://oi57.tinypic.com/b4gwn8.jpg)

Over 90% of this cumulative global heat accumulation is being deposited into the oceans.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 27, 2014, 01:27:53 AM
We should recognize that there is only going to be one SLR scenario that plays out by the end of this century and that no one can identify that exact scenario today, but the tribal concession case (i.e. the case that society is willing to acknowledge) need not be that single SLR scenario.  So at our best today we need to rely on expert opinion, which is something that changes with time and on who you are asking.  Nevertheless, I am prepared to accept the panel of experts that Horton vetted; which provided the opinions presented in the attached image when asked what their best projections are for RCP 8.5 by 2100.

Many people believe that RCP 8.5 is an extreme case, but it is actually the BAU case that we are currently following, and rather than being an extreme physical case, it seems to me to be the most extreme case that society is prepared to consider.  That said, I cannot believe that we will get off this pathway before 2050, and I believe that this case is highly relevant to a discussion about SLR that is dominated by the ocean's thermal inertia.

In this survey distribution the possibility of exceeding 1m of eustatic SLR by 2100 is well over 50%, and at least one true expert (not some outlier) believes that following a RCP 8.5 scenario will result in a 50%CL of 6m of eustatic SLR this century.  Some people feel good about these kinds of odds; however, I do not, as that one 6m projection might be right.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 27, 2014, 02:01:43 AM
Quote from: Horton 2013
For the unmitigated warming scenario (RCP 8.5), the likely ranges are 0.7–1.2 m by AD 2100 and 2–3 m by AD 2300.

That seems about right to me.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on May 27, 2014, 02:19:14 AM
Thanks for that clear graph, ASLR. But do note that the newest info on WAIS and GIS should presumably make that 2013 piece out of date and so wrong (so anyone agreeing with it is agreeing with something we know to be wrong). Specifically, it should be skewed toward the right. The question is, by how much?

I'm looking for anyone out there who is making guestimates at this point, since we will have to wait for another survey of experts. The whole point of blogs like this is to speculate based on most recent findings, isn't it?

I would also point out that Climate Central, the Guardian and The Environmentalist are generally well regarded sources (as MSM sources go), though not, of course, at the level of peer reviewed papers or surveys of experts.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 27, 2014, 02:33:39 AM
wili,

Your point is well taken with regard to the median value of the Horton survey; however, I believe that the fat tail of the distribution likely will not change much, as I suspect that the experts at this end of the graph have been aware of such as Rignot et al (2014) for some time.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Ned W on May 27, 2014, 02:57:56 AM
Quote from: wili
But do note that the newest info on WAIS and GIS should presumably make that 2013 piece out of date and so wrong (so anyone agreeing with it is agreeing with something we know to be wrong).
I am pretty sure that Eric Rignot understands the implications of "the newest info on WAIS and GIS"  since he was lead author on the WAIS paper and 2nd author on the GIS paper.  He is quoted as saying that SLR by 2100 is likely to be near the upper end of the AR5 range, i.e. around 98cm.  Which is right at the peak of the distribution in Horton 2013. 

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on May 27, 2014, 02:58:56 AM
Good point, ASLR.

Just to emphasize that I am interested in discussing a range of views, not engaging in some kind of high school debate, here is the latest on the issue from PhysOrg:
Quote
"All of our simulations show it will retreat at less than a millimeter of sea level rise per year for a couple of hundred years, and then, boom, it just starts to really go," Joughin said in a news release from the University of Washington...

Cochran agreed: The papers' message is "that … over the next couple hundred years, there's going to be a significant rise in sea level, and at this point we can't stop it." But, he added, "it doesn't say give up on trying to cut emissions. … [Just] don't buy land in Florida."

http://phys.org/news/2014-05-clock-west-antarctic.html#jCp (http://phys.org/news/2014-05-clock-west-antarctic.html#jCp)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 27, 2014, 05:33:42 AM
wili,

I appreciate all of the different sources of information that you are providing, and I also am not interested in winning a high school debate, or a popularity contest.  There is only one Earth that we all live on, and I also get frustrated that more scientists and policy makers want to follow the path of least drama when evaluating a situation that could push civil society past the tipping point.  Nevertheless, the best thing to do is to: (a) keep clarifying the facts/confusion; and (b) to help people to see that while this is a big problem, what they do as individuals matters.

That said, I would like to clarify that both Rignot et al's and Joughln's models can be taken as lower bound solutions to complex problems and cannot account for such positive feedback mechanisms for WAIS ice mass loss as:
(a) Likely calving from both the Pine Island Ice Shelf, PIIS, and the Eastern Thwaites Ice Shelf (note that the Thwaites Ice Tongue shown in the Rignot model currently has only a fraction of the structural integrity indicated by his model, due to extensive fracturing in the tongue); could both reduce buttressing support of both the PIG and the Thwaites Glacier, and also could trigger the SW tributary glacier feeding into PIIS, which in turn could activate the Eastern Shear Margin of the Thwaites Glacier.
(b) Most of the period that the models were calibrated to occurred during the recent hiatus period (including a low frequency of El Nino events) which certainly resulted in lower than potential ice mass loss from the ASE glaciers; and we can certainly expect this ice mass loss to accelerate during the coming positive Interdecadal Pacific Oscillation, IPO, phase (15 to 25 years or so).
(c) The models cannot replicate the Jakobshavn Effect that the ASE glaciers are subject to.
(d) As ice mass loss from the GIS results in amplified RSLR in Antarctica, the fact that the marine terminating glaciers in Greenland can contribute more to SLR than previously expected, will serve to destabilize the WAIS more in the future than previously expected.
(e) The basal melt water system beneath the ASE glaciers cannot have been fully modeled in either the Rignot or the Joughin projections, but this basal meltwater will increase as: (i) the glacier accelerate; (ii) as magma moves under the WAIS lithosphere due to isostatic rebound; and (c) due to increasing surface melting in the future.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on May 27, 2014, 08:44:04 AM
dear god:look at the numbers.
   
a) look at "glaciers and icecaps"  search term "GIC"   e.g.   doi:10.1038/nature10847
thats half a mm/yr  right now
b)look at antarctic peninsula search term "APIS"
c)Greenland SMB
d)WAIS

a) and b) will waste first and fastest. than  and there are tens  of centimeters SLR there.
GIS will undergo saddle collapse at 67N,

Sea level rise from the north, amplified by fingerprint effect will raise antarctic ice shelves and bathytherms, melting the gut outta WAIS.

But: we can help a) and b) and c) by cutting at least black carbon as fast as we can _today_, and CO2 to decrease radiative imbalance

This is important because

Sea level rise from the north, amplified by fingerprint effect will raise antarctic ice shelves and bathytherms, melting the gut outta WAIS.

Anyone who imagines the ocean will not rise much faster than before (this will be true for several centuries)  is deluded, or selling coastal real estate, fake insurance, or fossil fuel. Or worse.

We are committed to retreating coastline for centuries. May our children have mercy on our souls.
But perhaps we can buy them some precious time.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 27, 2014, 10:11:34 AM
ASLR,

Your (attached) figure showing results from Horton et al. is the same as figure 3 in this post by Stefan Rahmstorf on RealClimate:
http://www.realclimate.org/index.php/archives/2013/11/sea-level-rise-what-the-experts-expect/ (http://www.realclimate.org/index.php/archives/2013/11/sea-level-rise-what-the-experts-expect/)

The caption to his figure 3 says:
"Distribution of the experts’ answers to the upper limit of the ‘likely’ range for the RCP8.5 scenario by the year 2100. (These numbers can be compared to the value of 98 cm given in the IPCC report.)"

I think this means the experts estimate there's about a 17% chance of SLR around or over this upper limit. So, I'm not sure what you mean when you say:
Quote
at least one true expert (not some outlier) believes that following a RCP 8.5 scenario will result in a 50%CL of 6m of eustatic SLR this century
I think "50%" should be "17%". But maybe I misunderstand?

Figure 2 in Horton et al. itself (also attached) shows the distribution of the upper limit of the 'very likely' range:
https://marine.rutgers.edu/pubs/private/HortonQSR_2013.pdf (https://marine.rutgers.edu/pubs/private/HortonQSR_2013.pdf)

The caption to this figure reads:
"Box plots of survey results from all experts who provided at least partial responses to questions. The number of respondents for each of the four questions is shown in the top left corner; it is lower than the total of 90 participants since not all answered each question. Participants were asked to estimate likely (17th-83rd percentiles) and very likely (5th-95th percentiles) sea-level rise under two temperature scenarios and at two time points (AD 2100 and AD 2300), resulting in four sets of responses. Shaded boxes represent the range between the first and third quantiles of responses. Dashed horizontal line within the box is the median response. Whiskers (solid lines) represent two standard deviations of the responses. Filled circles show individual responses that are beyond two standard deviations of the median."

For 2100 apparently 5 out of 82 experts (6%) think a worst-case of 3m or more has about a 5% chance of occurring following BAU. About 50% of the experts think 1.5m or more has about a 5% chance of occurring in this scenario. About 33% think this worst-case risk is 2m or more. One expert even thinks this risk is 7m or more by 2100.

So depending on your criteria for a worst-case estimate it could be 1.5 to 7m by 2100. I think it's significant that 33% of experts think there's a 5% chance of 2m or more by 2100 under BAU. This was not in the IPCC-report, but it seems highly relevant to societal and political discussion on mitigation and adaptation options and negotiations.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 27, 2014, 11:09:38 AM
Lennart,

Thanks for expanding on the Horton survey.  It appears that Rahmstorf is correct that the figure he called figure 3 is at the upper limit of the 'likely' range for the RCP8.5 scenario by 2100, which would correspond to a 83%CL for that scenario. I focused on the term 'likely' which extends from the 17th-83rd percentile, and on the fact that the respondents are essentially guessing (and that scientific surveys have demonstrated that scientists typically select the least dramatic option for their estimates). 

Also, thanks for pointing out that at the 95%CL for this scenario that one researcher cited the possibility of a 7m eustatic SLR.  It is important to recognize that due to the fingerprint effect a 7m eustatic SLR by 2100 could mean 5m to 9m RSLR depending on location relative to the melted ice sheets.

Finally, I believe that wili has a point, that in a non-stationary world that surveys like Horton should be repeated at least annually if decision makers are suppose to base their decisions on such findings.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Gray-Wolf on May 27, 2014, 11:43:21 AM
Maybe a little less 'cutting edge' than all I've read above but the collective memories/cultural myths about a 'flood' event in humanities past would seem to suggest that we do see a phase of SSL that is near instant/daily rises?

Surely this is not just some echo of the Black sea inundation but a truly global event at the end of the last ice age where catastrophic collapse, and subsequent melt occurred?

We have already seen an Antarctic ice shelf collapse due to the storm swell sent by an Alaskan storm so should we not expect further such events from floating glacier tongues/shelfs?

Bad combinations of tide and swell could lead to pneumatic hammering type fractures of ice bodies that have sea water inundation. The nastiest area for this to happen ( in my mind) is the east of the Ross embayment ? We know that recent collapses of the WAIS has seen the channel linking Ross and Weddell opening up and looking at how the continent is today it makes more sense for such an event to begin from the ross side of the channel?

When we look at the amount of Sea level rise locked up in Ross then any partial collapse of the shelf could bring multiple feet of SLR over a period of less then a decade?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 27, 2014, 12:22:33 PM
ASLR,

Thanks for pointing out that the fingerprint effect will mean even higher SLR of up to 30% in some places. The same can probably be said for subsidence of cities like Jakarta.

And I agree that surveys like these should be repeated regularly.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 27, 2014, 12:38:34 PM
Gray-Wolf,

Maybe these flood memories/myths were related to Meltwater Pulse 1A about 14.500 years ago:
http://www.nature.com/nature/journal/v483/n7391/full/nature10902.html (http://www.nature.com/nature/journal/v483/n7391/full/nature10902.html)

Average SLR was probably over 4 meters/century for several centuries back then, so over 40 cm/decade. People would surely have noticed such exceptionally rapid SLR. Maybe their stories were the (or an important) basis for all the various flood legends that have been chronicled world-wide?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 27, 2014, 02:19:33 PM
I would prefer that we not use "biblical stories" to speculate on sea level rise. This is little different than deniers using Viking accounts to argue for natural variation.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: tombond on May 27, 2014, 03:13:00 PM
We know for certain that sea level is rising in response to global warming caused by rising GHG emissions and will continue to rise for centuries. 

What is uncertain, is how fast this sea level rise will be. 

The IPCC gives us two extremes. 

The first extreme is a low emissions scenario (RCP 2.6) where sea level rise (SLR) is expected to be under 0.5 of a metre by 2100.  This estimation is based on the belief that the global community will co-operate and substantially reduce emissions to almost zero by 2100.  With GHG emissions increasing at 2% per year so far this century, from a risk assessment point of view, this belief currently seems unlikely.

The second extreme is the high emissions scenario (RCP 8.5) where SLR is expected to be about 1 metre by 2100.  This estimation is based on the scientific belief that polar land ice melt will be minimal during this century.  With the polar land ice melt rate observations, as measured by satellite, currently doubling about every 10 years, from a risk assessment point of view, this belief also currently seems unlikely. 

Jim Hansen explores this ice melt doubling period scenario in this paper at www.columbia.edu/~jeh1/.../20121226_GreenlandIceSheetUpdate.pdf (http://www.columbia.edu/~jeh1/.../20121226_GreenlandIceSheetUpdate.pdf)

Using polar land ice melt doubling rates, Hansen calculates that for 5, 7 and 10 year doubling rates, that if maintained will give a 1 metre SLR about mid century or just after, much earlier than the more conservative, consensual IPCC predictions.

From a risk assessment point of view this is a more creditable estimation as it is based on current real world observations and data, not beliefs.

For SLR, global governments and communities would be wise to continually monitor the polar land ice melt doubling rates and use this data as the priority prediction input into SLR coastal planning. 

When adapting to continuous SLR whether it be short term protection or staged retreat, the impact on coastal communities can always be reduced by timely, long lead-time planning . 
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on May 27, 2014, 03:23:58 PM
Thanks all for info and speculations on slr issue.

Hank at RC suggested this article as one good starting point for how things looked to many experts before the latest findings:http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/feb/18/scientists-worried-ipcc-underestimate-sea-level-rise

The Vision Prize survey mentioned here is distinct from the Horton study referenced earlier (though the Guardian article then goes on to discuss that survey as well).

Quote
In its latest survey, the Vision Prize asked participants questions about technologies to limit climate change, and about the latest IPCC report. Two of these questions asked about the likelihood that global average sea level will rise less than the IPCC lowest estimate (0.25 meters, or 10 inches), or more than the IPCC highest estimate (0.91 meters, or 3 feet) by 2100. These estimates are about 60 percent higher than in the 2007 IPCC report, which intentionally left out dynamic processes that cause effects like the calving of ice shelves into the ocean, because at the time they were not well understood. As expected, research has shown that the previous IPCC report underestimated the rate of sea level rise.

The Vision Prize results revealed that despite the much higher sea level rise estimates this time around, the survey participants are worried that the IPCC is still underestimating future sea level rise. 41 percent responded that it's likely or very likely that sea level rise will exceed the IPCC highest estimate, and 71 percent answering that it's at least as likely as not. Conversely, only 5 percent responded that it's likely sea level rise will be less than the IPCC lowest estimate, and 83 percent called this scenario unlikely.

It strikes me that these experts did not say that their own highest estimate was higher than the IPCCs high estimat, but that they thought that, as I read it, actual sea level rise would exceed IPCC’s highest estimate of about a meter. One wonders, then, what their highest estimate would be. Especially in the light of the most recent research.

Presumably at this point we can conclude that most experts would expect actual sea level rise to exceed one meter by 2100. The questions remain:

>>By how much?
>>And what would the high-end estimates be, the ones that are so important for doing accurate risk assessment?
>>And how much faster do we expect these levels of sea rise to appear?

Any further light that any of our experts or search sleuths can throw on these important issues would be most welcome.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 27, 2014, 03:35:00 PM
Wili,

Thanks for the link to the Guardian article on the Vision Prize survey. Indeed it also mentions the Horton et al. survey:

"In this survey, 90 researchers who'd published sea level research in the last 5 years concluded that sea level rise by 2100 is likely to be between 0.7 and 1.2 meters if we continue on a business-as-usual greenhouse gas emissions path. Two-thirds of the experts responded that sea level could rise more than the upper end of the IPCC's projected range by 2100, consistent with the Vision Prize survey results."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 27, 2014, 04:07:05 PM
It seems the Vision Prize survey also implicitly asks the experts to make an estimate of the likelihood of BAU or mitigation. That's different from the Horton et al. survey which asked for estimates under BAU and under strong mitigation.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 27, 2014, 05:05:57 PM
Another consideration that I think that is important to remember with regard to the expert surveys, is that the experts are given the scenarios RCP 3-PD-2.6 & RCP 8.5, and they are not allowed to question this input.  Personally, I do not believe that RCP 3-PD2.6 is anything but a fantasy (this scenario assumes that the third world stayed relatively underdeveloped since the 1980's on, rather than experiencing relatively explosive economic growth), furthermore, as RCP 8.5 is calibrated to assume an ECS of about 3 degrees C, it could very easily be assuming 50% too low of forcing if say the Earth System Sensitivity, ESS, is 4.5 degrees C (many readers here would not be surprised if the Arctic Sea Ice extent and the Northern Hemisphere snow extent, both seasonally dropped markedly in the next decade, not to mention that the hiatus period is ending (for about 15 to 25 yrs), and that air pollution will likely be relatively reduced in the future).  If these ice experts were allowed to determine their own input values to their models, would they have higher projected ice mass loss values?

Furthermore, we have not cited any semi-empirical SLR projections, which uniformly have higher values than the AR5 SLR projections, so if you were to combine higher forcing values together with semi-empirical SLR functions, one should not be surprised if SLR well exceeds one meter by the end of this century.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Yuha on May 27, 2014, 05:40:42 PM
I've been reading the recent paper by Joughin, Smith and Medley (doi: 10.1126/science.1249055). Many places mention the 200-900 years until the collapse of the Thwaites Glacier but I don't think the 200 years should be taken as an absolute worst case. ASRL has already made this point but I'm adding my support.

In my interpretation, the paper is stating: "According to simulations, the Thwaites Glacier will collapse 200 to 300 years from now if it continues to melt at the rate observed in 1996-2013." More details and justification is provided by the following quotes from the paper:

Quote
We simulated Thwaites Glacier’s response to subshelf melt using a prognostic, finite-element, depth-averaged, shallow-shelf model (12, 22, 23).

Quote
Our simulations are not coupled to a global climate model to provide forcing nor do they include an ice-shelf cavity-circulation model to derive melt rates. Few if any such fully coupled models presently exist (13). As such, our simulations do not constitute a projection of future sea level in response to projected climate forcing.

Quote
The observed losses from 1996 to 2013 (Fig. 3A) fall between the results from our highest-melt (m = 3 and 4) simulations. Over this period, the average simulated melt of 84 Gt/year for m = 4 agrees well with recent melt estimates of 69 to 97 Gt/year (7,8), indicating that the higher-melt simulations’ early stages reasonably approximate present conditions.

Quote
Strong melt (m = 2 to 4) produces ice loss at rates of <0.25 mm/year of sea-level equivalent (sle) for the first century, beyond which there is a period in each strong-melt simulation when the grounding line retreats abruptly, producing greater ice loss (0.25 to 0.5 mm/year of sle).

Quote
When simulated losses exceed 1 mm/year of sle, much greater losses generally follow within a few years. Using our basin-scale model, however, such rapid collapse is difficult to model, especially because interaction with other basins becomes increasingly important. Thus, we take 1 mm/year of sle to be a threshold that, once crossed, marks the onset of rapid (decades) collapse as the grounding line reaches the deepest regions of the marine basin.

Quote
Table 1. Year in simulation when losses first exceed 1 mm/year of sle for standard and weak-margin models.

m Standard model (year) Weak-margin model (years)
0.5 >1000 >1000
1.0 870 573
2.0 460 342
3.0 343 253
4.0 292 212

Eric Rignot seems to agree that the worst case may be less than 200 years according to a News&Analysis piece in Science (doi: 10.1126/science.344.6185.683):

Quote
Eric Rignot, a climate scientist at the University of California, Irvine, and the lead author of the GRL study, is skeptical of Joughin’s timeline because the computer model used estimates of future melting rates instead of calculations based on physical processes such as changing sea temperatures. “These simulations ought to go to the next stage and include realistic ocean forcing,” he says. If they do, he says, they might predict an even more rapid retreat.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on May 27, 2014, 05:53:52 PM
Thanks for those insights and quote, Yuha.

"According to simulations, the Thwaites Glacier will collapse 200 to 300 years from now if it continues to melt at the rate observed in 1996-2013."

Holy smokes! Does anyone really think the rate is going to remain linear? Has it in the past. Compare the first 20 year period to the second in this graph from the Guardian article:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic.guim.co.uk%2Fsys-images%2FGuardian%2FPix%2Fpictures%2F2009%2F3%2F9%2F1236605575094%2FStefan-Rahmstorf-graph-sh-002.jpg&hash=19a46e2a508874a85be05ef013b234b8)

From my eyeballing, it looks like the rate essentially doubled, from 3 cm in 20 years up to 1990 to 6 cm in the following 20 years. Why should not this acceleration increase? Was there some peculiarity about this time period that we should not expect to repeat in future decades? On the contrary, aren't there now many feedbacks kicking in or about to do so that weren't in evidence in the last century? It sounds to me as if we can say pretty much for sure based on these assumptions that the collapse will come sooner than two centuries out. Am I missing something obvious?

...

ETA: RaenorShine posted these on the Greenland Melt thread, but they seem particularly relevant to this discussion, too:

Dr Jason Box on new Greenland Glacier Bottom Maps
http://climatecrocks.com/2014/05/27/greenland-dark-snow-project-now-more-important-than-ever/ (http://climatecrocks.com/2014/05/27/greenland-dark-snow-project-now-more-important-than-ever/)

Dr Richard Alley on the latest Antarctic and Greenland Studies
https://soundcloud.com/inquiringminds/35-richard-alley-west-antarctica-is-melting-and-we-cant-stop-it (https://soundcloud.com/inquiringminds/35-richard-alley-west-antarctica-is-melting-and-we-cant-stop-it)

The actual Alley interview starts just after the 16 minute mark. At about minute 22, Alley points out that at some point there is a runaway--tipping points where the ice flow increases dramatically. He then mentions 'centuries or maybe decades " but I'm unclear as to whether he means that these are periods from now within which we can expect to see these tipping points, or if he means these are the time periods after the tipping points over which we can expect all the ice to flow into the ocean.

I'm thinking/hoping it's the latter.

But then at 25:50 he says that the authors 'did not run the worst case scenario.'

He says, by the end of the century, the most likely slr is a couple of feet or so. It could be a little less than that (but not by much), or it could be a bit more than that. But there's a slight chance that it could be a lot more than that.

(Sorry to be giving this blow by blow, but this is the first 'expert' I've heard weigh in on these matters, rather than just authors of articles in MSM.)

Just before minute 33, the interviewer points out that already last year Archer had said that there is a possibility of WAIS collapse by the end of the century, though he considered it a small possibility at that point. Pressed by the interviewer whether that possibility was now larger, Archer pointed out how little we really know about the potential dynamics of these systems. He then points out that the usual thing we see in reconstructions of earlier melts of ice sheets is long periods of relatively slow melt followed by extremely rapid melt--as in not even pausing for a few months during winter.

We are dealing with a switch, not a dial. It is very easy to know what will happen if you very slowly move a dial. But with a switch, it is very hard to know ahead of time how hard of a push it takes till suddenly you are in a completely different state. WAIS is a switch, and it's very hard to know when it will flip.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 27, 2014, 06:32:27 PM
I attached the Mean Sea Level trend plot from circa 1993 to 2014 from the University of Colorado, issued May 23 2014 with data through mid-March 2014.  I also provide the following recent data from that same source (see the link):

http://sealevel.colorado.edu/files/2014_rel4/sl_ns_global.txt (http://sealevel.colorado.edu/files/2014_rel4/sl_ns_global.txt)

year      msl_ib_ns(mm)
2013.9450   54.943
2013.9721   59.019
2013.9993   62.872
2014.0264   64.153
2014.0536   62.231
2014.0807   57.746
2014.1079   60.575
2014.1350   63.326
2014.1621   66.086
2014.1893   67.650

While the MSL trend from 1993-2014 is 3.2 +/- 0.4 mm/yr this period (note that before this period the MSL trend rate was about 1.7 mm/yr) includes the hiatus period  (including reduced frequency of El Nino's) from about 1998.5 to 2014, and as sea level rises more during El Nino years, the Joughin et al (2014) assumption is very conservative.  This is indicated by the fact that precursor El Nino conditions in 2014 began with a Equatorial Kelvin Wave, EKW, around the end of January; which is reflected in the fact that sea level has increased about 1mm between the end of January and mid-March 2014.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 27, 2014, 07:52:34 PM
So,

Am I completely off base in expecting a non-linear 0-700M warming event for the Amundsen Sea over the next 40 years?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.naucat.com%2Fresources%2Fimage%2Fsanta%2520leda-01%281%29.jpg&hash=832a08fb5e5f85c750d1cd0e654ef32b)

http://www.atmos.washington.edu/~david/Steig_etal_2012.pdf (http://www.atmos.washington.edu/~david/Steig_etal_2012.pdf)
Tropical forcing of Circumpolar Deep Water Inflow and outlet
glacier thinning in the Amundsen Sea Embayment, West Antarctica

http://blogs.ei.columbia.edu/2010/12/14/deep-ocean-heat-is-melting-antarctic-ice/ (http://blogs.ei.columbia.edu/2010/12/14/deep-ocean-heat-is-melting-antarctic-ice/)

Quote
Martinson said that heat stored in deep waters far from Antarctica is being pushed southward and becoming entrained in the Antarctic Circumpolar Current, a vast, wind-driven water mass that constantly circles the frozen continent. The evidence comes from 18 years of Antarctic voyages Martinson has made to measure water temperature, salinity and other qualities at different depths. He called the increases in ocean heat in the past few decades “jaw dropping.”

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.washingtonpost.com%2Fblogs%2Fcapital-weather-gang%2Ffiles%2F2013%2F10%2Fheat_content2000m.jpg&hash=94830a739718cff7e97239ae0e3f0edd)

In view of the projected exponential growth in heat accumulation in the deep oceans over the next 6 decades, how does the fact that they did not project increasing warming into their scenarios makes 1M of sea level rise the new minimum expected rise by 2100?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 27, 2014, 08:19:18 PM
jai,

What the fundamental problem is that scientist are trained to only report what their models say, and the models are not yet sophisticated enough to correctly model the influence of the ocean heat on the ASE glaciers, and decision makers are not held accountable by the public for projecting beyond what the scientist tell them.  To be fair, glacial speeds for most of this century have been slow (glacial); but when they hit a certain point they accelerate exponentially as the Jakobshavn Glacier (in Greenland) has already started to do.  So the ready big uncertainty is when does the exponential acceleration begin (which is when the grounding line has retreated past the lip of the sea floor into a negative slope, and when the throat of the gateway widens enough for all the calving ice (due to a Jakobshavn Effect) to float out of the gateway)?  This could not start before 2040 in my opinion but it could be longer.

Also, separately, see the attached fingerprint map of RSLR associated with only the collapse of the WAIS.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Anne on May 27, 2014, 10:36:40 PM
Does that chart show feet or metres?  :o
Feet, I hope.
*Edit* I guess not
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 27, 2014, 11:00:49 PM
Does that chart show feet or metres?  :o
Feet, I hope.
*Edit* I guess not

I believe that is a multiple of the average. If average sea level  increases 1 meter than the east coast of the U.S. will see 1.4 meters.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: crandles on May 27, 2014, 11:44:15 PM
More details and justification is provided by the following quotes from the paper:

Quote
Our simulations are not coupled to a global climate model to provide forcing nor do they include an ice-shelf cavity-circulation model to derive melt rates. Few if any such fully coupled models presently exist (13). As such, our simulations do not constitute a projection of future sea level in response to projected climate forcing.

Quote
The observed losses from 1996 to 2013 (Fig. 3A) fall between the results from our highest-melt (m = 3 and 4) simulations. Over this period, the average simulated melt of 84 Gt/year for m = 4 agrees well with recent melt estimates of 69 to 97 Gt/year (7,8), indicating that the higher-melt simulations’ early stages reasonably approximate present conditions.

Quote
Strong melt (m = 2 to 4) produces ice loss at rates of <0.25 mm/year of sea-level equivalent (sle) for the first century, beyond which there is a period in each strong-melt simulation when the grounding line retreats abruptly, producing greater ice loss (0.25 to 0.5 mm/year of sle).

Quote
When simulated losses exceed 1 mm/year of sle, much greater losses generally follow within a few years. Using our basin-scale model, however, such rapid collapse is difficult to model, especially because interaction with other basins becomes increasingly important. Thus, we take 1 mm/year of sle to be a threshold that, once crossed, marks the onset of rapid (decades) collapse as the grounding line reaches the deepest regions of the marine basin.

Quote
Table 1. Year in simulation when losses first exceed 1 mm/year of sle for standard and weak-margin models.

m Standard model (year) Weak-margin model (years)
0.5 >1000 >1000
1.0 870 573
2.0 460 342
3.0 343 253
4.0 292 212


Thank you for these quotes.

The current 69-97 GT range averages to ~83GT. it takes 360GT to raise global sea level by 1mm and they are saying if the rate reaches 1mm per year, much greater losses generally follow.

So it only takes two doublings in the rate of loss to get pretty close to this. While I was a bit incredulous about doubling every 4-7 years, doubling every 20-40 years seems much more plausible than assuming the same linear rate as now. That would give a timescale of 40-80 years before even more rapid accelerations?

or am I misunderstanding?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on May 28, 2014, 12:23:11 AM
Joughin addresses Thwaites, which is the biggie. But it's not just Thwaites. Right there are PIG,Smith Haynes,Pope,Kohler. All bedded submarine.

i attach fig 1 and part of 3 from Rignot(2014) doi: 10.1002/2014GL060140

Fig 1 is self explanatory. The frames from Fig 3 are improved bedrock topo for b) PIG, d)Thwaites and Haynes f)Smith and Kohler.

Couple meters SLR right there.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 28, 2014, 02:39:24 AM
Study #1:
Shepherd et. al
Science 30 November 2012:
Vol. 338  no. 6111  pp. 1183-1189 
DOI: 10.1126/science.1228102

A Reconciled Estimate of Ice-Sheet Mass Balance

Quote
Between 1992 and 2011, the ice sheets of

East Antarctica, ---------  +14 ± 43
West Antarctica, ---------   –65 ± 26
Antarctic Peninsula ----------–20 ± 14

changed in mass gigatonnes per year.


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.sciencemag.org%2Fcontent%2F338%2F6111%2F1183%2FF5.large.jpg&hash=a34cd4152c445b2b2d28eaafdeb7e2f7)


Study #2
Mcmillian, Shepherd et. al
DOI: 10.1002/2014GL060111
AGU Letters:  2014

Quote
Between 2010 and 2013,
West Antarctica, ---------  −134 ± 27
East Antarctica, and the ----------  −3 ± 36
Antarctic Peninsula ------  −23 ± 18

changed in mass in Gt yr−1

please pardon the hand drawn images.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Foi59.tinypic.com%2F2n93e1.jpg&hash=6c87b8fef15181d4fdb6f1494b56738e)

http://www.theguardian.com/environment/2014/may/19/doubling-of-antarctic-ice-loss-revealed-by-european-satellite (http://www.theguardian.com/environment/2014/may/19/doubling-of-antarctic-ice-loss-revealed-by-european-satellite)

Quote
The new data, published in journal Geophysical Research Letters, comes from the European Space Agency’s CryoSat-2 satellite, which was launched in 2010.

It shows that the western Antarctica ice sheet is where 87% of the lost ice is being shed, with the east Antarctic and the Antarctic peninsula shedding the rest. The data collected from 2010-2013 was compared to that from 2005-2010.

So we see a real step-change in west mass loss beginning in 2006 and being maintained through 2013. 

With increased penetration into the continental valleys, there will be a greater exposure to warm waters, combine this with an increase in the temperature of the waters, likely a non-linear increase, which was not included in the model and we reach 1mm/year mass loss very quickly (1-2 decades).
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 28, 2014, 05:48:06 PM
jai,

While I to believe that the WAIS will contribute to abrupt SLR this century, I believe that it is not likely that the Thwaites Glacier will start showing Jakobshavn type behavior within 1 to 2 decades.

If you scan through the posts in the "Surge" thread of the Antarctic folder (see link below), you will find extensive discussion on just this topic:

http://forum.arctic-sea-ice.net/index.php/topic,21.100.html (http://forum.arctic-sea-ice.net/index.php/topic,21.100.html)

In particular, I note that while the McMillian, Shepherd et. al, DOI: 10.1002/2014GL060111, AGU Letters:  2014, findings based on corrected Cryosat data maybe new, the trend that you present in your hand drawn figures are not news to NASA, or to Rignot et al, at all as indicated by the GRACE satellite figure (see first attached figure) from December 2012, which you can also find in Reply #61 of the "Surge" thread; and NASA/Rignot merely prefer to error on the side of least drama in projecting ice mass loss.

Furthermore, if you look at the second attached figure (and Reply # 71 of the "Surge" thread) then you will see that there is reason to suspect that the GRACE satellite (and the McMillian et al 2014) is indicating too low of ice mass loss from the ASE as magma is moving back under the crust in the Byrd Subglacial Basin; which may infer a 2003 to 2009 average ice-mass loss of − 98.9 ± 13.7 Gt/yr for the Amundsen Sea sector alone (note that the British Antarctic Survey and others are currently gathering GPS data to confirm this behavior).

Lastly, I draw your attention to Reply #100 to #103 in the "Surge" thread that indicates some evidence that the subglacial cavity (or local area of grounding line retreat) beneath the Thwaites Ice Tongue may have been filled by surging ice (or the local area of the grounding line advanced) in the boreal Fall of 2012 (austral Spring of 2012), which is the main subject of the "Surge" thread.  Therefore, you cannot assume that grounding line retreat will occur in exactly the same manner in the Thwaites Glacier as is being observed in the PIG, and these differences can add decades to the onset of Jakobshavn type behavior in the Thwaites Glacier.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 28, 2014, 07:17:13 PM
SLR

Thank you for your post, so many really good posts on the thread.  I have learned so much!!

The ideas that Rignot did not include projected future warming to determine the Thwaites critical failure threshold in 200 to 300 years was illuminating.

Also, the GRACE image that you posted.

To clarify, I was referring to TOTAL Antarctica 1mm/year contribution, not THE Thwaites 1mm/year critical failure threshold of 1mm per year.

 The paleoclimate record is clear, there has been times when a 5cm per year rise has occurred, under normal Milankovitch cycle events.  We know that global ocean heat content is projected to accumulate 166% more energy in the next 30 years than it gained in the last 30 years.  (as a minimum).

Observations from the Circumpolar Deep Water show the recent tropical heating is moving into this Antarctic melt-source via some, currently low understood mechanism.

The observed change in West Antarctic mass loss rate also shows the increased deep water warming.

Therefore, the potential for current AR5 sea level rise projections over the next 20, 50 and 100 years, even the worst case scenarios, are now recognized to be extreme underestimates.

The increased accumulation of 20cm in the next 30 years will effectively double the current value of the social cost of carbon.  (at a ridiculously high 2.5% discount rate) of $57.00 per tonne

Therefore, instead of a double at 2.5% to $114.00 per metric tonne, the value that should be used (at 1.5% per metric tonne - following the Stern Report guidelines) would be closer to $250.00 per metric tonne.

http://www.whitehouse.gov/sites/default/files/omb/inforeg/social_cost_of_carbon_for_ria_2013_update.pdf (http://www.whitehouse.gov/sites/default/files/omb/inforeg/social_cost_of_carbon_for_ria_2013_update.pdf)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 28, 2014, 10:50:58 PM
I note that the most dramatic things that could happen in the next few years to either PIG and/or Thwaites would be for their ice shelves/tongue to break apart.  This topic is discussed in the following thread:

http://forum.arctic-sea-ice.net/index.php/topic,429.150.html (http://forum.arctic-sea-ice.net/index.php/topic,429.150.html)

The first attached image from Sentinal-1A radar image (I believe from late April 2014) shows how fractured both the Eastern Thwaites Ice Shelf and Ice Tongue are.

The second attached image from the Aqua satellite from March 29 2014, shows how concentrated the calving of the Pine Island Ice Shelf has been in the Northeastern corner over the past austral summer (which could lead to a future major calving event as occurred in November of 2013).
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 28, 2014, 11:30:44 PM
I just made a new post in the "Paleo-Evidence" thread of the Antarctic folder (see link below), about new evidence that directly ties major collapses of portions of the Antarctic Ice Sheet, particularly with Meltwater Pulse 1A, when sea level rose about 4m in about 100-years:

http://forum.arctic-sea-ice.net/index.php?board=13.0 (http://forum.arctic-sea-ice.net/index.php?board=13.0)

Editorial note: I have corrected the point that sea level rose up to 4m in about 100-years during MWP 1A.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 29, 2014, 01:05:26 AM
Thanks for that SLR.

There is so much evidence now for a 95% contribution of WAIS during the late Eemian melt pulse http://www.bitsofscience.org/eemian-sea-level-rise-greenland-antarctica-2487/ (http://www.bitsofscience.org/eemian-sea-level-rise-greenland-antarctica-2487/). 

Even the regional fauna indicate TOTAL WAIS collapse and population mixing between the Ross and Weddell seas during this time.  http://www.sciencedaily.com/releases/2012/05/120509111453.htm (http://www.sciencedaily.com/releases/2012/05/120509111453.htm)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fplanetearth.nerc.ac.uk%2Fimages%2Fuploaded%2Fcustom%2Fthickness-land-and-ice.jpg&hash=f5045b298a7a0e5eebe96f495d134988)
http://planetearth.nerc.ac.uk/multimedia/story.aspx?id=1401&cookieConsent=A (http://planetearth.nerc.ac.uk/multimedia/story.aspx?id=1401&cookieConsent=A)

As you posted earlier, this secondary collapse of the entire WAIS happened after a long period of Eemain warming with a sudden and catastrophic (8 meters in 1000 years at the tail end of that interglacial) - the 1000 years window being the highest sample resolution, the likely response time to modern warming is expected to be much less. 

Now that the grounding lines are retreating in depth and distance into the continent this will produce an increased pumping mechanism as warmer high-salinity water is pushed further into the continent and the surface wall of the grounding line is forced deeper into the valley. 

Combining this with the observed increase in southern ocean abyssal waters http://journals.ametsoc.org/doi/abs/10.1175/2010JCLI3682.1 (http://journals.ametsoc.org/doi/abs/10.1175/2010JCLI3682.1) 

I see no other option but significant increases in melt rates for at least the next several decades.







Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on May 29, 2014, 05:41:00 AM
" ... increases in melt rates for at least the next several decades."

That last word is really  "centuries"

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 29, 2014, 03:16:42 PM
Most of this thread focuses on eustatic sea level rise, but we all need to remember that this is only a fraction of the total future sea level change at any one give location.  I previously, posted an image showing that a 1m eustatic SLR contribution from the WAIS due to the fingerprint effect results in 1.4m of local SLR for most of the continental US, but this is only the start of determining the total future sea level change for say New York Harbor.

The first attached image shows the tide gage readings (in feet relative to MLLW) at the Battery Tide Station, NY at the peak water level during Super Storm Sandy, with the chart showing: (a) the high astronomical tide, HAT of just over 6-feet (1.83m); and (b) the observed maximum water level was 13.87-ft (4.23m).  The second attached image show the results from a NOAA SLOSH analysis showing the water height (relative to MLLW) at the entrance to New York Harbor during a Cat 4 Hurricane could be about 28-ft (8.54m) at today's sea level, during a high tide.

The third image shows a visual representation of the primary contributors to local sea level change including: eustatic SLR, regional SLR, tides, local land movements, and regional sea level variability.  The fourth image shows a plot from NOAA of sea level anomalies on May 23 2014, showing a sea level anomaly at the mouth of New York Harbor of about 0.25m (as an example of combined regional sea level variability and steric SLR)


Now it is important to realize that storm surge increases with SLR and for New York at a rate of about half of the RSLR.  So a 1m eustatic SLR contribution from the WAIS gives a 1.4m local SLR at New York Harbor, plus regional variability of say 0.25m, plus the conventional eustatic SLR at New York (say 1m by 2100, see Haigh et al 2014, nature communications, DOI: 10.1038/ncomms4635), gives a total RSLR of about 2.65m by 2100, plus the 50% increase effect on storm surge or 2.65m x 1.5 = 3.975m plus the storm tide of 8.54m for a Cat 4 event gives at total sea level change for inundation of 12.5 m compared to the 4.23m experienced during Super Storm Sandy.  So when you are reading scientific findings about SLR, I hope that you all are translating this into meaningful sea level changes that will impact society.

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 29, 2014, 03:36:46 PM
Such a  storm  surge would permanently alter the barrier islands along Long Island.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on May 29, 2014, 05:07:56 PM
AbruptSLR don't you forget the thermal expansion ? I hear 5% sometimes 50% ? 5% of what ? The whole volume of oceans ?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 29, 2014, 09:59:38 PM
SH,
Of course while Cat 4 hurricanes have hit New York in the past, their level of storm surge is dependent on the track that they take, and the surge that I show assumes a track similar to that of Hurricane Sandy.  However, with increasing global warming the number of Cat 4 hurricanes hitting New York should increase rapidly.  I believe that Super Storm Sandy was not even a Cat 1 Hurricane when it made landfall, and Hurricane Katrina was a Cat 3 when it made landfall, so we both can imagine how much damage a future Cat 4 Hurricane would have on greater NY/NJ if it were follow a Sandy type storm track.


Laurent,
The thermal expansion was included in the 0.25m of regional variability, and the 1m of process-based projected SLR, values that I assumed.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 29, 2014, 10:09:33 PM
The following link leads to advanced abstracts from the International Glacial Society Proceedings 65; which has a lot of information related to Marine Ice Sheet stability and its likely effects on sea level rise projection.  As there are so many abstracts, I just extracted the following three quotes related to our discussion here, and in the next day, or so, I will post many relevant abstracts in the Antarctic folder:

http://www.igsoc.org/symposia/2014/chamonix/proceedings/procsfiles/procabstracts_65.htm (http://www.igsoc.org/symposia/2014/chamonix/proceedings/procsfiles/procabstracts_65.htm)

The following Payne et al 2014 extract indicates that the authors try to identify likely SLR contribution ranges associated with Marine Ice Sheet instability not considered in AR5:
 
PAYNE et al (2014), "70A0915 - Ice sheets and sea-level projections in the Fifth Assessment Report of the IPCC", IGSOC Proceedings 65.

"Projections of sea-level rise by 2100 are presented as a likely range, which equates to a likelihood of about two-thirds. The assessed likely range does not allow for a Marine Ice Sheet Instability. Particular attention is paid to this possibility and a further assessment is made of the additional contribution that might arise from it."

I have investigated the collapse of the Paleo-Pine Island glacier, and while not confirmed it is highly likely that this collapse event occurred during Meltwater Pulse 1A, which would indicate that the Paleo-Pine Island glacier may have contributed up to 2m of the 4m total SLR that occurred over a 100-year period during MWP 1A, and the following extract from Schroeder et al 2014 indicates that the Thwaites Glacier is primed to degrade in a similar character and pacing:

SCHROEDER et al, (2014) "70A0914 - Radar-sounding observations of basal water, sediments and geothermal heat flux and their implications for the past and future sea-level contribution of the Amundsen Sea sector of West Antarctica", IGSOC Proceedings 65.

"We conclude that a transition in the basal hydrology of Paleo Pine Island was characteristic of its relatively rapid retreat across exposed bedrock on the inner continental shelf and that Thwaites Glacier may be currently configured for a retreat that is similar in character and pacing."

The following extract from Nias et al 2014 confirms that the Thwaites Glacier, TG, will degrade in a different manner than the PIG currently is exhibiting:

NIAS et. al., (2014), "70A0919  -  Contrasting dynamics and sensitivity of the Amundsen Sea ice streams", IGSOC Proceedings 65.

"Using BISICLES, we ran a perturbed model ensemble for PIG and TG. Latin hypercube sampling was used to generate sets of parameter values for a range of physical conditions, including ice rheology, basal sliding and bed topography. We present probability density functions of the likelihood of sea-level contributions from PIG and TG under the same oceanic forcing. Initial results suggest that these probability density functions are very different."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on May 29, 2014, 11:09:24 PM
I found that wikipedia stuff...if it does help...
https://en.wikipedia.org/wiki/Current_sea_level_rise
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 30, 2014, 04:10:48 PM
See the linked article (with a free access pdf) which states: " … the proportion of Category 4 and 5 hurricanes has increased at a rate of ~25–30 % per °C of global warming after accounting for analysis and observing system changes."  This supports my assumption of taking a Cat 4 hurricane for flood risks for New York Harbor by the end of this century, see Reply #91.

Greg Holland • Cindy L. Bruye`re (2014), "Recent intense hurricane response to global climate change", Clim Dyn (2014) 42:617–627, DOI 10.1007/s00382-013-1713-0


http://link.springer.com/article/10.1007%2Fs00382-013-1713-0 (http://link.springer.com/article/10.1007%2Fs00382-013-1713-0)

Abstract: "An Anthropogenic Climate Change Index (ACCI) is developed and used to investigate the potential global warming contribution to current tropical cyclone activity. The ACCI is defined as the difference between the means of ensembles of climate simulations with and without anthropogenic gases and aerosols. This index indicates that the bulk of the current anthropogenic warming has occurred in the past four decades, which enables improved confidence in assessing hurricane changes as it removes many of the data issues from previous eras. We find no anthropogenic signal in annual global tropical cyclone or hurricane frequencies. But a strong signal is found in proportions of both weaker and stronger hurricanes: the proportion of Category 4 and 5 hurricanes has increased at a rate of ~25–30 % per °C of global warming after accounting for analysis and observing system changes. This has been balanced by a similar decrease in Category 1 and 2 hurricane proportions, leading to development of a distinctly bimodal intensity distribution, with the secondary maximum at Category 4 hurricanes. This global signal is reproduced in all ocean basins. The observed increase in Category 4–5 hurricanes may not continue at the same rate with future global warming. The analysis suggests that following an initial climate increase in intense hurricane proportions a saturation level will be reached beyond which any further global warming will have little effect."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 31, 2014, 01:03:39 AM
While the linked article is a few months old, the following quote makes it painfully clear that with increasing storminess and increasing SLR we could see $100 trillion/year in storm surge damage by 2100, if we don't do something to stop it:

http://www.theecologist.org/News/news_round_up/2268503/storm_surges_to_cost_100_trillion_a_year_as_sea_levels_rise.html (http://www.theecologist.org/News/news_round_up/2268503/storm_surges_to_cost_100_trillion_a_year_as_sea_levels_rise.html)

Quote: "According to a study published in the Proceedings of the National Academy of Sciences, global average storm surge damages could increase from about $10-$40 billion per year today to up to $100,000 billion per year by the end of century, if no adaptation action is taken."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 31, 2014, 05:08:37 PM
Many researchers like to look to the Mid-Pliocene as a paleo-example of what the GCMs estimate the Earth could be like in the late 21st century, with regard to surface temperatures ( but not with regard to sea level which was at least 15 to 25 meter above modern levels, as the sea/ice responds more slowly than the atmosphere).  The following quote from the IPCC puts the Mid-Pliocene into context:

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch6s6-3-2.html (http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch6s6-3-2.html)

Quote: "The Mid-Pliocene (about 3.3 to 3.0 Ma) is the most recent time in Earth’s history when mean global temperatures were substantially warmer for a sustained period (estimated by GCMs to be about 2°C to 3°C above pre-industrial temperatures; Chandler et al., 1994; Sloan et al., 1996; Haywood et al., 2000; Jiang et al., 2005), providing an accessible example of a world that is similar in many respects to what models estimate could be the Earth of the late 21st century. The Pliocene is also recent enough that the continents and ocean basins had nearly reached their present geographic configuration. Taken together, the average of the warmest times during the middle Pliocene presents a view of the equilibrium state of a globally warmer world, in which atmospheric CO2 concentrations (estimated to be between 360 to 400 ppm) were likely higher than pre-industrial values (Raymo and Rau, 1992; Raymo et al., 1996), and in which geologic evidence and isotopes agree that sea level was at least 15 to 25 m above modern levels (Dowsett and Cronin, 1990; Shackleton et al., 1995), with correspondingly reduced ice sheets and lower continental aridity (Guo et al., 2004)."

Furthermore, I discuss the following linked reference (with a free access pdf) in both the "Forcing" thread (Reply #197) and the "PIG/Thwaites 2012 to 2040-2060" thread in the Antarctic folder, and the first attached image from Hill et al 2014 shows that polar amplification results in about 10 degrees C higher Surface Air Temperatures (SAT) in the Amundsen Sea Embayment, ASE, during the Mid-Pliocene than today, and that this amplification was largely related to reductions in clear sky albedo (see the second attached image), due to such factors as reduction in sea ice.

Hill, D. J., Haywood, A. M., Lunt, D. J., Hunter, S. J., Bragg, F. J., Contoux, C., Stepanek, C., Sohl, L., Rosenbloom, N. A., Chan, W.-L., Kamae, Y., Zhang, Z., Abe-Ouchi, A., Chandler, M. A., Jost, A., Lohmann, G., Otto-Bliesner, B. L., Ramstein, G., and Ueda, H.: Evaluating the dominant components of warming in Pliocene climate simulations, Clim. Past, 10, 79-90, doi:10.5194/cp-10-79-2014, 2014.

http://www.clim-past.net/10/79/2014/cp-10-79-2014.html (http://www.clim-past.net/10/79/2014/cp-10-79-2014.html)

To emphasize that while currently Antarctic sea ice extent is trending upward (a trend that is projected to reverse after 2080), currently the austral summer sea ice extent in the ASE is actually trending downward as illustrated by the third attached image of an Antarctic sea ice extent map for January 29 2014, and while the fourth attached image shows that solar insolation in Antarctic in January is actually higher than in the Arctic in July.

Taken together, this evidence indicates that by the late 21st century that we can expect extensive ice surface melting in the ASE during the austral summer; which will not only contribute to ice mass loss due to austral summertime runoff, but more importantly preliminary findings indicate that the presence of surface water can markedly accelerate ice mass loss due to the Jakobshavn Effect.  This is a very serious matter that could significantly accelerate SLR after about 2070.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 31, 2014, 07:55:05 PM
As frustrating as it is that neither Rignot et al 2014 nor Joughin et al 2014,  used the full RCP ocean forcing in their projections about the irreversibility, and coming acceleration, of ice mass loss from the Amundsen Sea Embayment, ASE, marine glaciers; I find it particularly worrisome that the RCP scenarios are calibrated using a nominal Equilibrium Climate Sensitivity, ECS, value of about 3 degrees C; while the following research indicates the true ECS is closer to 4 degrees C (and may be about 4.5 degrees C; see the "Forcing" thread in the Antarctic folder).  The linked video, quote, and attached image, indicates that this higher ECS value is related to differences between actual and previously modeled (in the RCP scenarios) in atmospheric convective mixing resulting in differences in tropical cloud cover.  As we enter a positive PDO phase for the next 15 to 25 years, the importance of these differences should be clearly demonstrated by an acceleration in the rate of SLR:

Sherwood, S.C., Bony, S. and Dufresne, J.-L., (2014) "Spread in model climate sensitivity traced to atmospheric convective mixing", Nature; Volume: 505, pp 37–42, doi:10.1038/nature12829

http://www.nature.com/nature/journal/v505/n7481/full/nature12829.html (http://www.nature.com/nature/journal/v505/n7481/full/nature12829.html)



http://www.youtube.com/watch?v=_YZxqRM97eo# (http://www.youtube.com/watch?v=_YZxqRM97eo#)

Quote from video: “Climate sceptics like to criticize climate models for getting things wrong, and we are the first to admit they are not perfect, but what we are finding is that the mistakes are being made by those models which predict less warming, not those that predict more,” said Prof. Sherwood.
“Rises in global average temperatures of this magnitude will have profound impacts on the world and the economies of many countries if we don’t urgently start to curb our emissions."

See also:

Shindell, D.T., (2014), "Inhomogeneous forcing and transient climate sensitivity", Nature Climate Change, Vol.: 4, pp: 274–277, doi:10.1038/nclimate2136.

http://www.nature.com/nclimate/journal/v4/n4/full/nclimate2136.html (http://www.nature.com/nclimate/journal/v4/n4/full/nclimate2136.html)

and also:

Fasullo, J.T. and Trenberth, K.E., (2012), "A Less Cloudy Future: The Role of Subtropical Subsidence in Climate Sensitivity", Science, vol. 338, pp. 792-794, 2012. http://dx.doi.org/10.1126/science.1227465. (http://dx.doi.org/10.1126/science.1227465.)

http://www.sciencemag.org/content/338/6108/792 (http://www.sciencemag.org/content/338/6108/792)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 31, 2014, 09:47:58 PM
I realize that I may be confusing some people by talking about Equilibrium Climate Sensitivity, ECS, sometimes, Transient Climate Response, TCR, sometimes, and Earth System Sensitivity, ESS, sometimes.  Therefore, I provide the following extract from Wikipedia, related to these terms:

http://en.wikipedia.org/wiki/Climate_sensitivity (http://en.wikipedia.org/wiki/Climate_sensitivity)


Extract: "The equilibrium climate sensitivity (ECS) refers to the equilibrium change in global mean near-surface air temperature that would result from a sustained doubling of the atmospheric (equivalent) carbon dioxide concentration (ΔTx2).
….
A model estimate of equilibrium sensitivity thus requires a very long model integration; fully equilibrating ocean temperatures requires integrations of thousands of model years. A measure requiring shorter integrations is the transient climate response (TCR) which is defined as the average temperature response over a twenty-year period centered at CO2 doubling in a transient simulation with CO2 increasing at 1% per year. The transient response is lower than the equilibrium sensitivity, due to the "inertia" of ocean heat uptake.

A less commonly used concept, the Earth system sensitivity (ESS), can be defined which includes the effects of slower feedbacks, such as the albedo change from melting the large ice sheets that covered much of the northern hemisphere during the last glacial maximum. These extra feedbacks make the ESS larger than the ECS — possibly twice as large —
 …."

In my last post I indicated that Sherwood et al (2014) and Fasullo and Trenberth (2012) indicate that ECS is likely between 4 and 4.5 degrees C; and Shindell (2014) indicates that TCR is also likely proportionally higher than the AR5 assumes.  Furthermore, while traditional process-based thinking assumes that ESS reaches it's full potential over a period of millennia, James Hansen warns that a significant fraction of the full potential of an ESS value can be realized within say one hundred years.

In this regards, the linked reference by Pagani et al 2009 (with a free pdf) and attached figure, indicate that in the early Pliocene (over 4 million years ago, when the world was about 4 degrees warmer than pre-industrial era and CO₂ concentrations were about 415ppm) that Earth Systems Sensitivity, ESS, was about 9.6 +/- 1.4 degrees C.

Mark Pagani, Zhonghui Liu, Jonathan LaRiviere, Ana Christina Ravelo (2009), "High Earth-System Climate Sensitivity determined from Pliocene CO2 Concentrations", Nature geoscience, doi:10.1038/NGEO724

http://people.earth.yale.edu/sites/default/files/files/Pagani/1_2009%20Pagani_NatureGeosci.pdf (http://people.earth.yale.edu/sites/default/files/files/Pagani/1_2009%20Pagani_NatureGeosci.pdf)

As the Arctic Sea Ice, the Northern Hemisphere snow cover, Antarctic Sea Ice and the WAIS, also show signs of potentially collapsing before the end of this century if we stay on a BAU pathway, it does not seem unreasonable to be concerned that 6 degree C of the ESS full potential could be realized this century, with potentially severe consequences on SLR this century.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 01, 2014, 01:46:34 AM
For those who are concerned that I may be over-stating the reasonable values for ESS this century, please review my Reply #151 in the "Potential Collapse Scenario for the WAIS" thread at the following link:

http://forum.arctic-sea-ice.net/index.php/topic,31.150.html (http://forum.arctic-sea-ice.net/index.php/topic,31.150.html)

This post cites a large number of factors that can be temporarily "masking" the true magnitude of the ESS; which may be more fully expressed in a few decades time due to changes such as: (a) reductions in the relative amount of air pollution/aerosols (particularly in China); (b) stress to much of the worlds vegetation from such factors as: heat, drought, floods, insects, and wildfires; (c) the coming positive PDO phase; (d) the coming acceleration in methane and CO2 emissions from both tundra and tropical wetlands; (e) the coming warming phase of the “Atlantic Multidecadal Oscillation” or “AMO”; and (f) a possible reduction in the relatively high recent number of significant volcanic eruptions.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on June 01, 2014, 02:58:06 AM
ASLR...

Thank you for these posts. Until you posted it, I was only aware of ECS. TCR and ESS are completely new to me.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 01, 2014, 01:15:39 PM
SH,

Thanks, sometimes it is difficult to know how much background to provide, or not.

For instance, at the following website, Aslak Grinsted, points out that in regards to sea level rise section of  the Summary for Policy Makers, SPM, of Assessment Report 5, AR5:

"The explanation is that the true uncertainty is considered to be greater than the model spread.
The supplementary material to the sea level chapter says that they follow section 12.4.1.2 when they use 5-95% as the likely range.

[EDIT: I just found an explanation in an SPM footnote: "Calculated from projections as 5−95% model ranges. These ranges are then assessed to be likely ranges after accounting for additional uncertainties or different levels of confidence in models. For projections of global mean sea level rise confidence is medium for both time horizons."]"

http://www.glaciology.net/Home/Miscellaneous-Debris/whatdoeslikelymean (http://www.glaciology.net/Home/Miscellaneous-Debris/whatdoeslikelymean)


Also, at the following link, Aslak Grinsted provides the accompanying figure with the following Legend


http://www.glaciology.net/Home/Miscellaneous-Debris/comparisonofsealevelprojections (http://www.glaciology.net/Home/Miscellaneous-Debris/comparisonofsealevelprojections)


Legend:
"•  Extrap: constant rate of sea level rise at present day trend from sealevel.colorado.edu. (An absolute lower limit of plausibility IMO)
• FAR: full range of SLR projections from FAR (taken from SAR table 7.8)
•  SAR: full range of SLR projections from SAR (taken from TAR table 11.14). (SARp369: "Excluding the possibility of collapse of the West Antarctic ice sheet").
•  TAR: full range of SLR projections from TAR table 11.14. (TAR p.642: "The range of projections given above makes no allowance for icedynamic instability of the WAIS".)
•  AR4: SLR projection excluding scaled-up ice sheet discharge. (AR4 WG1 Table 10.7).
•   AR4+: SLR projection including scaled-up ice sheet discharge. (AR4 WG1 Table 10.7). Context for "larger values cannot be excluded" can be found in the AR4 SPM.
•  SEM: full range of semi-empirical projections in AR5 (from AR5 fig.13.12).
•  AR5: "process based" ice sheet projections from AR5 table 13.5. These do not account for a potential collapse of Antarctic marine based sectors which may contribute up to several decimetres (indicated with thin shaded line).
•  Ice sheet experts*. refers to Bamber and Aspinall (2013) table S1 5-95% plus non ice sheet contributions from AR5 table 13.5. Note BA13 does not refer to a specific scenario (hence the asterisk)
•  SLR experts refers to the expert elicitation of Horton et al. 2013 (table 1). They do not provide RCP45 but only RCP85 and RCP3PD. However both SEMs and AR5 agree that the projection for RCP45 lies at about a third of the way between. So I have used this weighing. "



Furthermore, in the link at the end of this post, Aslak Grinsted goes on to say:

"…. To appreciate why 0.98 m is not an upper limit of SLR then you have to read on and understand the caveats stated in the AR5. The SPM also says:

"
The basis for higher projections of global mean sea level rise in the 21st century has been
considered and it has been concluded that there is currently insufficient evidence to evaluate
the probability of specific levels above the assessed likely range.
"

To parse this you need to understand the IPCC jargon. "Likely" means the 66% confidence interval. I.e. slightly less than a one sigma interval. So, the full uncertainties are at least twice as large but they are unwilling to say by how much exactly. They also say that there is an additional uncertainty that is unlikely to be anything but positive:

"Based on current understanding, only the collapse of marine-based sectors of the Antarctic ice sheet, if initiated, could cause global mean sea level to rise substantially above the likely range during the 21st century. However, there is medium confidence that this additional contribution would not exceed several tenths of a meter of sea level rise during the 21st century. {13.4, 13.5}"

It is unclear what they mean by "several tenths of a meter". I find it remarkable that they could not agree on a more quantitative statement considering they are only stating something with "medium confidence". In any case this excluded potential contribution is clearly positive. This uncertainty strongly affects the upper tail of the uncertainty range. It is effectively a bias. Ice sheet experts appear to judge this collapse scenario quite probable, and post-AR5 modelling indicates that Pine Island Glacier in Antarctica is already engaged in an unstable retreat (Favier et al., 2014).

The literal meaning of the AR5 likely range is that there is 17% chance of exceeding 1m SLR assuming that there is no marine instability (under RCP8.5). If there is an instability then the probability is greater."

http://www.glaciology.net/Home/Miscellaneous-Debris/ar5sealevelriseuncertaintycommunicationfailure (http://www.glaciology.net/Home/Miscellaneous-Debris/ar5sealevelriseuncertaintycommunicationfailure)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 01, 2014, 01:47:58 PM
In February 2002, the then U.S. defense secretary Donald Rumsfeld said: "There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – there are things we do not know we don't know."

While I am on a roll about providing background information, I will make a few more comments about uncertainties with regard to abrupt climate change, ACC.

For example, when generating Recommended Concentration Pathway, RCP, 8.5 (the highest Confidence Level, CL, family of scenarios) the IPCC calibrated this family of scenarios to match the 90th percentile of model projection published by 2007, and thus does not consider any new findings.  In this regard it is important to remember that GCM CL only address the uncertainties within the input variables, and not within such other vital factors as: (1) completeness of input scenarios, (2) model sensitivity/accuracy, and (3) calibration of models to actual climate sensitivities.  To elaborate on these three particular factors:

1.   The recent economic development of alternate fossil fuels such as shale gas and tar sands means that sufficient economically recoverable carbon-based fuels exist to continue following RCP 8.5 - 95% CL scenario to a 6oC global-mean temperature rise, by 2100, unless modern society makes extensive efforts to get off the concentration pathway that it has been following for over 30-years.  Of particular concern is the fact that many countries around the world have made commitments to develop large quantities of shale gas (most notably the EU following the Ukraine Crisis); which unless carefully regulated can make more radiative contributions to AGW than burning coal.
2.   No Global Circulation Model/Earth System Model (GCM/ESM) has sufficient accuracy, or sensitivity to accurately project any aspect of Abrupt Climate Change, ACC.  Therefore, if decision makers are expecting to receive early warning of ACC from the billions of dollars-worth of GCM/ESM projections, then they are likely to be as surprised.  It is noted that assessments of GCM/ESM projection indicate that the chain of positive feedback associated with the change in albedo associated with the loss of summer snow extent and polar sea ice area can temporarily change climate sensitivity from an effective current value of approximately 3oC to over 6 oC (when considering ESS, see the first attached image, from Hansen and Sato).
3.   Independent assessments (Hammitt and Shlyakhter, 1999) of the external uncertainty associated with projection methodologies such as those used by the IPCC indicate that in many applications, 20 % to 45% of actual results fall outside the previously assumed 98% confidence levels.  Thus policy makers should not be surprised if ACC probabilities of occurrence are actually 10 to 22.5 times more likely to occur than as reported by the AR5 (or AR4).

Furthermore, since the RCP scenarios were developed, subsequent research regarding fast climate response functions (see Rogelj et al. 2012, Henriksson et al. 2010, Annan and Hargreaves 2009, and Baker and Roe 2009) indicate that the expected mean temperature increase for RCP 8.5 now exceeds that projected for SRES A1FI (see the second attached image from Rogelj et al 2012).


"The dogmas of the quiet past are inadequate to the stormy present. The occasion is piled high with difficulty, and we must rise with the occasion. As our case is new, so we must think anew and act anew." President Abraham Lincoln

Selected References:

J.K. Hammitt and A.I. Shlyakhter, “The Expected Value of Information and the Probability of Surprise,” Risk Analysis 19(1): 135-152, 1999.

Hansen, J.E., and Sato, M., 2012, "Climate Sensitivity Estimated From Earth's Climate History", NASA Goddard Institute for Space Studies and Columbia University Earth Institute, New York.

Rogelj, J., Meinshausen, M. and Knutti, R., (2012), "Global warming under old and new scenarios using IPCC climate sensitivity range estimates", Nature Climate Change - Letters, doi: 10.1038/NCLIMATE1385.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on June 01, 2014, 03:34:53 PM
ASLR.....

I can only speak for myself but I find some background on a post that explores a specific issue is invaluable. It does not need to be extensive (a small part of the post is fine) and including links that explain the background further is fantastic.

I am trying to catch up with people here. Background helps.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on June 01, 2014, 03:41:06 PM
With regards to your explanation of sea level rise projections, it would not surprise me if the curve of these projections had a pronounced kurtosis. In fact, I would be shocked if this were not the case. The low end would be defined by the most recent slr contributions. No model would predict any possibility of a decline. Meanwhile, many models would likely have some possibility of substantial increases in the rate of slr.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 01, 2014, 06:38:35 PM
For those not so familiar with probability theory, I offer the following two definitions related to the shape of a Probability Density Function, PDF:

"Skewness is a measure of symmetry, or more precisely, the lack of symmetry. A distribution, or data set, is symmetric if it looks the same to the left and right of the center point.

Kurtosis is a measure of whether the data are peaked or flat relative to a normal distribution. That is, data sets with high kurtosis tend to have a distinct peak near the mean, decline rather rapidly, and have heavy tails. Data sets with low kurtosis tend to have a flat top near the mean rather than a sharp peak. A uniform distribution would be the extreme case."

So if one were to use the Horton expert survey (see Replies #52 and #60) for the 83rd percentile for the RCP 8.5 scenario as an approximation of a SLR PDF, then you have both a relatively high degree of kurtosis and of skewness.  However, as the expert's models improve, and they are willing to acknowledge more future SLR, one can expect the peak of the PDF to shift to the right (see for example the following link that indicates that 97% of climate change researchers believe that the AR5 SLR projections are too low; which implies to me that AR6 will have higher projections than AR5, just a AR5 had about 50% higher SLR projections than AR4; because the IPCC process is slow to acknowledge the most recent research):


http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/feb/18/scientists-worried-ipcc-underestimate-sea-level-rise (http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/feb/18/scientists-worried-ipcc-underestimate-sea-level-rise)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 01, 2014, 06:57:20 PM
I would also like to point out that all measurements of Black Carbon, BC, in the environment are currently considerably higher than that assumed in RCP 8.5 (see the "Forcing" thread in the Antarctic folder), and I am concerned that the following reference by Marin-Spiotta et al 2014 indicates that during marked climate change in the early Holocene, wildfires were very widespread (& they are becoming increasingly common now with AGW); which may indicate that more future wildfires will lead to more BC, and more albedo loss (particularly in the Arctic & tundra); which in-turn should drive the ESS value higher:

Marín-Spiotta, E., N.T. Chaopricha, A.F. Plante, A.F. Diefendorf, C.W. Müller, S. Grandy, and J.A. Mason. Long-term stabilization of deep soil carbon by fire and burial during early Holocene climate change. Nature Geoscience

http://www.nature.com/ngeo/journal/vaop/ncurrent/pdf/ngeo2169.pdf (http://www.nature.com/ngeo/journal/vaop/ncurrent/pdf/ngeo2169.pdf)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 01, 2014, 09:35:52 PM
While I am reviewing factors that could accelerate SLR, I would like to remind readers that no AR5 GCM projection included methane contribution from the expected degradation of the permafrost, see the first attached image of the projected permafrost carbon flux (atmospheric emission in billions of short tons per year) from the permafrost with time [from: NOAA and the National Snow and Ice Data Center (NSIDC), 2011.  This image indicates that there will be strong carbon flux (about 2.5% of which is expected to be methane) from permafrost decomposition before the end of the century. 
The second attached image shows the ratio of GHG equivalent of gas to coal vs methane emissions as a share of gas production and the assumed methane global warming potential, from IEA 2012.  Howarth et. al. 2012 indicates that new sources of shale gas, tight gas, and coal-bed methane normally have emissions of about 6%, with a 100-year GWP of 34 and a 20-year GWP of 105; which indicates that new sources of unconventional gases could induce radiative forcing from as much as that induced by new coal sources to as much as over 1.5 times that induced by new coal sources (see the second attached image), over a 20-year period.

This information indicates that methane's contribution to global warming will be accelerating until the end of the century and that current AR5 projections do not address this contribution.  Furthermore, methane hydrates are extensively discussed in other portions of this Forum (see the "Forcing" thread in the Antarctic folder); which represents a very real risk that increases rapidly after 2100.

Selected References:
Howarth RW, Santoro R, and Ingraffea A (2012b). "Venting and leakage of methane from shale gas development: Reply to Cathles et al. Climatic Change", doi:10.1007/s10584-012-0401-0
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on June 02, 2014, 01:18:24 AM
I think that you are touching on some serious deficiencies with the IPCC AR5.  I have pointed out these on several occasions here and elsewhere.

Not only do they use a nominal ECS of 3.0 Their entire basis for the ECS value is that Arctic sea ice will trend its' loss with CO2-equivalent atmospheric abundances.  In other words, a gradual decline in the models until it is gone in late September sometime in the year 2065.  Skeptical science did a good job showing that this was an obscene oversight by the IPCC.

In this simple statement:  The arctic sea ice will be summer ice-free several decades before the current IPCC models. Then we know that the non-linear temperature change in the arctic that will occur after this happens will necessarily push the ECS value above 4.0 and likely to 4.5.

It is this kind of reasoning that shows why Hansen has a curve that projects a 5 meter sea level rise by 2100. 

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fclimatewatch.typepad.com%2F.a%2F6a0176172a106b970c017d3fcf0dba970c-pi&hash=2cd4ca1384d42d732041da9b7abb036f)

In this graph he shows that the exponential result of positive feedbacks (both in deep ocean temperature increases and in WAIS melt dynamics, as well as regional Greenland ablation results from summer arctic sea ice being gone by June 21 2035, will create these exponential increases.

The basis for his understanding of these things is the simple fact that the rate of energy deposition into the earth (mostly into the ocean) is increasing at an exponential rate (Top of Atmospheric Energy imbalance) because the earth's temperature is not able to keep up with the increased forcing from greenhouse gasses.

To this end, the Rignot failure to include multiple ocean heat content dynamics (i.e. a doubling of volume and a tripling of injection temperature into the WAIS regression line melt from the Circumpolar Deep Water pool by 2060) necessarily underestimates projected sea level rise by up to one order of magnitude (total WAIS contribution by 2100 of 40 cm vs potential 400 cm.)

Surely we must realize that the current rate of Antarctic melt is responding to emissions levels that were generated two decades ago.  Therefore, in the following scenario, the Hansen & Soto melt rate makes much more sense:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Foi57.tinypic.com%2Fb4gwn8.jpg&hash=ef33f799448ab44dd4a6555f0c29d964)

http://oi57.tinypic.com/b4gwn8.jpg (http://oi57.tinypic.com/b4gwn8.jpg)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 02, 2014, 12:25:04 PM
jai,

As the January 2013 Fairfax SLR projection of over 11m circa 2075 seems to me to be erring on the side of most drama, I provide the attached figure from Hansen & Sato 2012 (see Figure 7 from the linked reference with a free access pdf), indicating 5m by 2100.

http://www.columbia.edu/~jeh1/mailings/2012/20121226_GreenlandIceSheetUpdate.pdf (http://www.columbia.edu/~jeh1/mailings/2012/20121226_GreenlandIceSheetUpdate.pdf)

Obviously, both numbers are relatively high; and the multi-meter difference illustrates how sensitive non-linear functions are, and emphasizes the need to calibrate, and to re-calibrate, them using the best information available.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 02, 2014, 02:55:17 PM
Clearly the attached GIS ice mass loss per the GRACE satellite through 2013, indicates that this trend is non-linear; however, once the marine-terminating glacier's ice mass loss slows-down, will the shape of the trend line change to something more dominated by surface ice mass loss?

http://www.arctic.noaa.gov/reportcard/greenland_ice_sheet.html (http://www.arctic.noaa.gov/reportcard/greenland_ice_sheet.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 02, 2014, 03:20:30 PM
Talking about trends in SLR contributions, per AR5 the SLR contribution from glaciers is currently slowing-down (see the first attached image, with the caption for Figure 1 below, from AR5), while the SLR contribution from both the GIS and the AIS is accelerating (see the second attached image, Figure 2, also from AR5), resulting in the linear sea level rise trend line over this period:

Caption for Figure 1: Recent trends in glacier mass loss during (a) 1850-2010 and (b) 1961-2010. Coloured lines indicate different models, shaded areas show uncertainty. Blue bars display number of measured mass balance glaciers (IPCC, 2013).

Caption for Figure 2: Contribution of global glaciers (red), Greendland (green) and Antarctica (blue) to sea level rise between 1992-2012. Positive correlation between cumulative ice mass loss and sea level equivalent, shaded areas indicate uncertainty.

see also:

https://www.ccin.ca/home/ccw/glaciers/current (https://www.ccin.ca/home/ccw/glaciers/current)

Also consider that an Atmospheric River event contributed to ice mass gain in the EAIS circa 2011, which temporarily served to mask the rate of acceleration of ice mass loss from the WAIS, as it is generally lumped together with the EAIS and reported as the AIS by the IPCC.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 02, 2014, 03:27:34 PM
For those not familiar with the Jakobshavn Effect, you can see it in dramatic action (in near real time) at the following link to the Greenland folder:

http://forum.arctic-sea-ice.net/index.php/topic,154.200.html#lastPost (http://forum.arctic-sea-ice.net/index.php/topic,154.200.html#lastPost)

Note that in a few decades time the Thwaites Glacier is likely to be subject to the same type of behavior as the Jakoshavn Glacier is exhibiting today.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on June 02, 2014, 04:50:26 PM
Aaacckkkkk! Not kurtosis, skewness.  :o
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on June 02, 2014, 05:09:29 PM
ASLR

Thanks for posting the real Hanson Graphic, that is the one I was looking for.  Didn't realize that the one I was posting was an adaption to it, now that you posted it I can see that their curve significantly steeper!
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on June 08, 2014, 09:37:14 PM
What a single American city is facing.....a $1 billion price tag to protect themselves from  1 foot sea level rise.

http://www.washingtonpost.com/business/economy/in-norfolk-evidence-of-climate-change-is-in-the-streets-at-high-tide/2014/05/31/fe3ae860-e71f-11e3-8f90-73e071f3d637_story.html (http://www.washingtonpost.com/business/economy/in-norfolk-evidence-of-climate-change-is-in-the-streets-at-high-tide/2014/05/31/fe3ae860-e71f-11e3-8f90-73e071f3d637_story.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 09, 2014, 05:35:57 AM
Given the very high amount of calving currently going on at Greenland's Jakobshavn glacier (see the following link)

http://forum.arctic-sea-ice.net/index.php/topic,154.200.html (http://forum.arctic-sea-ice.net/index.php/topic,154.200.html)

I believe that it appropriate to attached the following figure from Rahmstorf, Perrett and Vermeer (2011), in which the authors indicate with the red wedged lines the portion of ice sheet mass loss contribution to SLR that they feel are addressed by their semi-empirical model (see the following reference).  I note that most of the SLR contribution within the red wedged line area come from Greenland marine glaciers such as Jakobshavn glacier.

Rahmstorf, S., Perrett, M., and Vermeer, M. (2011), "Testing the robustness of semi-empirical sea level projections", Clim Dyn, Springer-Verlag, doi: 10.1007/s00382-011- 1226-7.

Thus I expect to see accelerating contributions to SLR from the GIS for at least the next 10 to 25 years; which I believe will serve to help destabilize several WAIS marine glaciers, resulting in the WAIS making the worlds largest SLR contributions after about 2035 to 2040.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 09, 2014, 11:41:30 AM
Regarding my last post about ice mass loss from Greenland's Jakobshavn glacier, I provide the following linked reference with a free access pdf (by Hughes et al 2014) comparing the Jakobshavn Effect for both the Jakobshavn (GIS) and Byrd (EAIS) glaciers.  This paper provides the two attached images related to the Jakobshaven glacier; which indicate that if the calving face retreats another 7 to 10km then it will have retreated past a bottom pinning point, and would thereafter be free to retreat many kilometers:

Hughes, T., Sargent, A., Fastook, J., Purdon, K., Li, J., Yan, J.-B., and Gogineni, S.: Quantifying the Jakobshavn Effect: Jakobshavn Isbrae, Greenland, compared to Byrd Glacier, Antarctica, The Cryosphere Discuss., 8, 2043-2118, doi:10.5194/tcd-8-2043-2014, 2014.

http://www.the-cryosphere-discuss.net/8/2043/2014/tcd-8-2043-2014.pdf (http://www.the-cryosphere-discuss.net/8/2043/2014/tcd-8-2043-2014.pdf)

"Abstract. The Jakobshavn Effect is a series of positive feedback mechanisms that was first observed on Jakobshavn Isbrae, which drains the west-central part of the Greenland Ice Sheet and enters Jakobshavn Isfjord at 69°10'. These mechanisms fall into two categories, reductions of ice-bed coupling beneath an ice stream due to surface meltwater reaching the bed, and reductions in ice-shelf buttressing beyond an ice stream due to disintegration of a laterally confined and locally pinned ice shelf. These uncoupling and unbuttressing mechanisms have recently taken place for Byrd Glacier in Antarctica and Jakobshavn Isbrae in Greenland, respectively. For Byrd Glacier, no surface meltwater reaches the bed. That water is supplied by drainage of two large subglacial lakes where East Antarctic ice converges strongly on Byrd Glacier. Results from modeling both mechanisms are presented here. We find that the Jakobshavn Effect is not active for Byrd Glacier, but is active for Jakobshavn Isbrae, at least for now. Our treatment is holistic in the sense it provides continuity from sheet flow to stream flow to shelf flow. It relies primarily on a force balance, so our results cannot be used to predict long-term behavior of these ice streams. The treatment uses geometrical representations of gravitational and resisting forces that provide a visual understanding of these forces, without involving partial differential equations and continuum mechanics. The Jakobshavn Effect was proposed to facilitate terminations of glaciation cycles during the Quaternary Ice Age by collapsing marine parts of ice sheets. This is unlikely for the Antarctic and Greenland ice sheets, based on our results for Byrd Glacier and Jakobshavn Isbrae, without drastic climate warming in high polar latitudes. Warming would affect other Antarctic ice streams already weakly buttressed or unbuttressed by an ice shelf. Ross Ice Shelf would still protect Byrd Glacier."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 09, 2014, 11:54:20 AM
In regards to my last post about the Jakobshavn glacier possibly retreating past its pinning point (note that some researchers have shown numerically that surface meltwater entering crevasses near the calving face of Jakobshavn would be sufficient to get the calving point to retreat upstream of the pinning point), I provide the following link to a NASA YouTube video focused on Rignot et al's 2014 work on six Amundsen Sea Embayment marine glaciers; which notes that most of the grounding lines for these glaciers have already retreated past their pinning points (see the first attached image).  The second attached image shows how interferometry is used from ESA satellite surface elevation data tidal fluctuations to determine where the grounding line has retreated to for the Pine Island Glacier:

https://www.youtube.com/watch?v=W2pYHMx5bN8 (https://www.youtube.com/watch?v=W2pYHMx5bN8)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 16, 2014, 04:56:22 PM
It should not come as a surprise to regular readers that previous estimates of the social cost/consequences of carbon have been vastly underestimated as indicated by new research cited in the following linked article:

http://www.independent.co.uk/environment/climate-change/climate-change-will-cost-world-far-more-than-estimated-9539147.html (http://www.independent.co.uk/environment/climate-change/climate-change-will-cost-world-far-more-than-estimated-9539147.html)

Also see:

http://thinkprogress.org/climate/2014/06/16/3449645/stern-updated-climate-model-economic/ (http://thinkprogress.org/climate/2014/06/16/3449645/stern-updated-climate-model-economic/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on June 16, 2014, 09:29:43 PM
what we didn't realize is that Ackerman was underestimating. . .

http://www.nytimes.com/cwire/2011/07/14/14climatewire-administration-grossly-underestimated-carbon-69396.html (http://www.nytimes.com/cwire/2011/07/14/14climatewire-administration-grossly-underestimated-carbon-69396.html)

Administration Grossly Underestimated Carbon Cost, Says Study

By TIFFANY STECKER of ClimateWire
 
Published: July 14, 2011

linked document: 

it turns out we were at $245 per ton of CO2 back in 1995 (http://www.economics-ejournal.org/economics/journalarticles/2012-10[/url)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on June 17, 2014, 12:11:20 PM
The abstract of the Dietz & Stern paper says [my emphasis]:
http://www.lse.ac.uk/GranthamInstitute/wp-content/uploads/2014/06/Working-Paper-180-Dietz-and-Stern-2014.pdf (http://www.lse.ac.uk/GranthamInstitute/wp-content/uploads/2014/06/Working-Paper-180-Dietz-and-Stern-2014.pdf)

'To slow or not to slow' (Nordhaus, 1991) was the first economic appraisal of greenhouse gas emissions abatement and founded a large literature on a topic of great, worldwide importance. In this paper we offer our assessment of the original article and trace its legacy, in particular Nordhaus' later series of 'DICE' models. From this work many have drawn the conclusion that an efficient global emissions abatement policy comprises modest and modestly increasing controls. On the contrary, we use DICE itself to provide an initial illustration that, if the analysis is extended to take more strongly into account three essential elements of the climate problem - the endogeneity of growth, the convexity of damages, and climate risk - optimal policy comprises strong controls. To focus on these features and facilitate comparison with Nordhaus' work, all of the analysis is conducted with a high pure-time discount rate, notwithstanding its problematic ethical foundations.

On p.6 they say about social discounting:
"the rate of pure-time preference is 1.5% and the elasticity of marginal social utility of consumption is 1.5, so that with growth of consumption per capita of, say, 2%, the social discount rate would be 4.5%. We have written elsewhere about why we think it is inappropriate to posit such a high rate of pure-time preference (e.g. Stern, 2013, forthcominga,f) - and we return to explain why in Section 5 - but for the purpose of clarity of comparison we set aside our misgivings, concerning this and other features, in the modelling that comprises the core of this paper."

In Section 5 they give their conclusions and say about discounting (p.23):
"This has not been a paper about the sensitivity of results to pure-time discounting, or other parameters and structures relevant to discounting. As we found in the technical annex to Stern (2007) and in Dietz et al. (2007c; 2007a), lower pure-time discounting does indeed favour stronger and earlier action to curb emissions. Those results were from the 'PAGE' IAM (Hope, 2006), but we know from other work that this is also true of DICE (Nordhaus, 2007). We have argued elsewhere that careful scrutiny of the ethical issues around pure-time discounting points to lower values than are commonly assumed (usually with little serious discussion). Pure-time discounting is essentially discrimination by date of birth in the sense that a life, which is identical in all respects (including time patterns of consumption) but happens to start later, has a lower value. If, for example, the pure-time discount rate were 2%, a life starting 35 years later, but otherwise the same, would have half the value of a life starting now. The time horizon essential to a discussion of climate change makes careful examination of these ethical issues unavoidable. Preliminary calculations indicate that low pure-time discounting will significantly increase the optimal controls in this paper as well."

So it seems Dietz & Stern still estimate the social cost of carbon conservatively.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on June 18, 2014, 06:11:01 PM
Climate Policies Deserve a Negative Discount Rate

http://www.law.uchicago.edu/files/files/Fleurbaey%20paper_0.pdf (http://www.law.uchicago.edu/files/files/Fleurbaey%20paper_0.pdf)

Marc Fleurbaey & Stéphane Zuber

Quote
Therefore, if climate policies such as mitigation efforts are paid by the affluent populations of the present generations and greatly benefit the worst off of the distant future generations in the most catastrophic scenarios, it is very likely that the correct discount rates for the evaluation of such policies should be negative, which means that a dollar of benefit in the distant future is worth more than a dollar of effort today.

Cass Sunstein remarked that the fundamental premise of intergenerational discounting (positive) assumes that future generations will be better off than those of today.  It is clear that the current crisis in Syria is directly attributed to a crushing 3 year drought in early 2010 which has now spilled over to Iraq.  The climate-induced heatwaves of India have already led to riots and the El Nino induced late monsoons have exacerbated economic loss and social unrest in the region.  Couple this with the recent increases in oil costs due to the political unrest in Iraq and the "threat multiplier" of climate change on a geopolitical realm is clear.

the potential for widescale economic disruption in India due to climate-induced stresses is multiplied by the political unrest generated in the middle east that was largely attributed to climate-induced stresses several years ago.  This is producing a compounding effect.

we have currently locked in 0.8C of additional globally averaged warming at our current GHG abundances. (that is Hansens' estimate - I believe that even his estimate is conservative).

It is clear that without some kind of mitigation/adaption strategy on a global scale, we will lose our modernity.  In this scenario then, a negative discount rate is more than appropriate (dismal).
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on June 26, 2014, 05:38:00 PM
Bangladesh's sea walls may make floods worse
http://www.newscientist.com/article/mg22229752.700-bangladeshs-sea-walls-may-make-floods-worse.html?cmpid=RSS (http://www.newscientist.com/article/mg22229752.700-bangladeshs-sea-walls-may-make-floods-worse.html?cmpid=RSS)|NSNS|2012-GLOBAL|environment#.U6w8-lFJzlc
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on June 26, 2014, 10:27:24 PM
Half of Bangladesh is history, and the residents know it. One of my nightmares is that the next Osama is a child in Dacca today.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 04, 2014, 12:24:13 AM
The following link and the associated attached image indicates the projected increase in extreme weather events (the attached figure shows the increase in crop loss) in the USA for the different RCP scenarios; which illustrates the high social cost of carbon, particularly for RCP 8.5 (however the attached image neglects SLR):

http://riskybusiness.org/report/overview/executive-summary (http://riskybusiness.org/report/overview/executive-summary)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Bruce Steele on August 23, 2014, 02:17:13 AM
http://sealevelrise.assembly.ca.gov/reports (http://sealevelrise.assembly.ca.gov/reports)

Here is a link to a California Assembly report on sea level rise. Ninety pages. I testified on the industry panel and so some of my testimony is included. Although sea level rise and thermal expansion of sea water are intimately linked I make the point that water temperature increases will negatively impact certain fisheries. It should be noted that the infrastructure impacts that get the largest attention in this report are also major contributors to the problem( global warming ). I won't be holding my breath until a report on the biological consequences is convened. Gretchen Hoffman did address  ocean acidification so the committee was somewhat inclusive of biological impacts but I would hope people can increase their focus on habitat loss and shoreline losses as estuary and shorelines move inland and meet highways, railways, and seawalls. Planning on leaving some room for natural shorelines to expand inland will help mitigate some losses but triage for what wildlife remains isn't at this point in planning stages. Many more downsides for wildlife I am undoubtably missing.
     
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on September 02, 2014, 12:11:59 AM
New satellite maps show polar ice caps melting at 'unprecedented rate'
http://www.theguardian.com/environment/2014/sep/01/new-satellite-maps-show-polar-ice-caps-melting-at-unprecedented-rate (http://www.theguardian.com/environment/2014/sep/01/new-satellite-maps-show-polar-ice-caps-melting-at-unprecedented-rate)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on September 04, 2014, 05:49:42 PM
The crisis of rising sea level.
http://www.reuters.com/investigates/special-report/waters-edge-the-crisis-of-rising-sea-levels/ (http://www.reuters.com/investigates/special-report/waters-edge-the-crisis-of-rising-sea-levels/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Rick Aster on September 06, 2014, 12:35:29 AM
The crisis of rising sea level.
http://www.reuters.com/investigates/special-report/waters-edge-the-crisis-of-rising-sea-levels/ (http://www.reuters.com/investigates/special-report/waters-edge-the-crisis-of-rising-sea-levels/)
The Reuters special investigation focuses on coastal damage already occurring in the United States because of rising sea levels. Slightly higher sea levels means there are roughly twice as many coastal flood events:
Quote
The analysis was then narrowed to include only the 25 gauges with data spanning at least five decades. It showed that during that period, the average number of days a year that tidal waters reached or exceeded flood thresholds increased at all but two sites and tripled at more than half of the locations.
The combined costs of flood damage and flood control initiatives are huge.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on September 06, 2014, 01:38:25 PM
The increase with SLR should follow the increase in melt in Greenland and Antartica, a doubling every 5 year...
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Clare on September 07, 2014, 08:40:50 AM
This article includes photos of the potential impacts of sea level of 1-2m including storm surges, rise in Auckland, I'm sure some of you will be familiar with this city.

""This new research shows sea level rises could be much higher than a metre by the end of this century," Antarctic Research Centre director and New Zealand's IPCC author Tim Naish said.

"My personal view is that the IPCC has always underestimated sea level rise. When we go back and measure what actually happened with time images and satellites, we find the observations are always above the upper bounds of their predictions," he said.

Naish's views are backed by others including US Antarctic ice sheet modelling expert Professor Rob DeConto. He said warming water around the ice shelves has the potential to destabilise land based ice sheets and contribute to rises of about 4m by 2100."

http://www.stuff.co.nz/environment/10459124/Climate-worries-focus-on-melting-ice (http://www.stuff.co.nz/environment/10459124/Climate-worries-focus-on-melting-ice)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: ritter on September 12, 2014, 10:17:58 PM
It's happening....

Quote
Celebrities and billionaires powerless as their multimillion-dollar Malibu homes are mercilessly battered by huge waves
http://www.dailymail.co.uk/news/article-2753877/Celebrities-billionaires-powerless-multimillion-dollar-Malibu-homes-mercilessly-battered-huge-waves-dragging-fences-glass-panels-furniture-sea.html (http://www.dailymail.co.uk/news/article-2753877/Celebrities-billionaires-powerless-multimillion-dollar-Malibu-homes-mercilessly-battered-huge-waves-dragging-fences-glass-panels-furniture-sea.html)

(granted, not the best source.)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on September 13, 2014, 06:09:27 PM
The linked reference reminds us that in addition to anthropogenic SLR projections, we need to add both: (a) local/regional SLR variability; and (b) long-term natural regional SLR contributions:

Dangendorf, S., D. Rybski, C. Mudersbach, A. Müller, E. Kaufmann, E. Zorita, and J. Jensen, (2014), "Evidence for long-term memory in sea level", Geophys. Res. Lett., 41, 5564–5571, doi:10.1002/2014GL060538.

http://onlinelibrary.wiley.com/doi/10.1002/2014GL060538/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2014GL060538/abstract)

Abstract: "Detection and attribution of anthropogenic climate change signals in sea level rise (SLR) has experienced considerable attention during the last decades. Here we provide evidence that superimposed on any possible anthropogenic trend there is a significant amount of natural decadal and multidecadal variability. Using a set of 60 centennial tide gauge records and an ocean reanalysis, we find that sea levels exhibit long-term correlations on time scales up to several decades that are independent of any systematic rise. A large fraction of this long-term variability is related to the steric component of sea level, but we also find long-term correlations in current estimates of mass loss from glaciers and ice caps. These findings suggest that (i) recent attempts to detect a significant acceleration in regional SLR might underestimate the impact of natural variability and (ii) any future regional SLR threshold might be exceeded earlier/later than from anthropogenic change alone."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on September 13, 2014, 08:51:45 PM
The Yale Climate Forum came out with a new video on Greenland

https://www.youtube.com/watch?v=_PEi0Retg8A (https://www.youtube.com/watch?v=_PEi0Retg8A)

Quote from Prof. Jason Box
Geological Survey of Denmark and Greenland

Quote
Greenland's sea level contribution 10 years ago was 1/2 a millimeter per year.  Ten years later it is 1 mm per year.  It is expected that this loss rate will continue to double with a period of somewhere between 5-12 years.  So, the next decade Greenland is losing 2mm/year, the next decade it is 4 mm/year and the next is 8 mm/year.  You take that to the end of the century and the Greenland ice sheet has yielded about 1 meter of sea level rise.

The previous meltwater pulse 2B video, also from the Yale Climate Forum
upthread but repost here:  https://www.youtube.com/watch?v=71l9lzLsBRc (https://www.youtube.com/watch?v=71l9lzLsBRc)

indicates that the Contribution to Sea Level from WAIS is already grossly underestimated in the IPCC AR5

Combine these factors with the thermal expansion potential of 20cm to 50cm by 2100 and the gravitational effects of mid-latitude rise caused by the melt of Antarctica and we are

Easily looking at 1.8 to 3.4 Meters of sea level rise (or more) by 2100.  The More being a worst case scenario RPC 8.5 with multiple natural feedback mechanisms leading to 7C warming by 2100 and 21C warming in the arctic by then.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on September 15, 2014, 04:11:28 AM
Easily looking at 1.8 to 3.4 Meters of sea level rise (or more) by 2100.  The More being a worst case scenario RPC 8.5 with multiple natural feedback mechanisms leading to 7C warming by 2100 and 21C warming in the arctic by then.

jai,

Are you saying that for a RCP 8.5 anthropogenic GHG scenario with multiple positive feedback mechanisms, that SLR could be more than 3.4 m by 2100?  If so, how high do you think that it could go?

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on September 15, 2014, 08:26:47 AM
You know SLR.  If the Fat Tail is correct and our ECS is closer to 6C for 2X CO2 and we produce a massive permafrost destabilization and the overturning circulation halts causing a step-change decrease in natural CO2 sequestration and the peat burns in the arctic and the tropical forests burn in the amazon and Indonesia.  Well, we will be looking at even more than the potential 7.5C high range estimate of globally averaged temperatures by 2100.  In this case, one where the scientists expect things are going, but rely on "magical thinking" to give them a reasonable argument to leave out the estimations from their current models (atmospheric fraction is not modeled to increase, but it will.  methane and co2 contributions from permafrost are not modeled in the RCP 8.5 analysis but we know that about 55% of the CO2 will be releases into the atmosphere.  The carbon and methane emission of burning peat and forests around the world is not included in the analysis. . .)

In this scenario then, with massive potential positive feedbacks, the arctic temperatures could see a 17C-22C average warming by 2100. (estimate global average warming to be 10C on its way to +24C by 2300)

This rapid warming would lead to a total collapse of the Greenland ice sheet in the course of a few decades due to hydro fracture,  The WAIS is completely gone and a significant portion of the east shelf is also gone.

so,

Quote
Are you saying that for a RCP 8.5 anthropogenic GHG scenario with multiple positive feedback mechanisms, that SLR could be more than 3.4 m by 2100?  If so, how high do you think that it could go?

you tell me.

Note: I updated the potential warming from 7C globally averaged to 10C due to the ECS adjustment from 4.5C to 6C per 2X CO2.  The previous 7C was only considering 4.5C with feedbacks.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: crandles on September 15, 2014, 04:49:23 PM
http://julesandjames.blogspot.co.uk/search/label/climate%20sensitivity (http://julesandjames.blogspot.co.uk/search/label/climate%20sensitivity)

Quote
the additional decade of temperature data from 2000 onwards (even the AR4 estimates typically ignored the post-2000 years) can only work to reduce estimates of sensitivity, and that's before we even consider the reduction in estimates of negative aerosol forcing, and additional forcing from black carbon (the latter being very new, is not included in any calculations AIUI). It's increasingly difficult to reconcile a high climate sensitivity (say over 4C)

I think the data is doing quite well at thinning that fat tail which can arise if you only look at limited data in certain ways.

You are looking at the high end so no real complaint with 4.5C for doubled CO2 ignoring long term feedbacks. Earth system sensitivity of 6C seems quite possible but to assume that kicks in by 2100 seems remarkably rapid even if you think it reasonable to start invoking things like " massive permafrost destabilization and the overturning circulation halts".

Seems like quite a few big 'ifs'.

"total collapse of the Greenland ice sheet in the course of a few decades"
Hmm. If 5 year doublings continue through 2100 then the rate of SLR from ice sheet outflow rates would be pretty substantial. I struggle to comprehend how you could get that many doublings or where adequate heat to allow that would come from. But if you are invoking several low probability events each causing positive feedbacks .....

Maybe somebody should consider this, but I think it would be appropriate if it had clear warnings that it assumes several events considered unlikely.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on September 15, 2014, 06:20:26 PM
so,

Quote
Are you saying that for a RCP 8.5 anthropogenic GHG scenario with multiple positive feedback mechanisms, that SLR could be more than 3.4 m by 2100?  If so, how high do you think that it could go?

you tell me.

Note: I updated the potential warming from 7C globally averaged to 10C due to the ECS adjustment from 4.5C to 6C per 2X CO2.  The previous 7C was only considering 4.5C with feedbacks.

jai,

Since you ask my opinion on a likely RCP 8.5 SLR scenario, I provide the attached image of a probability density function, PDF, of for RSLR of the coast of California by 2070 and 2100.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Bruce Steele on September 15, 2014, 06:51:53 PM
 Poll
What is the maximum sea level rise you would expect by 2100?
< 1 meter
2 (4%)1.0 meters
2 (4%)1.5 meters
12 (24%)2.0 meters
9 (18%)2.5 meters
6 (12%)3.0 meters
2 (4%)> 3 meters
17 (34%)
Total Members Voted: 50
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Author Topic: Sea Level Rise by 2100 (POLL)  (Read 5918 times)
OldLeatherneck
Sr. Member

 
Posts: 361
   

Sea Level Rise by 2100 (POLL)
« on: April 28, 2013, 08:01:13 PM »
Quote
There are various estimates and models of how much sea levels will rise during the 21st century.  If and when policy makers and planners begin to take AGW/CC seriously they need to have some basis for determining what to be prepared for in terms of sea level rise.  If you were to advise them of what they need to be prepared for in terms of anticipated sea levels, how would you advise them, and why?
Report to moderator     Logged
"Share Your Knowledge.  It's a Way to Achieve Immortality."  ......the Dalai Lama

No need to start a new poll but for those who missed this I wanted to point it out. About a year and a half ago.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on September 16, 2014, 12:24:57 AM
The linked Aviso data indicates that in June 2014 mean sea level was at its highest level on record:

ftp://ftp.aviso.oceanobs.com/pub/oceano/AVISO/indicators/msl/MSL_Serie_MERGED_Global_IB_RWT_GIA_Adjust.txt

Date               Mean Sea level (cm)
2014.350338    6.645029e-02
2014.377486    6.631584e-02
2014.404633   6.686508e-02
2014.431781   6.806793e-02
2014.458928    6.941100e-02
2014.486076    7.049582e-02
2014.513223    7.123972e-02
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on September 16, 2014, 02:03:59 AM
Re: several low probability feedbacks.

We already are seeing the slowdown of the Meridional Overturning Circulation.  The positive feedback of a snow-free/Ice free northern hemisphere by may 30th, 2099 would produce enough regional warming in the northern hemisphere over the following 3 months to produce an albedo feedback event (not currently modeled) with equivalent forcing of an ADDITIONAL doubling of CO2.

The forests of the Amazon and the peat/forests of Indonesia are already burning, This will continue, There is more carbon ready to release in northern hemisphere permafrost than is in our current atmosphere abundance.  This release on its own, without additional anthropogenic emissions would effectively raise global CO2 to 800ppmv.   

I project that, if RCP 8.5 is continued that the decline of natural sinks and the arctic becoming a net source (future) vs. net sink (now) will produce an additional 20% persistence of annual anthropogenic emissions in the next 40 years and an additional 10% persistence in the next 60 years.  (in this scenario I do not see human civilization lasting beyond 60 years from today).

These feedbacks are already being observed.  You cannot pretend that the permafrost melt and the albedo feedback mechanisms are not happening already.  We cannot afford to pretend that the boreal forests are not already being lost to wildfire each summer and that massive peat fires are not already burning in Siberia and in the Yukon.   Indonesia started to burn in the summer of 1999. 

There has been no analogous period in the geologic record.  In every single one of those previous warming events there was a slower (by several orders of magnitude) event causing the warming within a primordial world with an ancient abundance of  terrestrial and oceanic carbon-based organisms, in the forms of northern hemispheric primordial forests stretching well into the arctic circle and all the bony fish that the ocean could hold; a combined total body mass of several hundred billions of tons of carbon sequestration capacity working constantly to mitigate the climate transition.  ALL LOST NOW. 

Human activity has already worked to destroy those mitigating factors throughout the worlds oceans and the northern hemisphere, produced a pulse forcing more rapid and intense than any time in the world's history.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on September 16, 2014, 05:11:25 AM
Anyone interested in adding to the list of positive feedback mechanisms that jai just cited, then take a look at the numerous factors documented in the following thread (but be sure to look at all seven pages of posts):

http://forum.arctic-sea-ice.net/index.php/topic,41.300.html (http://forum.arctic-sea-ice.net/index.php/topic,41.300.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: nowayout on September 16, 2014, 12:15:59 PM
Me thinks one honorable mention is missing, even if included in the Selected Forcing Factors thread: methane from the Arctic sea shelf. The warm currents both from the Atlantic and the Pacific side won't do any good, and even without a Big Burrp it will increasingly contribute to the methane levels.
The melting permafrost on land can refreeze in winter. The inundated permafrost is probably more vulnerable.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on September 18, 2014, 11:18:05 AM
Climate Report Details Flood Risk to Sites in Washington
http://www.nytimes.com/2014/09/17/us/climate-report-details-flood-risk-to-sites-in-washington.html?partner=rss&emc=rss (http://www.nytimes.com/2014/09/17/us/climate-report-details-flood-risk-to-sites-in-washington.html?partner=rss&emc=rss)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on September 18, 2014, 05:45:59 PM
City of Miami Beach, Florida:  New water pumps are being installed as part of a new storm water infrastructure.
"City officials say the annual king tides are expected to be almost three inches higher than last year. Extreme high tides in the fall and spring push seawater up through aging infrastructure, flooding some Miami Beach streets with more than a foot of water even on sunny days, snarling vehicle and pedestrian traffic."

Cost: $400 million to help protect the city for the next "25 to 30 years."

http://www.washingtonpost.com/national/energy-environment/miami-beach-prepares-for-extreme-high-tides/2014/09/17/5926dc16-3e96-11e4-a430-b82a3e67b762_story.html (http://www.washingtonpost.com/national/energy-environment/miami-beach-prepares-for-extreme-high-tides/2014/09/17/5926dc16-3e96-11e4-a430-b82a3e67b762_story.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: ritter on September 18, 2014, 08:16:04 PM
Cost: $400 million to help protect the city for the next "25 to 30 years."
This isn't climate adaptation. This is panic, knee-jerk, band-aidism. Just what do they expect will be necessary in 25 years?!  :o

We, as a species, desperately need to lengthen our planning horizon.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on September 20, 2014, 01:38:50 AM
In Post #139 I provided GMSL data from Aviso indicating that in June 2014 global mean sea level was the highest in the satellite era.  The attached plot issued by NASA for August 27 2014, confirms the Aviso data for June, but indicates that by August 27 2014 sea level had dropped back to the mean of the trend line:
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on September 24, 2014, 01:58:42 PM
New paper by Kopp et al. 2014 with some interesting SLR-projections for 2100-2200:
http://onlinelibrary.wiley.com/doi/10.1002/2014EF000239/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2014EF000239/abstract)

Probabilistic 21st and 22nd century sea-level projections at a global network of tide-gauge sites
Robert E. Kopp, Radley M. Horton, Christopher M. Little, Jerry X. Mitrovica, Michael Oppenheimer, D. J. Rasmussen, Benjamin H. Strauss and Claudia Tebaldi

Abstract
Sea-level rise due to both climate change and non-climatic factors threatens coastal settlements, infrastructure, and ecosystems. Projections of mean global sea-level (GSL) rise provide insufficient information to plan adaptive responses; local decisions require local projections that accommodate different risk tolerances and time frames and that can be linked to storm surge projections. Here we present a global set of local sea-level (LSL) projections to inform decisions on timescales ranging from the coming decades through the 22nd century. We provide complete probability distributions, informed by a combination of expert community assessment, expert elicitation, and process modeling. Between the years 2000 and 2100, we project a very likely (90% probability) GSL rise of 0.5–1.2 m under representative concentration pathway (RCP) 8.5, 0.4–0.9 m under RCP 4.5, and 0.3–0.8 m under RCP 2.6. Site-to-site differences in LSL projections are due to varying non-climatic background uplift or subsidence, oceanographic effects, and spatially variable responses of the geoid and the lithosphere to shrinking land ice. The Antarctic ice sheet (AIS) constitutes a growing share of variance in GSL and LSL projections. In the global average and at many locations, it is the dominant source of variance in late 21st century projections, though at some sites oceanographic processes contribute the largest share throughout the century. LSL rise dramatically reshapes flood risk, greatly increasing the expected number of “1-in-10” and “1-in-100” year events.

*************
See particularly their table 1 (attached):
It shows a 5% chance of more than 1.2m of SLR by 2100 and more than 3.7m by 2200 in RCP8.5 and a 0.5% chance of more than 1.8m by 2100 and more than 6.3m by 2200 in that scenario.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on September 26, 2014, 02:38:11 PM
New paper by Grant, Rohling et al 2014 on rates of SLR over the past five glacial cycles, which shows that rates of at least 1-2 meters/century seem very plausible over the coming centuries:
http://www.nature.com/ncomms/2014/140925/ncomms6076/abs/ncomms6076.html (http://www.nature.com/ncomms/2014/140925/ncomms6076/abs/ncomms6076.html)

Sea-level variability over five glacial cycles
K. M. Grant, E. J. Rohling, C. Bronk Ramsey, H. Cheng,   R. L. Edwards, F. Florindo, D. Heslop, F. Marra, A. P. Roberts, M. E. Tamisiea & F. Williams, 2014, Nature Communications

Abstract
Research on global ice-volume changes during Pleistocene glacial cycles is hindered by a lack of detailed sea-level records for time intervals older than the last interglacial. Here we present the first robustly dated, continuous and highly resolved records of Red Sea sea level and rates of sea-level change over the last 500,000 years, based on tight synchronization to an Asian monsoon record. We observe maximum ‘natural’ (pre-anthropogenic forcing) sea-level rise rates below 2 m per century following periods with up to twice present-day ice volumes, and substantially higher rise rates for greater ice volumes. We also find that maximum sea-level rise rates were attained within 2 kyr of the onset of deglaciations, for 85% of such events. Finally, multivariate regressions of orbital parameters, sea-level and monsoon records suggest that major meltwater pulses account for millennial-scale variability and insolation-lagged responses in Asian monsoon records.

****************

Rohling also gave this presentation yesterday at a big conference in Rotterdam, Delta's in Time of Climate Change, based in part on this new paper:
http://edepot.wur.nl/314954 (http://edepot.wur.nl/314954)

What seems to be missing from this presentation is the (explicit) observation that the current and future global climate forcing is probably many times stronger than forcings during past deglaciations and interglacials. Therefore SLR of 1-2 meters/century over the coming centuries seems to be a best-case scenario. A substantial risk of higher rates seems very plausible, based on this line of research.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on September 26, 2014, 08:05:36 PM
Rohling explains for a lay audience:
http://theconversation.com/why-ice-sheets-will-keep-melting-for-centuries-to-come-32171 (http://theconversation.com/why-ice-sheets-will-keep-melting-for-centuries-to-come-32171)

But again he doesn't point out that the current/future forcing is much bigger than those in the past.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on September 27, 2014, 04:52:18 PM
City of Miami Beach, Florida:  New water pumps are being installed as part of a new storm water infrastructure.
"City officials say the annual king tides are expected to be almost three inches higher than last year. Extreme high tides in the fall and spring push seawater up through aging infrastructure, flooding some Miami Beach streets with more than a foot of water even on sunny days, snarling vehicle and pedestrian traffic."

Cost: $400 million to help protect the city for the next "25 to 30 years."

http://www.washingtonpost.com/national/energy-environment/miami-beach-prepares-for-extreme-high-tides/2014/09/17/5926dc16-3e96-11e4-a430-b82a3e67b762_story.html (http://www.washingtonpost.com/national/energy-environment/miami-beach-prepares-for-extreme-high-tides/2014/09/17/5926dc16-3e96-11e4-a430-b82a3e67b762_story.html)

I have posted this before and skeptics will point out the source as evidence that it should be ignored but the investigative reporting is sound. (It's a shame that the U.S. press is so damaged that we need to rely on the Rolling Stone for accuracy regarding sea level rise.)

http://www.rollingstone.com/politics/news/why-the-city-of-miami-is-doomed-to-drown-20130620 (http://www.rollingstone.com/politics/news/why-the-city-of-miami-is-doomed-to-drown-20130620)

Basically, Miami, much of southeast Florida actually, will be abandoned by the end of the century and the finest engineering companies in the world (from Holland) whose expertise is keeping sea water from penetrating coastal land, says there is nothing that can be done.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on September 27, 2014, 05:06:33 PM
Cost: $400 million to help protect the city for the next "25 to 30 years."
This isn't climate adaptation. This is panic, knee-jerk, band-aidism. Just what do they expect will be necessary in 25 years?!  :o

We, as a species, desperately need to lengthen our planning horizon.

Climate adaptation for this part of the U.S. is going to be quite shocking. By 2100, the populations of Dade and Broward counties (4.4 million) will need to be relocated. This relocation will begin in earnest by 2070, perhaps as early as 2050.

There is nothing that the richest country in the world can do to prevent this.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on September 27, 2014, 05:41:34 PM
Climate Report Details Flood Risk to Sites in Washington
http://www.nytimes.com/2014/09/17/us/climate-report-details-flood-risk-to-sites-in-washington.html?partner=rss&emc=rss (http://www.nytimes.com/2014/09/17/us/climate-report-details-flood-risk-to-sites-in-washington.html?partner=rss&emc=rss)

Every city along the coast of Chesapeake Bay is at serious risk by the end of this century. Take a  look at an elevation map of Philadelphia. A person might be mistaken to simply look at the elevations and conclude that the portion 1 meter above sea level or below is fairly small but this is a simplistic way of viewing the risk and impact of sea level rise. The real risk is on infrastructure that is buried below ground, water mains, sewers etc. All or much of this infrastructure could be rendered unusable. Sewers are particularly susceptible to water table rise. Imagine a Philadelphia without working sanitation facilities.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on September 28, 2014, 05:11:25 PM
The inevitable future of much of the low lying coastal regions of the U.S.

http://www.theguardian.com/news/datablog/2011/feb/09/louisiana-population-us-census-new-orleans (http://www.theguardian.com/news/datablog/2011/feb/09/louisiana-population-us-census-new-orleans)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on September 28, 2014, 06:40:20 PM
To get a sense of the size of the exodus, nearly 250K people have moved from the most vulnerable areas of the Louisiana coastline since Katrina. They will not be returning. The exodus will continue through this century and it will spread to adjacent areas of the coastline as sea levels rise.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on September 28, 2014, 07:29:44 PM
This winter and spring the waves were particularly strong on the coasts of France, especially in the south west.
Here is a video that can give an idea of what is going on :
Quand la dune s'effondre on Vimeo (http://vimeo.com/106099613)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on September 29, 2014, 03:17:58 AM
Sea level rise is changing the real estate market in Norfolk, Virginia, USA.

Quote
About a quarter of properties in Norfolk - just over 17,000 - are in high-risk flood plains, with values totaling 34 percent of the tax base, according to city figures.

The number of homes that repeatedly flood, so-called "repetitive loss" properties, has increased from about 200 in 2002 to almost 900 today, said Lenny Newcomb, the city's zoning administrator.
http://hamptonroads.com/2014/09/norfolk-sea-level-rise-takes-shine-waterfront-homes (http://hamptonroads.com/2014/09/norfolk-sea-level-rise-takes-shine-waterfront-homes)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on September 29, 2014, 03:54:43 PM
If we think about the process of relocation of households in this country, the process is by individual choice, regardless of the driving factor. The movement of Americans from urban cores to the suburbs and then exurbs is a perfect example of this. The movement to the suburbs began post WWII and accelerated through the 70's and 80's as residents who could afford to do so left cities to the relative safety of the suburbs and this flight to the suburbs impoverished many of our cities. This migration took decades and for some cities has recently reversed as the urban cores redevelop and attract families.

This very large migration (30% of residents) from New Orleans and Jefferson Parish, by contrast, has happened in only one decade and yet it is still the result of individual choices as families who can afford to move leave these regions vulnerable to flooding. We should expect that this ongoing migration will cause a decline in incomes and an increasing rate of poverty in New Orleans and Jefferson Parish. Areas along the waterfront that have traditionally attracted the well to do and had higher property values should see steep declines.

A look at the income trends in New Orleans would suggest that this may be happening.

http://www.deptofnumbers.com/income/louisiana/new-orleans/ (http://www.deptofnumbers.com/income/louisiana/new-orleans/)

While the decline in household incomes since 2007 is due, in part, to the Great Recession, the declines in New Orleans have been more pronounced than the state of Louisiana or the U.S. as a whole. This is a trend that should be closely watched but, if the out migration continues, we should expect this income trend gap to grow.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on September 29, 2014, 04:14:42 PM
If you read the article on the Norfolk, Virginia area above, linked to by Sigmetnow, it is clear that the trend we are seeing in New Orleans and Jefferson Parish will inevitably occur here as well. These tidewater regions have traditionally been some of the wealthiest regions of Virginia. As flooding worsens, the first response will be to strengthen defenses against flooding but, eventually, well to do families will move away from these coastal regions that are prone to flooding and property values and incomes of these regions will fall.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on October 02, 2014, 06:38:02 PM
"Students to gather on Miami Beach to combat sea level rise apathy on King Tide Day (Oct 9th)."

There is so much denial going on in Florida, particularly south Florida, which makes, I think, this all the more newsworthy.

http://blogs.miaminewtimes.com/cultist/2014/09/king_tide_day_students_gather_on_miami_beach_to_combat_sea_level_rise_apathy.php (http://blogs.miaminewtimes.com/cultist/2014/09/king_tide_day_students_gather_on_miami_beach_to_combat_sea_level_rise_apathy.php)


Quote of the week:  "Climate change is a really slow, creepy thing."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on October 02, 2014, 07:20:53 PM
On the last post there is this website : http://www.eyesontherise.org/ (http://www.eyesontherise.org/)
And that video in it.
https://www.youtube.com/watch?feature=player_embedded&v=WQCbjyZFbtw (https://www.youtube.com/watch?feature=player_embedded&v=WQCbjyZFbtw)

I like the way professors who are not necessarily climate scientists teach to their students that the situation is dire.
Also some picts about the reality of what is going on around Miami.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on October 08, 2014, 09:54:03 AM
US east coast cities face frequent flooding due to climate change
http://www.theguardian.com/environment/2014/oct/08/us-east-coast-cities-face-frequent-flooding-due-to-climate-change (http://www.theguardian.com/environment/2014/oct/08/us-east-coast-cities-face-frequent-flooding-due-to-climate-change)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on October 11, 2014, 04:16:20 PM
Flooding averted -- this time!  Well done.
$15 million down, over $500 million more to go, for perhaps 30 years' worth of sea level rise adaptation in Miami Beach, Florida.

http://www.miamiherald.com/news/local/community/miami-dade/miami-beach/article2633647.html (http://www.miamiherald.com/news/local/community/miami-dade/miami-beach/article2633647.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on October 13, 2014, 09:06:33 PM
New SLR-paper by Jevrejeva, Grinsted & Moore:
http://iopscience.iop.org/1748-9326/9/10/104008/article (http://iopscience.iop.org/1748-9326/9/10/104008/article)

They estimate a 5% risk of 1.8m of SLR by 2100, based on expert elicitation (Bamber & Aspinall) and physical modeling.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on October 13, 2014, 09:35:05 PM
New SLR-paper by Jevrejeva, Grinsted & Moore:
http://iopscience.iop.org/1748-9326/9/10/104008/article (http://iopscience.iop.org/1748-9326/9/10/104008/article)

They estimate a 5% risk of 1.8m of SLR by 2100, based on expert elicitation (Bamber & Aspinall) and physical modeling.

Interesting, I was just reading:

Quote
To explore these remaining uncertainties, ice2sea has used a less-formal approach of an “expert elicitation.” This method concluded that there is a less than 1-in-20 risk of the contribution of ice sheets to global sea-level rise exceeding 84cm by 2100.

http://www.ice2sea.eu/2013/05/14/from-ice-to-high-seas/ (http://www.ice2sea.eu/2013/05/14/from-ice-to-high-seas/)

So on this scale, if we plot the 5% expert elicitation results, we will gain 1 meter of SLR every 2 years or so????
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on October 13, 2014, 10:15:28 PM
Jai,

That's the same expert elicitation: Bamber & Aspinall 2013. Jevrejeva et al use the 5% risk of 84 cm ice sheet contribution by 2100 to get a 5% risk of 1.8m of total SLR by 2100, but then confirmed by the summed maximum contributions of process based models.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on October 13, 2014, 10:43:58 PM
It would be interesting to see an analysis of the experts they elicited and the kinds of results they came up with.

I'm guessing that the experts that have been most active in the field most recently may be on the high end while those who were very familiar with the science and very active in research ten or even five years ago but are now not following it as closely may be less pessimistic (though, of course, the opposite may be true, which would also be important to know).

 Such distributions should be made clear so people can make their own judgments rather than just lumping all 'experts' together.

Also note this from the abstract:

Quote
The agreement between the methods may suggest more confidence than is warranted since large uncertainties remain due to the lack of scenario-dependent projections from ice sheet dynamical models, particularly for mass loss from marine-based fast flowing outlet glaciers in Antarctica.

This leads to an intrinsically hard to quantify fat tail in the probability distribution for global mean sea level rise. Thus our low probability upper limit of sea level projections cannot be considered definitive.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on October 14, 2014, 12:51:04 AM
Lambeck (2014) doi:10.1073/pnas.1411762111

seems like we have pulled the trigger. The figure below shows that SLR was less than 0.1m/kiloyr
for the last couple millennia. Today of course we have 3m/kiloyr, a rate last seen about 7kiloyr ago
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 14, 2014, 12:57:10 AM
Here is a more complete reference to the article that sidd just posted about:

Kurt Lambeck, Hélène Rouby, Anthony Purcell, Yiying Sun, and Malcolm Sambridge, "Sea level and global ice volumes from the Last Glacial Maximum to the Holocene", PNAS, doi: 10.1073/pnas.1411762111

http://www.pnas.org/content/early/2014/10/08/1411762111 (http://www.pnas.org/content/early/2014/10/08/1411762111)

Abstract: "The major cause of sea-level change during ice ages is the exchange of water between ice and ocean and the planet’s dynamic response to the changing surface load. Inversion of ∼1,000 observations for the past 35,000 y from localities far from former ice margins has provided new constraints on the fluctuation of ice volume in this interval. Key results are: (i) a rapid final fall in global sea level of ∼40 m in <2,000 y at the onset of the glacial maximum ∼30,000 y before present (30 ka BP); (ii) a slow fall to −134 m from 29 to 21 ka BP with a maximum grounded ice volume of ∼52 × 106 km3 greater than today; (iii) after an initial short duration rapid rise and a short interval of near-constant sea level, the main phase of deglaciation occurred from ∼16.5 ka BP to ∼8.2 ka BP at an average rate of rise of 12 m⋅ka−1 punctuated by periods of greater, particularly at 14.5–14.0 ka BP at ≥40 mm⋅y−1 (MWP-1A), and lesser, from 12.5 to 11.5 ka BP (Younger Dryas), rates; (iv) no evidence for a global MWP-1B event at ∼11.3 ka BP; and (v) a progressive decrease in the rate of rise from 8.2 ka to ∼2.5 ka BP, after which ocean volumes remained nearly constant until the renewed sea-level rise at 100–150 y ago, with no evidence of oscillations exceeding ∼15–20 cm in time intervals ≥200 y from 6 to 0.15 ka BP."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on October 14, 2014, 01:51:59 AM
probably dont need to point out that the graph i posted from Lambeck(2014) indicates very sharp changes in rate of SLR. When it begins to change it is step change ... ie the acceleration (second derivative) of SLR is huge. The graph i posted is of course only the first derivative. However it is probably not possible to recover acceleration from the data, since every differentiation amplifies data noise.

Nice paper tho, reconciles lots and lots of paleo records

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on October 14, 2014, 03:07:04 AM
Jai,

That's the same expert elicitation: Bamber & Aspinall 2013. Jevrejeva et al use the 5% risk of 84 cm ice sheet contribution by 2100 to get a 5% risk of 1.8m of total SLR by 2100, but then confirmed by the summed maximum contributions of process based models.

http://www.nature.com/nclimate/journal/v3/n4/full/nclimate1778.html (http://www.nature.com/nclimate/journal/v3/n4/full/nclimate1778.html)

An expert judgement assessment of future sea level rise from the ice sheets
Received  31 July 2012

That means that the assessment was performed in the 3rd and 4th quarters of 2011.

Since then we have had so much work submitted on the subject that has pushed up the estimates.  I believe it was rignot, and the GRACE data for Greenland and WAIS that first gave indication that the 1m SLR by 2100 was now the new minimum.  Now the heat accumulation data from Durack also shows an increase in SLR thermal expansion.   

Any other papers submitted since q3 2011 that have shown a likely increase in the estimates of SLR?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on October 14, 2014, 03:12:16 AM
From the abstract posted by ASLR: "≥40 mm⋅y−1"

So that's over 40 cm (nearly 16 inches) per decade of sea level rise!

Yikes!

Over 4 meters per century. Ouch!

And our forcings are much larger and faster today than then, right?

Sooo, why would we think we are in for anything less, either in terms of magnitude or speed??
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on October 14, 2014, 03:39:36 AM
Grant(2014) DOI:10.1038/ncomms6076 points out that the maximum SLR rates over the last 5 glacial cycles show dependence on the ice volume present at the start of deglaciation events or the start of a pulse of SLR. I reproduce fig 4 a,b (the ice volume relative to today at the start of a deglaciation and the start of a pulse respectively on the x axis, and max SLR rate on the y axis, the green point is MWP1A)

Note that the largest SLR rates are only observed at ice volume above  approx twice that of today.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on October 14, 2014, 12:49:20 PM
Thanks, sidd. That makes sense.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 14, 2014, 06:15:48 PM
Thanks, sidd. That makes sense.

wili,

sidd knows well my position on the Grant et al (2014) data/plot that he just referenced, as we have discussed this matter in the Antarctic folder.  First, let me acknowledge that averaged over long periods of time (say 1,000 yrs) sidd is making a very strong point.  For example, during Melt-Pulse 1A when SLR rates were sustained for 500 years at greater than 40 mm per year, there many more marine glaciers in the world than now, and paleo-evidence of debris from icebergs around the Southern Ocean show that during MP 1A many of the marine glaciers (now gone) in Antarctic collapsed to contribute to this pulse.  However, sidd's point does not protect the modern world from SLR rates on the order of 40 mm per year over shorter periods of time (say 100-years), as there are still many marine glaciers in Antarctica (primarily in the West Antarctic, but also in the East Antarctic [say Totten]) that are primed to begin collapsing this century, as are several marine-terminating glaciers in Greenland (say the Jakobshavn Glacier).  The attached image provides paleo-evidence (from O'Leary et al 2013) from relative sea level data for Western Australia that shows that from 119 to 120 kyr sea level rose about 6m in no more than 1,000 yrs (or 6 mm per year) at ice levels essentially at today's levels.  However, as both Grant et al (2014) and O'Leary et at (2013) do not report data at less than 1,000 year resolution, we are left guessing whether, or not, a SLR rate of 30 to 40 mm/yr is going to happen this century; however the National Academy of Science says that such a pulse is plausible.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 14, 2014, 06:50:14 PM
wili,

To get a slightly better feel for what type of Russian Roulette risks society is taking with regard to the risk of abrupt SLR this century, I post the attached image from Rohling (2008 data) of paleo-sea level-data with sea level above modern conditions.  While the smoothed curves (averaged over 1,000 year period) paint a less dramatic picture of say 1.6m per century SLR, the data points show sharp peaks that result possible periods of short bursts of SLR, so that Rohling 2008 gives a SLR rate of 1.6 +/- 1.0 m per century, or a reasonable rise of 2.6m of SLR this century based on paleo-evidence without considering the much higher rates of forcing in the modern era.

edit: With regard to modern forcing, please be aware that for SLR contribution from Antarctica the most important forcing is due to the ozone hole over Antarctica that has increased the westerly wind velocities, which have directed warm Circumpolar Deep Water, CDW, to the groundling lines of many key marine glaciers in Antarctica (including: the Pine Island Glacier, the Thwaites Drainage Basin and the Getz Drainage Basin, not to mention the Totten area) already today, so the argument that the beginning of a modern collapse of remaining marine, and marine terminating (like Jakobshavn, whose grounding line is also exposed to warm ocean water), glacier could be a long-time from now is a red-herring as the GRACE and GOCE measurement show that these ice mass loss from these key glaciers is accelerating today.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on October 14, 2014, 09:08:08 PM
1)Grant(2014) is a 500 yr smooth (datapoints are at 250 yr intervals)
2)note the outlier at approx 1.6 time present ice volume and 2m/yr SLR. Prof. Grant was kind enuf to inform in a personal communication that the outlier is at 9.5 Kyr. From Weber(2014), doi:10.1038/nature13397 this seems to be about the time of the event AID1 (Antarctic Ice Sheet Discharge 1)
3)Most important: Forcing today is very different from Milankovich forcing amplified by other feedbacks. Hansen and others have made a strong case that spring and summer insolation in N. Hemisphere pace the glacial cycles, amplified by feedbacks. But today we have a very different situation indeed.
i)We have manmade greenhouse gas forcing which a)acts all over the globe, not just in N. Hemis. b)acts all the time not just in spring and summer daytime
ii)we have huge deleterious human impact on natural ecosystems and natural carbon reserves
iii)we have huge depletion of freshwater aquifers in coastal areas leading to land subsidence in precisely those populated coastal areas most at risk from SLR
iv)we are in an interglacial already so our forcings exacerbate the ntural forcing that led to this interglacial, and may have already suppressed the next few glacial cycles

The list goes on. So comparison with glacial cycles is only a very rough guide to what awaits. I post these last references to indicate the _low_ end of what we might expect. In this context perhaps the right analogs are the ANDRILL results showing deglaciation of large parts of Antarctica in the Pliocene, before the Pleistocene glacials. See for example Pollard(2009) doi:10.1038/nature07809

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on October 14, 2014, 10:45:38 PM
Thank, both ASLR and sidd. Much to chew on here.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 14, 2014, 11:13:01 PM
sidd,

Thanks, I always learn something (or re-learn something I overlooked) from your posts.

Best, ASLR

Also, if anyone wants to correlate the iceberg data provided by Weber (2014) with the past retreats of the Amundsen Sea Embayment, ASE, marine glaciers, then the following linked reference provides paleo data (see attached plot [where GL = grounding line]).  Such a correlation might give some rough idea about how fast future grounding line retreats could be for the remaining marine glaciers in the ASE:

James A. Smith , Claus-Dieter Hillenbrand, Gerhard Kuhn, Johann Phillip Klages, Alastair G.C. Graham, Robert D. Larter, Werner Ehrmann, Steven G. Moreton, Steffen Wiers, & Thomas Frederichs, (2014), "New constraints on the timing of West Antarctic Ice Sheet retreat in the eastern Amundsen Sea since the Last Glacial Maximum", Global and Planetary Change, DOI: 10.1016/j.gloplacha.2014.07.015

http://www.sciencedirect.com/science/article/pii/S0921818114001489 (http://www.sciencedirect.com/science/article/pii/S0921818114001489)


edit: For anyone needing the reference information for Weber et al (2014) it is as follows:

M. E. Weber, P. U. Clark, G. Kuhn, A. Timmermann, D. Sprenk, R. Gladstone, X. Zhang, G. Lohmann, L. Menviel, M. O. Chikamoto, T. Friedrich & C. Ohlwein, (2014), "Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation", Nature, 510, 134–138, doi:10.1038/nature13397

http://www.nature.com/nature/journal/v510/n7503/abs/nature13397.html (http://www.nature.com/nature/journal/v510/n7503/abs/nature13397.html)

Abstract: "Our understanding of the deglacial evolution of the Antarctic Ice Sheet (AIS) following the Last Glacial Maximum (26,000–19,000 years ago) is based largely on a few well-dated but temporally and geographically restricted terrestrial and shallow-marine sequences. This sparseness limits our understanding of the dominant feedbacks between the AIS, Southern Hemisphere climate and global sea level. Marine records of iceberg-rafted debris (IBRD) provide a nearly continuous signal of ice-sheet dynamics and variability. IBRD records from the North Atlantic Ocean have been widely used to reconstruct variability in Northern Hemisphere ice sheets, but comparable records from the Southern Ocean of the AIS are lacking because of the low resolution and large dating uncertainties in existing sediment cores. Here we present two well-dated, high-resolution IBRD records that capture a spatially integrated signal of AIS variability during the last deglaciation. We document eight events of increased iceberg flux from various parts of the AIS between 20,000 and 9,000 years ago, in marked contrast to previous scenarios which identified the main AIS retreat as occurring after meltwater pulse 1A and continuing into the late Holocene epoch. The highest IBRD flux occurred 14,600 years ago, providing the first direct evidence for an Antarctic contribution to meltwater pulse 1A. Climate model simulations with AIS freshwater forcing identify a positive feedback between poleward transport of Circumpolar Deep Water, subsurface warming and AIS melt, suggesting that small perturbations to the ice sheet can be substantially enhanced, providing a possible mechanism for rapid sea-level rise."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 15, 2014, 12:19:21 AM
As a point of reference, the attached NOAA plot of global mean sea level, GMSL, with Jason-2 data through October 3 2014, indicates that during the satellite recorded indicated, sea level has been rising at a rate of 3.17 +/- 0.4 mm/yr, and during this non-El Nino year GMSL is currently following that trend line:

ftp://podaac.jpl.nasa.gov/allData/merged_alt/preview/global_mean_sea_level/GMSL_TPJAOS.jpg
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 16, 2014, 10:27:56 PM
The forward to the linked (free access) US Department of Defense report on Climate Change Adaption, includes the following statement:

extract: "In places like the Hampton Roads region in Virginia, which houses the largest concentration of US military sites in the world, we see recurrent flooding today, and we are beginning work to address a projected sea-level rise of 1.5 feet over the next 20 to 50 years."

http://www.acq.osd.mil/ie/download/CCARprint.pdf (http://www.acq.osd.mil/ie/download/CCARprint.pdf)

http://www.newscientist.com/article/dn26379-pentagon-warns-the-us-military-of-climate-change.html#.VD7h_KPn_IU (http://www.newscientist.com/article/dn26379-pentagon-warns-the-us-military-of-climate-change.html#.VD7h_KPn_IU)

This statement by the US Secretary of Defense Chuck Hagel indicates that at the upper end, the US military is planning to deal with 1.5 ft of sea-level rise over 20 yrs; which is an average of 22.9 mm/yr; however as currently, SLR is 3.17 mm/yr, and using a linear approximation, this implies that the military is planning for a SLR of about 43 mm/yr by 2034 offshore of Virginia.  This is only possible if the US military is acknowledging that it is plausible that key parts of the West Antarctic Ice Sheet, WAIS, could begin collapsing within the next approximately 5 years.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: opensheart on October 17, 2014, 06:26:15 PM
I would take this to mean a local Sea Level Rise, which is different and can be greater than the global sea level rise.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 17, 2014, 08:18:37 PM
opensheart,

I concur this 43-mm/yr RSLR rate by 2034 offshore of Virginia, is clearly a local SLR value.  That said even if one accounts for the local subsidence and the local steric SLR, and other local corrections; in order to get anywhere near 43-mm/yr one must assume a partial collapse of the WAIS by that date.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: opensheart on October 21, 2014, 06:51:30 PM
In this age of budget cuts, one must demonstrate superior need to get funding approved.  If one is going to ask for funding, one only wants to ask once.   Cost overruns can be scandalous.   In such environments, spinning the need in the most urgent language possible is normal. 

If turns out to be the one chance to raise the land or build sea walls, etc, at such densely used area, one would want to make sure it was enough to last a good long time.   If one is going to do something, it might as well be big.    Politicians like to approve Big projects for their districts.

Once they ask to address the issue, their solution has to cover everything.   If 20 years from now a Superstorm Sandy storm surge makes a direct hit on the highest tide of the year, Congress is going to ask why they didn’t foresee that when the work was done.    This leads to inflating the best reasonable guesstimate by a healthy fudge factor, just to be safe.

Likewise the published timeframe may be more of a budgetary, resource planning target for getting the work done, than a scientific forecast of what will happen by when.

I would believe their request is worded to have the most chance of approval without it ever coming back to haunt them, rather than what they believe will actually happen.       As such, I highly doubt it was formulated from a vision that a specific event like the West Antarctic Ice Sheet will collapse X amount by Y year.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 21, 2014, 11:33:56 PM
opensheart,

While the DoD did not say that the WAIS would collapse X amount by Y year; its partial collapse is the only way that I can see that the DoD could estimate the possibility of 1.5 ft of relative sea-level rise at Norfolk by 2034.  As to the scientific plausibility of such a partial WAIS collapse this century, please see the following document (and associated extract):

National Research Council, NRC, (2013), Abrupt Impacts of Climate Change Anticipating Surprises, The National Academies Press, Washington D.C.

Extract: "Because large uncertainties remain, the Committtee judges an abrupt change in the WAIS with this century to be plausible, with an unknown although probably low probability."

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on October 26, 2014, 05:58:06 PM
Two Years After Sandy’s Surge, New York City Shifts Toward a Softer Relationship with the Sea.
http://dotearth.blogs.nytimes.com/2014/10/26/two-years-after-sandys-surge-new-york-city-shifts-toward-a-softer-relationship-with-the-sea/?partner=rss&emc=rss (http://dotearth.blogs.nytimes.com/2014/10/26/two-years-after-sandys-surge-new-york-city-shifts-toward-a-softer-relationship-with-the-sea/?partner=rss&emc=rss)

Nice video ! informative about the consequences of "Sandy".
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 27, 2014, 10:43:56 PM
While the authors of the linked paper are very conservative (and thus ignore any possible contribution to SLR from a possible collapse of the WAIS this century); nevertheless, the paper (see associated images and caption) does indicate that SLR will be noticeable by 2030 for most parts of the world for all RCP scenarios:


Kewei Lyu, Xuebin Zhang, John A. Church, Aimée B. A. Slangen & Jianyu Hu, (2014), "Time of emergence for regional sea-level change", Nature Climate Change, doi:10.1038/nclimate2397


http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2397.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2397.html)


Abstract: "Determining the time when the climate change signal from increasing greenhouse gases exceeds and thus emerges from natural climate variability (referred to as the time of emergence, ToE) is an important climate change issue. Previous ToE studies were mainly focused on atmospheric variables Here, based on three regional sea-level projection products available to 2100, which have increasing complexity in terms of included processes, we estimate the ToE for sea-level changes relative to the reference period 1986–2005. The dynamic sea level derived from ocean density and circulation changes alone leads to emergence over only limited regions. By adding the global-ocean thermal expansion effect, 50% of the ocean area will show emergence with rising sea level by the early-to-middle 2040s. Including additional contributions from land ice mass loss, land water storage change and glacial isostatic adjustment generally enhances the signal of regional sea-level rise (except in some regions with decreasing total sea levels), which leads to emergence over more than 50% of the ocean area by 2020. The ToE for total sea level is substantially earlier than that for surface air temperature and exhibits little dependence on the emission scenarios, which means that our society will face detectable sea-level change and its potential impacts earlier than surface air warming.

Caption first image: "The blue curve shows projected sea level, the red curve shows the same projections once year-to-year variations have been removed. The grey and black lines show the range of natural variability. The asterisk denotes the time of emergence when sea level moves beyond the realm of natural variability.

Caption for second image: "The likely Time of Emergence (year) for regional sea-level change for a business-as-usual scenario. The warm (cold) colours represent rising (falling) sea level."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 29, 2014, 01:05:32 AM
In stark contract to the findings of the paper (Lyu et al 2014) that I posted about in may last post: In the extract form the linked article, ODU = Old Dominion University's Center for Sea Level Rise; and working for the US military, ODH calculates that sea level could raise by 1-ft (0.3m) by 2030; which is an average annual rate of increase of about 20mm/year:

http://www.military.com/daily-news/2014/10/27/hampton-roads-military-bases-brace-for-climate-change-sea-level.html (http://www.military.com/daily-news/2014/10/27/hampton-roads-military-bases-brace-for-climate-change-sea-level.html)

Extract: "Sea levels have risen 14 inches since 1930, according to the ODU center. That's a rate of more than five millimeters per year and is accelerating, Kreidel said. Some calculations show it will rise a foot by 2030 and 2 feet by 2050. By 2100, it could rise 7.5 feet."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on October 29, 2014, 05:01:22 PM
Life on a Louisiana island slowly disappearing into the sea
http://www.bbc.com/news/magazine-29796842 (http://www.bbc.com/news/magazine-29796842)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on October 30, 2014, 04:29:38 PM
New research quantifies what's causing sea level to rise
http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/oct/30/new-research-quantifies-sea-level-rise (http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/oct/30/new-research-quantifies-sea-level-rise)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 30, 2014, 05:38:55 PM
As a follow-on to Laurent's post: What Purkey et al (2014) do not point-out is that while the mass contribution to sea level rise has stayed nearly constant at 1.5 +/- 0.4 mm/yr from 1996 to 2013, the contribution from glaciers and ice caps has started to decline while the contribution from ice sheets has started to accelerate (see attached image).  Therefore, we appear to be in a period of relatively calm transition to a more rapid acceleration of SLR (assuming that the contribution from ice sheets continues to accelerate):

Sarah G. Purkey, Gregory C. Johnson and Don P. Chambers, (2014), "Relative contributions of ocean mass and deep steric changes to sea level rise between 1993 and 2013", Journal of Geophysical Research: Oceans, DOI: 10.1002/2014JC010180

http://onlinelibrary.wiley.com/doi/10.1002/2014JC010180/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2014JC010180/abstract)

Abstract:  "Regional and global trends of Sea Level Rise (SLR) owing to mass addition centered between 1996–2006 are assessed through a full-depth SLR budget using full-depth in-situ ocean data and satellite altimetry. These rates are compared to regional and global trends in ocean mass addition estimated directly using data from the Gravity Recovery and Climate Experiment (GRACE) from 2003–2013. Despite the two independent methods covering different time periods with differing spatial and temporal resolution, they both capture the same large-scale mass addition trend patterns including higher rates of mass addition in the North Pacific, South Atlantic, and the Indo-Atlantic Sector of the Southern Ocean, and lower mass addition trends in the Indian, North Atlantic, South Pacific, and the Pacific Sector of the Southern Ocean. The global mean trend of ocean mass addition is 1.5 (±0.4) mm yr-1 for 1996–2006 from the residual method and the same for 2003–2013 from the GRACE method. Furthermore, the residual method is used to evaluate the error introduced into the mass budget if the deep steric contributions below 700, 1000, 2000, 3000, and 4000 m are neglected, revealing errors of 65%, 38%, 13%, 8% and 4% respectively. The two methods no longer agree within error bars when only the steric contribution shallower than 1000 m is considered."

The attached figure is from
https://www.ccin.ca/home/ccw/glaciers/current (https://www.ccin.ca/home/ccw/glaciers/current)


edit: here is a link to a free access pdf of the Purkey et al paper:

http://www.pmel.noaa.gov/people/gjohnson/Ocean_mass_trends_v2.pdf (http://www.pmel.noaa.gov/people/gjohnson/Ocean_mass_trends_v2.pdf)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 30, 2014, 10:58:37 PM
The following link leads to an article that provides a reasonable summary of reasons why the IPCC's SLR projections are too low:

http://www.washingtonpost.com/blogs/wonkblog/wp/2014/10/30/climate-scientists-arent-too-alarmist-theyre-too-conservative/ (http://www.washingtonpost.com/blogs/wonkblog/wp/2014/10/30/climate-scientists-arent-too-alarmist-theyre-too-conservative/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Bruce Steele on October 31, 2014, 05:10:00 PM
If you extend the trend lines in the Glaciers and Ice Sheet contribution to SLR chart it looks like the Ice Sheets may already have passed the Glaciers in their contribution to SLR. Totals look to be in excess of 3 mm annually . Does anyone have info on when in the past this happened last? Quite the transition to transpire without note.
 
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 31, 2014, 09:15:03 PM
If you extend the trend lines in the Glaciers and Ice Sheet contribution to SLR chart it looks like the Ice Sheets may already have passed the Glaciers in their contribution to SLR. Totals look to be in excess of 3 mm annually . Does anyone have info on when in the past this happened last? Quite the transition to transpire without note.

Bruce,

Thanks for all of your observations.  Part of the problem with getting people to recognize the risks associated with sea level rise (beyond the IPCC's behavior of erring on the side of least drama) include such factors as:

(a) The observed data record is so small that short-term rainfall/snow events can hide the contribution that the ice sheets are making to SLR.  For example an Atmospheric River event hit East Antarctica around 2011 which dumped a lot of snow there, which due to the mass balance approach used to report SLR contribution, makes the Antarctic Ice Sheet, ASE, ice melting appear small than it really is.

(b) There is so much ice mass loss occurring in the Amundsen Sea Embayment glaciers that the ground is rebounding so quickly that it is drawing magma beneath the lithosphere, which is adding confusion to the gravity change measurements of the GRACE satellite (see that attached GRACE measurement of ice mass loss from the West Antarctic Ice Sheet, which is already accelerating faster than the ASE rate, even before probable corrections for land rebound [isostatic] corrections); which again masks the true amount of ice melting.

(c) Most importantly ice melting from the ice sheets for the next century will be dominated by ocean water melting of the ice at the grounding line; therefore, even if society gets off of the RCP 8.5 scenario within the next few years, the ice mass contribution from marine terminating glaciers (in Greenland) and marine glaciers (in Antarctica) have already been triggered and we will be now experiencing that SLR no matter what (even if climate sensitivity is smaller than expected).
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on November 12, 2014, 12:42:05 AM
I decided to post the attached recent SLR trend plot from the University of Colorado issued Nov 4, 2014 indicating that even with the ENSO currently being neutral sea-level rise continues to trend upwards.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on November 14, 2014, 01:07:38 AM
Floating above the rising tides

Keren Bolter

Floating above the rising tides debate: Keren Bolter at TEDxMiami 2013 (http://www.youtube.com/watch?v=BEhx-Q43Tfo#ws)

Perhaps more of our scientists need to get this passionate!
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on November 14, 2014, 08:52:41 AM
Wow, that's powerful and hurts.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on November 19, 2014, 09:47:51 AM
New protocol improves predictions of sea-level rise
http://www.deltares.nl/en/news/news-item/item/18171/new-protocol-improves-predictions-of-sea-level-rise (http://www.deltares.nl/en/news/news-item/item/18171/new-protocol-improves-predictions-of-sea-level-rise)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on December 21, 2014, 10:15:09 PM
About the Miami Beach inundation:
Quote
Wanless remembers when he first started getting calls for help from local authorities.

"In around 2008 or 2009, one of the first years we had a lot of water in the Miami Beach area, the public works people called me for help and I went into this room in their government building and they were all in their coats and ties and they said, 'We are having a little problem in Miami Beach, we are getting water in the streets. Where do you suggest we put it?'

 "I held my laughter. The ocean had arrived. You can put the water anywhere you want, but it is going to keep coming."

Wanless believes the hundreds of millions of dollars that have already been spent of flood mitigation infrastructure around Miami have been wasted because the sea cannot be held back.

"We are in the position where we think we are going to fight it and win. We are not going to win."

Soon, he believes, insurance companies will stop underwriting homes in the worst affected areas and then owners will be unable to sell.

Money should be saved for moving people away while all levels of government work to reduce emissions, he argues.
http://www.brisbanetimes.com.au/world/warming-worlds-rising-seas-wash-away-some-of-south-floridas-glitz-20141220-129wub.html (http://www.brisbanetimes.com.au/world/warming-worlds-rising-seas-wash-away-some-of-south-floridas-glitz-20141220-129wub.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on December 24, 2014, 08:09:35 PM
New study says damage this century in U.S. due to sea level rise (SLR) that includes storm surge could be more than twice estimates due to SLR alone.
Quote
The results show that the U.S. is facing what until now has been a hidden financial risk, not unlike the mortgage backed securities that helped blow up the U.S. economy in 2008. Scientists have improved their tracking and projections of sea level rise — but they have not, until now, figured out a way to estimate the combined economic impact of storm surges and sea level rise nationwide.
...
According to the new study, the combined costs from sea level rise and storm surge events, including sea level rise adaptation measures like raising home elevations, abandoning some properties and building new sea walls to defend others, comes to between $930 billion to $1.1 trillion nationally by 2100, which is 84% to 110% higher than the projected costs from sea level rise alone, the study says.
http://mashable.com/2014/12/23/sea-level-rise-storm-surge-1-trillion/ (http://mashable.com/2014/12/23/sea-level-rise-storm-surge-1-trillion/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on December 24, 2014, 09:12:54 PM
Thanks for this article.

In the abstract of the paper they say:
Quote
For a mid-range climate-sensitivity scenario that incorporates dynamic ice sheet melting, the approach yields national estimates of the impacts of storm surge and SLR of $990 billion through 2100 (net of adaptation, cumulative undiscounted 2005$); GHG mitigation policy reduces the impacts of the mid-range climate-sensitivity estimates by $84 to $100 billion.

So these are only adaptation costs? Or also potential damage costs? In that case it would be interesting to know what assumptions they make about the timing of adaptation investments. And how much SLR do they take into account?

In any case the news article says it may still be an under-estimate:
Quote
The study's results, as eye-popping as they may be, likely represent an underestimate of the total economic impacts from sea level rise and storm surge events — because it does not include several key factors. For one, it doesn't incorporate storm surges from storms that are not tropical storms and hurricanes, such as nor'easters. Also absent is wave action, which tends to increase the damage from storm surge events. The study also doesn't factor in regional variations in sea level rise, with the Mid-Atlantic and Northeast projected to be a regional hotspot for sea level rise due to regional ocean currents and other factors. Damage to infrastructure, such as coastal roads and airports, and ecosystem damages are not included either.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on December 24, 2014, 11:51:21 PM
Published on Nov 25, 2014


Jeremy Jackson, senior scientist emeritus at the Smithsonian Institution and professor of oceanography Emeritus at the Scripps Institution of Oceanography, discusses how saving the oceans and ourselves will require fundamental changes in the ways we live and obtain food and energy for everything we do. Recorded Nov. 20, 2014, in Mayser Gymnasium.

cut ahead to where he talks about sea level rise at minute 27 in talk. 

https://www.youtube.com/watch?v=ljM2o6bIHSo&t=27m (https://www.youtube.com/watch?v=ljM2o6bIHSo&t=27m)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: GeoffBeacon on December 27, 2014, 12:25:31 AM
Jai

Thanks.

But

Quote
cut ahead to where he talks about sea level rise at minute 27 in talk.


Don't cut ahead if you've got an hour. An amazing talk.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on December 27, 2014, 02:23:17 PM
Is that possible: 4m of SLR in a 'couple of years', when WAIS abruptly collapses/disintegrates?

What science is that statement by Jackson based on? Maybe 4m in a couple of decades, but years? How would that work?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on December 27, 2014, 02:41:51 PM
It took 4 weeks for Larsen B to collapse !?...
The size does not seem to matter, past a certain threshold in temps, patatra ?...
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on December 27, 2014, 03:11:07 PM
Yes, but is that science or just wild speculation? In that case, why not say 4m in a few weeks may be possible? Or in a few days? Why even do science at all, if it's that easy to infer the risk of ice sheet collapse from the observed collapse of an ice shelf? It seems too much like those reverse statements of pseudo-sceptics to me, unless there's some more reasoned and peer-reviewed argument behind Jackson's statement. Or at least a speculation by a glacialogist instead of an oceanographist.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on December 27, 2014, 03:45:13 PM
I do not infer anything, just recall a recent past that should remain in memory. A fast collapse is just something we should not exclude. Off course we have to study the pig ice shelf in 3D if we want to predict something.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 27, 2014, 06:05:59 PM
Is that possible: 4m of SLR in a 'couple of years', when WAIS abruptly collapses/disintegrates?

What science is that statement by Jackson based on? Maybe 4m in a couple of decades, but years? How would that work?

Lennart,

First, I do not know what was the source of Jackson's statement that the WAIS could substantially collapse within 2-years after it reaches some undefined tipping point at some undefined date in the future.  That said, I imagine that this date in the future would probably be after 2070; which time I believe would be necessary to precondition the WAIS marine ice sheets by grounding line retreat, fracturing of the ice streams, etc. to allow an armada of icebergs to calve and float-out of the various WAIS basins in a manner similar to the Heinrich and Bond events discussed in the Paleo thread at the following link:
http://forum.arctic-sea-ice.net/index.php/topic,130.msg1757/topicseen.html#msg1757 (http://forum.arctic-sea-ice.net/index.php/topic,130.msg1757/topicseen.html#msg1757)

In this regard, see the horizontal error bars in the first attached image from O'Leary et al 2013, illustrating that sea level rose over 5m, during the Eemian, in as much as a few thousand years or as little as a couple of years (again see the overlapping error bars)
Michael J. O’Leary, Paul J. Hearty,William G. Thompson, Maureen E. Raymo, Jerry X. Mitrovica and Jody M.Webster (2013), doi:10.1038/ngeo1890


http://www.nature.com/ngeo/journal/v6/n9/full/ngeo1890.html (http://www.nature.com/ngeo/journal/v6/n9/full/ngeo1890.html)
http://www.nature.com/ngeo/journal/v6/n9/fig_tab/ngeo1890_F1.html (http://www.nature.com/ngeo/journal/v6/n9/fig_tab/ngeo1890_F1.html)


Similarly, the second image from Grant et al 2012 also shows the possibility that during the Eemian sea level may (or may not) have risen over 5m in a few years (or not):

Grant et al 2012 (doi:10.1038/nature11593)

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on December 27, 2014, 07:29:58 PM
This has been well documented here (by ASLR) but is worth repeating.

Quote
“All of our simulations show it will retreat at less than a millimeter of sea level rise per year for a couple of hundred years, and then, boom, it just starts to really go,” Joughin said.

Researchers did not model the more chaotic rapid collapse, but the remaining ice is expected to disappear within a few decades.

http://www.washington.edu/news/2014/05/12/west-antarctic-ice-sheet-collapse-is-under-way/ (http://www.washington.edu/news/2014/05/12/west-antarctic-ice-sheet-collapse-is-under-way/)

I believe that his analysis of a few years is certainly after 2100 and is predicated on losing the Ronne's significant buttressing ice shelf effect and the Thwaites glacier which both allow for an "unpinning" of the remaining western sheet.

The only mechanism I have seen is the Larsen B scenario where rapid surface warming/cooling produces hydrofracture events and, coupled with the above loss of pinning allows for rapid collapse of land based sheets.

This will almost certainly happen by 2300 under a RCP 8.5 scenario with globally averaged temperatures reaching somewhere around 14-16C above pre-industrial averages.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 27, 2014, 08:15:55 PM
While I do not seem to have the time nor the energy to detail how it might be physically possible (however likely, or not likely) to produce an armada of icebergs from the WAIS in a few years, I would note that debris fields in Drakes Passage have shown that during Meltwater Pulse 1A (with different conditions than today) such iceberg armadas did exist and circled around the Southern Ocean.


See: Weber(2014) doi:10.1038/nature13397 on timing of iceberg-rafted Antarctic debris

http://www.nature.com/nature/journal/v510/n7503/abs/nature13397.html (http://www.nature.com/nature/journal/v510/n7503/abs/nature13397.html)


See also: Research published in Nature Communications showing that current Southern Ocean waters are becoming more layered with cold water on top and warm water below; which promotes ice melting near the grounding lines of Antarctic marine glaciers, as occurred 14,000 years ago during the Meltwater Pulse 1A.  This clear indicates an increasing risk of multiple meters of SLR this century:

http://www.sciencecodex.com/changing_antarctic_waters_could_trigger_steep_rise_in_sea_levels-142713 (http://www.sciencecodex.com/changing_antarctic_waters_could_trigger_steep_rise_in_sea_levels-142713)

Extract: "The research published in Nature Communications found that in the past, when ocean temperatures around Antarctica became more layered - with a warm layer of water below a cold surface layer - ice sheets and glaciers melted much faster than when the cool and warm layers mixed more easily.

This defined layering of temperatures is exactly what is happening now around the Antarctic.
"The reason for the layering is that global warming in parts of Antarctica is causing land-based ice to melt, adding massive amounts of freshwater to the ocean surface," said ARC Centre of Excellence for Climate System Science researcher Prof Matthew England an author of the paper.
"At the same time as the surface is cooling, the deeper ocean is warming, which has already accelerated the decline of glaciers on Pine Island and Totten. It appears global warming is replicating conditions that, in the past, triggered significant shifts in the stability of the Antarctic ice sheet.""

Returning to the main topic: jai pointed out that Joughin's lower bound estimate of it taking about a couple of hundred years to pre-condition the WAIS into a collapse mode; however, I could image that on a BAU pathway such conditions could be achieved by about 2090 (see the WAIS Collapse thread in the Antarctic folder).  For such a condition: (a) ice shelves for the PIG & Thwaites, and the FRIS & RIS could be subject to the melt-pond hydro-fracturing scenario that jai mentions, and (b) the thinning ice streams for all of the WAIS marine ice streams could result in upstream crevasses that could be subject to a similar hydro-fracturing mechanism as that being considered for the Jakobshavn Glacier (see the following post by A-team in the Greenland folder):


https://agu.confex.com/data/handout/agu/fm14/Paper_28053_handout_1869_0.pdf (https://agu.confex.com/data/handout/agu/fm14/Paper_28053_handout_1869_0.pdf) # Greenland # Saturated Crevasses along Shear Margins of Jakobshavn # A Ring # "temporal increase in lateral drag seems to indicate  long-­‐term stress loading of the shear margins as the ice  stream response to down stream mass perturbations at  the terminus. Differences in transects indicate that  regions where water-­‐filled crevasses are found the  magnitude of lateral drag is less and the rate of drag  increase is smaller than regions without water. Given  this, preliminary results suggest that water-­‐filled  crevasses are weakening the shear margins and likely  resulting in enhanced stress loading in other parts of  the shear margins that are devoid of water."

In the PIG/Thwaites thread in the Antarctic folder, I call this the Thwaites Effect (after the well documented Jakobshavn Effect), where a marine ice stream without an ice shelf can progressively calve potentially producing an armada of icebergs.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on December 27, 2014, 09:22:03 PM
Rignot recently estimated 100-200 years for one third of WAIS to collapse into the ocean, so about 1m in one century at the fastest:
http://www.washingtonpost.com/national/health-science/research-casts-alarming-light-on-decline-of-west-antarctic-ice-sheets/2014/12/04/19efd3e4-7bbe-11e4-84d4-7c896b90abdc_story.html (http://www.washingtonpost.com/national/health-science/research-casts-alarming-light-on-decline-of-west-antarctic-ice-sheets/2014/12/04/19efd3e4-7bbe-11e4-84d4-7c896b90abdc_story.html)

Blanchon et al 2009 estimate 2-3m in as little as 50 years during the Eemian:
http://thinkprogress.org/climate/2009/04/15/203960/nature-sea-level-rise-global-warming-reefs/ (http://thinkprogress.org/climate/2009/04/15/203960/nature-sea-level-rise-global-warming-reefs/)

Richard Alley speaks of 3m in centuries or decades (at 40m10s):
http://youtu.be/o4oMsfa_30Q?t=40m10s (http://youtu.be/o4oMsfa_30Q?t=40m10s)

Rohling et al 2013 estimate a maximum potential rate of 1 meter/decade in their figure 2a:
http://www.nature.com/srep/2013/131212/srep03461/fig_tab/srep03461_F2.html (http://www.nature.com/srep/2013/131212/srep03461/fig_tab/srep03461_F2.html)

Meltwater Pulse 1A was 4-6 meter/century, probably, but in different conditions, with more ice, but lower climate forcing.

So my view so far is that 4m in four decades is to some extent supported by some experts as the most extreme worst-case possibility. Jackson's 4m in a 'couple of years' I've not heard before, so I'll ask him what his argument is for that statement.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on December 27, 2014, 09:37:38 PM
Here is the reference doc looking at Antarctica's meltwater pulse 1A contribution.  Note the paleo grounding lines extending out beyond the current limits of the Ronne and Ross Ice Shelves.

http://www.nature.com/ncomms/2014/140929/ncomms6107/full/ncomms6107.html (http://www.nature.com/ncomms/2014/140929/ncomms6107/full/ncomms6107.html)

Antarctic contribution to meltwater pulse 1A from reduced Southern Ocean overturning
doi:10.1038/ncomms6107
N. R. Golledge et. al.

Quote
During the last glacial termination, the upwelling strength of the southern polar limb of the Atlantic Meridional Overturning Circulation varied, changing the ventilation and stratification of the high-latitude Southern Ocean. During the same period, at least two phases of abrupt global sea-level rise—meltwater pulses—took place. Although the timing and magnitude of these events have become better constrained, a causal link between ocean stratification, the meltwater pulses and accelerated ice loss from Antarctica has not been proven. Here we simulate Antarctic ice sheet evolution over the last 25 kyr using a data-constrained ice-sheet model forced by changes in Southern Ocean temperature from an Earth system model. Results reveal several episodes of accelerated ice-sheet recession, the largest being coincident with meltwater pulse 1A. This resulted from reduced Southern Ocean overturning following Heinrich Event 1, when warmer subsurface water thermally eroded grounded marine-based ice and instigated a positive feedback that further accelerated ice-sheet retreat.

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on December 27, 2014, 10:32:25 PM
Yes, but do we know how fast SLR was during Meltwater Pulse 1A?

Deschamps et al give 14-18m over about 350 years, so that would be about 4-5 meter/century on average:
http://www.nature.com/nature/journal/v483/n7391/full/nature10902.html (http://www.nature.com/nature/journal/v483/n7391/full/nature10902.html)

If there were separate shorter pulses during MWP 1A, then the maximum rate of SLR was maybe even faster than 4-5 meter/century. So who knows, maybe even 4-5 meters in a few decades?

Golledge et al think Antarctica probably contributed about 3-4 meter of SLR in a few centuries to MWP 1A:
http://www.reportingclimatescience.com/news-stories/article/antarctic-changes-could-trigger-steep-sea-level-rise.html (http://www.reportingclimatescience.com/news-stories/article/antarctic-changes-could-trigger-steep-sea-level-rise.html)

For the possibility of a few meters in a few years I've not seen any indications so far.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 27, 2014, 11:25:28 PM
Yes, but do we know how fast SLR was during Meltwater Pulse 1A?

Deschamps et al give 14-18m over about 350 years, so that would be about 4-5 meter/century on average:
http://www.nature.com/nature/journal/v483/n7391/full/nature10902.html (http://www.nature.com/nature/journal/v483/n7391/full/nature10902.html)

If there were separate shorter pulses during MWP 1A, then the maximum rate of SLR was maybe even faster than 4-5 meter/century. So who knows, maybe even 4-5 meters in a few decades?

Golledge et al think Antarctica probably contributed about 3-4 meter of SLR in a few centuries to MWP 1A:
http://www.reportingclimatescience.com/news-stories/article/antarctic-changes-could-trigger-steep-sea-level-rise.html (http://www.reportingclimatescience.com/news-stories/article/antarctic-changes-could-trigger-steep-sea-level-rise.html)

For the possibility of a few meters in a few years I've not seen any indications so far.

Lennart,

It is good that you are going to e-mail Jackson for his source because I doubt that you will find in a published reference with any statement that at some indefinite point in the future that the WAIS could collapse in a couple of years.  That said you should remain aware about the difference between a statement (by Jackson) that as an upper bound physical possibility that the WAIS could collapse in a couple of years is much different than getting a computer model to simulate and forecast such a possibility (including confidence levels); which is about the only thing besides an expert opinion poll that can be peer reviewed.  I suspect that the ACME projections, completed in about 10-years, will be the only reliable first approximation of such a possibility/probability; and it may well be several more decades after that before a model can make a meaningful projection of this risk (note that earthquakes, volcanoes, basal melting, changes in currents, winds and possible future rain events and interaction with Greenland events, etc. would need to be considered to establish an upper physical bound [which the IPCC does not address]).

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on December 27, 2014, 11:36:46 PM
I cannot recall specifically but I think that the model involved a grounding line retreat such that the PIG eventually meets the Ronne-Filchner sea with a seaway. oh looky I found a link to the resident master's analyses!

Yes, the idea is that significantly increased flowrates produce rapid collapse once a seaway is opened beneath the sheets.

http://forum.arctic-sea-ice.net/index.php/topic,31.0/nowap.html (http://forum.arctic-sea-ice.net/index.php/topic,31.0/nowap.html)

In the accompanying figure from Vaughan et al. 2011, the researcher postulate that the indicated seaways opened in the WAIS during the Eemian period some 124,000 years ago.  Vaughan et al. proved that for an upper bound that the longest of these seaways formed within less than a thousand years (which is well within the timeframe of the Eemian peak proving that WAIS could have contributed at least 3.4 to 3.8 m to eustatic SLR in that period) .  I propose that by 2100 such seaways could be re-established in the WAIS via a combination of: (a) floatation of ice sheet sections that have thinned sufficiently for them to float; (b) the formation of a network of interconnected subglacial cavities paralleling the seaways identified by Vaughan et al., which (when interconnected) would allow tidally induced flushing of CDW to rapidly melt the basal ice around the expanding interconnected cavities; (c) accelerated caving of both glaciers and ice shelves due to such factors as increasing CDW temperatures, tidal action, periodic subglacial meltwater network lubrication of basal friction (see surge post topic), and increased wave action due to telecommunication from the Topical Pacific Ocean; (d) a melt-pond mechanism collapse of the Ross Ice shelf after 2050; and (e) a change in the currents in the Weddell Sea after 2050 leading to accelerated CDW advection forced retreat of the glaciers grounding lines in that region so that the grounding lines retreat past buttressing ridges that have been supporting those glaciers.

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on December 27, 2014, 11:41:54 PM
More from SLRs thread

As my proposed WAIS collapse scenario has many similarities as to what may have happened during the Eemian, I provide the accompanying figure from Barnes et al 2010 showing the probable condition of the WAIS at the Eemian peak.  This condition is supported both on the fossil records of Bryozoans and on DNA of existing  family of Antarctic octopus the West Antarctic.  Furthermore, in 2011 based on marine sediments it was found that GIS could only have contributed 1.6-2.2m to Eemian sea level; while in 2012, based on GIS ice core (NEEM) findings, the high-end of this contribution was further limited indicating that the WAIS contributed at least 3.5 to 3.8m at that time.

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 28, 2014, 12:05:03 AM
jai,

Indeed, if you want to talk about non-peer reviewed scenarios, then the attached image from Reply #23 (from the linked Antarctic fold thread on the WAIS Collapse), shows a conceivable scenario of how the WAIS could be on the brink of total collapse by 2090, following a RCP 8.5 50% CL pathway.

http://forum.arctic-sea-ice.net/index.php/topic,31.0.html (http://forum.arctic-sea-ice.net/index.php/topic,31.0.html)

However, I think that Lennart is looking for more of a peer-reviewed published reference; which according to RAND and the Robust Decision Making methodology is the wrong thing to be looking for, because by the time that you have that, you will be well past the tipping point.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on December 28, 2014, 12:27:54 AM
"Rignot recently estimated 100-200 years for one third of WAIS to collapse into the ocean, so about 1m in one century at the fastest"

From that one source. So the max in one century would be considerably higher when you add in GIS, glaciers and expansion, twice as fast. And of course there are known and unknowns unknowns that could accelerate that further.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on December 28, 2014, 12:41:06 AM
ASLR, Jai,

Let's just say I would like to know how people like Hansen, Pfeffer, Rignot, Alley, Rohling, Joughin, Vaughan, etc. think of Jeremy Jackson's statement. They all have peer-reviewed papers published, but they also make statements in lectures and popular articles, or via expert elicitations, that indicate their thinking beyond their scientific papers. I've referred to a few of those statements above.

I've sent Jackson an email and will let you know if and when he replies. It could also be he meant decades instead of years. It has happened to me that I said meters/year when I meant meters/century during a presentation.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on December 28, 2014, 12:50:24 AM
wili,
You're right of course. That 1 meter of Rignot could make total SLR by 2100 near 2m, or even some more. And from 2100 to 2200 maybe 4, 5 or even 6-7 meter could be added, according to Kopp  et al 2014. But all that would imply 4m in a few decades as the most abrupt SLR considered plausible by the experts so far.

Who knows it can go even faster, but that's a speculation that Jackson did not present as such. So either he knows more than others, of he made a mistake, or he speculated without making that explicit, or he tried to alarm his audience by making the science sound even more alarming than it already is.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 28, 2014, 12:51:30 AM
"Rignot recently estimated 100-200 years for one third of WAIS to collapse into the ocean, so about 1m in one century at the fastest"

From that one source. So the max in one century would be considerably higher when you add in GIS, glaciers and expansion, twice as fast. And of course there are known and unknowns unknowns that could accelerate that further.

I think that we should all recognize that in the following extract, Rignot does suggest that within 100 to 150-years 1/3 of the WAIS could be gone.  However, if one realizes that any such SLR contribution must accelerate non-linearly from about 0.3mm/year today to say 1,500 mm/year by the end of 100 to 150-years, then it may be conceivable that Jackson's statement might be approximately correct at the end of such a period of non-linear acceleration (obviously my projection of such a rate of SLR contribution being possible between 2090 and 2100 is contingent upon the effective climate sensitivity also increasing to something like 6 C by 2100):

http://www.washingtonpost.com/national/health-science/research-casts-alarming-light-on-decline-of-west-antarctic-ice-sheets/2014/12/04/19efd3e4-7bbe-11e4-84d4-7c896b90abdc_story.html (http://www.washingtonpost.com/national/health-science/research-casts-alarming-light-on-decline-of-west-antarctic-ice-sheets/2014/12/04/19efd3e4-7bbe-11e4-84d4-7c896b90abdc_story.html)

Extract: "So how fast could the loss of West Antarctica unfold? Velicogna’s co-author, Eric Rignot of UC-Irvine, suggested that in his view, within 100 to 200 years, one-third of West Antarctica could be gone.
Rignot noted that the scientific community “still balks at this” — particularly the 100-year projection — but said he thinks observational studies are showing that ice sheets can melt at a faster pace than model-based projections take into account."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 28, 2014, 01:03:18 AM
The following quote by Rignot is from the 2014 Rolling Stone article:

"Thwaites glacier started to accelerate after 2006 and in 2011 we detected a huge retreat of the glacier grounding lines since 2000. Detailed reconstructions of the glacier bed further confirmed that no mountain or hill in the back of these glaciers could act as a barrier and hold them up; and 40 years of glacier flow evolution showed that the speed-up was a long story.
At the current rate, a large fraction of the basin will be gone in 200 years, but recent modelling studies indicate that the retreat rate will increase in the future.
Controlling climate warming may ultimately make a difference not only about how fast West Antarctic ice will melt to sea, but also whether other parts of Antarctica will take their turn. Several "candidates" are lined up, and we seem to have figured a way to push them out of equilibrium even before warming of air temperature is strong enough to melt snow and ice at the surface.
Unabated climate warming of several degrees over the next century is likely to speed up the collapse of West Antarctica, but it could also trigger irreversible retreat of marine-based sectors of East Antarctica. Whether we should do something about it is simply a matter of common sense. And the time to act is now; Antarctica is not waiting for us."

Obviously, until we know what the climate sensitivity and the radiative forcing will be, we are all (including experts like Rignot) just guessing how bad the rate of Antarctic contribution to SLR could be by the end of the next 100 to 200 years.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on December 28, 2014, 01:49:41 AM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fbibleencyclopedia.com%2Fnasbsmall%2FNASB_Romans_1-22.jpg&hash=400e312496e5c11817d78fab9fad821c)

Similar to the projections of declines in Sea Ice Extent,
Similar to the hesitancy to use PIOMAS volume data instead of Sea Ice Extent,


Is the reluctance to accept that current model projections neglect to include newly discovered and thoroughly unexpected causal mechanisms of transformation.  These mechanisms, due to their unknown origin and, in some cases, uncertain effects cannot be constrained within standard climate model projections. 

For instance:  What if recently observed Circumpolar Deep Water temperatures continue to increase at the "jaw dropping" rates observed recently, and that this trend is the primary force that caused the massive contribution to SLR by Antarctica under meltwater pulse 1A?

http://blogs.ei.columbia.edu/2010/12/14/deep-ocean-heat-is-melting-antarctic-ice/ (http://blogs.ei.columbia.edu/2010/12/14/deep-ocean-heat-is-melting-antarctic-ice/)

Quote
Martinson said that heat stored in deep waters far from Antarctica is being pushed southward and becoming entrained in the Antarctic Circumpolar Current, a vast, wind-driven water mass that constantly circles the frozen continent. The evidence comes from 18 years of Antarctic voyages Martinson has made to measure water temperature, salinity and other qualities at different depths. He called the increases in ocean heat in the past few decades “jaw dropping.”



Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on December 28, 2014, 11:01:01 AM
Could we ever reach 1500 mm/yr of SLR?

Bouman et al 2014 measured about 0.5 mm/yr SLR from WAIS from 2009-2012:
http://onlinelibrary.wiley.com/doi/10.1002/2014GL060637/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2014GL060637/abstract)

Jeremy Jackson said in his lecture last month that when WAIS collapses, and this will happen, he said, then that would mean '4m of SLR in a couple of years'. So let's say that would mean 1000 mm/yr SLR from WAIS, for a few years.

Rignot, Alley, Joughin etc indicate a potential WAIS-collapse, once initiated, within a few decades. Let's say about 3m in three decades, or about 100 mm/yr, at or around the end of this century at the earliest.

About 100 mm/yr is also the highest rate of SLR thought plausible by Rohling et al.

For the Amundsen Sector of WAIS, which contains about 1.2m of SLR rapid collapse will start once its SLR-contribution is about 1 mm/yr, according to Rignot et al 2014 and Joughin et al 2014:
http://onlinelibrary.wiley.com/doi/10.1002/2014GL060140/full (http://onlinelibrary.wiley.com/doi/10.1002/2014GL060140/full)

And:
http://www.sciencemag.org/content/344/6185/735.abstract (http://www.sciencemag.org/content/344/6185/735.abstract)

So how could we go from the current 0.5 mm/yr SLR from WAIS to 100 or even 1000 mm/yr?

If we assume, inspired by Jim Hansen, that SLR from WAIS will be 0.5 mm/yr from 2005-2015 and would double every 10 years, then we would need eight doublings to reach 128 mm/yr from 2085-2095, and three more doublings to reach 1024 mm/yr from 2115-2125. One more doubling would give 2048 mm/yr from 2125-2135.

This in turn would imply 2.55m of SLR from WAIS by 2095, and almost another meter by 2100, so let's say 3.5m by 2100, with about 3m in the last three decades of this century. Then all the most vulnerable ice from WAIS would be pretty much gone and it would have fully collapsed.

Total SLR by 2100 would then be 4-5m, depending on the GIS-contribution. If this could not be reached by 2100, then maybe shortly thereafter.

So could total SLR ever speed up to more than say 100-200 mm/yr, not just mathematically, but also physically?

That would probably require EAIS to be about as vulnerable as WAIS, at least from about 2100 onwards. Or a little less vulnerable relative to its greater size: since it contains about 19m of marine based ice it can afford to lose less ice per year per basin to reach a comparable SLR-contribution to WAIS. But then this would still seem only enough to sustain SLR at this very high speed of 100-200 mm/yr.

Also Pfeffer and Hansen have pointed to likely kinematic constraints and a negative iceberg cooling effect, which could imply maximum SLR could be rate-limited, as Rohling calls it. So maybe about 100 mm/yr is about the maximum plausible SLR that could be sustained for more than a few decades even under very strong forcing?

At least it's hard to see how it could become even faster than the 100-200 mm/yr we find via assuming a 10-year doubling time for ice mass loss (or what we could call a Hansen thought experiment or extrapolation). The doubling time could also be 5 or 20 years, but sooner or later it would stop because the (vulnerable) ice would be gone.

So the question is: will ice loss grow exponentially and if so, how fast and far? And how abrupt can the ice loss become, whether it will grow exponentially or not?

In any case, Jackson's 4m in a few years, seems impossible to me, but maybe others see possibilities for it to become reality nevertheless.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 28, 2014, 01:02:34 PM
Lennart,

As you are willing to consider contributions to SLR other than from the WAIS in Jackson's statement: I first provide the following quote from the Rolling Stone article about Jason Box's theory about why Greenland ice sheet is disappearing (and will continue to disappear at accelerating rates) faster than previously predicted:

http://www.rollingstone.com/feature/greenland-melting (http://www.rollingstone.com/feature/greenland-melting)

Quote: "In early 2012, Box predicted there would be surface melting across the entirety of Greenland within a decade.  Again, many scientists dismissed this as alarmist claptrap. If anything, Box was too conservative – it happened a few months later.  He also believes that the climate community is underestimating how much sea levels could rise in the coming decades.  When I ask him if he thinks the high-end projections of six feet are too low, he doesn't hesitate: "Shit, yeah."
"Jason has one very important quality as a scientist," says Thomas Painter, a research scientist at NASA's Jet Propulsion Laboratory in Pasadena, California.  "He is willing to say crazy stuff and push the boundaries of conventional wisdom.""

Next, regarding SLR contributions from the EAIS, it is important to remember that several of these catchment basins immediately adjoin the WAIS and it is probable that Jackson would have lumped them in with the WAIS statement that he made.  For example: the article at the following link makes clear the projected introduction of warm water into the Weddell sea could eventually trigger between 3 and 4 m of SLR contribution from the Recovery catchment basin (see the associated first attached image):

http://www.bbc.co.uk/news/science-environment-25173121 (http://www.bbc.co.uk/news/science-environment-25173121)

Finally, I provide the second attached image of the time history of ice velocities for the Hudson Strait Ice Stream during the LGM, which shows that when the associated ice shelf breaks off (ala the Larsen-B shelf collapse), the ice velocities can peak for a short period of years; which if coupled with a subsequent Thwaites (Jakobshavn) Effect, might (just conceivably) make Jackson's statement plausible, if say a SLR surge from Greenland (or a large seismic event in West Antarctica) were to simultaneously trigger a shelf collapse/Thwaites Effect for multiple WAIS marine glaciers and the Recovery Ice Stream.

Alvarez-Solas, J., Robinson, A., and Ritz, C. (2012),  “Can recent ice discharges following the Larsen-B ice-shelf collapse be used to infer the driving mechanisms of millennial-scale variations of the Laurentide ice sheet?”, The Cryosphere, 6, 687–693, 2012, www.the-cryosphere.net/6/687/2012/ (http://www.the-cryosphere.net/6/687/2012/) doi:10.5194/tc-6-687-2012.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Gray-Wolf on December 28, 2014, 01:28:31 PM
And what of the 'unexpected' ( i.e. that which was unthinkable only 20yrs ago?) I've been a keen observer of Ross for the past decade and more and have had cause to approach Bob Grumbine concerning a crevasse that he was deploying seismometers into to map any changes there. It , to me, appears to be the next major calve from Ross but is far larger than the last major calve. The crevasse runs from the Roosevelt island end of Ross to beyond the central section ( heading out toward the U.S. Base). Is this not the end of Ross that needs to go before we see West Antarctica again become an island? I recall some NASA images of melt up to a mile up the trans Antarctic range to the rear of Ross so are we not now seeing the start of the process of the breakup of Ross. We know that the warm waters are now at that end of Ross so should we also now be expecting the grounding line to be retreating back toward this huge crevasse?

Changes below the feed glaciers at this end of Ross, due to the upland melt, could alter the response once this section of 'buttress' has been removed ( radar images show a huge ruck in the ice from when the shelf finally held up the ice flow and it ran over itself)?

For me Ross is the issue as we have huge amounts of ice ready to 'float off'. Any changes in either the buttress or the back pressure from the feed glaciers could lead to shear failure at the base of the shelf and catastrophic float off of large sections.

But first we have the next major calve to wait for!
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on December 28, 2014, 03:50:24 PM
LvdL wrote: "will ice loss grow exponentially and if so, how fast and far?"

Aren't there other possibilities besides linear and exponential rates of increased ice loss? Aren't there possibilities/probabilities of discontinuities--as our colleagues handle says: Abrupt SLR?

Isn't that what Alley and others are talking about happening when warm water starts to flow under the main ice sheet beneath the parts that are grounded below sea level?



Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: GeoffBeacon on December 28, 2014, 04:15:41 PM
Earthquakes and climate change (https://forum.arctic-sea-ice.net/index.php/topic,283 (https://forum.arctic-sea-ice.net/index.php/topic,283))

Any recent information that might be relevent here?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Gray-Wolf on December 28, 2014, 04:17:25 PM
This is my main concern Wili! At times i think it unhelpful to look at past warmings , and the changes they wrought, because the forcing this time is novel and incredibly fast?

When I look at loading's in nature a slow build up in pressure will not drive the same results as an instant forcing of that pressure? And if this is true of the ice then would we not see a domino kind of response as other areas are forced to fail by the speed of change?

The warm bottom waters have only recently made it around to Ross but I do not think it necessarily means Thwaites/PIG will have a head start in any collapse? Each outlet is different.

The ruck in the ice beneath Ross, does that act like a spring or has all the stresses now dissipated from the tension of the ice buried there? Could the 'normal' calving at the edge of Ross lead to an abnormal response now warm waters are eating away at the base of the sheet there? Has increased melt in the mountains to the rear lead to different dynamics in the feed glaciers to the rear of the shelf?

I do hope that everything is fine and we ought expect a slow 'drip,drip' type melt but Nature does seem to like the odd catastrophic collapse in systems?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on December 28, 2014, 04:30:45 PM
One thing that I find rather stunning when I step back a bit and consider the nature of the debate, is that what we are essentially discussing is ice melting. One would think that understanding how and at what pace ice melts would be the most elementary type of physics imaginable. Yet the uncertainties about how and at what rate these particular kinds of ice will melt in various potential scenarios quickly becomes mind-numbingly complex. (The same, of course, goes for the complexities of Arctic sea ice.)

Thanks to all for helping to unravel some of that complexity for my perhaps-too-easily-benumbed brain.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on December 28, 2014, 05:30:04 PM
Quote
As for Jason Box, I will ask him what he thinks of Jackson's statement as well.

Response by Box:
"4m in a 'couple of years' is really far far outside of expectations. Let us see if that 3 mm per year doubles in the coming decade to 6 mm then I would say we are on track for more than 2 m by end of century."

I then asked him what he thinks the worst-case rate of SLR for after 2100 could be, but no reply yet.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on December 28, 2014, 05:52:45 PM
One thing that I find rather stunning when I step back a bit and consider the nature of the debate, is that what we are essentially discussing is ice melting. One would think that understanding how and at what pace ice melts would be the most elementary type of physics imaginable. Yet the uncertainties about how and at what rate these particular kinds of ice will melt in various potential scenarios quickly becomes mind-numbingly complex. (The same, of course, goes for the complexities of Arctic sea ice.)

wili,
I guess the melting itself may not be so complex, but how the ice will move and how the heat will get to the ice seem to be the complex questions, that are especially hard to answer since the current situation is without natural precedent.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on December 28, 2014, 06:16:57 PM
Good points, LvdL.  "3m in three decades" That's plenty fast enough for me. I hope we can all agree that Hollywood-style instant super-tidal waves coming from ice sheet melt are not in the cards. Even 3-7m in less than a decade is beyond what I, at least, can wrap my head around (though that alone is not particularly probative one way or the other, of course).

Since this thread is about slr and cost, I am going to ask something that should probably really go in the 'stupid questions' thread:

If one of the main mechanisms for destabilization of the Antarctic ice sheets is the incursion of warm ocean water under the sheet, would it ultimately be cheaper to try to build structures that might impede or obstruct that flow in a few crucial places than to pay for the massive infrastructures that would be needed to protect coastlines around the world?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on December 28, 2014, 06:45:36 PM
Almost 7,000 UK properties to be sacrificed to rising seas
http://www.theguardian.com/environment/2014/dec/28/7000-uk-properties-sacrificed-rising-seas-coastal-erosion (http://www.theguardian.com/environment/2014/dec/28/7000-uk-properties-sacrificed-rising-seas-coastal-erosion)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on December 28, 2014, 07:05:17 PM
If one of the main mechanisms for destabilization of the Antarctic ice sheets is the incursion of warm ocean water under the sheet, would it ultimately be cheaper to try to build structures that might impede or obstruct that flow in a few crucial places than to pay for the massive infrastructures that would be needed to protect coastlines around the world?

wili,
Some people have had similar ideas for melting or preserving Arctic ice by damming the Bering Strait:
http://www.adn.com/article/could-massive-dam-between-alaska-and-russia-save-arctic (http://www.adn.com/article/could-massive-dam-between-alaska-and-russia-save-arctic)

I haven't heard of any similar ideas for Antarctica, but who knows it could help to slow the melting.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on December 28, 2014, 07:18:15 PM
I think Grey-Wolf is hitting on it quite clearly. 

Imagine Antarctica conditions in 2150 under RCP 8.5

If we are seeing surface warming above the Ross shelf (1 mile as Grey says) what will it look like if the average temperature is 20C warmer? (assuming Antarctic amplification of 1.3)  What kind of surface melt dynamics would we see? How high up?  what if, by this time, all of the shelves are gone and multiple under ice channels have opened up between the Ronne-Filchner to the Admusen and even over to the Ross seas.  These channels allowing direct current flow of Deep water to melt the ice with significantly higher temperature water at flowrates 100 times the current rates of intrusion?

This is a snapshot of what it will most likely look like, in this scenario what does Greenland look like?

What will be the average sea level rise by this time under these scenarios? 2 meters? 5 meters?

if only 2 meters by 2150, what is the effect of this sea level rise on lifting current grounding lines?

------------

I write these things to remind all that the radical environmental changes that will be incurred by RCP 8.5 over the next few hundred years is inconceivable within current models.  It is far too different than current conditions.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 28, 2014, 09:49:04 PM
I would like to note that some issues associated with the potential collapse of the FRIS/RIS ice shelves can be found in the Antarctic folder at the following link (which discusses melt pond risks, calving risks and changes in warm ocean currents).

http://forum.arctic-sea-ice.net/index.php/topic,117.0.html (http://forum.arctic-sea-ice.net/index.php/topic,117.0.html)

Furthermore, I would like to note that due to systemic pressures most scientists have to date focused on either the most likely future scenarios, and/or the scenarios that err on the side of least drama.  Even efforts such as Tad Pfeffer's efforts to define an upper limit to SLR (or 2m) based on ice flow kinematics were based on the assumption that the ice streams would remain grounded.  For Jackson to be correct (assuming that he did not misspeak) then it is clear that the only mechanism that could achieve such a rapid rate of SLR would be the formation of icebergs (as within 2 years there would not be sufficient time for the ice to melt) from the previously grounded ice streams.  While the near simultaneous formation of armadas of icebergs may not appear to be terribly likely; in my opinion such scenarios merit serious investigation as the consequence of such a scenario are so very high.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on December 29, 2014, 01:41:19 PM
Is the present the key to the future?

doi:10.1016/j.earscirev.2014.12.005

Quote
The empirical and conceptual relationships between Earth surface processes and global changes are very complex. The concept that “the present is the key of the future” implies that we know enough the present to be able to extend our knowledge forward to focus on the future. Field and remote observations on the present-day Earth surface processes represent the methodological instruments for the forecasting. At the end of the 1980s, the scientific community predicted a significant increase of global warming followed by changes in the trends of related surface processes. Some processes, such as the Arctic and Antarctic snow melting are now accelerating and even irreversible, thus these trends show that we are now in an ‘out of scale’ discontinuity moment. Present-day measures and observations could be scarcely significant and may add uncertainty in the prediction of future trends. The ‘out-of-scale’ trend raises a fundamental question regarding the present, since it may provide a new angle of thought for contemporary theoretical approaches. The need for reducing the uncertainty in the trends of future processes requires a deep rethinking of the current paradigms in order to consider also the ‘out of scale‘ trends.

http://www.sciencedirect.com/science/article/pii/S0012825214002256 (http://www.sciencedirect.com/science/article/pii/S0012825214002256)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on December 29, 2014, 08:47:10 PM
East Cost "nuisance" flooding already increasing
http://www.enn.com/environmental_policy/article/48133?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+EnvironmentalNewsNetwork+%28Environmental+News+Network%29 (http://www.enn.com/environmental_policy/article/48133?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+EnvironmentalNewsNetwork+%28Environmental+News+Network%29)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 03, 2015, 10:45:19 PM
The following abstract from DeConto & Pollard (2014) confirms the disturbing message that I have been conveying by saying:

"… the same model shows the potential for massive ice and freshwater discharge beginning in the second half of this century.
 …
In the more aggressive (and arguably more likely) RCP8.5 scenario, Pine Island Bay retreat is followed by more massive retreat of the entire WAIS, and eventual ice retreat into deep East Antarctic basins.

Here, we demonstrate that large portions of the Antarctic Ice Sheet (in West and East Antarctica) can retreat on relatively short (decadal to centennial) timescales, posing a serious threat to global populations."

DeConto R, and Pollard D., (2014), "Antarctica's potential contribution to future sea-level rise", SCAR - COMNAP Symposium

http://www.scar2014.com/assets/SCAR_and_COMNAP_2014_Abstract_Document.pdf (http://www.scar2014.com/assets/SCAR_and_COMNAP_2014_Abstract_Document.pdf)

Abstract: "A hybrid ice sheet-shelf model with freely migrating grounding lines is improved by accounting for 1) surface meltwater enhancement of ice shelf calving; and 2) the structural stability of thick (>800 m), marine-terminating (tidewater) grounding lines. When coupled to a high-resolution atmospheric model with imposed or simulated ocean temperatures, the new model is demonstrated to do a good job simulating past geologic intervals with high (albeit uncertain) sea levels including the Pliocene (3Ma; +20 ±10m) and the Last Interglacial (130-115ka; +4-9m).  When applied to future IPCC CMIP5 RCP greenhouse gas forcing scenarios with ocean temperatures provided by the NCAR CCSM4, the same model shows the potential for massive ice and freshwater discharge beginning in the second half of this century. In both RCP2.6 and 8.5 scenarios considerable retreat begins in the Pine Island Bay region of West Antarctica. In the more aggressive (and arguably more likely) RCP8.5 scenario, Pine Island Bay retreat is followed by more massive retreat of the entire WAIS, and eventual ice retreat into deep East Antarctic basins. During peak rates of retreat, freshwater discharge exceeds 1 Sv and exceeds 0.2 Sv for several centuries with potential to disrupt ocean circulation in addition to contributing between 2m and 9m sea level rise within the next 500 years. Here, we demonstrate that large portions of the Antarctic Ice Sheet (in West and East Antarctica) can retreat on relatively short (decadal to centennial) timescales, posing a serious threat to global populations."


Edit:

Lennart,

Maybe this explains (partially) what Jackson was talking about (surface meltwater entering crevasses of marine glaciers more than 800 m thick, such as Thwaites)?

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 04, 2015, 02:12:16 AM
As a follow-up note to my last post:  Sea level rise due to melting glaciers is about ~ 0.01 Sv, and as glaciers currently contribute about 0.71mm/year to SLR; therefore the peak 1.0 Sv discharge that DeConto & Pollard 2014 cite is equal to a rate of SLR of about 0.071meters per year, or about 1/30th the rate that Jackson cited.

Edit: I fixed a math error
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on January 04, 2015, 07:41:27 AM
1) That 800 m thickness is related to an earlier paper (whose name escapes me, and for which i have not time now to search) giving the upper limit for marine fonted ice mass thickness as a kilometer.

2) 0.071 m/yr is 1 m in 15 yr, exceeding estimated peak rate at MWP1A of 1 m/20 yr, although of course the latter persisted for 500 yr ...

3) decadal to centennial scale sounds bad

4)second half of this century sounds bad too ...

O dear, Pollard and Diconto have got much more assuredly pessimistic since a few years ago. So has Rignot.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on January 04, 2015, 10:13:32 AM
Sea level rise due to melting glaciers is about ~ 0.01 Sv, and as glaciers currently contribute about 0.71mm/year to SLR; therefore the peak 1.0 Sv discharge that DeConto & Pollard 2014 cite is equal to a rate of SLR of about 0.071meters per year, or about 1/30th the rate that Jackson cited.

ALSR,

Thanks, I'd not realized yet that 1 Sv of meltwater sustained for a year contributes about 86 mm to SLR. So add in thermal expansion and meltwater from GIS, and about 100 mm/yr of SLR would be possible as a peak rate, according to DeConto & Pollard. This is also the maximum rate of SLR thought plausible in Rohling et al 2013, based only on geological evidence. Sustained for a decade that would be 1 meter/decade. Still about an order of magnitude smaller than Jackson's remark, but plenty abrupt enough for human societies, it seems.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on January 04, 2015, 08:38:32 PM
NOAA establishes 'tipping points' for sea level rise related flooding
http://www.terradaily.com/reports/NOAA_establishes_tipping_points_for_sea_level_rise_related_flooding_999.html (http://www.terradaily.com/reports/NOAA_establishes_tipping_points_for_sea_level_rise_related_flooding_999.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 05, 2015, 01:28:33 AM
The linked article indicates that before the end of the century super-typhoons could attain wind speed of 85 to 90 m/sec, which will of course increase storm surge on top of SLR.

Kazuhisa Tsuboki, Mayumi Yoshioka, Taro Shinoda, Masaya Kato, Sachie Kanada and Akio Kitoh, (2014), "Future increase of super-typhoon intensity associated with climate change", Geophysical Research Letters, DOI: 10.1002/2014GL061793


http://onlinelibrary.wiley.com/doi/10.1002/2014GL061793/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2014GL061793/abstract)

Abstract "Increases of tropical cyclone intensity with global warming have been demonstrated by historical data studies and theory. This raises great concern regarding future changes in typhoon intensity. The present study addressed the problem to what extent super-typhoons will become intense in the global warming climate of the late twenty-first century. Very high-resolution downscale experiments using a cloud-resolving model without convective parameterizations were performed for the 30 most intense typhoons obtained from the 20-km-mesh global simulation of a warmer climate. Twelve super-typhoons occurred in the downscale experiments and the most intense super-typhoon attained a central pressure of 857 hPa and a wind speed of 88 m s−1. The maximum intensity of the super-typhoon was little affected by uncertainties that arise from experimental settings. This study indicates that the most intense future super-typhoon could attain wind speeds of 85–90 m s−1 and minimum central pressures of 860 hPa."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on January 06, 2015, 01:45:58 PM
US coastal cities face daily flooding by mid-century – NOAA - S
http://www.rtcc.org/2015/01/06/us-coastal-cities-face-daily-flooding-by-mid-century-noaa/ (http://www.rtcc.org/2015/01/06/us-coastal-cities-face-daily-flooding-by-mid-century-noaa/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on January 06, 2015, 02:13:34 PM
Quote
Although the term “nuisance floods” may connote minor flooding with little reason for concern, the impacts of repetitive floods should not be underestimated, the study’s lead author, William Sweet of the National Oceanic and Atmospheric Administration (NOAA), told reporters at the annual meeting of the American Geophysical Union on Thursday.

“It’s an emerging flooding crisis,” Sweet, an oceanographer with NOAA’s National Ocean Service, said.
http://mashable.com/2014/12/20/washington-dc-sea-level-rise/ (http://mashable.com/2014/12/20/washington-dc-sea-level-rise/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on January 07, 2015, 12:07:52 AM
Quote
As for Jason Box, I will ask him what he thinks of Jackson's statement as well.

Response by Box:
"4m in a 'couple of years' is really far far outside of expectations. Let us see if that 3 mm per year doubles in the coming decade to 6 mm then I would say we are on track for more than 2 m by end of century."

I then asked him what he thinks the worst-case rate of SLR for after 2100 could be, but no reply yet.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: tombond on January 07, 2015, 12:39:26 AM
Quote
As for Jason Box, I will ask him what he thinks of Jackson's statement as well.

Response by Box:
"4m in a 'couple of years' is really far far outside of expectations. Let us see if that 3 mm per year doubles in the coming decade to 6 mm then I would say we are on track for more than 2 m by end of century."

Very realistic reply from Jason Box.  The key to the timing of abrupt sea level rise is the rate of acceleration in the land ice melt rate.  If ice melt rates and thus sea level rise doubles every decade (or less) then we could see a one metre sea level rise by mid century or just after.

This possibility should be central to all coastal infrastructure planning world wide.

 


Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 07, 2015, 12:50:34 AM
Quote
As for Jason Box, I will ask him what he thinks of Jackson's statement as well.

Response by Box:
"4m in a 'couple of years' is really far far outside of expectations. Let us see if that 3 mm per year doubles in the coming decade to 6 mm then I would say we are on track for more than 2 m by end of century."

I then asked him what he thinks the worst-case rate of SLR for after 2100 could be, but no reply yet.

Lennart,

Thanks for the great follow-up on this matter.  While I fully agree with Jason Box's response, I will play a little bit of the devil's advocate by citing the following few ways that such an occurrence so far far outside of expectations "might" (or might not) actually happen:

1.  The Earth's magnetic dipole is currently on a pace to flip 180 degrees within the next 100-years.  Thus given the Byrd Subglacial Basin's exceptionally thin crust, it may be that sometime after 2050 the magma beneath the BSB may change (may become: less viscous, faster flowing, etc.) sufficiently to induce seismic/volcanic activity or extreme basal ice melting in the BSB by 2100.
2.  ECS may very well currently be 4.5 C, and if society stays on a BAU pathway the effective climate sensitivity could equal or exceed 6 C by 2100; which in turn could lead to excessive surface ice melting on the West Antarctic ice shelves and on the lower altitude perimeter of the WAIS itself; which could accelerate marine glacier calving rates well beyond that cited by Bassis & Jacobs 2013 (due to hydrostatic pressure within the Bassis & Jacobs postulated crevasses).
3.  I am concerned that the projected increased magnitude and frequencies of both El Nino and cyclonic events will increase advection of ocean water into increasingly deep subglacial marine cavities; which will also cause accelerated calving.

Obviously, other extreme scenarios are possible, but until we have more/better evidence, or better Earth System Models, a SLR contribution from the WAIS by 2100 of 1m to 2m would appear to be much more likely.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 07, 2015, 01:50:18 AM
With a hat tip to Lennart from the WAIS Collapse thread in the Antarctic folder, the linked reference (with a free access pdf) shows that assuming both cliff failure, and melt-driven hydrofracturing, active the WAIS could contribute from 2m to 3m to SLR by 2100 (note that almost all of my posts in the Antarctic folder support this approximation), per the attached image and associated caption:

Pollard, D., DeConto, R.M. and Alley, R.B., (2015), "Potential Antarctic Ice Sheet retreat driven by hydrofracturing and ice cliff failure", Earth and Planetary Science Letters, Volume 412, 15 February 2015, Pages 112–121, doi:10.1016/j.epsl.2014.12.035

http://www.sciencedirect.com/science/article/pii/S0012821X14007961 (http://www.sciencedirect.com/science/article/pii/S0012821X14007961)



Abstract: "Geological data indicate that global mean sea level has fluctuated on 103 to 106 yr time scales during the last ∼25 million years, at times reaching 20 m or more above modern. If correct, this implies substantial variations in the size of the East Antarctic Ice Sheet (EAIS). However, most climate and ice sheet models have not been able to simulate significant EAIS retreat from continental size, given that atmospheric CO2 levels were relatively low throughout this period. Here, we use a continental ice sheet model to show that mechanisms based on recent observations and analysis have the potential to resolve this model–data conflict. In response to atmospheric and ocean temperatures typical of past warm periods, floating ice shelves may be drastically reduced or removed completely by increased oceanic melting, and by hydrofracturing due to surface melt draining into crevasses. Ice at deep grounding lines may be weakened by hydrofracturing and reduced buttressing, and may fail structurally if stresses exceed the ice yield strength, producing rapid retreat. Incorporating these mechanisms in our ice-sheet model accelerates the expected collapse of the West Antarctic Ice Sheet to decadal time scales, and also causes retreat into major East Antarctic subglacial basins, producing ∼17 m global sea-level rise within a few thousand years. The mechanisms are highly parameterized and should be tested by further process studies. But if accurate, they offer one explanation for past sea-level high stands, and suggest that Antarctica may be more vulnerable to warm climates than in most previous studies."

Caption: "Global mean equivalent sea level rise in warm-climate simulations. Time series of global mean sea level rise above modern are shown, implied by reduced Antarctic ice volumes. The calculation takes into account the lesser effect of melting ice that is originally grounded below sea level. Cyan: with neither cliff failure nor melt-driven hydrofracturing active. Blue: with cliff failure active. Green: with melt-driven hydrofracturing active. Red: with both these mechanisms active."

Edit: I note that the values given in the attached image are for a simple Pliocene-like warming scenario, and not for any RCP or SRES pathways.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 07, 2015, 04:21:20 PM
As Pollard, DeConto & Alley 2015 use a simple Pliocene-like initial condition, the real question is how soon will the waters and atmosphere around the Western Antarctic reach these conditions (allowing for both cliff failure and hydrofracturing).  While I do not have time to repeat my posts in the Antarctic folder (look there if you have time), I believe that the PIG/Thwaites basins will reach the cliff failure threshold by 2040 (this is based on both the ozone hole increasing the westerly winds which has increase upwelling of warm ocean water near the grounding line in this area and the increasing frequency of El Nino events in this timeframe), and that hydrofracturing will be more prevalent around the WAIS perimeter (& ice shelves) by the 2060 to 2070 assuming that society stay near an RCP 8.5 pathway through the 2040 to 2050 timeframe.  This could result collapse of the WAIS at the rates cited by Pollard, DeConto & Alley 2015 between 2070 & 2100.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on January 07, 2015, 07:23:50 PM
This could result collapse of the WAIS at the rates cited by Pollard, DeConto & Alley 2015 between 2070 & 2100.

ASLR,
Are you thinking about 1m SLR from WAIS between 2070 and 2100? Or complete collapse, so 3m in three decades?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on January 07, 2015, 08:58:14 PM
This could result collapse of the WAIS at the rates cited by Pollard, DeConto & Alley 2015 between 2070 & 2100.

ASLR,
Are you thinking about 1m SLR from WAIS between 2070 and 2100? Or complete collapse, so 3m in three decades?

are we talking under RCP 8.5 worst case scenario or RCP 7.0 (I made it up but basically what EXXON recently predicted) or a more aggressive RCP 6.0 with a moderate ECS of 3.0???

or

are we talking about what you, ASLR or I think will actually happen to temperatures and melt dynamics over the next 100 years?

In my understanding, we have significantly underestimated carbon cycle and climate feedbacks of arctic region effects.  We have locked in 2.3C of warming over the next 5 decades at current CO2 forcing.  By the time we are done with our moderately aggressive (near term) and very aggressive (mid term) emissions reductions we will have locked in about 4C of warming by 2065.

At this point natural feedbacks will dominate and we will pass 5C of warming by 2100.

Under this scenario, the massive destabilization of Greenland and the arctic melt will disrupt overturning circulations and lead to a massive increase in Circumpolar deep water temperatures, increased surface melting by 2030 will begin to rapidly destabilize the WAIS and by 2070 the East Antarctic will begin to experience extreme melt effects.  by 2100 we will see 3-5 meters of sea level rise, with an additional 25% increases in the northern mid-latitudes due to gravity effects from losing Antarctic mass.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 07, 2015, 11:25:30 PM
This could result collapse of the WAIS at the rates cited by Pollard, DeConto & Alley 2015 between 2070 & 2100.

ASLR,
Are you thinking about 1m SLR from WAIS between 2070 and 2100? Or complete collapse, so 3m in three decades?

Lennart,

If we stay on a BAU to the end of the century then I think that it is reasonable to believe that the WAIS will likely contribute 3m by 2100; however, if we back down to RCP 6 then maybe 2m is reasonable, and if we can get to RCP 4 then maybe 1m is a reasonable contribute to assume from the WAIS.  These are just my opinions; but if you are concerned about The Netherlands, do not forget the fingerprint effect (which I believe is about 1.1 for Holland and up to 1.4 for parts of the USA).

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 10, 2015, 10:41:56 PM
If the AIS contributes 3m, the GRIS contributes 1m and steric contributes 1m to SLR by 2100 following a BAU scenario then James Hansen's warnings may be supported by Pollard et al 2015's findings.  Therefore, I thought that I would post the four attached images regarding the impacts of a 5m SLR occurrence by 2100; and I would especially like to note that a great main of the great river deltas will all be inundated at the same time and consequently a great about of rice production (e.g. the Mekong, the Jamuna, the Nile, etc.) will be lost abruptly.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 10, 2015, 10:43:21 PM
The attached image indicates which country's populations will me impacted by 5m of SLR (eg China, Egypt, Vietnam, Indonesia, Japan, Bangaladesh and India)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on January 11, 2015, 05:14:11 PM
Tried  to post a comment and I believe it got hung up. Tried to repost and it said I had already posted it.     :-[
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Neven on January 12, 2015, 12:59:13 AM
Tried  to post a comment and I believe it got hung up. Tried to repost and it said I had already posted it.     :-[

I'm sorry this happened, SH. I don't think I can retrieve that comment.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on January 12, 2015, 10:46:14 PM
New paper on Social Cost of Carbon:
http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2481.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2481.html)

"We implement empirical estimates of temperature effects on GDP growth rates in the DICE model through two pathways, total factor productivity growth and capital depreciation. This damage specification, even under optimistic adaptation assumptions, substantially slows GDP growth in poor regions but has more modest effects in rich countries. Optimal climate policy in this model stabilizes global temperature change below 2 °C by eliminating emissions in the near future and implies a social cost of carbon several times larger than previous estimates."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on January 13, 2015, 02:48:34 AM
Stanford study: social cost of carbon may be $220/ton, not the previously-estimated $37/ton.
Quote
"If the social cost of carbon is higher, many more mitigation measures will pass a cost-benefit analysis," Diaz said. "Because carbon emissions are so harmful to society, even costly means of reducing emissions would be worthwhile."
http://phys.org/news/2015-01-social-climate-scientists.html (http://phys.org/news/2015-01-social-climate-scientists.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on January 13, 2015, 08:14:13 AM
New paper on costs of SLR by Pycroft et al 2014:
http://rd.springer.com/article/10.1007%2Fs10640-014-9866-9 (http://rd.springer.com/article/10.1007%2Fs10640-014-9866-9)

Their high scenario has 1.75m of SLR by 2080 and 0.5% global GDP and 2% welfare loss, with up to 12% in some places, without adaptation. For what it's worth.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 14, 2015, 05:52:01 PM
The linked reference indicates that SLR will likely increase parasite trematode-bivalve infections:

John Warren Huntley, Franz T. Fürsich, Matthias Alberti, Manja Hethke, and Chunlian Liu, (2015), "A complete Holocene record of trematode–bivalve infection and implications for the response of parasitism to climate change", PNAS, vol. 111 no. 51,  pp. 18150–18155, doi: 10.1073/pnas.1416747111

http://www.pnas.org/content/111/51/18150.abstract (http://www.pnas.org/content/111/51/18150.abstract)

Significance: "There is growing concern about how parasites will respond to climate change. Previous studies were based on data from short time scales (10−1 to 103 y), but here we present, to our knowledge, the first analysis of the response of parasites to global change on a longer time scale (104 y), utilizing the subfossil record. A 9,600-y record of clams and flatworm parasites from the Pearl River Delta exhibits a significant spike in parasite prevalence during the initial phase of sea-level rise. This increase is not related to changes in salinity or intermediate host availability. Temperature and productivity cannot be quantified and tested as driving factors. These results suggest stark implications for macrobenthos, fisheries, and human health in the context of climate change."

Abstract: "Increasing global temperature and sea-level rise have led to concern about expansions in the distribution and prevalence of complex-lifecycle parasites (CLPs). Indeed, numerous environmental variables can influence the infectivity and reproductive output of many pathogens. Digenean trematodes are CLPs with intermediate invertebrate and definitive vertebrate hosts. Global warming and sea level rise may affect these hosts to varying degrees, and the effect of increasing temperature on parasite prevalence has proven to be nonlinear and difficult to predict. Projecting the response of parasites to anthropogenic climate change is vital for human health, and a longer term perspective (104 y) offered by the subfossil record is necessary to complement the experimental and historical approaches of shorter temporal duration (10−1 to 103 y). We demonstrate, using a high-resolution 9,600-y record of trematode parasite traces in bivalve hosts from the Holocene Pearl River Delta, that prevalence was significantly higher during the earliest stages of sea level rise, significantly lower during the maximum transgression, and statistically indistinguishable in the other stages of sea-level rise and delta progradation. This stratigraphic paleobiological pattern represents the only long-term high-resolution record of pathogen response to global change, is consistent with fossil and recent data from other marine basins, and is instructive regarding the future of disease. We predict an increase in trematode prevalence concurrent with anthropogenic warming and marine transgression, with negative implications for estuarine macrobenthos, marine fisheries, and human health."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on January 14, 2015, 09:05:01 PM
Rate of sea-level rise 'steeper'
http://www.bbc.com/news/science-environment-30816143 (http://www.bbc.com/news/science-environment-30816143)

The tides are changing: Sea levels rising at faster rate than predicted, study finds
http://www.independent.co.uk/environment/climate-change/the-tides-are-changing-sea-levels-rising-at-faster-rate-than-predicted-study-finds-9978390.html (http://www.independent.co.uk/environment/climate-change/the-tides-are-changing-sea-levels-rising-at-faster-rate-than-predicted-study-finds-9978390.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 14, 2015, 10:05:43 PM
Rate of sea-level rise 'steeper'
http://www.bbc.com/news/science-environment-30816143 (http://www.bbc.com/news/science-environment-30816143)

The tides are changing: Sea levels rising at faster rate than predicted, study finds
http://www.independent.co.uk/environment/climate-change/the-tides-are-changing-sea-levels-rising-at-faster-rate-than-predicted-study-finds-9978390.html (http://www.independent.co.uk/environment/climate-change/the-tides-are-changing-sea-levels-rising-at-faster-rate-than-predicted-study-finds-9978390.html)

To add some details to your post: The linked reference finds that the acceleration in sea level rise seen in recent decades is more rapid (by about 25% since 1990, see attached plot & caption) than scientists previously thought:

Hay CC, Morrow E, Kopp RE, Mitrovica JX, (2015) "Probabilistic reanalysis of twentieth-century sea-level rise", Nature. 2015 Jan 14. doi: 10.1038/nature14093

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14093.html (http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14093.html)

Abstract: "Estimating and accounting for twentieth-century global mean sea-level (GMSL) rise is critical to characterizing current and future human-induced sea-level change. Several previous analyses of tide gauge records—employing different methods to accommodate the spatial sparsity and temporal incompleteness of the data and to constrain the geometry of long-term sea-level change—have concluded that GMSL rose over the twentieth century at a mean rate of 1.6 to 1.9 millimetres per year. Efforts to account for this rate by summing estimates of individual contributions from glacier and ice-sheet mass loss, ocean thermal expansion, and changes in land water storage fall significantly short in the period before 1990. The failure to close the budget of GMSL during this period has led to suggestions that several contributions may have been systematically underestimated. However, the extent to which the limitations of tide gauge analyses have affected estimates of the GMSL rate of change is unclear. Here we revisit estimates of twentieth-century GMSL rise using probabilistic techniques and find a rate of GMSL rise from 1901 to 1990 of 1.2 ± 0.2 millimetres per year (90% confidence interval). Based on individual contributions tabulated in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, this estimate closes the twentieth-century sea-level budget. Our analysis, which combines tide gauge records with physics-based and model-derived geometries of the various contributing signals, also indicates that GMSL rose at a rate of 3.0 ± 0.7 millimetres per year between 1993 and 2010, consistent with prior estimates from tide gauge records. The increase in rate relative to the 1901–90 trend is accordingly larger than previously thought; this revision may affect some projections of future sea-level rise."


Caption: "Time series of global mean sea level for the period 1900-2010. Figure shows estimates of sea level from the two methods used in this study: 'KS' (blue line) and 'GPR' (black line), and two methods used in the latest IPCC report: 'Ref.4' (purple line) from Church et al. ( 2011) and 'Ref. 3' (red line) from Jevrejeva et al. ( 2008). Inset table shows trends for three different time periods. Source: Hay et al. (2015)"

See also:
http://www.carbonbrief.org/blog/2015/01/global-sea-levels-rising-faster-than-previously-thought-study-shows/ (http://www.carbonbrief.org/blog/2015/01/global-sea-levels-rising-faster-than-previously-thought-study-shows/)
http://in.reuters.com/article/2015/01/14/climatechange-seas-idINL6N0US3IZ20150114 (http://in.reuters.com/article/2015/01/14/climatechange-seas-idINL6N0US3IZ20150114)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Steven on January 14, 2015, 10:26:53 PM
Rate of sea-level rise 'steeper'
http://www.bbc.com/news/science-environment-30816143 (http://www.bbc.com/news/science-environment-30816143)

Blog post by Stefan Rahmstorf at RealClimate about the new sea level study (Hay et al.):
http://www.realclimate.org/index.php/archives/2015/01/a-new-sea-level-curve (http://www.realclimate.org/index.php/archives/2015/01/a-new-sea-level-curve)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.realclimate.org%2Fimages%2F%2Fhaysl13.jpg&hash=ac58b205ab431ca4ed19d37a8bece22b)

Quote
Hay et al. find that the acceleration of sea-level rise since 1900 AD is larger than in previous reconstructions, but it has been generally questioned whether the quadratic acceleration (derived from a parabolic fit) is a useful number in cases where a parabola doesn’t fit the data well (Rahmstorf and Vermeer 2011, Foster and Brown 2014). Taking a step back, in my view the “big picture” on acceleration is that we have moved from a stable preindustrial sea level to one now rising at 3 mm/year

...

"To sum up, in my view the strength of the method of Hay et al. is that it uses the expected “fingerprints” of the global warming signal, while the strength of Church & White is to take into account the empirical patterns of natural variability. Ideal would of course be a combination of both, and this could be the next step for further research.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on January 15, 2015, 01:08:19 AM
That table says estimates of acceleration over the last period have roughly doubled. If read as exponential (which is a very large assumption) that's a SLR doubling time of a decade or so. The graph at realclimate of acceleration is too noisy to say much, expected when you try to differentiate noisy data.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 15, 2015, 01:18:27 AM
The linked reference (with a free access pdf) presents a relatively conservative briefing on SLR and AIS contributions

Ted Scambos & John Abraham, (2014), "Briefing: Antarctic ice sheet mass loss and future sea-level rise", Proceedings of the ICE - Forensic Engineering, DOI: 10.1680/feng.14.00014

http://www.icevirtuallibrary.com/content/article/10.1680/feng.14.00014 (http://www.icevirtuallibrary.com/content/article/10.1680/feng.14.00014)

Abstract: "Sea-level rise, one of the most obvious consequences of climate change, has direct impacts on coastal communities and economic infrastructure. It is important to assess current sea-level rise and forecast future rates. These predictions are made difficult because the potential for rapid destabilisation of some of the world's large ice sheets, in particular the west Antarctic ice sheet, remains poorly constrained. In particular, new processes and new mapping and modelling, currently emerging from the science community, may have a radical impact on forecasts. Here, a summary of observations and models of recent west Antarctic ice sheet dynamics are provided. This summary highlights that sea-level rise above the ∼1 m expected by 2100 is possible if ice sheet response begins to exceed present rates. Moreover, ice losses from Antarctica have an amplified impact on the coastlines of North America and Europe, because of the resulting redistribution of water due to the changed gravitational field near the ice sheet."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Rick Aster on January 15, 2015, 02:01:44 AM
Reuters story at The Guardian:  Sea levels rising faster than previously thought says new study; Assessment of 600 tidal gauges across the globe suggests a 25% greater acceleration in the rise over the past 20 years http://www.theguardian.com/environment/2015/jan/15/sea-levels-rising-faster-than-previously-thought-says-new-study (http://www.theguardian.com/environment/2015/jan/15/sea-levels-rising-faster-than-previously-thought-says-new-study)

Despite the headline, the story reports on a study published in Nature that says earlier sea level rises were smaller than previously estimated, making the current rate of change more alarming:
Quote
The study said sea level rise, caused by factors including a thaw of glaciers, averaged about 1.2 millimetres (0.05 inch) a year from 1901-90 - less than past estimates - and leapt to 3 mm a year in the past two decades, apparently linked to a quickening thaw of ice.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on January 15, 2015, 10:08:51 AM
An other point of view on the matter :

New Research May Solve Puzzle in Sea Level’s Rise
http://www.nytimes.com/2015/01/15/science/earth/new-research-may-solve-a-puzzle-in-sea-levels-rise.html?partner=rss&emc=rss (http://www.nytimes.com/2015/01/15/science/earth/new-research-may-solve-a-puzzle-in-sea-levels-rise.html?partner=rss&emc=rss)

Quote
Instead of rising about six inches over the course of the 20th century, as previous research suggested, the sea actually rose by approximately five inches, the team from Harvard and Rutgers Universities found. The difference turns out to be an immense amount of water: on the order of two quadrillion gallons, or enough to fill three billion Olympic-size swimming pools.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on January 15, 2015, 02:46:06 PM
From the abstract:

"sea-level rise above the ∼1 m expected by 2100 is possible if ice sheet response begins to exceed present rates"

What are the chances that ice sheet response will not begin to exceed present rates??
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 16, 2015, 12:54:22 AM
As it is never possible to over cite the excellent research by Purkey et al, the linked paper discusses regional differences in SLR, and indicates that this topic merits still further research:

Purkey, S. G., G. C. Johnson, and D. P. Chambers, (2014), "Relative contributions of ocean mass and deep steric changes to sea level rise between 1993 and 2013", J. Geophys. Res. Oceans, 119, 7509–7522, doi:10.1002/2014JC010180.

http://onlinelibrary.wiley.com/doi/10.1002/2014JC010180/abstract;jsessionid=EB0B6BE46C64753DF09932ACAE4AC179.f01t04 (http://onlinelibrary.wiley.com/doi/10.1002/2014JC010180/abstract;jsessionid=EB0B6BE46C64753DF09932ACAE4AC179.f01t04)

Abstract: "Regional and global trends of Sea Level Rise (SLR) owing to mass addition centered between 1996 and 2006 are assessed through a full-depth SLR budget using full-depth in situ ocean data and satellite altimetry. These rates are compared to regional and global trends in ocean mass addition estimated directly using data from the Gravity Recovery and Climate Experiment (GRACE) from 2003 to 2013. Despite the two independent methods covering different time periods with differing spatial and temporal resolution, they both capture the same large-scale mass addition trend patterns including higher rates of mass addition in the North Pacific, South Atlantic, and the Indo-Atlantic sector of the Southern Ocean, and lower mass addition trends in the Indian, North Atlantic, South Pacific, and the Pacific sector of the Southern Ocean. The global mean trend of ocean mass addition is 1.5 (±0.4) mm yr−1 for 1996–2006 from the residual method and the same for 2003–2013 from the GRACE method. Furthermore, the residual method is used to evaluate the error introduced into the mass budget if the deep steric contributions below 700, 1000, 2000, 3000, and 4000 m are neglected, revealing errors of 65%, 38%, 13%, 8%, and 4% respectively. The two methods no longer agree within error bars when only the steric contribution shallower than 1000 m is considered."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 18, 2015, 05:48:49 PM
With a hat-tip to Lennart van der Linde in the Greenland folder, the following extract from Applegate et al 2014 indicates that the future contributions to SLR from the Greenland Ice Sheet, GIS, is approximately exponential with increasing Greenland surface temperature change (see first attached associated image).   Furthermore, I point-out that the Pollard et al 2015 findings (see second attached associated image) indicate that this consideration is even more true for the Antarctic Ice Sheet, AIS, than for the GIS, in the coming 100 to 200 years.  These findings imply that if modern society had any meaningful willpower then decision makers could buy future generations a lot more "... time to design and implement improved strategies for adapting to sea level change" by reducing GHG emission sooner rather than later.  Alternately, as societal willpower w.r.t climate change appears to be lacking at the moment, future generations may need to get use to climate shock (including abrupt SLR, with possible increases in sea level of up to 5m by 2100) beginning no later than 2050 following a BAU pathway.

Also, I include the third and fourth attached images of the GIS & AIS elevations and latitudes, respectively, to illustrate that while the WAIS is located further pole-ward than the GIS, its elevation is already lower than that for the GIS; which supports the position that major portions of the WAIS may likely be subject to surface ice melting (which leads to hydrofracturing and cliff failures) starting sometime between 2050 and 2100 when following a BAU pathway.

Patrick J. Applegate, Byron R. Parizek, Robert E. Nicholas, Richard B. Alley & Klaus Keller, (2014), "Increasing temperature forcing reduces the Greenland Ice Sheet’s response time scale", Climate Dynamics, DOI: 10.1007/s00382-014-2451-7

http://link.springer.com/article/10.1007/s00382-014-2451-7 (http://link.springer.com/article/10.1007/s00382-014-2451-7)

Extract: "We speculate that near-term reductions in greenhouse gas emissions could pay large dividends in terms of avoided sea level rise. Our results suggest that the relationships between temperature change, GIS response time scale, and GIS equilibrium sea level contribution are approximately exponential (Fig. 2). Thus, the benefit, in terms of avoided sea level rise contributions from the GIS, of a unit of avoided emissions is greatest if emissions reductions are begun before much temperature change has already happened. Alternatively, one could say that mitigation becomes less effective in preventing or delaying sea level rise contributions from the Greenland Ice Sheet as temperature rises. Near-term reductions in greenhouse gas emissions may also buy time to design and implement improved strategies for adapting to sea level change."

Pollard, D., DeConto, R.M. and Alley, R.B., (2015), "Potential Antarctic Ice Sheet retreat driven by hydrofracturing and ice cliff failure", Earth and Planetary Science Letters, Volume 412, 15 February 2015, Pages 112–121, doi:10.1016/j.epsl.2014.12.035

http://www.sciencedirect.com/science/article/pii/S0012821X14007961 (http://www.sciencedirect.com/science/article/pii/S0012821X14007961)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on January 19, 2015, 05:48:07 PM
Given the future contributions to SLR from Greenland is exponential, do we have any sense of what the doubling time period is?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on January 19, 2015, 06:18:50 PM
Between (around) 2000-2005 : 600 Gt
                                  2005-2010 : 1100 Gt
                                  2010-2015 : 1400 Gt
 
It is hard to tell yet, I would say a doubling between 5 to 10 years. Recent numbers seem to slow.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on January 20, 2015, 10:39:45 PM
Prof. Kopp, one of the authors of Hay(2015,  doi:10.1038/nature14093 ) , writing at realclimate, points out one of the strong achievements of the paper:

"I should note one element of the paper not highlighted in this write-up: the closing of the 1901-1990 sea-level rise budget."

He goes on:

" ...  no net contribution from polar ice sheets is needed over 1901-1990. By contrast, there is of course a significant contribution over the past 20 years, observed directly ... "

So the polar ice sheet destabilization unequivocally began and accelerated over the last twenty five years. We are at roughly 500 GT mass waste today (360 GT = 1 mm SLR) from AIS and GIS, beginning from zero in 1990.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on January 29, 2015, 07:07:03 PM
Update on the story of the Kirabati refugee who applied to stay in New Zealand because his family home on the tiny island is threatened by sea level rise.  He has become the test case for climate change refugees.
http://foreignpolicy.com/2015/01/28/the-making-of-a-climate-refugee-kiribati-tarawa-teitiota/ (http://foreignpolicy.com/2015/01/28/the-making-of-a-climate-refugee-kiribati-tarawa-teitiota/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 29, 2015, 08:33:26 PM
I thought that I would post the three attached images all illustrating how quickly groundwater levels are dropping around the world, and to point-out that as the groundwater level is being drawing down quickly in many coastal areas, it will become more and more difficult to stop seawater from flowing into the depleted coastal groundwater level areas with continued SLR increasing the amount of the pressure head gradient from the ocean to the depleted groundwater level areas.

Edit: I point-out that: (a) the Sacramento Delta is at sea level and represents a major avenue for seawater to enter the groundwater in California's Central Valley, and (b) Bangladesh represents a major avenue for seawater to enter the groundwater beneath the northern plains of India.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on January 30, 2015, 03:32:50 PM
Slope on the ocean surface lowers the sea level in Europe
http://phys.org/news/2015-01-slope-ocean-surface-lowers-sea.html (http://phys.org/news/2015-01-slope-ocean-surface-lowers-sea.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on January 31, 2015, 12:02:27 AM
Obama Moves To Protect Against Flooding From Rising Sea Levels
http://www.huffingtonpost.com/2015/01/30/obama-sea-level-rise_n_6581980.html?utm_hp_ref=green&ir=Green (http://www.huffingtonpost.com/2015/01/30/obama-sea-level-rise_n_6581980.html?utm_hp_ref=green&ir=Green)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on January 31, 2015, 05:09:05 AM
The USA presidential directive linked in the previous post is big. Now USA fed planning has to take SLR into account, regardless of state level morons. This will affect fed spending in a big way.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on January 31, 2015, 10:04:36 PM
Outbreak of the plague in Madagascar.  The plague is caused by Yersinia pestis, a bacteria found in rodents and spread by fleas.

Recent flooding in Madagascar has displaced tens of thousands of people and an "untold numbers of rats," leading to fears the disease could spread further.

http://www.cnn.com/2015/01/31/health/madagascar-plague/index.html (http://www.cnn.com/2015/01/31/health/madagascar-plague/index.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 01, 2015, 04:57:14 AM
Not to detract from the significance of the outbreak of the plague in Madagascar, but per the linked article the flooding that displaced the poor and "untold" rats that can transmit the plague, was caused by rainwater from Tropical Storm Chedza on January 16 2015 (not due to SLR):

http://thewatchers.adorraeli.com/2015/01/19/severe-tropical-storm-chedza-flooded-madagascar-and-affected-more-than-50-000/ (http://thewatchers.adorraeli.com/2015/01/19/severe-tropical-storm-chedza-flooded-madagascar-and-affected-more-than-50-000/)

Extract: "Severe Tropical Storm "Chedza" made landfall north of Morondava, Madagascar between 15:00 and 16:00 UTC on January 16, 2015 bringing heavy thunderstorm rains across much of the country."

Edit: Here is a map of the storm track for Tropical Storm Chedza.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 02, 2015, 05:36:19 PM
The linked research could result in a relatively inexpensive means to estimate the contribution of ice calving to SLR:

Glowacki, O., G. B. Deane, M. Moskalik, P. Blondel, J. Tegowski, and M. Blaszczyk (2015), Underwater acoustic signatures of glacier calving, Geophys. Res. Lett., 42, doi:10.1002/2014GL062859.

http://onlinelibrary.wiley.com/doi/10.1002/2014GL062859/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2014GL062859/abstract)

Abstract: "Climate-driven ice-water interactions in the contact zone between marine-terminating glaciers and the ocean surface show a dynamic and complex nature. Tidewater glaciers lose volume through the poorly understood process of calving. A detailed description of the mechanisms controlling the course of calving is essential for the reliable estimation and prediction of mass loss from glaciers. Here we present the potential of hydroacoustic methods to investigate different modes of ice detachments. High-frequency underwater ambient noise recordings are combined with synchronized, high-resolution, time-lapse photography of the Hans Glacier cliff in Hornsund Fjord, Spitsbergen, to identify three types of calving events: typical subaerial, sliding subaerial, and submarine. A quantitative analysis of the data reveals a robust correlation between ice impact energy and acoustic emission at frequencies below 200 Hz for subaerial calving. We suggest that relatively inexpensive acoustic methods can be successfully used to provide quantitative descriptions of the various calving types."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 06, 2015, 09:59:41 PM
The linked open access reference investigates the economic impact of rapid SLR, and examines up to 1.75 m of SLR by 2085 (see the attached image and the associate extract showing that Southeast Asia would be impacted the most, followed by China).

Jonathan Pycroft, Jan Abrell, Juan-Carlos Ciscar, (2015), "The Global Impacts of Extreme Sea-Level Rise: A Comprehensive Economic Assessment", Environmental and Resource Economics, DOI: 10.1007/s10640-014-9866-9

http://download.springer.com/static/pdf/503/art%253A10.1007%252Fs10640-014-9866-9.pdf?auth66=1423255498_13cf655ea315d2e24fcd392571319f47&ext=.pdf (http://download.springer.com/static/pdf/503/art%253A10.1007%252Fs10640-014-9866-9.pdf?auth66=1423255498_13cf655ea315d2e24fcd392571319f47&ext=.pdf)


Abstract: "This paper investigates the world-wide economic cost of rapid sea-level rise of the kind that could be caused by accelerated ice flow from the West Antarctic and/or the Greenland ice sheets. Such an event would have direct impacts on economic activities located near the coastline and indirect impacts further inland. Using data from the DIVA model on sea floods, river floods, land loss, salinisation and forced migration, we analyse the effects of these damages in a computable general equilibrium model for 25 world regions. We consider three sea-level rise scenarios that correspond to 0.47, 1.12 and 1.75 m by the 2080s. By incorporating a wider range of damage categories, implemented in an economy-wide framework and including very rapid sea-level rise, the study offers a new contribution to climate change impact studies. We find that the loss of GDP worldwide is 0.5 % in the highest sea-level rise scenario, with a loss of welfare (equivalent variation) of almost 2 % world-wide. Within these aggregates, there are large regional disparities, with the Central Europe North region and parts of South-East Asia and South Asia being especially prone to high costs (welfare losses in the range of 4–12 %). The analysis assumes that there is not public adaptation, which would substantially lower the costs. In this way, the analysis demonstrates what is at risk, and could be used to justify adaptation expenses."

Extract referring to Figure 1: "In the High scenario, Rest of South-East Asia shows a huge 12.91% loss, followed by China (5.63%) and South Asia (5.20 %).  The less affected regions are South Africa, Mexico and Russia, who experience equivalent variation losses in a range between 0.1 and 0.3%."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on February 06, 2015, 10:59:15 PM
1.  The word "rice" is not found within the entire document.  Nor are the compounding effects of higher wave-height and storm surge functions as a result of higher sea surface temperatures in the future warming scenarios.   These kinds of compounding secondary damage functions are totally absent from the paper (see below)

2.  Instead of attempting to model actual secondary effects of SLR, say, a loss of 27% of south east Asian rice cultivation in 20 years (high scenario).  With the resulting regional political instability caused by famine and mass migrations.  They look to a "damage to capital" indicating, I suppose the reduction in capital stock for the increase of GDP. 

3.  The damage to capital is modeled under 3 tenuous assumption regimes and their effect assume functional markets and the maintenance of regional infrastructure, and the absence of regional conflict.

I find this to be a wholly inadequate methodology, though, to give them some credit, they appear to be using the models with some effective results (for measuring direct impacts).
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on February 18, 2015, 06:57:18 PM
here are a couple pieces on slr:

An oldie-but-goodie lecture by Jeremy Jackson that recently came to my attention again:

https://www.youtube.com/watch?v=TAtCQ7REXAc (https://www.youtube.com/watch?v=TAtCQ7REXAc)

Something recent from the main stream-ish press, Rolling Stone:

http://www.rollingstone.com/politics/news/the-pentagon-climate-change-how-climate-deniers-put-national-security-at-risk-20150212 (http://www.rollingstone.com/politics/news/the-pentagon-climate-change-how-climate-deniers-put-national-security-at-risk-20150212)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on February 18, 2015, 09:25:52 PM
I have issues with the Pycroft paper.

1) It uses Tol's methodology from 2006 for damage estimates. Better estimates are available today.  To take just one feature, following Tol, damages due to forced migration are taken to be three times GDP per capita of the affected population. This is laughable. Consider that after 1971,displaced persons camps in India which housed refugees from Bangladesh were still in operation after a decade, accruing huge costs to both India and Bangladesh.

2)Pycroft assumes  capital depreciation (the quantity D in the only equation in the paper) are unaffected. This is dubious, see for example, Moore(2015)  doi:10.1038/NCLIMATE2481 arguing that both capital depreciation and total factor productivity growth are adversely affected, increasing cumulative cost.

3)There are other arguments in Moore(2015) indicating higher damage estimates than the conventional DICE model, I do urge everyone to read the paper, especially the supplementary material.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on February 18, 2015, 10:52:03 PM
Unawatuna beach: A call for action
http://www.dailymirror.lk/63827/unawatuna-beach-a-call-for-action (http://www.dailymirror.lk/63827/unawatuna-beach-a-call-for-action)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on February 19, 2015, 08:05:31 PM
Ullapool high tide set for 19-year record
http://www.ross-shirejournal.co.uk/News/Ullapool-high-tide-19022015.htm (http://www.ross-shirejournal.co.uk/News/Ullapool-high-tide-19022015.htm)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on February 19, 2015, 08:06:33 PM
Karachi could submerge by 2060
http://www.pakistantoday.com.pk/2015/02/19/comment/karachi-could-submerge-by-2060/ (http://www.pakistantoday.com.pk/2015/02/19/comment/karachi-could-submerge-by-2060/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on February 24, 2015, 08:35:25 PM
‘Monster’ Hurricanes Have Hit New England For 2,000 Years
http://scienceblog.com/77140/monster-hurricanes-have-hit-new-england-for-2000-years/#PUTB8yuTR1ieTZFd.991 (http://scienceblog.com/77140/monster-hurricanes-have-hit-new-england-for-2000-years/#PUTB8yuTR1ieTZFd.991)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on February 24, 2015, 09:25:45 PM
US sea level north of New York City 'jumped by 128mm'
http://www.bbc.com/news/science-environment-31604953 (http://www.bbc.com/news/science-environment-31604953)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on February 25, 2015, 03:01:15 PM
US sea level north of New York City 'jumped by 128mm'
http://www.bbc.com/news/science-environment-31604953 (http://www.bbc.com/news/science-environment-31604953)
That's just over 5 inches!, for the metrically-challenged. ::)  And it happened within two years.  :o
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on February 25, 2015, 03:33:23 PM
Well that's obvious that the trend is not good at all...wake up people... (either to late or not something has to be done...come back to 300 ppm CO2eq... )
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on February 25, 2015, 03:34:51 PM
As I understand it, the only thing that could change sea level that fast in one location is a shift in ocean currents. Does anyone have a good bead on what has been happening with the AMOC recently?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sleepy on February 25, 2015, 04:16:00 PM
More here, with a link to the paper at the bottom.
http://www.reportingclimatescience.com/news-stories/article/sea-level-rise-running-amoc.html (http://www.reportingclimatescience.com/news-stories/article/sea-level-rise-running-amoc.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: ritter on February 25, 2015, 06:02:42 PM
US sea level north of New York City 'jumped by 128mm'
http://www.bbc.com/news/science-environment-31604953 (http://www.bbc.com/news/science-environment-31604953)
That's just over 5 inches!, for the metrically-challenged. ::)  And it happened within two years.  :o
:o indeed!

Things seem to be rapidly escalating in rate of change. The split weather pattern we are experiencing here in the US is really concerning. Out here in California, there's no rain in the forecast. Still. Maybe Boston can send us some snow cones? When you start putting all the pieces together in these threads into one picture, it's hard to not hide under the bed!
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: ritter on February 25, 2015, 06:10:50 PM
As I understand it, the only thing that could change sea level that fast in one location is a shift in ocean currents. Does anyone have a good bead on what has been happening with the AMOC recently?

You go, Wili! From Sleepy's link:
Quote
Co-author Jianjun Yin, UA assistant professor of geosciences, said, "We are the first to establish the extreme sea level rise event and its connection with ocean circulation."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on February 25, 2015, 08:19:56 PM
Given the anomalous warmth of the seas off the northeast U.S. coast, a change in the Gulf Stream flow would certainly fit.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Steven on February 25, 2015, 08:28:55 PM
Does anyone have a good bead on what has been happening with the AMOC recently?

See website of the RAPID-MOC project:

http://www.rapid.ac.uk/rapidmoc/ (http://www.rapid.ac.uk/rapidmoc/)

(https://pbs.twimg.com/media/B5O0ypXIAAAOEZZ.png)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on February 25, 2015, 10:06:32 PM
Thanks, Steven. My reactions went from 'Wow! Cool!" quickly to "Oh oh!"

25% (5 Sv) loss in volume in ten years!

At that rate, it will be gone in 30 years. I would presume that effects of a much slower current would be strongly felt long before that.

Why don't we hear more about the consequences of this weakening?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 25, 2015, 10:41:45 PM
wili,

The following extract is from the RAPID - MOC website "Overview" tab:

Extract: "There is a northward transport of heat throughout the Atlantic, reaching a maximum of 1.3PW (25% of the global heat flux) around 24.5°N. The heat transport is a balance of the northward flux of a warm Gulf Stream, and a southward flux of cooler thermocline and cold North Atlantic Deep Water that is known as the meridional overturning circulation (MOC). The heat transported by the MOC is given off to the atmosphere and much of it is carried eastward by westerly winds. This is an important contribution to northwestern Europe's mild climate. Numerical models suggest that the MOC is likely to weaken by about 30% in the coming century as a consequence of greenhouse gas emissions."

Thus you can expect another 30% reduction in the AMOC by 2100, resulting in a continued high rate of RSLR for the US East Coast  through the end of the century, but do not expect a collapse of the AMOC.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: LRC1962 on February 26, 2015, 02:23:40 AM
Apologies if discussed elsewhere.
Instead of stopping could it be possible we could see a similar occurrence with the ocean currents as we see with the jet streams. Some slow way down and get wavyer not following traditional paths and others pick up speed and get straighter. All this resulting in very cold spots and very very hot spots. Not only that but varying where the exact spots are over a long period of time. Somewhat like now but far more exaggerated. if this occurs then you could end up with even a worse situation where globally the average gets higher, but for any given local you could get extremes over the years from very low (relative to average) to extremely high and back to low.
In this scenario if a shipping port is in such a local how do you build the docks and infrastructure?
We can give anticipated averages even for a general location, but if ocean currents became far more unpredictable as the heated up oceans affect them, would it be possible to determine what SL would be on any given year even if we knew how fast SLR was occurring?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on February 26, 2015, 03:13:39 AM
Thanks, ASLR.

I still find it hard to believe that we will only see about the same amount of slowing over the whole rest of the century as we've seen in just the last ten years. Most trends don't seem to be slowing down like that--just the opposite.

I guess we'll see, or not.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 26, 2015, 04:27:47 AM
Thanks, ASLR.

I still find it hard to believe that we will only see about the same amount of slowing over the whole rest of the century as we've seen in just the last ten years. Most trends don't seem to be slowing down like that--just the opposite.

I guess we'll see, or not.

wili,

Per the article in the linked website, the AMOC oscillates and since 2004 it has been on a downward cycle (see the attached image).  The 30% figure that I mentioned is the projected reduction in the AMOC by 2100 due to GHG that needs to be superimposed on top of the oscillations.

Best,
ASLR

http://www.eoearth.org/view/article/150290/ (http://www.eoearth.org/view/article/150290/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Pmt111500 on February 26, 2015, 04:34:47 AM
US sea level north of New York City 'jumped by 128mm'
http://www.bbc.com/news/science-environment-31604953 (http://www.bbc.com/news/science-environment-31604953)

Mmm... likely this would be a consequence of changing the downwelling area in the North Atlantic. The Gulf Stream (not the NA drift) operates as it has been (or somewhat slower and the cold from Nares (not from east Greenland) is enough to slow down the NA Drift so the warm water from Gulf of Mexico stack up here. A temporary effect at best imho, will drop some summer when the ice is out in the north.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on February 26, 2015, 04:40:22 AM
Thanks again, ASLR. I was wondering about whether there was some cyclicity going on here. That makes sense.

From your graph, though, it sure looks as though the periods when the AMO is on the positive side have gotten shorter through the century and a half, or so, of that record.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Bruce Steele on February 26, 2015, 06:06:45 AM
I think the combination of a very negative NAO 2009/2010 and the general decadal weakening of the AMOC resulting in 4 inches of anomalous sea rise is something to note . If that 2009/2010 window included a Sandy 4 inches of additional sea rise would do a lot of damage.
 From the following link " Note also that the winter 2009/2010 had the most negative NAO index measured during the almost 190 year record."

 http://www.cru.uea.ac.uk/~timo/datapages/naoi.htm (http://www.cru.uea.ac.uk/~timo/datapages/naoi.htm)

The premise that a strongly negative NAO in combination with weakened Atlantic meridional overturning resulting in predictably high tides should probably go into someones risk analysis planning.
?   
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 26, 2015, 04:03:03 PM
From your graph, though, it sure looks as though the periods when the AMO is on the positive side have gotten shorter through the century and a half, or so, of that record.

Also, the length of the PDO/IPO cycles are forecast (by climate models) to become shorter, as some scientists seem to think that we should not be entering the positive PDO phase that we entered last summer for another 4 to 5 years.  In a non-stationary climate it can be difficult to determine what is model signal vs model noise vs model bias.  Nevertheless, it is safe to say that we have already entered a period of increasingly extreme weather, annual, decadal, multi-decadal, and climatic events, all superimposed on top of each other and frequently working synergistically (in a chaotic manner).

As the ocean has at least 40 to 50-years of thermal inertia built-in (which affects: currents, prevailing wind patterns, barometric pressures, ice melting rates, storm surge & wave action), we are all guaranteed a wild ride for at least decades to come even if we both rapidly reduce GHG emissions and implement both Solar Radiation Management, SRM, and Negative Emissions Technology, NET, geoengineering.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 26, 2015, 05:08:34 PM
For what it is worth, the attached is the AR5 RCP 4.5 mean SLR forecasts with steric, dynamic ocean and mean barometric pressure contributions but without dynamic ice melting contributions.

http://www.icdc.zmaw.de/ar5_slr.html?&L=1 (http://www.icdc.zmaw.de/ar5_slr.html?&L=1)

Different sets of assumptions about contributions result in different forecasts.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on February 26, 2015, 08:32:15 PM
Thanks, ASLR. I can't figure out exactly what that last cool map is telling us besides that it looks like the NE coast of the US and Canada, along with most of coastal northern Europe look like they're in trouble.

Can you translate it into how many meters of SLR are predicted by when?

..............
WRT the earlier graph, here's a nice recent piece by M. Mann on oscillations and recent climate trends:

http://www.realclimate.org/index.php/archives/2015/02/climate-oscillations-and-the-global-warming-faux-pause/ (http://www.realclimate.org/index.php/archives/2015/02/climate-oscillations-and-the-global-warming-faux-pause/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Steven on February 26, 2015, 08:51:41 PM
"Numerical models suggest that the MOC is likely to weaken by about 30% in the coming century as a consequence of greenhouse gas emissions."

See also Section 12.4.7.2 (http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter12_FINAL.pdf) of the IPCC AR5 report:

Quote
It is very likely that the Atlantic Meridional Overturning Circulation (AMOC) will weaken over the 21st century but it is very unlikely that the AMOC will undergo an abrupt transition or collapse in the 21st century. Best estimates and ranges for the reduction from CMIP5 are 11% (1 to 24%) in RCP2.6 and 34% (12 to 54%) in RCP8.5. There is low confidence in assessing the evolution of the AMOC beyond the 21st century. {12.4.7, Figure 12.35}

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F4GQUgi9.png&hash=549b6decd4e6065a3693b22e82b0d08d)

Caption of the above Figure:

Quote
Atlantic Meridional Overturning Circulation (AMOC) strength at 30°N (Sv) as a function of year, from 1850 to 2300 as simulated by different Atmosphere–Ocean General Circulation Models in response to scenario [RCP8.5]. The vertical black bar shows the range of AMOC strength measured at 26°N, from 2004 to 2011 {Figures 3.11, 12.35}
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 26, 2015, 09:19:56 PM
Thanks, ASLR. I can't figure out exactly what that last cool map is telling us besides that it looks like the NE coast of the US and Canada, along with most of coastal northern Europe look like they're in trouble.

Can you translate it into how many meters of SLR are predicted by when?

wili,

If you either move the slide bar on the image to the right, or if you click on the image, you will see the color code legend on the right side of the image showing that for the mean RCP 4.5 without dynamic ice melting contribution the regional SLR off of New England will "Likely" (i.e. with a 66% confidence interval) be about 0.3m by 2081−2100 with medium confidence i.e. assuming an ECS about 3 C; which is largely due to both ocean water warming and the slowdown of the AMOC (note that you would need to add ice melt contribution to get an actual forecast of RSLR).

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on February 27, 2015, 08:26:56 AM
IPCC SLR projections not fit for coastal risk management:
http://www.eurekalert.org/pub_releases/2015-02/uos-isr022615.php (http://www.eurekalert.org/pub_releases/2015-02/uos-isr022615.php)

"The sea-level rise scenarios of the Intergovernmental Panel on Climate Change (IPCC) do not necessarily provide the right information for high-risk coastal decision-making and management, according to new research involving scientists from the University of Southampton.

A commentary, published today in the journal Nature Climate Change, warns that the IPCC scenarios are often inappropriate or incomplete for the management of high-risk coastal areas as they exclude the potential for extreme sea-level rises. This missing information is also crucial for a number of policy processes, such as discussions by G7 countries to establish climate insurance policies and allocations of adaptation funding by the Green Climate Funds."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on March 02, 2015, 11:31:40 PM
The University of Colorado updated its global mean SLR curve on Feb 24 2015, with the latest data showing the influence of the currently strengthening Equatorial Kelvin Wave (or a possible forming El Nino event, which typically increases SLR above the average of the trend line):
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on March 05, 2015, 08:47:04 AM
Flooding Google: Google's New Headquarters and the Threat of Sea-Level Rise
http://www.huffingtonpost.com/peter-h-gleick/flooding-google-googles-n_b_6804300.html?utm_hp_ref=green&ir=Green (http://www.huffingtonpost.com/peter-h-gleick/flooding-google-googles-n_b_6804300.html?utm_hp_ref=green&ir=Green)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on March 05, 2015, 06:23:53 PM
Testing new housing designed for flood-prone areas.

http://www.reuters.com/article/2015/03/05/us-disaster-risk-architecture-idUSKBN0M100N20150305 (http://www.reuters.com/article/2015/03/05/us-disaster-risk-architecture-idUSKBN0M100N20150305)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on March 06, 2015, 08:21:02 AM
The tides they are a changin'
http://phys.org/news/2015-03-tides-changin.html (http://phys.org/news/2015-03-tides-changin.html)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on March 07, 2015, 10:05:59 AM
Fast rise in sea level in 20 years, faster in Bengal
http://www.telegraphindia.com/1150307/jsp/nation/story_7331.jsp#.VPq9-s13_z8 (http://www.telegraphindia.com/1150307/jsp/nation/story_7331.jsp#.VPq9-s13_z8)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on March 11, 2015, 01:33:44 PM
Climate change in the Marshall Islands and Kiribati, before and after – interactive
http://www.theguardian.com/environment/ng-interactive/2015/mar/11/climate-change-in-the-marshall-islands-and-kiribati-before-and-after-interactive (http://www.theguardian.com/environment/ng-interactive/2015/mar/11/climate-change-in-the-marshall-islands-and-kiribati-before-and-after-interactive)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on March 11, 2015, 03:42:42 PM
With a hat-tip to bassman (from the "2015 El Nino?" thread), I provide the accompanying image and link indicating that the global mean sea level rise trend line has surged upward in the past few months.  Possible causes include: (a) Net drought on land resulting in more water in the ocean; (b) a weak El Nino increasing the rainfall in the ocean; (c) increased ice melting; and (d) natural variability:

http://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level.html (http://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: RaenorShine on March 11, 2015, 04:01:38 PM
With a hat-tip to bassman (from the ?2015 El Nino?" thread), I provide the accompanying image and link indicating that the global mean sea level rise trend line has surged upward in the past few months.  Possible causes include: (a) Net drought on land resulting in more water in the ocean; (b) a weak El Nino increasing the rainfall in the ocean; (c) increased ice melting; and (d) natural variability.

It is a fairy impressive upswing in SLR for 2014. I checked the data file on the site and there is a 8.9mm rise from the first reading of 2014 to the last one in the data set (Day 346) by my calculations. That's almost 3 times the average annual rise of 3.28mm indicated by the trend line.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on March 14, 2015, 01:52:05 AM
Nice episode of VICE on HBO, featuring Eric Rignot on WAIS-collapse and showing effects of SLR in Bangladesh today:
https://www.youtube.com/watch?v=_h92Ath_2XA&feature=youtu.be (https://www.youtube.com/watch?v=_h92Ath_2XA&feature=youtu.be)

We need more of these.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on March 14, 2015, 07:16:03 AM
Thanks, Steven. My reactions went from 'Wow! Cool!" quickly to "Oh oh!"

25% (5 Sv) loss in volume in ten years!

At that rate, it will be gone in 30 years. I would presume that effects of a much slower current would be strongly felt long before that.

Why don't we hear more about the consequences of this weakening?

you do realize that once the arctic reaches a late September sea ice free state that this current will drop to near zero, right???
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on March 14, 2015, 04:28:22 PM
jm, I don't follow you. Please explain.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on March 14, 2015, 07:31:27 PM
Wili,

The state change of going fro ice to ice-free conditions in august or even September will radically shift the temperature regimes in the arctic, this will cause significant surface warming.  This is going to produce a step-change reduction in the AMOC that will work against the inertia of the flow behind it to produce a piling up in the north atlantic

The model runs that steven used did not include the step-change effect of ice free conditions, but rather reflect a gradual increase in regional temperatures due to increased forcing.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on March 15, 2015, 01:45:35 AM
Thanks, jai. I guess I just hadn't thought through it that far.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on March 17, 2015, 12:56:26 AM
New Shindell Paper on the Social Cost of Carbon

http://link.springer.com/article/10.1007/s10584-015-1343-0 (http://link.springer.com/article/10.1007/s10584-015-1343-0)

ABSTRACT
Quote
I present a multi-impact economic valuation framework called the Social Cost of Atmospheric Release (SCAR) that extends the Social Cost of Carbon (SCC) used previously for carbon dioxide (CO2) to a broader range of pollutants and impacts. Values consistently incorporate health impacts of air quality along with climate damages. The latter include damages associated with aerosol-induced hydrologic cycle changes that lead to net climate benefits when reducing cooling aerosols. Evaluating a 1 % reduction in current global emissions, benefits with a high discount rate are greatest for reductions of co-emitted products of incomplete combustion (PIC), followed by sulfur dioxide (SO2), nitrogen oxides (NOx) and then CO2, ammonia and methane. With a low discount rate, benefits are greatest for PIC, with CO2 and SO2 next, followed by NOx and methane. These results suggest that efforts to mitigate atmosphere-related environmental damages should target a broad set of emissions including CO2, methane and aerosol/ozone precursors. Illustrative calculations indicate environmental damages are $330-970 billion yr−1 for current US electricity generation (~14–34¢ per kWh for coal, ~4–18¢ for gas) and $3.80 (−1.80/+2.10) per gallon of gasoline ($4.80 (−3.10/+3.50) per gallon for diesel). These results suggest that total atmosphere-related environmental damages plus generation costs are much greater for coal-fired power than other types of electricity generation, and that damages associated with gasoline vehicles substantially exceed those for electric vehicles.

How much do you want to bet that he utilized the CMIP5 multi-model average to determine the damage loss estimates of sea level rise?  How much do you want to bet that his maximum sea level rise estimate by 2100 was .7 meters of sea level rise?

So, these values are only half of the values that they should be, based on that simple fact alone.

in the related article:  http://qz.com/355923/if-we-paid-for-the-hidden-cost-of-emissions-gas-would-be-6-25-a-gallon/ (http://qz.com/355923/if-we-paid-for-the-hidden-cost-of-emissions-gas-would-be-6-25-a-gallon/)

It says that gasoline should be 6.25 a gallon, Diesel should be 7.50 a gallon and goal electricity should be .30 cents per Kwh (it is .10 now)

As I said, the real values based on latest work are easily double this rate.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on March 19, 2015, 09:12:25 PM
The authors of the linked reference corrected for the influence of the PDO and identified an anthropogenic SLR signal in the Tropical Pacific Ocean associated with warming of the Tropical Indian Ocean:

B. D. Hamlington, M. W. Strassburg, R. R. Leben, W. Han, R. S. Nerem & K-Y. Kim (2014), "Uncovering an anthropogenic sea-level rise signal in the Pacific Ocean", Nature Climate Change, 4,  782–785, doi:10.1038/nclimate2307

http://www.nature.com/nclimate/journal/v4/n9/full/nclimate2307.html (http://www.nature.com/nclimate/journal/v4/n9/full/nclimate2307.html)

Abstract: "Internal climate variability across a range of scales is known to contribute to regional sea-level trends, which can be much larger than the global mean sea-level trend in many parts of the globe. Over decadal timescales, this internal variability obscures the long-term sea-level change, making it difficult to assess the effect of anthropogenic warming on sea level. Here, an attempt is made to uncover the sea-level rise pattern in the tropical Pacific Ocean associated with anthropogenic warming. More specifically, the sea-level variability associated with the Pacific Decadal Oscillation is estimated and removed from the regional sea-level trends computed from satellite altimetry measurements over the past two decades. The resulting pattern of regional sea-level rise uncovered in the tropical Pacific Ocean is explained in part by warming in the tropical Indian Ocean, which has been attributed to anthropogenic warming. This study represents one of the first attempts at linking the sea-level trend pattern observed by satellite altimetry to anthropogenic forcing."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on March 20, 2015, 06:02:39 AM
Agricultural Use of Groundwater as a Contributor to Sea Level Rise

http://www.motherjones.com/environment/2015/03/groundwater-pumping-sea-level-rise (http://www.motherjones.com/environment/2015/03/groundwater-pumping-sea-level-rise)

Quote
"Long-term groundwater depletion represents a large transfer of water from the continents to the oceans," retired hydrogeologist Leonard Konikow wrote earlier this year in one article. "Thus, groundwater depletion represents a small but nontrivial contributor to SLR [sea-level rise]."

Makes sense: If you pull 20,000 year old subterranean water from the earth, it will eventually end up in the ocean.  As an added bonus, by drawing down the deep aquifers, the resident coastline will also subside, leading to an increased sea rise effect.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on March 25, 2015, 09:18:38 PM
Here is another reference on the topic of groundwater depletion & SLR:

Wada, Y., L. P. H. van Beek, C. M. van Kempen, J. W. T. M. Reckman, S. Vasak, and M. F. P. Bierkens (2010), "Global depletion of groundwater resources", Geophys. Res. Lett., 37, L20402, doi:10.1029/2010GL044571.

http://onlinelibrary.wiley.com/doi/10.1029/2010GL044571/abstract (http://onlinelibrary.wiley.com/doi/10.1029/2010GL044571/abstract)

 Abstract: "In regions with frequent water stress and large aquifer systems groundwater is often used as an additional water source. If groundwater abstraction exceeds the natural groundwater recharge for extensive areas and long times, overexploitation or persistent groundwater depletion occurs. Here we provide a global overview of groundwater depletion (here defined as abstraction in excess of recharge) by assessing groundwater recharge with a global hydrological model and subtracting estimates of groundwater abstraction. Restricting our analysis to sub-humid to arid areas we estimate the total global groundwater depletion to have increased from 126 (±32) km3 a−1 in 1960 to 283 (±40) km3 a−1 in 2000. The latter equals 39 (±10)% of the global yearly groundwater abstraction, 2 (±0.6)% of the global yearly groundwater recharge, 0.8 (±0.1)% of the global yearly continental runoff and 0.4 (±0.06)% of the global yearly evaporation, contributing a considerable amount of 0.8 (±0.1) mm a−1 to current sea-level rise."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on March 26, 2015, 05:03:47 AM
http://www.ecoshock.net/downloads/ES_150325_Show.mp3 (http://www.ecoshock.net/downloads/ES_150325_Show.mp3)

Kevin Anderson on a variety of climate topics.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on April 04, 2015, 05:19:25 PM
A tiny step back from North Carolina's stance of "No Sea Level Rise Rate Increase allowed here, no sir."

The chairman of the state’s coastal planning board wants to let local towns and counties decide how North Carolina will cope with a rising sea level.

http://www.charlotteobserver.com/news/local/article17363684.html (http://www.charlotteobserver.com/news/local/article17363684.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 06, 2015, 11:43:16 PM
The two linked references discuss the influence of uncertainties, regional conditions and initial oceanic conditions on long-term SLR projections.

Little, C.M., R.M. Horton, R.E. Kopp, M. Oppenheimer, and S. Yip, 2015: Uncertainty in twenty-first-century CMIP5 sea level projections. J. Climate, 28, no. 2, 838-852, doi:10.1175/JCLI-D-14-00453.1.

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-14-00453.1 (http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-14-00453.1)

Abstract: "The representative concentration pathway (RCP) simulations included in phase 5 of the Coupled Model Intercomparison Project (CMIP5) quantify the response of the climate system to different natural and anthropogenic forcing scenarios. These simulations differ because of 1) forcing, 2) the representation of the climate system in atmosphere–ocean general circulation models (AOGCMs), and 3) the presence of unforced (internal) variability. Global and local sea level rise projections derived from these simulations, and the emergence of distinct responses to the four RCPs depend on the relative magnitude of these sources of uncertainty at different lead times. Here, the uncertainty in CMIP5 projections of sea level is partitioned at global and local scales, using a 164-member ensemble of twenty-first-century simulations. Local projections at New York City (NYSL) are highlighted. The partition between model uncertainty, scenario uncertainty, and internal variability in global mean sea level (GMSL) is qualitatively consistent with that of surface air temperature, with model uncertainty dominant for most of the twenty-first century. Locally, model uncertainty is dominant through 2100, with maxima in the North Atlantic and the Arctic Ocean. The model spread is driven largely by 4 of the 16 AOGCMs in the ensemble; these models exhibit outlying behavior in all RCPs and in both GMSL and NYSL. The magnitude of internal variability varies widely by location and across models, leading to differences of several decades in the local emergence of RCPs. The AOGCM spread, and its sensitivity to model exclusion and/or weighting, has important implications for sea level assessments, especially if a local risk management approach is utilized."


Jianjun Yin  (2015), "Long-term projection: Initializing sea level", Nature Climate Change, Volume: 5, Pages: 301–302, doi:10.1038/nclimate2589


http://www.nature.com/nclimate/journal/v5/n4/full/nclimate2589.html (http://www.nature.com/nclimate/journal/v5/n4/full/nclimate2589.html)

Summary: "Long-term climate change and sea-level rise in model projections have been primarily determined by external forcing of climate conditions. Now, research shows that centennial projections of the dynamic sea level are also sensitive to the ocean's initial conditions."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on April 09, 2015, 02:13:48 AM
How Flood Insurance Could Drive Americans From Coasts
Quote
The new paper, written by Moore and NRDC water official Becky Hayat, lays out one vision for how Congress could re-imagine the flood insurance program in two years, when it’s next due to be reauthorized.

Under their proposal, property owners would continue to receive discounts on their federal flood insurance coverage. In exchange, those owners would agree to not rebuild after their house is substantially damaged by a flood, and instead accept an offer from the government to purchase their property — for its pre-flood value.
http://www.climatecentral.org/news/flood-insurance-americans-on-coasts-18863 (http://www.climatecentral.org/news/flood-insurance-americans-on-coasts-18863)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on April 09, 2015, 08:06:00 PM
you know, when the flood does come to south florida we are going to see a MASSIVE economic boost as hundreds of billions of dollars are spent disassembling infrastructure, lifting and relocating houses and producing whatever adaption responses are necessary for those sites that cannot be moved and must be protected for the next 20 years or so before they must ultimately be abandoned. 

So maybe the actual destruction of huge swaths of our currently inhabited regions are really an economic boon!
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 25, 2015, 06:03:11 PM
While the linked reference about observed accelerated rates of Elevation-Dependent Warming (EDW) has bad implications for many different topics, I post this here because accelerated EDW will continue to drive glacial ice melting that will contribute to SLR:

N. Pepin, R. S. Bradley, H. F. Diaz, M. Baraer, E. B. Caceres, N. Forsythe, H. Fowler, G. Greenwood, M. Z. Hashmi, X. D. Liu, J. R. Miller, L. Ning, A. Ohmura, E. Palazzi, I. Rangwala, W. Schöner, I. Severskiy, M. Shahgedanova, M. B. Wang, S. N. Williamson & D. Q. Yang (2015), "Elevation-dependent warming in mountain regions of the world", Nature Climate Change, doi:10.1038/nclimate2563

http://www.nature.com/nclimate/journal/v5/n5/full/nclimate2563.html (http://www.nature.com/nclimate/journal/v5/n5/full/nclimate2563.html)

Abstract: "There is growing evidence that the rate of warming is amplified with elevation, such that high-mountain environments experience more rapid changes in temperature than environments at lower elevations. Elevation-dependent warming (EDW) can accelerate the rate of change in mountain ecosystems, cryospheric systems, hydrological regimes and biodiversity. Here we review important mechanisms that contribute towards EDW: snow albedo and surface-based feedbacks; water vapour changes and latent heat release; surface water vapour and radiative flux changes; surface heat loss and temperature change; and aerosols. All lead to enhanced warming with elevation (or at a critical elevation), and it is believed that combinations of these mechanisms may account for contrasting regional patterns of EDW. We discuss future needs to increase knowledge of mountain temperature trends and their controlling mechanisms through improved observations, satellite-based remote sensing and model simulations."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: RaenorShine on May 01, 2015, 12:32:31 PM
Saw a comment on Robert Scribblers blog re a spike in sea level rise recently, just checked the numbers on AVISO and the late spike in 2014 has continued upwards.

http://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level.html (http://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level.html) has the graph and also a link to the raw data.

The latest 2015 value (for day 50) shows a 2.8mm rise from the highest value of 2014 already this year (the rise is 3.3mm from the final value in 2014, and 8.7mm from a year ago).  We are almost 1cm above trend of 3.3mm per year, and looks to be close to record variablity from the graph.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 01, 2015, 12:55:11 PM
The question is how we can seperate natural short-term sea level variability, on scales of months to over a year to a decade, from potential long term acceleration. For factors influencing short-term fluctuations:
http://en.wikipedia.org/wiki/Sea_level#Short_term_and_periodic_changes (http://en.wikipedia.org/wiki/Sea_level#Short_term_and_periodic_changes)

From this plot it seems too early to say if there's an acceleration in the longer term trend:
http://sealevel.colorado.edu/content/2015rel1-global-mean-sea-level-time-series-seasonal-signals-retained (http://sealevel.colorado.edu/content/2015rel1-global-mean-sea-level-time-series-seasonal-signals-retained)

But sooner or later we do expect to see such an acceleration, so we keep watching out for the first signs...
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: RaenorShine on May 01, 2015, 02:12:12 PM
Lennart, agree entirely with your points, one high period doesnt make a trend (just as a low one does not mean a 'recovery').  It is very much still 'weather' rather than 'climate'. That doesn't mean we can't point the record data out though, just that we should be very careful about projecting forward from it.

The AVISO data is detrended for the regular annual and semi annual signals, but not as far as I can see for El Nino etc (see the peak in 1997-8). We'll have to see where this peak has come from in due course. The higher the peak goes the more likely a rebound dip comes on the other side (as in 1999).

It will take several years of higher rates to show a statistically significant shift. Just as with the recent global tempurature values it acts as a reminder of how we are changing the planet.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 02, 2015, 11:02:44 AM
Some indications that SLR may have been accelerating over the past few years:
http://onlinelibrary.wiley.com/doi/10.1002/2015GL063902/abstract?utm_content=buffer63d49&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://onlinelibrary.wiley.com/doi/10.1002/2015GL063902/abstract?utm_content=buffer63d49&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

"The global mean sea level (GMSL) was reported to have dropped 5 mm due to the 2010/11 La Niña and have recovered in one year. With longer observations, it is shown that the GMSL went further up to a total amount of 11.6 mm by the end of 2012, excluding the 3.0 mm/yr background trend. A reconciled sea level budget, based on observations by Argo project, altimeter and gravity satellites, reveals that the true GMSL rise has been masked by ENSO-related fluctuations and its rate has increased since 2010. After extracting the influence of land water storage, it is shown that the GMSL have been rising at a rate of 4.4 ± 0.5 mm/yr for more than three years, due to an increase in the rate of both land ice loss and steric change."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 02, 2015, 02:34:29 PM
I've gotten myself in trouble before, talking about growth systems, but here I go again.

It does not surprise me in the least that there is evidence that SLR is accelerating. This acceleration will continue and I suspect we will be shocked by the annual SLR by mid century.

Why?

Most research studying the planets response to rising temperatures show that the processes that contribute to SLR are accelerating. Whether it is the speed of individual glaciers, ice mass loss for  GIS, WAIS and EAIS, or the temperature of the ocean, we are seeing these processes exhibit exponential behaviors. It is only logical that SLR, which is a result of these distinct processes,   would exhibit similar behaviors.

http://papers.risingsea.net/future-sea-level-rise.html (http://papers.risingsea.net/future-sea-level-rise.html)

It is difficult to recognize these accelerations when you are relatively early in a growth pattern. This is especially true when you are dealing with a huge initial stock such as the volume of the ocean waters which has processes that cause SLR to naturally fluctuate. Be patient, the exponential growth behavior will become quite obvious within a decade and the annual gains will eventually dwarf any natural fluctuations in sea level.

The effect will be that we are going to spend the century continuously astonished by how rapid the seas rise.

Our expectations will always be, quite literally, behind the curve.

I do not know if this chart accurately reflects current IPCC estimates for SLR (I believe it was published in 2007.) but the instrumental record clearly suggests an exponential growth pattern. I expect actual SLR to be above the upper boundary of estimates, significantly above as the growth of the contributing processes continue to accelerate.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 02, 2015, 02:48:58 PM
Once we recognize that a particular process is a growth process, it is relatively easy to project the future as it becomes a simple math problem. We first need to determine the doubling rate. How much time has it taken for the growth in SLR to double? Once we have made this calculation, we simply need to calculate the future rise by doubling the rate of growth of SLR through the end of the century.

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on May 02, 2015, 03:56:05 PM
The problem is that the doubling rate is also decreasing, it won't be so simple to calculate...what are we waiting for anyway just 50 cm of SLR is dramatic for many coastal regions !?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 02, 2015, 04:15:33 PM
The problem is that the doubling rate is also decreasing, it won't be so simple to calculate...what are we waiting for anyway just 50 cm of SLR is dramatic for many coastal regions !?

Yes.

The source of most of our surprise is that we confuse stocks and flows in a growth system. All growth systems consist of stocks and flows. SLR is actually a measure of stock in the system, the aggregate volume of the oceans. These stocks grow exponentially due to the flows that feed the stock. EAIS volume loss is a flow. WAIS volume loss is a flow. GIS volume loss is a flow. These volume losses are contributing to the accelerating  growth in the stock (again, the aggregate volume of  the oceans).

This is no different than what we find when we invest or save money. If we are receiving a 3% return on our investments and savings (the flow) we will see an exponential growth rate in our wealth (the stock).

Unless someone can show me where the volume losses will stop or slow significantly, we should expect the current doubling rate of our wealth the aggregate volume of  the oceans) to  continue. If any of the flows (EAIS, WAIS or GIS ice sheet volume losses) are growing, then the doubling time for growth in the stock will shorten.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 02, 2015, 09:13:17 PM
The problem is that the doubling rate is also decreasing, it won't be so simple to calculate...what are we waiting for anyway just 50 cm of SLR is dramatic for many coastal regions !?

Yes.

The source of most of our surprise is that we confuse stocks and flows in a growth system. All growth systems consist of stocks and flows. SLR is actually a measure of stock in the system, the aggregate volume of the oceans. These stocks grow exponentially due to the flows that feed the stock. EAIS volume loss is a flow. WAIS volume loss is a flow. GIS volume loss is a flow. These volume losses are contributing to the accelerating  growth in the stock (again, the aggregate volume of  the oceans).

This is no different than what we find when we invest or save money. If we are receiving a 3% return on our investments and savings (the flow) we will see an exponential growth rate in our wealth (the stock).

Unless someone can show me where the volume losses will stop or slow significantly, we should expect the current doubling rate of our wealth the aggregate volume of  the oceans) to  continue. If any of the flows (EAIS, WAIS or GIS ice sheet volume losses) are growing, then the doubling time for growth in the stock will shorten.

SH,

As you can see from scanning through earlier posts in this thread, that Hansen & Sato (2012) have already done what you suggest and instead of finding a maximum SLR by 2100 of 0.5m (per AR4); they estimated that the maximum SLR value by 2100 could likely be about 5m (see the first attached image).

Nevertheless, NOAA (who is the USA's primary science advisor to policy makers on SLR) chose to ignore Hansen & Sato (2012) in their December 2012 SLR guidance, where instead they used the 2008 maximum SLR values give by Pfeffer et al as I have noted on the second attached image of the 2012 NOAA- Parris SLR guidance that gives policy makers four curves to choose from, with the lowest curve assuming a linear rate of SLR 1.7 mm/yr through 2100, and the highest curve projecting 2m of SLR by 2100.  This illustrates that we currently live in the Anthropocene Era where much of the public and many of the policy makers feel entitled to choose what to accept how the Earth Systems will respond to continued radiative forcing; which is why the CoP21 national contributions to control GHG emissions are voluntary.

I concur that in the next decade of two that it will become more difficult to ignore high Earth System responses to continued radiative forcing; but in the meantime you should be aware that IPCC SLR model projections are probably one of the least accurate projections in AR5 (which are about 50% higher than for the AR4 SLR projections that you posted).

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 04, 2015, 12:44:46 AM
Thanks ASLR. You, and others, post so much great material here that I am able to read only a small portion of  the research and understand only a portion of that. It does not surprise me that extensive research has already been done to either confirm or completely refute  any comment I make. It also doesn't surprise  me that this research is linked  above.

Keep it  coming. I am learning.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 04, 2015, 01:41:10 AM
SH,

The linked article presents two figures that elucidate the IPCC's thinking in AR5 SLR projections (see attached images & associated captions); which show how much they increased their SLR projections compared to the AR4 image that you posted.  However, the Oct 2014 ThinkProgress article also cite research published after the AR5 cut-off date indicating the the SLR contribution from the Antarctic, and Greenland, Ice Sheets will likely be considerably higher than assumed in AR5; and since the Oct 2014 ThinkProgress article a significant number of papers have been published indicating the SLR contribution from the West Antarctic Ice Sheet could be over 2m by 2100 if we stay on a BAU pathway (see the link at the bottom of this post for discussion on this matter):

http://thinkprogress.org/climate/2014/10/16/3580131/worst-case-sea-level-rise/ (http://thinkprogress.org/climate/2014/10/16/3580131/worst-case-sea-level-rise/)

Caption Figure 1: "Projected component of global sea level rise by 2100 relative to 2000 and their uncertainty. Vertical light grey bars indicate the 5, 50 and 95th percentiles in the uncertainty distribution. Dark grey bars represent projected sea level components calculated in this study. Thick red lines show the likely range of the sea level contributions from the AR5 and red thin lines are our fit to the AR5 distribution."

Caption Figure 2: "Projected global mean sea level rise by 2100 relative to 2000 for the RCP8.5 scenario and uncertainty. Vertical grey bars indicate the 5, 17, 50, 83, and 95th percentiles in the uncertainty distribution."

http://forum.arctic-sea-ice.net/index.php/topic,31.350.html (http://forum.arctic-sea-ice.net/index.php/topic,31.350.html)

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on May 05, 2015, 09:31:20 PM
Hansen chimes in on an Australian radio:

"The ice sheets are losing mass faster and faster with a doubling the of about 10 years. If that continues, we would get sea-level rises of several metres within 40 to 50 years."

http://rabett.blogspot.com/2015/05/why-jim-hansen-worries.html (http://rabett.blogspot.com/2015/05/why-jim-hansen-worries.html)

and
http://www.abc.net.au/radionational/programs/breakfast/two-degrees-of-global-warming-is-not-safe/6444698 (http://www.abc.net.au/radionational/programs/breakfast/two-degrees-of-global-warming-is-not-safe/6444698)




Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 11, 2015, 11:52:58 PM
The link leads to an article indicating that the rate of SLR over the past two decades was faster than previously realized:

http://www.theguardian.com/environment/2015/may/11/sea-level-rise-accelerated-over-the-past-two-decades-research-finds (http://www.theguardian.com/environment/2015/may/11/sea-level-rise-accelerated-over-the-past-two-decades-research-finds)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 12, 2015, 07:03:59 AM
From the Guardian article ALSR linked:
"Watson’s team found that the record of sea level rise during the early 1990s was too high. The error gave the illusion of the rate of sea level rise decreasing by 0.058 mm/year2 between 1993 and 2014, when in reality it accelerated by between 0.041 and 0.058 mm/year2... The IPCC’s landmark report in 2013 found the sea had risen on average by 3.2 mm per year since 1993. Waston’s study found the rate was slightly slower, between 2.6 and 2.9 mm per year."

So the acceleration of SLR was faster than previously thought, but the average rate of SLR itself was somewhat slower than earlier estimates, according to this research.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 12, 2015, 05:47:44 PM
So the acceleration of SLR was faster than previously thought, but the average rate of SLR itself was somewhat slower than earlier estimates, according to this research.

Here is a link to the paper where even White & Church are admitting that over the past 10-years SLR contributions from ice sheets are causing global mean sea level rise rates to accelerate (faster than previously thought):

Christopher S. Watson, Neil J. White, John A. Church, Matt A. King, Reed J. Burgette & Benoit Legresy (2015), "Unabated global mean sea-level rise over the satellite altimeter era ", Nature Climate Change, doi:10.1038/nclimate2635


http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2635.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2635.html)


Abstract: "The rate of global mean sea-level (GMSL) rise has been suggested to be lower for the past decade compared with the preceding decade as a result of natural variability, with an average rate of rise since 1993 of +3.2 ± 0.4 mm yr−1. However, satellite-based GMSL estimates do not include an allowance for potential instrumental drifts (bias drift). Here, we report improved bias drift estimates for individual altimeter missions from a refined estimation approach that incorporates new Global Positioning System (GPS) estimates of vertical land movement (VLM). In contrast to previous results, we identify significant non-zero systematic drifts that are satellite-specific, most notably affecting the first 6 years of the GMSL record. Applying the bias drift corrections has two implications. First, the GMSL rate (1993 to mid-2014) is systematically reduced to between +2.6 ± 0.4 mm yr−1 and +2.9 ± 0.4 mm yr−1, depending on the choice of VLM applied. These rates are in closer agreement with the rate derived from the sum of the observed contributions GMSL estimated from a comprehensive network of tide gauges with GPS-based VLM applied and reprocessed ERS-2/Envisat altimetry. Second, in contrast to the previously reported slowing in the rate during the past two decades, our corrected GMSL data set indicates an acceleration in sea-level rise (independent of the VLM used), which is of opposite sign to previous estimates and comparable to the accelerated loss of ice from Greenland and to recent projections, and larger than the twentieth-century acceleration."

See also:

http://thinkprogress.org/climate/2015/05/12/3657633/study-sea-level-rise-accelerating/ (http://thinkprogress.org/climate/2015/05/12/3657633/study-sea-level-rise-accelerating/)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 12, 2015, 06:24:18 PM
ASLR,

The abstract of Watson et al 2015 says:
"In contrast to previous results, we identify significant non-zero systematic drifts that are satellite-specific, most notably affecting the first 6 years of the GMSL record. Applying the bias drift corrections has two implications. First, the GMSL rate (1993 to mid-2014) is systematically reduced to between +2.6 ± 0.4 mm yr−1 and +2.9 ± 0.4 mm yr−1, depending on the choice of VLM applied."

The Climate Progress news article says:
"Using the newly recalibrated data, the researchers found that sea level rise between 1993 and 1999 — the earliest segment of satellite data — was overstated. According to satellite data, over that six-year period, global sea level rose 3.2 milimeters (about .12 inches) per year; using Watson’s recalibrated data, sea levels probably rose closer to between 2.6 to 2.9 mm (about .1 to .11 inches) per year."

It seems this is not correct, since the abstract says: "the GMSL rate (1993 to mid-2014) is systematically reduced to between +2.6 ± 0.4 mm yr−1 and +2.9 ± 0.4 mm yr−1".

So Watson et al are talking about 2.6-2.9 mm/yr for 1993-2014, not only for 1993-1999. Or am I misunderstanding something?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 12, 2015, 06:34:11 PM
ASLR,

The abstract of Watson et al 2015 says:
"In contrast to previous results, we identify significant non-zero systematic drifts that are satellite-specific, most notably affecting the first 6 years of the GMSL record. Applying the bias drift corrections has two implications. First, the GMSL rate (1993 to mid-2014) is systematically reduced to between +2.6 ± 0.4 mm yr−1 and +2.9 ± 0.4 mm yr−1, depending on the choice of VLM applied."

The Climate Progress news article says:
"Using the newly recalibrated data, the researchers found that sea level rise between 1993 and 1999 — the earliest segment of satellite data — was overstated. According to satellite data, over that six-year period, global sea level rose 3.2 milimeters (about .12 inches) per year; using Watson’s recalibrated data, sea levels probably rose closer to between 2.6 to 2.9 mm (about .1 to .11 inches) per year."

It seems this is not correct, since the abstract says: "the GMSL rate (1993 to mid-2014) is systematically reduced to between +2.6 ± 0.4 mm yr−1 and +2.9 ± 0.4 mm yr−1".

So Watson et al are talking about 2.6-2.9 mm/yr for 1993-2014, not only for 1993-1999. Or am I misunderstanding something?

Lennart,

You need to be very careful when using averaged numbers such as the average from 1993 to 2014, as they can mask acceleration trend in the data as noted in the following quote from the Watson et al 2015 abstract:

Extract: "... Second, in contrast to the previously reported slowing in the rate during the past two decades, our corrected GMSL data set indicates an acceleration in sea-level rise (independent of the VLM used), which is of opposite sign to previous estimates and comparable to the accelerated loss of ice from Greenland and to recent projections, and larger than the twentieth-century acceleration."

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 12, 2015, 06:57:22 PM
ASLR,
Yes, they're talking about more acceleration than previously thought, but slower total SLR over 1993-2014 than previously thought. So logically average SLR over say 1993-2003 should be less than over 2003-2014 and than over the whole period 1993-2014. The question is how much SLR they estimate over the last decade. Since their estimated acceleration is about 0.05 mm/yr2 over the whole period, total acceleration should be about 1 mm over this 20-yrs period. So I would estimate average SLR around 1993 to have been about 2.1-2.4 mm/yr and around 2014 about 3.1-3.4 mm/yr.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 12, 2015, 06:58:51 PM
Lennart,

Also see the following extract that helps to elaborate on this matter, but be aware that as Church is a co-author this paper likely errs on the side of least drama:

http://www.straitstimes.com/news/world/more-world-stories/story/sea-level-rise-accelerating-earths-ice-sheets-melt-say-scientist (http://www.straitstimes.com/news/world/more-world-stories/story/sea-level-rise-accelerating-earths-ice-sheets-melt-say-scientist)

Extract: "The new study, published in the journal Nature Climate Change, takes land movement into account, along with an important statistical tweak - hourly data from a network of tide gauges deployed around the world's oceans. It finds that the overall rate of sea level rise between 1993 and mid-2014 is between 2.6 and 2.9 mm per year, with a margin of error of plus or minus 0.4 mm. The bad news is that the first six years of the satellite data - 1993 to 1999 - is the period that is most affected by these corrections. For those six years, estimates have to be scaled down by 0.9-1.5 mm a year. That mean in more recent years the rate of sea-level rise has actually increased rather than declined, according to the paper, led by Christopher Watson of the University of Tasmania, Australia. The acceleration "is higher than the observed twentieth-century acceleration but in reasonable agreement with an accelerating contribution from the Greenland and West Antarctic ice sheets over this period", the team said."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 12, 2015, 07:08:06 PM
Lennart,

I re-post your Reply #341 below:

"Some indications that SLR may have been accelerating over the past few years:
http://onlinelibrary.wiley.com/doi/10.1002/2015GL063902/abstract?utm_content=buffer63d49&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://onlinelibrary.wiley.com/doi/10.1002/2015GL063902/abstract?utm_content=buffer63d49&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

"The global mean sea level (GMSL) was reported to have dropped 5 mm due to the 2010/11 La Niña and have recovered in one year. With longer observations, it is shown that the GMSL went further up to a total amount of 11.6 mm by the end of 2012, excluding the 3.0 mm/yr background trend. A reconciled sea level budget, based on observations by Argo project, altimeter and gravity satellites, reveals that the true GMSL rise has been masked by ENSO-related fluctuations and its rate has increased since 2010. After extracting the influence of land water storage, it is shown that the GMSL have been rising at a rate of 4.4 ± 0.5 mm/yr for more than three years, due to an increase in the rate of both land ice loss and steric change.""

Therefore, we all need to remember that GMSL dropped 5m due to the 2010/2011 La Nina, are impacting Watson et al 2015 numbers; while GMSL has "... been rising at a rate of 4.4 +/- 0.5 mm/yr for more than three years now; and in this current El Nino year GMSL is jumping up still high.  We all need to be very careful with using SLR rate values that do not consider the influence of the coming 20, or so, years of positive PDO; and the likely accelerating contribution from ice sheets (which the AR5 panel on SLR that Church chaired underestimated).

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 12, 2015, 08:35:41 PM
The link leads to an article indicating that the rate of SLR over the past two decades was faster than previously realized:

ASLR,
My first reaction to your original post on this matter was to the part in bold (but I forgot to point this out, so maybe that was not so clear). Watson et al 2015 say the rate of SLR of the past two decades was slower, not faster, than previously realized. They also say the acceleration over this period was faster than previoulsy thought. And this doesn't exclude the possibility that over 2010-2012 the rate of SLR and acceleration was even faster than in the years before. A correction for the influence of El Nino en La Nina on the numbers of Watson et al 2015 (and IPCC) seems useful, but how much that would change the average over 1993-2014 does not seem obvious to me.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on May 12, 2015, 08:48:45 PM
Watson(2015) is a carefully done paper. As to acceleration:

" the previously reported deceleration[1] , estimated here as −0.057 ± 0.058 mm/yr/yr (over 1993–2014), becomes an acceleration of +0.041 ± 0.058 mm/yr/yr "

The previously reported deceleration is from a paper by Cazenave last year.

Watson et al. go on to note:

"Neither of these is significantly different from zero, however, the revised estimate is significantly different from the earlier estimate derived from data unadjusted for the effects of bias drift."

and

"Our computed acceleration is higher than the observed twentieth-century acceleration[2,8,23] but in reasonable agreement with an accelerating contribution from the Greenland and West Antarctic ice sheets over this period[2,24] , and the Intergovernmental Panel on Climate Change projections[2,10] of acceleration in sea-level rise during the early decades of the twenty-first century of about +0.07 mm/yr/yr ."

The numbers in brackets are references.

My takeaway is that the satellite record so far cannot definitely ascribe nonzero acceleration, and that OHC is still a major player in SLR. Once ice sheet melt takes off, the acceleration will become unmistakable, and it will be clearly too late to forestall eventual SLR rates of 1 meter every score of years. One might speculate that the recently observed mass waste acceleration in west antarctica (or Greenland) with a doubling time of a decade will dominate SLR in the future. With current contribution of about 1/3 mm/yr to SLR from WAIS out of the total observed 3mm/yr, naive extrapolation  shows WAIS waste dominating in 30-40 years. Greenland seems to be contributing around a mm/yr right now, so a decadal doubling there would give more than cm/yr by midcentury. And after that, a deluge comparable to MWP1A.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 12, 2015, 10:10:51 PM
To me it is clear that as Church is Chairman of the IPCC SLR committee, that any paper that he co-authors must err on the side of least drama.  Therefore, I lean more towards sidd's rough assessment above than to Watson et al 2015 use of limited historical SLR data to characterize ice sheet contributions to global mean sea level rise.

However, I point out that sidd's use of the average WAIS SLR contribution of about 1/3 mm/yr; does not fully illustrate our true risks, as the attached GOCE measurement of SLR contribution from the Amundsen Sea Sector alone was 0.51mm/yr averaged from November 2009 to June 2012 (which includes the major 2010/11 La Nina event), see the attached image & the linked article.

http://www.esa.int/Our_Activities/Observing_the_Earth/GOCE/GOCE_reveals_gravity_dip_from_ice_loss (http://www.esa.int/Our_Activities/Observing_the_Earth/GOCE/GOCE_reveals_gravity_dip_from_ice_loss)

The point that I am trying to make is that by talking about averaged data, we underestimate the future risks of SLR contribution from such exponentially degrading areas as the Amundsen Sea Sector (& I give Pollard et al 2015's assessment of this risk much more credence than some short-term tide gauge record gathered predominately during the last negative PDO cycle).

Edit: I forgot to note that the GOCE estimated SLR contribution form the Amundsen Sea Sector, by eventually need to be increased by up to 40% in order to correct for the GIA (glacial isostatic adjustment); which is currently being measured in this sector.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Michael Hauber on May 13, 2015, 04:33:21 AM
Just for fun, the current rate of 2.6ymm/year, and acceleration of 0.04 mm/year gives an increase to 6.6 mm/year and a 46cm total sea level rise for the next century.  If we assume that the acceleration is exponential (i.e. 0.04/2.6 % compound growth) this gives a rate of 11.8mm/year in 100 years, and a total of 61 cm of sea level rise.

We need more acceleration than is being currently observed to get anything above 1 meter for the next century.  If I remember right a faster exponential growth on just the ice sheet portion of the current melt as Hansen calculated could get us to 7 meters in a hundred years.

 
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on May 13, 2015, 07:07:22 AM
"We need more acceleration than is being currently observed ..."

Precisely. And I claim

1) the acceleration from WAIS and GIS is not visible yet inSLR
2) When it is, doom is nigh.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 13, 2015, 04:32:48 PM
"We need more acceleration than is being currently observed ..."

Precisely. And I claim

1) the acceleration from WAIS and GIS is not visible yet inSLR
2) When it is, doom is nigh.

sidd

I concur with sidd that policy makers who over-emphasize the importance of the past couple of decades of observed record will likely be in for a big surprise when the highly non-linear positive SLR feedbacks (such as PIG, Thwaites, Jakobshaven etc) accelerate rapidly while the largely linear negative SLR feedbacks (such as episodic atmospheric river driven snow fall in Antarctica or La Nina driven rainfall in the tropical land areas) accelerate slowly.  The only justification for MH-type of projections is if one has a high tolerance for transferring risk to others; by thinking that in a zero-sum game that you can do alright at the expense of others.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 13, 2015, 05:09:15 PM
Also see this comparison of collapsing ice sheets with avalanches:
http://johnenglander.net/sea-level-rise-blog/inability-predict-slr-similar-avalanche-problem (http://johnenglander.net/sea-level-rise-blog/inability-predict-slr-similar-avalanche-problem)

"The most common question about sea level rise is 'how high will it rise by when.' It surprises many to learn that there is no way to predict that answer with any certainty. Also many mistakenly believe that projections for three or six feet are really the worst case scenario, which they are definitely not.

One of the ways that I explain our inability to predict when catastophic sea level rise (SLR) could happen, is to use avalanches as an example. (The recent tragedy in Nepal makes this very poignant.)

Many of us have been in areas of heavy snow and been told there is the "potential for an avalanche." Yet there is absolutely no way to predict if or when an avalanche could occur. It could start in 3 minutes or 3 weeks, or never. There is simply no way to model the complex dynamics of melting heavy snowmass to know when the structure will hit a critical point of failure.

A slightly different metaphor is an earthquake. In spite of thousands of earthquakes to study, and putting sensors on known fault lines, we cannot predict an earthquake. Last summer for example, in the San Francisco Bay Area, seismologists were proud that they were able to issue a 10 second warning of a significant earthquake allowing some people to get out of elevators or buildings. There is simply no way to predict how the pressures on the tectonic plates will suddenly shift.

The ice sheets in Greenland and Antarctica are similar.  They are two or three miles thick. Like a potential avalanche there is no way to model exactly when they will collapse.  When they collapse we will get many feet of SLR, in fact, eventually we will get tens of feet of SLR. Because scientists cannot predict whether that will happen by the year 2100, or in the following century, that potential is generally omitted from the SLR projections. Scientists need to be able to cite objective data, based on measurements that can be verified. The collapse of the glaciers and two great ice sheets do not follow that.

We need to explain this phenomenon better. People, communities, companies, and governments need to understand that we are going to get tens of feet of sea level rise sometime in the next few centuries. In the second half of this century we could start to see catastropic SLR.  Now is the time to do strategic planning. One way to explain the misleading or misunderstood limitations about rising sea level may be mountain avalanches -- though that is of course very counterintuitive."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 13, 2015, 07:10:40 PM
Also see this comparison of collapsing ice sheets with avalanches:
http://johnenglander.net/sea-level-rise-blog/inability-predict-slr-similar-avalanche-problem (http://johnenglander.net/sea-level-rise-blog/inability-predict-slr-similar-avalanche-problem)

Lennart,

Thanks for the link to the John Englander website:

http://johnenglander.net/ (http://johnenglander.net/)

Englander seems to have a lot of very reasonable things to say about SLR in the numerous posts on his blog site.

I hope that efforts like efforts like the 10-yr ACME program will identify the true SLR risks before large-scale cliff failure and hydrofracturing calving events become common in marine glaciers in both the GIS and the AIS:

http://climatemodeling.science.energy.gov/sites/default/files/publications/acme-project-strategy-plan.pdf (http://climatemodeling.science.energy.gov/sites/default/files/publications/acme-project-strategy-plan.pdf)

http://climatemodeling.science.energy.gov/ (http://climatemodeling.science.energy.gov/)

http://crf.sandia.gov/acme-climate-modeling-powered-by-doe-supercomputers-tamed-by-uncertainty-quantification/ (http://crf.sandia.gov/acme-climate-modeling-powered-by-doe-supercomputers-tamed-by-uncertainty-quantification/)

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Martin Gisser on May 13, 2015, 08:17:10 PM
Also see this comparison of collapsing ice sheets with avalanches:
http://johnenglander.net/sea-level-rise-blog/inability-predict-slr-similar-avalanche-problem (http://johnenglander.net/sea-level-rise-blog/inability-predict-slr-similar-avalanche-problem)
I hope I misunderstood  this article... He seems to tell that SLR from ice sheet collapse cannot be predicted by comparing this to the problem of predicting when an avalanche or earth quake gets loose. That looks totally wrong to me: The collapse will not come sudden, like a house collapsing due to an earth quake. No, the collapse is already happening! (E.g. Rignot et al found WAIS collapse now is even irreversible). But it is happening in slow motion.

The avalanche metaphor seems quite apt, but only when taken in slow motion. (I'm no ice sheet expert and wanted to ask for this today somewhere on the forum - so I searched for the key word "exponential" and thus came here. :) )

The ice sheet "avalanche" is already rolling upon us, meanwhile, accumulating in mass, growing more exponentially than linearly. (+). Taking a conservative estimate of 10y doubling time of melt rate and taking just Greenland, then we get 3.5-7 meters SLR by 2100, as Hansen said long time ago. (Now imagine that it looks more like 5y doubling time - the avalanche then growing monstrously bigger and faster. I hear it roaring...)

Problem with extrapolating exponential trends is of course the growing error margin (E.g.: Is it half of Greenland by 2100 or all of it?). But that doesn't mean prediction is impossible -  you just have to get rid of the common image of a linear scale of numbers. (Maybe play with an ancient mechanical slide rule calculator. Every pre-calc math student should have one.)

Albert Bartlett's famous dictum:
Quote
The greatest shortcoming of the human race is our inability to understand the exponential function.
(Well, methinks that's due to the cultural dominance of left brain hemisphere thinking, which only can do linear bean counting (however complex it may be) but fails at holistic systems grasp. Grasping exponential stuff (and its vagaries in a finite real world) is more for the right hemisphere. But that's for a different thread...)

--------------------
(+) Edit, P.S.:
There are general systems thinking reasons for preferring exponential over linear. (A bit more detail in my 2009 comment here (http://www.realclimate.org/index.php/archives/2009/01/sea-will-rise-to-levels-of-last-ice-age/comment-page-1/#comment-110846).) Me dunno know more. And Hansen said the same. :) Meanwhile, my impression is that it's almost consensus amongst ice sheet experts to assume exponential decay (and monstrous SLR as a corollary) - drawing from their expert intuition about the concrete physical system at hand.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 13, 2015, 08:58:16 PM
Also see this comparison of collapsing ice sheets with avalanches:
http://johnenglander.net/sea-level-rise-blog/inability-predict-slr-similar-avalanche-problem (http://johnenglander.net/sea-level-rise-blog/inability-predict-slr-similar-avalanche-problem)
I hope I misunderstood  this article... He seems to tell that SLR from ice sheet collapse cannot be predicted by comparing this to the problem of predicting when an avalanche or earth quake gets loose. That looks totally wrong to me: The collapse will not come sudden, like a house collapsing due to an earth quake. No, the collapse is already happening! (E.g. Rignot et al found WAIS collapse now is even irreversible). But it is happening in slow motion.

If you want to know more about this topic you may wish to review the following reference and the following linked threads in the Antarctic folder:

Pollard, D., R.M. DeConto and R.B. Alley (2015) "Potential Antarctic Ice Sheet retreat driven by hydrofracturing and ice cliff failure", Earth Plan. Sci. Lett., 412, 112-121

http://www.sciencedirect.com/science/article/pii/S0012821X14007961 (http://www.sciencedirect.com/science/article/pii/S0012821X14007961)

http://forum.arctic-sea-ice.net/index.php/topic,130.150.html (http://forum.arctic-sea-ice.net/index.php/topic,130.150.html)

http://forum.arctic-sea-ice.net/index.php/topic,263.100.html#lastPost (http://forum.arctic-sea-ice.net/index.php/topic,263.100.html#lastPost)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 13, 2015, 10:31:54 PM
With a hat tip to Lennart from the WAIS Collapse thread in the Antarctic folder, the linked reference (with a free access pdf) shows that assuming both cliff failure, and melt-driven hydrofracturing, active the WAIS could contribute from 2m to 3m to SLR by 2100 (note that almost all of my posts in the Antarctic folder support this approximation), per the attached image and associated caption:

Pollard, D., DeConto, R.M. and Alley, R.B., (2015), "Potential Antarctic Ice Sheet retreat driven by hydrofracturing and ice cliff failure", Earth and Planetary Science Letters, Volume 412, 15 February 2015, Pages 112–121, doi:10.1016/j.epsl.2014.12.035

http://www.sciencedirect.com/science/article/pii/S0012821X14007961 (http://www.sciencedirect.com/science/article/pii/S0012821X14007961)



Abstract: "Geological data indicate that global mean sea level has fluctuated on 103 to 106 yr time scales during the last ∼25 million years, at times reaching 20 m or more above modern. If correct, this implies substantial variations in the size of the East Antarctic Ice Sheet (EAIS). However, most climate and ice sheet models have not been able to simulate significant EAIS retreat from continental size, given that atmospheric CO2 levels were relatively low throughout this period. Here, we use a continental ice sheet model to show that mechanisms based on recent observations and analysis have the potential to resolve this model–data conflict. In response to atmospheric and ocean temperatures typical of past warm periods, floating ice shelves may be drastically reduced or removed completely by increased oceanic melting, and by hydrofracturing due to surface melt draining into crevasses. Ice at deep grounding lines may be weakened by hydrofracturing and reduced buttressing, and may fail structurally if stresses exceed the ice yield strength, producing rapid retreat. Incorporating these mechanisms in our ice-sheet model accelerates the expected collapse of the West Antarctic Ice Sheet to decadal time scales, and also causes retreat into major East Antarctic subglacial basins, producing ∼17 m global sea-level rise within a few thousand years. The mechanisms are highly parameterized and should be tested by further process studies. But if accurate, they offer one explanation for past sea-level high stands, and suggest that Antarctica may be more vulnerable to warm climates than in most previous studies."

Caption: "Global mean equivalent sea level rise in warm-climate simulations. Time series of global mean sea level rise above modern are shown, implied by reduced Antarctic ice volumes. The calculation takes into account the lesser effect of melting ice that is originally grounded below sea level. Cyan: with neither cliff failure nor melt-driven hydrofracturing active. Blue: with cliff failure active. Green: with melt-driven hydrofracturing active. Red: with both these mechanisms active."

Edit: I note that the values given in the attached image are for a simple Pliocene-like warming scenario, and not for any RCP or SRES pathways.

Martin,

I also reproduce Reply #250 here & I noted that if Abrupt Sea Level Rise, ASLR, occurs faster than society can respond, then the analogy with a slow moving avalanche seem apropos.

ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Martin Gisser on May 13, 2015, 11:11:08 PM
If you want to know more about this topic you may wish to review the following reference and the following linked threads in the Antarctic folder:

Pollard, D., R.M. DeConto and R.B. Alley (2015) "Potential Antarctic Ice Sheet retreat driven by hydrofracturing and ice cliff failure", Earth Plan. Sci. Lett., 412, 112-121

http://www.sciencedirect.com/science/article/pii/S0012821X14007961 (http://www.sciencedirect.com/science/article/pii/S0012821X14007961)

http://forum.arctic-sea-ice.net/index.php/topic,130.150.html (http://forum.arctic-sea-ice.net/index.php/topic,130.150.html)

http://forum.arctic-sea-ice.net/index.php/topic,263.100.html#lastPost (http://forum.arctic-sea-ice.net/index.php/topic,263.100.html#lastPost)

Thanks!
But methinks that doesn't change my criticism of Englander's article: Pollard et al just explain a mechanism by which the avalanche accumulates momentum even faster. There is not one point of failure (and then there goes the avalanche or tumbles the building) - but lots of calving and sliding away at many ends, adding/averaging up to a rather smooth process. A quite possibly exponential one (e.g. due to feedback by lowering elevation of ice sheets or e.g. widening of calving fronts, etc.). When much of the ice is gone (e.g. perhaps half - here's the rub perhaps) things might slow down and get linear and finally equilibrate.

Pollard et al:
Quote
Incorporating these mechanisms in our ice-sheet model accelerates the expected collapse of the West Antarctic Ice Sheet to decadal time scales, and also causes retreat into major East Antarctic subglacial basins, producing ∼17 m global sea-level rise within a few thousand years. The mechanisms are highly parameterized and should be tested by further process studies. But if accurate, they offer one explanation for past sea-level high stands, and suggest that Antarctica may be more vulnerable to warm climates than in most previous studies.

That doesn't change my exponential-qualitative data driven impression much. (Luckily the EAIS looks still a millenium away...) Except I now tend more toward a 5y doubling time. And thus I'm now more sure that I will see some of the monstrosity of things to come within my own life time.  (But it doesn't change the monstrosity of mankind's ecocide cum genosuicide cum econocide if SLR hits 4m by 2050 or by 2100.)


-------------
P.S.: Last Edit done, then noted your post right above :)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Martin Gisser on May 13, 2015, 11:33:07 PM
Regarding the avalanche metaphor, I'd say to the society: "Better run now and fast and don't gaze at the funny snow movement up the mountain! We don't know how large it will get and when or if it will hit us and how deep we could get buried. And forget about the fat stupid uncle."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Michael Hauber on May 14, 2015, 07:40:47 AM
"We need more acceleration than is being currently observed ..."

Precisely. And I claim

1) the acceleration from WAIS and GIS is not visible yet inSLR
2) When it is, doom is nigh.

sidd

I concur with sidd that policy makers who over-emphasize the importance of the past couple of decades of observed record will likely be in for a big surprise when the highly non-linear positive SLR feedbacks (such as PIG, Thwaites, Jakobshaven etc) accelerate rapidly while the largely linear negative SLR feedbacks (such as episodic atmospheric river driven snow fall in Antarctica or La Nina driven rainfall in the tropical land areas) accelerate slowly.  The only justification for MH-type of projections is if one has a high tolerance for transferring risk to others; by thinking that in a zero-sum game that you can do alright at the expense of others.

You brought up the Church paper claiming that it showed sea level rise was faster than previously thought.  When it was pointed out to you that the paper reduced the sea level rise from 3.2 to 2.6 you said that was missing the point because it found that there was now an acceleration.  I showed how much sea level rise the acceleration rate from the paper you originally promoted would actually cause in the next century and you talk about MH-type projections.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 14, 2015, 05:19:17 PM
"We need more acceleration than is being currently observed ..."

Precisely. And I claim

1) the acceleration from WAIS and GIS is not visible yet inSLR
2) When it is, doom is nigh.

sidd

I concur with sidd that policy makers who over-emphasize the importance of the past couple of decades of observed record will likely be in for a big surprise when the highly non-linear positive SLR feedbacks (such as PIG, Thwaites, Jakobshaven etc) accelerate rapidly while the largely linear negative SLR feedbacks (such as episodic atmospheric river driven snow fall in Antarctica or La Nina driven rainfall in the tropical land areas) accelerate slowly.  The only justification for MH-type of projections is if one has a high tolerance for transferring risk to others; by thinking that in a zero-sum game that you can do alright at the expense of others.

You brought up the Church paper claiming that it showed sea level rise was faster than previously thought.  When it was pointed out to you that the paper reduced the sea level rise from 3.2 to 2.6 you said that was missing the point because it found that there was now an acceleration.  I showed how much sea level rise the acceleration rate from the paper you originally promoted would actually cause in the next century and you talk about MH-type projections.

Per the linked article (& associated extract) if the rate of sea level rise from 1993 to 1999 was slower than previously thought, but if estimates of current sea level remains essentially unchanged; then the rate of sea level rise from 1999 to now must have accelerated faster than previously thought; which implies that the SLR contributions from ice sheets is accelerating; which is the key point of the Watson et al 2015 paper.


http://www.straitstimes.com/news/world/more-world-stories/story/sea-level-rise-accelerating-earths-ice-sheets-melt-say-scientist (http://www.straitstimes.com/news/world/more-world-stories/story/sea-level-rise-accelerating-earths-ice-sheets-melt-say-scientist)

Extract: "The new study, published in the journal Nature Climate Change, takes land movement into account, along with an important statistical tweak - hourly data from a network of tide gauges deployed around the world's oceans. It finds that the overall rate of sea level rise between 1993 and mid-2014 is between 2.6 and 2.9 mm per year, with a margin of error of plus or minus 0.4 mm. The bad news is that the first six years of the satellite data - 1993 to 1999 - is the period that is most affected by these corrections. For those six years, estimates have to be scaled down by 0.9-1.5 mm a year. That mean in more recent years the rate of sea-level rise has actually increased rather than declined, according to the paper, led by Christopher Watson of the University of Tasmania, Australia. The acceleration "is higher than the observed twentieth-century acceleration but in reasonable agreement with an accelerating contribution from the Greenland and West Antarctic ice sheets over this period", the team said."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on May 14, 2015, 07:49:15 PM
Quote
I showed how much sea level rise the acceleration rate from the paper you originally promoted would actually cause in the next century

 >:(  I don't know why I bother coming here when I can just as easily gather lots of other disinformation about climate sciences from watts up with that. . .

are you then claiming that sea level rise will not continue to accelerate in a warming world?  really???

 ??? ??? ???
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Michael Hauber on May 14, 2015, 09:58:53 PM
Quote
I showed how much sea level rise the acceleration rate from the paper you originally promoted would actually cause in the next century

 >:(  I don't know why I bother coming here when I can just as easily gather lots of other disinformation about climate sciences from watts up with that. . .

are you then claiming that sea level rise will not continue to accelerate in a warming world?  really???

 ??? ??? ???

I am pointing out that the acceleration reported in the paper ASLR quoted is only enough to give about a meter of sea level rise of 1 meter in the next hundred years. 

I've already said that other sources such as Hansen can give a higher sea level rise such as 7 meters (although his analysis is highly speculative extrapolation of 'what if the ice sheet melt keeps doubling throughout the century'), and I have no problem with the chart ASLR posted earlier which shows 5 meters over the next 200 years.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on May 15, 2015, 09:48:05 PM
@billmckibben: Kivalina--Arctic village imperiled by climate change--needs $ to build a road to its new school. Donations welcome.
http://storm-swan.wix.com/relocatekivalina (http://storm-swan.wix.com/relocatekivalina)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 16, 2015, 02:58:23 PM
From the Guardian article ALSR linked:
"Watson’s team found that the record of sea level rise during the early 1990s was too high. The error gave the illusion of the rate of sea level rise decreasing by 0.058 mm/year2 between 1993 and 2014, when in reality it accelerated by between 0.041 and 0.058 mm/year2... The IPCC’s landmark report in 2013 found the sea had risen on average by 3.2 mm per year since 1993. Waston’s study found the rate was slightly slower, between 2.6 and 2.9 mm per year."

So the acceleration of SLR was faster than previously thought, but the average rate of SLR itself was somewhat slower than earlier estimates, according to this research.

I am trying not to comment often on these threads as I do not understand much of the science (I do visit every day and read almost every thread.) but this discovery is frightening to me. The acceleration of SLR is far more important than the average rate in the same period.

SLR is simply the best, the most accurate aggregate measure of what is happening in the cryosphere. Every study I have read here has shown acceleration in the melt of ice. Glaciers are speeding up and thinning faster. Greenland mass loss is accelerating. Previously stable glaciers are beginning to show signs of deterioration. The WAIS mass loss is accelerating. Specific ice shelves and glaciers defending the WAIS are thinning and speeding up at an accelerating rate. Ice caps previously considered stable (Northeast Greenland and the EAIS) are now exhibiting signs of  accelerating melt and increasing mass loss. Given this, SLR cannot do anything but accelerate and I expect this acceleration to continue in a warming world as this rise captures, in aggregate, the increasing melt across the planet.

I cannot imagine any argument that would convince me that a linear or near linear increase in SLR is what we should expect through this century. Given this acceleration in SLR, the only conclusion that can be drawn is that a doubling rate of growth in SLR is a reality. We should expect that the SLR rate will exhibit an exponential trend. The only question.......what is that doubling rate and where will we end up at the end of the century? My fear is that Hansen is more correct than the current projections of the various models.

(Graph taken from Church 2008)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 16, 2015, 03:18:57 PM
In August of 2012, the North Carolina legislature passed a law that required all state planning agencies to only use historical SLR and ignore science that shows that the rise in sea levels will accelerate.

http://abcnews.go.com/US/north-carolina-bans-latest-science-rising-sea-level/story?id=16913782 (http://abcnews.go.com/US/north-carolina-bans-latest-science-rising-sea-level/story?id=16913782)

Specific language of the legislation.....

"These rates shall only be determined using historical data, and these data shall be limited to the time period following the year 1900. Rates of seas-level rise may be extrapolated linearly …"

They calculate the average rate of SLR from 1900 and then use this linear rate to predict future SLR. This is ignorant and laughable.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 16, 2015, 03:51:16 PM
With regards to the doubling rate, this can be hard to calculate given the difficulty in measuring accurately small increases in SLR in an environment where ocean levels have a natural variation. I expect that, within a decade, we should have a much better sense of the doubling rate and it will not be pretty.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 16, 2015, 05:37:13 PM
Just for fun, the current rate of 2.6ymm/year, and acceleration of 0.04 mm/year gives an increase to 6.6 mm/year and a 46cm total sea level rise for the next century.  If we assume that the acceleration is exponential (i.e. 0.04/2.6 % compound growth) this gives a rate of 11.8mm/year in 100 years, and a total of 61 cm of sea level rise.

We need more acceleration than is being currently observed to get anything above 1 meter for the next century.  If I remember right a faster exponential growth on just the ice sheet portion of the current melt as Hansen calculated could get us to 7 meters in a hundred years.

I may be missing something or misunderstanding how compounding works but how exactly did you arrive at the 2.6% compound growth which suggests a 27 year doubling rate.

From a comment by ASLR above...

Also see the following extract that helps to elaborate on this matter, but be aware that as Church is a co-author this paper likely errs on the side of least drama:

http://www.straitstimes.com/news/world/more-world-stories/story/sea-level-rise-accelerating-earths-ice-sheets-melt-say-scientist (http://www.straitstimes.com/news/world/more-world-stories/story/sea-level-rise-accelerating-earths-ice-sheets-melt-say-scientist)

Extract: "The new study, published in the journal Nature Climate Change, takes land movement into account, along with an important statistical tweak - hourly data from a network of tide gauges deployed around the world's oceans. It finds that the overall rate of sea level rise between 1993 and mid-2014 is between 2.6 and 2.9 mm per year, with a margin of error of plus or minus 0.4 mm. The bad news is that the first six years of the satellite data - 1993 to 1999 - is the period that is most affected by these corrections. For those six years, estimates have to be scaled down by 0.9-1.5 mm a year. That mean in more recent years the rate of sea-level rise has actually increased rather than declined, according to the paper, led by Christopher Watson of the University of Tasmania, Australia. The acceleration "is higher than the observed twentieth-century acceleration but in reasonable agreement with an accelerating contribution from the Greenland and West Antarctic ice sheets over this period", the team said."


And from another post by ASLR above...

Lennart,

I re-post your Reply #341 below:

"Some indications that SLR may have been accelerating over the past few years:
http://onlinelibrary.wiley.com/doi/10.1002/2015GL063902/abstract?utm_content=buffer63d49&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://onlinelibrary.wiley.com/doi/10.1002/2015GL063902/abstract?utm_content=buffer63d49&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

"The global mean sea level (GMSL) was reported to have dropped 5 mm due to the 2010/11 La Niña and have recovered in one year. With longer observations, it is shown that the GMSL went further up to a total amount of 11.6 mm by the end of 2012, excluding the 3.0 mm/yr background trend. A reconciled sea level budget, based on observations by Argo project, altimeter and gravity satellites, reveals that the true GMSL rise has been masked by ENSO-related fluctuations and its rate has increased since 2010. After extracting the influence of land water storage, it is shown that the GMSL have been rising at a rate of 4.4 ± 0.5 mm/yr for more than three years, due to an increase in the rate of both land ice loss and steric change.""

Therefore, we all need to remember that GMSL dropped 5m due to the 2010/2011 La Nina, are impacting Watson et al 2015 numbers; while GMSL has "... been rising at a rate of 4.4 +/- 0.5 mm/yr for more than three years now; and in this current El Nino year GMSL is jumping up still high.  We all need to be very careful with using SLR rate values that do not consider the influence of the coming 20, or so, years of positive PDO; and the likely accelerating contribution from ice sheets (which the AR5 panel on SLR that Church chaired underestimated).


Since you gave no link to support this 2.6% figure and since we cannot be certain what the true compound rate of growth is, I thought I would also speculate but draw on the linked articles.

The first article suggests that the rate of growth from 1993 to 1999 is 1.2 mm per year. (I know. I am using the mid point with no recognition of error but I'm speculating, right?) This article also states that the average rate of increase for the period between 1993 to 2014 is 2.75. (Yes, again the midpoint.) Meanwhile, the second article calculates the annual rise in sea level is 4.4 mm per year for the most recent 3 years. (Please don't make me point out that I have again used the midpoint. Oh damn! I've already done it.) Purely speculative of course, but these measurements suggest a doubling rate of 10 years. A 7% growth rate compounded for the rest of the century, means that in the last decade of this century, SLR will be 1126 mm per year.

Do I believe that SLR will be more than a meter per year by the end of the century? No. Do I believe the doubling rate is 27 years as you suggest? No. Mine is grossly over estimated and yours is grossly underestimated.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on May 17, 2015, 07:28:54 AM
Re: SLR in 2100

1m/yr by century's end stretches credibility, but 1m/20yr was seen in MWP1A, lasting  for five centuries. That's 50mm/yr,  4 doublings or a factor of 16 away. Two score years, say around midcentury.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on May 17, 2015, 03:19:20 PM
Re: SLR in 2100

1m/yr by century's end stretches credibility, but 1m/20yr was seen in MWP1A, lasting  for five centuries. That's 50mm/yr,  4 doublings or a factor of 16 away. Two score years, say around midcentury.

Absolutely. There is no way 1m/yr could happen.

I suppose the only point my post makes is how silly it is to take compound rate of growth and extrapolate it out to the end of the century to conclude we are fine (MH) or screwed (me).This is entirely different than observing that we are currently experiencing an exponential growth in SLR and concluding that this trend will continue for some time as I think it will. What is flawed in my analysis is not so much my suggestion that we are currently seeing a doubling every 10 years but that this doubling would continue until 2100. Obviously, some powerful negative feedbacks would show up (the disappearance of sea terminating glaciers and ice shelves etc.)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on May 17, 2015, 07:40:50 PM
"silly ... to ... extrapolate"

If a bit of mathematical humor may be allowed at this point:

(https://imgs.xkcd.com/comics/extrapolating.png)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 20, 2015, 10:08:29 PM
Recent lecture by Richard Alley, including remarks on Pollard et al 2015 and Applegate et al 2014 on potentially very fast ice loss from WAIS and GIS:
https://www.youtube.com/watch?v=yCunWFmvUfo (https://www.youtube.com/watch?v=yCunWFmvUfo)

Thanks to Colorado Bob for posting this over at the ASIB.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on June 06, 2015, 09:54:33 PM
Growing climate change threat to Britain's historic coastline
http://www.telegraph.co.uk/news/earth/environment/climatechange/11655087/Growing-climate-change-threat-to-Britains-historic-coastline.html (http://www.telegraph.co.uk/news/earth/environment/climatechange/11655087/Growing-climate-change-threat-to-Britains-historic-coastline.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: anotheramethyst on June 10, 2015, 05:16:43 AM
math humor??!!!

5 out of 4 people have trouble with fractions.

there are 10 kinds of people in this world, those who understand binary and those who don't.

sorry, continue.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on June 10, 2015, 07:32:57 PM
Rignot on ice sheet models and Hansen's 5m by 2100 thought experiment:
http://climatestate.com/2015/06/09/eric-rignot-observations-suggest-that-ice-sheets-and-glaciers-can-change-faster-sooner-and-in-a-stronger-way-than-anticipated/ (http://climatestate.com/2015/06/09/eric-rignot-observations-suggest-that-ice-sheets-and-glaciers-can-change-faster-sooner-and-in-a-stronger-way-than-anticipated/)

"Machens: Hansen (2007), assumed an ice sheet contribution of 1 cm for the decade 2005–15, with a potential ten year doubling time for sea-level rise, based on a nonlinear ice sheet response, which would yield 5 m this century. Considering past sea level sometimes rose quickly, jumps associated with catastrophic ice-sheet collapses, Hansen appears plausible. Thus, are we getting closer to modeling ice sheet dynamics in a nonlinear fashion?

Rignot: Jim’s calculations are back of the envelope calculations that do not include any ice physics. That ice sheet loss will proceed in a non linear fashion is certainly a given but from there on a whole variety of scenarios are possible, and we do not have the tools in hand to answer that question. We need fully coupled ice sheet/ocean/sea ice/atmosphere models and we do not have them now. 5 m this century is hard to conceive, because even a speed up of all glaciers in Antarctica and Greenland by a factor 10 would not get us there in time. But I would rather hear Jim’s upper bounds being discussed than the overly conservative scenarios from existing, poorly skilled numerical models."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 10, 2015, 05:47:41 PM
I thought that I would post this in this thread even though  it is cited already in other threads, as it indicates that we could be headed to more than 6m of eustatic SLR:

A. Dutton, A. E. Carlson, A. J. Long, G. A. Milne, P. U. Clark, R. Deconto, B. P. Horton, S. Rahmstorf, M. E. Raymo. Sea-level rise due to polar ice-sheet mass loss during past warm periods. Science, 2015 DOI: 10.1126/science.aaa4019

http://www.sciencemag.org/content/349/6244/aaa4019 (http://www.sciencemag.org/content/349/6244/aaa4019)

Abstract: "Interdisciplinary studies of geologic archives have ushered in a new era of deciphering magnitudes, rates, and sources of sea-level rise from polar ice-sheet loss during past warm periods. Accounting for glacial isostatic processes helps to reconcile spatial variability in peak sea level during marine isotope stages 5e and 11, when the global mean reached 6 to 9 meters and 6 to 13 meters higher than present, respectively. Dynamic topography introduces large uncertainties on longer time scales, precluding robust sea-level estimates for intervals such as the Pliocene. Present climate is warming to a level associated with significant polar ice-sheet loss in the past. Here, we outline advances and challenges involved in constraining ice-sheet sensitivity to climate change with use of paleo–sea level records."

Caption for the attached figure: "Peak global mean temperature, atmospheric CO2, maximum global mean sea level (GMSL), and source(s) of meltwater.
Light blue shading indicates uncertainty of GMSL maximum. Red pie charts over Greenland and Antarctica denote fraction (not location) of ice retreat."


See also:
http://www.climatecentral.org/news/sea-levels-rise-20-feet-19211 (http://www.climatecentral.org/news/sea-levels-rise-20-feet-19211)
&
http://www.washingtonpost.com/news/energy-environment/wp/2015/07/09/why-the-earths-past-has-scientists-so-worried-about-sea-level-rise/ (http://www.washingtonpost.com/news/energy-environment/wp/2015/07/09/why-the-earths-past-has-scientists-so-worried-about-sea-level-rise/)
Extract: " As a result, he thinks that currently, the mid-Pliocene is a better analogy for where we could be headed, given the comparable carbon dioxide levels. “In the Pliocene, global temperatures 1 – 2 °C warmer than present came with at least 6 m of rise,” Rahmstorf wrote. Thus, while we may not currently be committed to raising seas as much as occurred in these past periods, if we don’t get global warming under control, that could change."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on July 15, 2015, 08:32:41 PM
New paper by Rignot et al on depth of Greenland fjords, implying faster potential ice melt and SLR:
http://blogs.agu.org/geospace/2015/07/15/greenlands-fjords-are-far-deeper-than-previously-thought-and-glaciers-will-melt-faster-researchers-find/#.VaadhJ2OWMI.twitter (http://blogs.agu.org/geospace/2015/07/15/greenlands-fjords-are-far-deeper-than-previously-thought-and-glaciers-will-melt-faster-researchers-find/#.VaadhJ2OWMI.twitter)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on July 18, 2015, 01:10:26 PM
WaPo on the Greenland fjords study:
Quote
The shape and depth of fjords have big implications for the ice sheet, which has been melting both from the top and the bottom and contains 20 feet of potential sea level rise in total. Warm air erodes ice above the water, but warmer waters — which reside at deep levels in some parts of the polar regions — undercut glaciers and melt ice from below. “As they melt faster, they can slide out to sea,” said Eric Rignot, leader researcher and a glaciologist at the University of California at Irvine.

Deeper fjords means there are “a lot more places where the warm water, subsurface water, can reach the glaciers,” Rignot said. Shallow fjords don’t pose as much of a threat.

On average, the fjords in this region are about 200 to 300 meters deeper than previously thought in some areas, he added. Glaciers undercut by warm water can melt twice as fast as those in colder waters, all other things being equal.
http://www.washingtonpost.com/news/energy-environment/wp/2015/07/17/the-troubling-reason-why-greenland-may-melt-faster-than-expected/ (http://www.washingtonpost.com/news/energy-environment/wp/2015/07/17/the-troubling-reason-why-greenland-may-melt-faster-than-expected/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on July 20, 2015, 09:00:44 AM
On the new paper by Hansen et al coming out this week:
http://www.thedailybeast.com/articles/2015/07/20/climate-seer-james-hansen-issues-his-direst-forecast-yet.html (http://www.thedailybeast.com/articles/2015/07/20/climate-seer-james-hansen-issues-his-direst-forecast-yet.html)

Apparently warning for 3m of SLR by 2100...
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on July 20, 2015, 04:57:36 PM
James Hansen:  3.2 meters of sea level rise by 2100

http://www.thedailybeast.com/articles/2015/07/20/climate-seer-james-hansen-issues-his-direst-forecast-yet.html (http://www.thedailybeast.com/articles/2015/07/20/climate-seer-james-hansen-issues-his-direst-forecast-yet.html)

Quote
This apocalyptic scenario illustrates why the goal of limiting temperature rise to 2 degrees Celsius is not the safe “guardrail” most politicians and media coverage imply it is, argue Hansen and 16 colleagues in a blockbuster study they are publishing this week in the peer-reviewed journal Atmospheric Physics and Chemistry. On the contrary, a 2 C future would be “highly dangerous.”

If Hansen is right—and he has been right, sooner, about the big issues in climate science longer than anyone—the implications are vast and profound.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 20, 2015, 05:50:55 PM
Here is another link about the new Hansen paper with much the same information:

http://www.rtcc.org/2015/07/20/hansen-2c-warming-will-raise-sea-level-several-metres/ (http://www.rtcc.org/2015/07/20/hansen-2c-warming-will-raise-sea-level-several-metres/)

Extract: "Hansen: 2C warming will raise sea level several metres -
Scientists warn feedback effects will melt polar ice faster than thought, causing “highly dangerous” impacts this century"
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on July 20, 2015, 06:22:01 PM
So it appears this paper is not peer-reviewed before publication... (in contrast to what the news-article by Mark Hertsgaard suggested).
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on July 20, 2015, 06:55:32 PM
If the purpose is to claim that we are facing a greater threat than expected...then ok, good. But if it is to say we are aiming at 3 meters of SLR then I disagree ! Why don't we have figures explaining things just like these two ?  Assuming that we can absorb carbon (globally) is just non sense for the moment.
There is two point, one is the 400 ppm of  CO2 and the other one is 485 ppm of CO2 eq where we are now. At the end of the century if everything goes well meaning we keep the pace at 3 ppm of CO2 eq per year, we will be at 800 ppm of CO2...well off the charts...
I am not a scientist so if you have something more precise and with references, I would be very glad.
(I assume that in the past the CO2 eq was not very different than the CO2)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on July 20, 2015, 07:47:02 PM
More on the new Hansen paper in this excellent Washington Post article:
http://www.washingtonpost.com/news/energy-environment/wp/2015/07/20/the-worlds-most-famous-climate-scientist-just-outlined-an-alarming-scenario-for-our-planets-future/ (http://www.washingtonpost.com/news/energy-environment/wp/2015/07/20/the-worlds-most-famous-climate-scientist-just-outlined-an-alarming-scenario-for-our-planets-future/)

The peer review has begun, sort of... :)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 21, 2015, 05:19:16 PM
I thought that the following quotes from the new Hansen et al (2015) paper (per the linked Washington Post article provided by Lennart) was worth highlighting.  They point-out that ice mass loss from the GIS, the WAIS and the Totten/Aurora basins are all growing nonlinearly with doubling times of about 10 years; which if continued could result in several (as in over three) meters of SLR by 2065. 

http://www.washingtonpost.com/news/energy-environment/wp/2015/07/20/the-worlds-most-famous-climate-scientist-just-outlined-an-alarming-scenario-for-our-planets-future/ (http://www.washingtonpost.com/news/energy-environment/wp/2015/07/20/the-worlds-most-famous-climate-scientist-just-outlined-an-alarming-scenario-for-our-planets-future/)

Extract: " “Ice mass losses from Greenland, West Antarctica and Totten/Aurora basin in East Antarctica are growing nonlinearly with doubling times of order 10 years,” notes the study. Elsewhere, it notes that “Doubling times of 10, 20 or 40 years yield sea level rise of several meters in 50, 100 or 200 years.”"

I imagine that any such projection of over 3m of SLR by 2065 must be a fat-tailed upper limit of the PDF comparable to the attached figure from the 2014 paper by Jevrejeva, Grinsted & Moore:

Jevrejeva, Grinsted, Moore (2014), Upper limit for sea level projections by 2100, Environ. Res. Lett. 9 104008 doi:10.1088/1748-9326/9/10/104008
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on July 21, 2015, 05:41:29 PM
Scientific American had a short interview with Hansen as well:
http://www.scientificamerican.com/article/fossil-fuels-must-be-phased-out-to-avoid-drowned-coastlines/ (http://www.scientificamerican.com/article/fossil-fuels-must-be-phased-out-to-avoid-drowned-coastlines/)

It's time we can read the paper ourselves...
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on July 21, 2015, 10:01:22 PM
One more news article on Hansen et al:
http://insideclimatenews.org/news/21072015/new-study-says-even-2-degrees-warming-highly-dangerous (http://insideclimatenews.org/news/21072015/new-study-says-even-2-degrees-warming-highly-dangerous)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on July 22, 2015, 09:12:24 AM
Climate Cenrtral on Hansen et al:
http://www.climatecentral.org/news/dire-climate-warning-questions-19268 (http://www.climatecentral.org/news/dire-climate-warning-questions-19268)

And Science Insider:
http://news.sciencemag.org/climate/2015/07/climate-researcher-blasts-global-warming-target-highly-dangerous (http://news.sciencemag.org/climate/2015/07/climate-researcher-blasts-global-warming-target-highly-dangerous)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on July 22, 2015, 04:40:24 PM
National Geographic article on Hansen et al:
http://news.nationalgeographic.com/2015/07/150721-james-hansen-sea-level-rise-climate-change-global-warming-science/?utm_source=Twitter&utm_medium=Social&utm_content=link_tw20150722news-sealevel&utm_campaign=Content&sf11210763=1 (http://news.nationalgeographic.com/2015/07/150721-james-hansen-sea-level-rise-climate-change-global-warming-science/?utm_source=Twitter&utm_medium=Social&utm_content=link_tw20150722news-sealevel&utm_campaign=Content&sf11210763=1)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on July 22, 2015, 05:35:57 PM
The paper itself should appear here, one of these days:
http://www.atmos-chem-phys-discuss.net/papers_in_open_discussion.html (http://www.atmos-chem-phys-discuss.net/papers_in_open_discussion.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 22, 2015, 06:23:44 PM
The following extract about Hansen et al (2015) new paper indicates that: (a) sea level could rise by 4.9m (16-ft) by 2100; and (b) this paper is primarily an elaboration on projections that Hansen and his various co-authors have been making for at least 20-years.


http://news.discovery.com/earth/global-warming/dire-climate-warning-raises-questions-not-answers-150721.htm (http://news.discovery.com/earth/global-warming/dire-climate-warning-raises-questions-not-answers-150721.htm)

Extract: "The paper uses paleoclimate data and modeling to show that if ice sheets in Greenland and West Antarctica continue to double their melt rates every 10 years as they currently are, sea levels could rise up to 16 feet as soon as 2100.
A sudden influx of fresh, cold water to oceans around Antarctica and Greenland could have other notable impacts. The study argues that it could slow down ocean conveyor belts that shuttle water around the world’s oceans and alter air temperatures and storm tracks. Most provocatively, the study indicates it could cause cooling over the southern third of the globe as well as parts of the northern Atlantic and Europe and slow warming in other parts of the globe."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on July 23, 2015, 02:39:19 AM
It's game over if we get 5m SLR by 2100. The world economy will be delivered a gut punch which it cannot survive.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sleepy on July 23, 2015, 04:24:30 AM
SH, I think 3m is enough to 2100 and it's also what I think is plausible. Let's see what happens with the measurements when the ongoing El Nino fades out. It will drop back initially but then I think we will see larger increases the following two years after.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sleepy on July 23, 2015, 04:39:07 AM
And oh, it's nice to see you posting again ASLR!
Guess I'm not the only one waiting for the Hansen paper.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 23, 2015, 05:13:24 PM
And oh, it's nice to see you posting again ASLR!
Guess I'm not the only one waiting for the Hansen paper.

Sleepy,

It is an honor to be posting again with such fine fellows.  Also, Lennart provided the following link to Hansen et al's paper in another thread:

Hansen, J., Sato, M., Hearty, P., Ruedy, R., Kelley, M., Masson-Delmotte, V., Russell, G., Tselioudis, G., Cao, J., Rignot, E., Velicogna, I., Kandiano, E., von Schuckmann, K., Kharecha, P., Legrande, A. N., Bauer, M., and Lo, K.-W.: Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming is highly dangerous, Atmos. Chem. Phys. Discuss., 15, 20059-20179, doi:10.5194/acpd-15-20059-2015, 2015.

http://www.atmos-chem-phys-discuss.net/15/20059/2015/acpd-15-20059-2015.html (http://www.atmos-chem-phys-discuss.net/15/20059/2015/acpd-15-20059-2015.html)

Abstract. There is evidence of ice melt, sea level rise to +5–9 m, and extreme storms in the prior interglacial period that was less than 1 °C warmer than today. Human-made climate forcing is stronger and more rapid than paleo forcings, but much can be learned by combining insights from paleoclimate, climate modeling, and on-going observations. We argue that ice sheets in contact with the ocean are vulnerable to non-linear disintegration in response to ocean warming, and we posit that ice sheet mass loss can be approximated by a doubling time up to sea level rise of at least several meters. Doubling times of 10, 20 or 40 years yield sea level rise of several meters in 50, 100 or 200 years. Paleoclimate data reveal that subsurface ocean warming causes ice shelf melt and ice sheet discharge. Our climate model exposes amplifying feedbacks in the Southern Ocean that slow Antarctic bottom water formation and increase ocean temperature near ice shelf grounding lines, while cooling the surface ocean and increasing sea ice cover and water column stability. Ocean surface cooling, in the North Atlantic as well as the Southern Ocean, increases tropospheric horizontal temperature gradients, eddy kinetic energy and baroclinicity, which drive more powerful storms. We focus attention on the Southern Ocean's role in affecting atmospheric CO2 amount, which in turn is a tight control knob on global climate. The millennial (500–2000 year) time scale of deep ocean ventilation affects the time scale for natural CO2 change, thus the time scale for paleo global climate, ice sheet and sea level changes. This millennial carbon cycle time scale should not be misinterpreted as the ice sheet time scale for response to a rapid human-made climate forcing. Recent ice sheet melt rates have a doubling time near the lower end of the 10–40 year range. We conclude that 2 °C global warming above the preindustrial level, which would spur more ice shelf melt, is highly dangerous. Earth's energy imbalance, which must be eliminated to stabilize climate, provides a crucial metric.


However, as the linked Mashable article on this subject, the science establishment is stating that the Hansen et al paper raises more questions than it provides answers:

http://mashable.com/2015/07/22/james-hansen-scary-new-climate-study/ (http://mashable.com/2015/07/22/james-hansen-scary-new-climate-study/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sleepy on July 23, 2015, 05:27:01 PM
Thanks ASLR!
I only checked my mail this morning and not the topics, I see now that he posted it one hour before my comment here this morning. ;D
Time to read.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on July 23, 2015, 05:31:26 PM
There is no way we will limit temperature at 2°C we are on track for 4°C and more. The doubling every 10 years is now, but there is an acceleration in the acceleration, Does someone plot that ?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 23, 2015, 06:29:11 PM
There is no way we will limit temperature at 2°C we are on track for 4°C and more. The doubling every 10 years is now, but there is an acceleration in the acceleration, Does someone plot that ?

Laurent,

The following is a re-post from January in this thread; however, to check to see ice sheet mass loss acceleration trends I recommend looking at the Antarctic thread, and/or to wait for the Alley et al paper on that topic later this fall.

Best,
ASLR

Re-post begins here:

The linked reference finds that the acceleration in sea level rise seen in recent decades is more rapid (by about 25% since 1990, see attached plot & caption) than scientists previously thought:

Hay CC, Morrow E, Kopp RE, Mitrovica JX, (2015) "Probabilistic reanalysis of twentieth-century sea-level rise", Nature. 2015 Jan 14. doi: 10.1038/nature14093

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14093.html (http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14093.html)

Abstract: "Estimating and accounting for twentieth-century global mean sea-level (GMSL) rise is critical to characterizing current and future human-induced sea-level change. Several previous analyses of tide gauge records—employing different methods to accommodate the spatial sparsity and temporal incompleteness of the data and to constrain the geometry of long-term sea-level change—have concluded that GMSL rose over the twentieth century at a mean rate of 1.6 to 1.9 millimetres per year. Efforts to account for this rate by summing estimates of individual contributions from glacier and ice-sheet mass loss, ocean thermal expansion, and changes in land water storage fall significantly short in the period before 1990. The failure to close the budget of GMSL during this period has led to suggestions that several contributions may have been systematically underestimated. However, the extent to which the limitations of tide gauge analyses have affected estimates of the GMSL rate of change is unclear. Here we revisit estimates of twentieth-century GMSL rise using probabilistic techniques and find a rate of GMSL rise from 1901 to 1990 of 1.2 ± 0.2 millimetres per year (90% confidence interval). Based on individual contributions tabulated in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, this estimate closes the twentieth-century sea-level budget. Our analysis, which combines tide gauge records with physics-based and model-derived geometries of the various contributing signals, also indicates that GMSL rose at a rate of 3.0 ± 0.7 millimetres per year between 1993 and 2010, consistent with prior estimates from tide gauge records. The increase in rate relative to the 1901–90 trend is accordingly larger than previously thought; this revision may affect some projections of future sea-level rise."


Caption: "Time series of global mean sea level for the period 1900-2010. Figure shows estimates of sea level from the two methods used in this study: 'KS' (blue line) and 'GPR' (black line), and two methods used in the latest IPCC report: 'Ref.4' (purple line) from Church et al. ( 2011) and 'Ref. 3' (red line) from Jevrejeva et al. ( 2008). Inset table shows trends for three different time periods. Source: Hay et al. (2015)"

See also:
http://www.carbonbrief.org/blog/2015/01/global-sea-levels-rising-faster-than-previously-thought-study-shows/ (http://www.carbonbrief.org/blog/2015/01/global-sea-levels-rising-faster-than-previously-thought-study-shows/)
http://in.reuters.com/article/2015/01/14/climatechange-seas-idINL6N0US3IZ20150114 (http://in.reuters.com/article/2015/01/14/climatechange-seas-idINL6N0US3IZ20150114)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Anne on July 23, 2015, 06:32:20 PM
English language interview with Stefan Rahmstorf by Irene Quaile of Deutsche Welle, broadcast on 16 July. No real news except his optimism about the possibility of reducing FF use and keeping below 2oC increase in the light of progress in development of renewables. He has hopes of the UN Paris summit and says he sees an increase in political will but doesn't explain why he sees this... He goes on to outline the horrors of SLR.
(Just under 8 minutes)
http://www.dw.com/en/living-planet-living-planet-in-harmony-with-nature-2015-07-17/e-18531083#18589842 (http://www.dw.com/en/living-planet-living-planet-in-harmony-with-nature-2015-07-17/e-18531083#18589842)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on July 23, 2015, 06:46:06 PM
Thanks AbruptSLR !
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 23, 2015, 07:07:01 PM
Thanks AbruptSLR !

Since I raised the topic of accelerating ice mass loss from the WAIS, I thought that I would provide the following linked reference and associated image, in order to help quantify the current rate of acceleration, i.e. "Ignoring GIA model uncertainty, over the period 2003–2014, West Antarctica has been losing ice mass at a rate of −121 ±8 Gt/yr and has experienced large acceleration of ice mass losses along the Amundsen Sea coast of −18 ±5 Gt/yr2, doubling the mass loss rate in the past six years":

Christopher Harig & Frederik J. Simons (2015), "Accelerated West Antarctic ice mass loss continues to outpace East Antarctic gains", Earth Planet. Sc. Lett., 415, 134-141, doi:10.1016/j.epsl.2015.01.029
 

http://www.princeton.edu/geosciences/people/simons/pdf/EPSL-2015a.pdf (http://www.princeton.edu/geosciences/people/simons/pdf/EPSL-2015a.pdf)


Abstract: "While multiple data sources have confirmed that Antarctica is losing ice at an accelerating rate, different measurement techniques estimate the details of its geographically highly variable mass balance with different levels of accuracy, spatio-temporal resolution, and coverage. Some scope remains for methodological improvements using a single data type. In this study we report our progress in increasing the accuracy and spatial resolution of time-variable gravimetry from the Gravity Recovery and Climate Experiment (GRACE). We determine the geographic pattern of ice mass change in Antarctica between January 2003 and June 2014, accounting for glacio-isostatic adjustment (GIA) using the IJ05_R2 model.  Expressing the unknown signal in a sparse Slepian basis constructed by optimization to prevent leakage out of the regions of interest, we use robust signal processing and statistical estimation methods.  Applying those to the latest time series of monthly GRACE solutions we map Antarctica’s mass loss in space and time as well as can be recovered from satellite gravity alone. Ignoring GIA model uncertainty, over the period 2003–2014, West Antarctica has been losing ice mass at a rate of −121 ±8 Gt/yr and has experienced large acceleration of ice mass losses along the Amundsen Sea coast of −18 ±5 Gt/yr2, doubling the mass loss rate in the past six years. The Antarctic Peninsula shows slightly accelerating ice mass loss, with larger accelerated losses in the southern half of the Peninsula. Ice mass gains due to snowfall in Dronning Maud Land have continued to add about half the amount of West Antarctica’s loss back onto the continent over the last decade. We estimate the overall mass losses from Antarctica since January 2003 at −92 ±10 Gt/yr."


See also
http://www.princeton.edu/main/news/archive/S43/04/11E77/index.xml?section=topstories (http://www.princeton.edu/main/news/archive/S43/04/11E77/index.xml?section=topstories)

Caption: "Princeton University researchers "weighed" Antarctica's ice sheet using gravitational satellite data and found that during the past decade, Antarctica's massive ice sheet lost twice the amount of ice in its western portion compared to what it accumulated in the east. The researchers used monthly data from GRACE, or the Gravity Recovery and Climate Experiment, a dual-satellite mission that measures gravity changes; as Antarctic land ice melts, the reduction in ice mass is picked up by GRACE. In the past 11 years, the Antarctic ice sheet lost 92 billion tons of ice per year, which, if stacked on the island of Manhattan, would be more than a mile high — more than five times the height of the Empire State Building. As shown in the figure above, from Jan. 2003 to June 2014, the vast majority of ice loss was from West Antarctica's Amundsen Sea region (box a) and the Antarctic Peninsula (box b) that winds up toward South America. The ice sheet on East Antarctica (box c) primarily thickened during that same time. The color scale indicates mass — equivalent to centimeters of water — of the land ice, with red denoting the largest loss and blue standing for the largest gain. (Image by Christopher Harig)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 27, 2015, 04:21:35 PM
The University of Colorado has updated both their change in global mean sea level trend line and their correlation of the detrended GMSL time series vs the MEI time series (see attached plots, respectively) through July 23 2015.  As it seems likely to me that we are very likely headed towards a super El Nino event in 2015-2016 comparable to the 97-98 event; it seems to me that not only is the El Nino leading to record high sea levels but also that SLR contributions from the ice sheets are accelerating:

http://sealevel.colorado.edu/ (http://sealevel.colorado.edu/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on July 27, 2015, 05:19:45 PM
Yi et al 2015 find a recent acceleration in SLR (as posted earlier, but good to keep in mind here):
http://onlinelibrary.wiley.com/wol1/doi/10.1002/2015GL063902/abstract (http://onlinelibrary.wiley.com/wol1/doi/10.1002/2015GL063902/abstract)

Abstract
"The global mean sea level (GMSL) was reported to have dropped 5 mm due to the 2010/2011 La Niña and have recovered in 1 year. With longer observations, it is shown that the GMSL went further up to a total amount of 11.6 mm by the end of 2012, excluding the 3.0 mm/yr background trend. A reconciled sea level budget, based on observations by Argo project, altimeter, and gravity satellites, reveals that the true GMSL rise has been masked by El Niño–Southern Oscillation-related fluctuations and its rate has increased since 2010. After extracting the influence of land water storage, it is shown that the GMSL has been rising at a rate of 4.4 ± 0.5 mm/yr for more than 3 years, due to an increase in the rate of both land ice loss and steric change."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on July 28, 2015, 12:46:06 PM
"Compound flooding."  The risks are increasing.

Scientists Identify 'Triple Threat' Endangering US Coastal Cities
Quote
A trio of phenomena attributed at least in part to climate change—sea-level rise, storm surges, and heavy rainfall—poses an increasing risk to residents of major U.S. cities including Boston, New York, Houston, San Diego, and San Francisco, according to new research published Monday in the journal Nature Climate Change.
http://www.commondreams.org/news/2015/07/27/scientists-identify-triple-threat-endangering-us-coastal-cities (http://www.commondreams.org/news/2015/07/27/scientists-identify-triple-threat-endangering-us-coastal-cities)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on July 28, 2015, 01:06:09 PM
Florida leads nation in property at risk from climate change
Quote
Florida has more private property at risk from flooding linked to climate change than any other state, an amount that could double in the next four decades, according to a new report by the Risky Business Project.

By 2030, $69 billion in coastal property in Florida could flood at high tide that is not at risk today, the report found. That amount is projected to climb to $152 billion by 2050.

http://www.miamiherald.com/news/local/environment/article29029159.html (http://www.miamiherald.com/news/local/environment/article29029159.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on July 28, 2015, 02:55:24 PM
Florida leads nation in property at risk from climate change
Quote
Florida has more private property at risk from flooding linked to climate change than any other state, an amount that could double in the next four decades, according to a new report by the Risky Business Project.

By 2030, $69 billion in coastal property in Florida could flood at high tide that is not at risk today, the report found. That amount is projected to climb to $152 billion by 2050.

http://www.miamiherald.com/news/local/environment/article29029159.html (http://www.miamiherald.com/news/local/environment/article29029159.html)

If you want to retire to Miami, go for it. Just make sure you rent and don't buy. In fact, I would hesitate to buy any property in low lying coastal regions of the U.S. Except in North Carolina, of course, where the legislature passed laws prohibiting sea level rise....or something like that.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on August 27, 2015, 01:04:57 AM
The linked August 26 2015 announcement indicates that several feet of SLR is unavoidable in the future:

http://www.jpl.nasa.gov/news/news.php?feature=4700 (http://www.jpl.nasa.gov/news/news.php?feature=4700)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on August 27, 2015, 06:27:32 PM
After Hurricane Katrina, New Orleans' Climate Conundrum: Fight or Flight?
A decade later, many still wrestle with staying home vs. leaving—a decision millions more will face along the coasts as seas rise and storms intensify.
http://insideclimatenews.org/news/27082015/after-katrina-new-orleans-climate-conundrum-fight-or-flight (http://insideclimatenews.org/news/27082015/after-katrina-new-orleans-climate-conundrum-fight-or-flight)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on August 27, 2015, 09:09:15 PM
WaPo on NASA's "Oceans Melting Greenland" study.

The troubling reasons why NASA is so focused on studying sea level rise
http://www.washingtonpost.com/news/energy-environment/wp/2015/08/26/the-troubling-reasons-why-nasa-is-so-focused-on-studying-on-sea-level-rise/ (http://www.washingtonpost.com/news/energy-environment/wp/2015/08/26/the-troubling-reasons-why-nasa-is-so-focused-on-studying-on-sea-level-rise/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on August 27, 2015, 09:24:54 PM
SLR over the past 20 yrs was 7.4cm, so on average 3.7mm/yr:
http://www.carbonbrief.org/blog/2015/08/new-nasa-videos-show-stark-ice-loss-from-earths-ice-sheets/?utm_content=buffer0f12f&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://www.carbonbrief.org/blog/2015/08/new-nasa-videos-show-stark-ice-loss-from-earths-ice-sheets/?utm_content=buffer0f12f&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Acceleration?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on August 27, 2015, 09:34:38 PM
Quote
@Climatologist49: Coastal #flooding happening in #Barrow, AK, right now. Image source: http://t.co/gN4AZL2Eml (http://t.co/gN4AZL2Eml) http://t.co/1sOsFe5jln (http://t.co/1sOsFe5jln)

https://twitter.com/climatologist49/status/636960959265828864 (https://twitter.com/climatologist49/status/636960959265828864)

Barrow Sea Ice Webcam
http://seaice.alaska.edu/gi/observatories/barrow_webcam (http://seaice.alaska.edu/gi/observatories/barrow_webcam)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on August 27, 2015, 09:57:36 PM
Barrow, AK.  Waves crashing over sea wall.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on August 27, 2015, 10:02:16 PM
Gale.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on August 27, 2015, 10:18:53 PM
SLR over the past 20 yrs was 7.4cm, so on average 3.7mm/yr:
http://www.carbonbrief.org/blog/2015/08/new-nasa-videos-show-stark-ice-loss-from-earths-ice-sheets/?utm_content=buffer0f12f&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://www.carbonbrief.org/blog/2015/08/new-nasa-videos-show-stark-ice-loss-from-earths-ice-sheets/?utm_content=buffer0f12f&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Acceleration?

As the two IPCC figures point-out, until now the acceleration of ice mass loss from ice sheets has been masked by the deceleration of ice mass loss from glaciers.  However, now the ice sheets are beginning to dominate the SLR trend so we can expect an upward bending curve instead of a straight line:

Caption for Figure 1: Recent trends in glacier mass loss during (a) 1850-2010 and (b) 1961-2010. Coloured lines indicate different models, shaded areas show uncertainty. Blue bars display number of measured mass balance glaciers (IPCC, 2013).

Caption for Figure 2: Contribution of global glaciers (red), Greendland (green) and Antarctica (blue) to sea level rise between 1992-2012. Positive correlation between cumulative ice mass loss and sea level equivalent, shaded areas indicate uncertainty.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on August 27, 2015, 10:22:33 PM
Also, note that in the attached NASA (Gollard 2015) image GRACE shows that the combined ice mass loss has contributed 1.9 mm/year to SLR; and as ice mass loss from ice sheets accelerate you can expect this number to increase:
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on August 27, 2015, 11:47:41 PM
Barrow: Attempting to reinforce the sea wall.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on August 31, 2015, 07:45:45 PM
Examining Bjørn Lomborg's (denier) position on sea level rise.  By Stefan Rahmstorf.

Quote
...Lomborg has a simple, single message: don’t worry about reducing fossil emissions. Whether he denies or plays down the seriousness of global warming, sings the praises of adaptation, advocates to prioritize other problems or pushes geoengineering, the message is always the same: anything is better than phasing out fossil fuels.
http://www.realclimate.org/index.php/archives/2015/08/bjorn-lomborg-just-a-scientist-with-a-different-opinion/#.dpuf (http://www.realclimate.org/index.php/archives/2015/08/bjorn-lomborg-just-a-scientist-with-a-different-opinion/#.dpuf)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: skanky on September 02, 2015, 10:21:29 AM
This article on NASA's issues from SLR gives an indicator to future problems. Magnify these issues across the country, with multiple civilian ownership and critical infrastructure, etc. and contrast that to a single, scientific and engineering agency planning, then also consider the same issues across many different countries.

http://earthobservatory.nasa.gov/Features/NASASeaLevel/?src=features-hp&eocn=home&eoci=feature (http://earthobservatory.nasa.gov/Features/NASASeaLevel/?src=features-hp&eocn=home&eoci=feature)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Steven on September 04, 2015, 06:13:01 PM
New paper on sea level during the mid-Pliocene warm period:

http://geology.gsapubs.org/content/early/2015/08/21/G36999.1.abstract (http://geology.gsapubs.org/content/early/2015/08/21/G36999.1.abstract)

From the abstract:

Quote
The mid-Pliocene warm period (MPWP, 3.3-2.9 Ma), with reconstructed atmospheric pCO2 of 350-450 ppm, represents a potential analogue for climate change in the near future. Current highly cited estimates place MPWP maximum global mean sea level (GMSL) at 21 ± 10 m above modern, requiring total loss of the Greenland and marine West Antarctic Ice Sheets and a substantial loss of the East Antarctic Ice Sheet, with only a concurrent 2–3 °C rise in global temperature.

...

we present a new Pliocene GMSL estimate of 9-13.5 m above modern, which suggests that the East Antarctic Ice Sheet is less sensitive to radiative forcing than previously inferred from the geologic record.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on September 11, 2015, 07:37:19 PM
As alarming as the linked NASA video is about sea level rise over the past 23-years of the satellite era, it is important to remember that this period is dominated by the hiatus, so get reading to see still faster rates of SLR now that we are in a positive PDO period:

http://www.techinsider.io/nasa-animated-sea-level-rise-map-climate-change-2015-9 (http://www.techinsider.io/nasa-animated-sea-level-rise-map-climate-change-2015-9)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on September 12, 2015, 08:28:44 PM
Mashable:
"Those results may be too conservative"

Burn all fossil fuels, lose all of Florida, study says
Quote
Burning all of the currently accessible oil, natural gas and coal in the world would have catastrophic consequences for coastal populations around the world, a new study shows.

The amount of planet-warming greenhouse gases released by this combustion would be sufficient to warm the planet by at least 16 degrees Fahrenheit on average and melt the entire Antarctic ice sheet — as well as Greenland.

In other words, we could be headed for a completely ice-free world.
...
The study, published on Friday in the journal Science Advances, is the first to look at the long-term consequences of burning all of the fossil fuels currently in the ground (and considered to be economically accessible) when it comes to temperature trends and sea level rise. It adds to the growing body of evidence showing that in order to avert the worst impacts of global warming, a significant amount of available fossil fuels will have to stay in the ground.
http://mashable.com/2015/09/11/antarctica-complete-melt-fossil-fuels/ (http://mashable.com/2015/09/11/antarctica-complete-melt-fossil-fuels/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on September 12, 2015, 09:14:43 PM
This sign from the People's Climate March, in New York City, September 2014.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on September 12, 2015, 09:32:50 PM
Pacific leaders respond to Australian minister's sea level remarks
Quote
Pacific leaders have hit out at the insensitivity of an Australian minister’s apparent joke at the expense of low-lying nations struggling against rising sea levels.
http://www.theguardian.com/australia-news/2015/sep/11/pacific-leaders-australian-minister-sea-levels-tony-de-brum-marshall-islands (http://www.theguardian.com/australia-news/2015/sep/11/pacific-leaders-australian-minister-sea-levels-tony-de-brum-marshall-islands)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on September 13, 2015, 12:08:57 AM
Not surprising, given the previous comment above.

Tony Abbott faces down Pacific island nations' calls for tougher action on climate change
http://www.abc.net.au/news/2015-09-11/pacific-leaders-fail-to-reach-consensus-on-climate-change/6767038 (http://www.abc.net.au/news/2015-09-11/pacific-leaders-fail-to-reach-consensus-on-climate-change/6767038)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on September 14, 2015, 11:20:43 PM
The following is AVISO SLR data from the begin of 2015 until late June 2015, showing the highest SLR satellite measurement ever reported through that date:

2015.001879 7.390021e-02
2015.029027 7.370672e-02
2015.056175 7.418527e-02
2015.083322 7.546662e-02
2015.110470 7.684320e-02
2015.137617 7.744393e-02
2015.164765 7.704646e-02
2015.191912 7.625656e-02
2015.219060 7.592576e-02
2015.246207 7.635819e-02
2015.273355 7.704768e-02
2015.300503 7.722826e-02
2015.327650 7.661682e-02
2015.354798 7.578150e-02
2015.381945 7.570608e-02
2015.409093 7.665680e-02
2015.436240 7.803072e-02
2015.463388 7.922665e-02
2015.490535 8.002329e-02

Edit: see the attached plot
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on September 18, 2015, 01:24:39 AM
Satire from The Onion.

Atlantic Ocean Excited To Move Into Beautiful Beachfront Mansion Soon
http://www.theonion.com/article/atlantic-ocean-excited-move-beautiful-beachfront-m-51303 (http://www.theonion.com/article/atlantic-ocean-excited-move-beautiful-beachfront-m-51303)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on September 18, 2015, 01:45:38 AM
This is awesome!  ;D  I imagine they could also warn about forecasted storm surge, if done before the storm.

Moo-ve to Higher Ground- The Tsunami Sirens of Cannon Beach Oregon
When staring at a grave threat, be funny about it.
https://medium.com/west-coast-life-frankystein123/moo-ve-to-higher-ground-the-tsunami-sirens-of-cannon-beach-oregon-d30f0e683f1
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on September 22, 2015, 01:44:49 AM
Pacific Islanders Plead for Urgent Climate Action as Seas Rise
http://www.bloomberg.com/news/articles/2015-09-21/pacific-islanders-plead-for-urgent-climate-action-as-seas-rise (http://www.bloomberg.com/news/articles/2015-09-21/pacific-islanders-plead-for-urgent-climate-action-as-seas-rise)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on September 22, 2015, 07:08:48 PM
Arctic melting will cost the global economy £33 trillion by end of next century, scientists calculate
Quote
The melting of the Arctic permafrost and the subsequent release of carbon dioxide and methane gas into the atmosphere will alone add an extra $43 trillion (£33tn) cost of climate change to the global economy by the end of the next century, scientists have calculated.

This represents a 13 per cent increase on the predicted economic impact of climate change by 2200, up from $326tn to $369tn, according to a study by Cambridge University and the US National Snow and Ice Data Centre in Boulder, Colorado.
http://www.independent.co.uk/environment/climate-change/arctic-melting-will-alone-cost-the-global-economy-33tn-by-end-of-next-century-scientists-calculate-10511426.html (http://www.independent.co.uk/environment/climate-change/arctic-melting-will-alone-cost-the-global-economy-33tn-by-end-of-next-century-scientists-calculate-10511426.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 14, 2015, 12:25:30 AM
The linked reference indicates that the is still missing information necessary to close the Sea Level Budget:

Dieng, H. B., Cazenave, A., von Schuckmann, K., Ablain, M., and Meyssignac, B.: Sea level budget over 2005–2013: missing contributions and data errors, Ocean Sci., 11, 789-802, doi:10.5194/os-11-789-2015, 2015.

http://www.ocean-sci.net/11/789/2015/os-11-789-2015.pdf (http://www.ocean-sci.net/11/789/2015/os-11-789-2015.pdf)

Abstract: "Based on the sea level budget closure approach, this study investigates the residuals between observed global mean sea level (GMSL) and the sum of components (steric sea level and ocean mass) for the period January 2005 to December 2013. The objective is to identify the impact of errors in one or several components of the sea level budget on the residual time series. This is a key issue if we want to constrain missing contributions such as the contribution to sea level rise from the deep ocean (depths not covered by observations). For that purpose, we use several data sets as processed by different groups: six altimetry products for the GMSL, four Argo products plus the ORAS4 ocean reanalysis for the steric sea level and three GRACE-based ocean mass products. We find that over the study time span, the observed differences in trend of the residuals of the sea level budget equation can be as large as ~ 0.55 mm yr−1 (i.e., ~ 17 % of the observed GMSL rate of rise). These trend differences essentially result from differences in trends of the GMSL time series. Using the ORAS4 reanalysis (providing complete geographical coverage of the steric sea level component), we also show that lack of Argo data in the Indonesian region leads to an overestimate of the absolute value of the residual trend by about 0.25 mm yr−1. Accounting for this regional contribution leads to closure of the sea level budget, at least for some GMSL products. At short timescales (from sub-seasonal to interannual), residual anomalies are significantly correlated with ocean mass and steric sea level anomalies (depending on the time span), suggesting that the residual anomalies are related to errors in both GRACE-based ocean mass and Argo-based steric data. Efforts are needed to reduce these various sources of errors before using the sea level budget approach to estimate missing contributions such as the deep ocean heat content."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on October 14, 2015, 03:57:33 PM
More Than 400 U.S. Cities May Be 'Past The Point Of No Return' With Sea Level Threats
But there are still cities that could be saved by reducing carbon emissions.
http://www.huffingtonpost.com/entry/us-cities-sea-level-threats_561d338fe4b0c5a1ce60a45c (http://www.huffingtonpost.com/entry/us-cities-sea-level-threats_561d338fe4b0c5a1ce60a45c)


Climate Central's interactive U.S. map lets you choose between different emissions and duration scenarios to see the eventual Sea Level Rise.
http://choices.climatecentral.org/#10/25.7708/-80.2544?compare=scenarios&carbon-end-yr=2050&scenario-a=unchecked&scenario-b=extreme-cuts (http://choices.climatecentral.org/#10/25.7708/-80.2544?compare=scenarios&carbon-end-yr=2050&scenario-a=unchecked&scenario-b=extreme-cuts)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 17, 2015, 07:13:18 PM
The University of Colorado posted the attached sea level trend line plot yesterday, Oct 16 2015, indicating that currently sea level is increase significantly faster than during the 1997 Super El Nino event, indicating that at a minimum the variance for SLR is increasing and more likely that ice mass contribution to SLR is accelerating:
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 20, 2015, 12:47:43 AM
The linked open access reference concludes that the oceanic part of the Earth is expanding and is thus contributing directly to SLR; which is a surprise to me as I believe that current estimates of GIA assume that the oceanic part of the Earth is contracting as the land part of the Earth rebounds from the last ice age:

Wenbin Shen, Ziyu Shen, Rong Sun and Yuri Barkin (July 2015), "Evidences of the expanding Earth from space-geodetic data over solid land and sea level rise in recent two decades", Geodesy and Geodynamics, Volume 6, Issue 4, Pages 248–252, doi:10.1016/j.geog.2015.05.006


http://www.sciencedirect.com/science/article/pii/S1674984715000518 (http://www.sciencedirect.com/science/article/pii/S1674984715000518)

Abstract: "According to the space-geodetic data recorded at globally distributed stations over solid land spanning a period of more than 20-years under the International Terrestrial Reference Frame 2008, our previous estimate of the average-weighted vertical variation of the Earth's solid surface suggests that the Earth's solid part is expanding at a rate of 0.24 ± 0.05 mm/a in recent two decades. In another aspect, the satellite altimetry observations spanning recent two decades demonstrate the sea level rise (SLR) rate 3.2 ± 0.4 mm/a, of which 1.8 ± 0.5 mm/a is contributed by the ice melting over land. This study shows that the oceanic thermal expansion is 1.0 ± 0.1 mm/a due to the temperature increase in recent half century, which coincides with the estimate provided by previous authors. The SLR observation by altimetry is not balanced by the ice melting and thermal expansion, which is an open problem before this study. However, in this study we infer that the oceanic part of the Earth is expanding at a rate about 0.4 mm/a. Combining the expansion rates of land part and oceanic part, we conclude that the Earth is expanding at a rate of 0.35 ± 0.47 mm/a in recent two decades. If the Earth expands at this rate, then the altimetry-observed SLR can be well explained."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on October 20, 2015, 06:49:22 PM
if you expand the edges of a bowl, it pushes the water higher (less volume inside)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 20, 2015, 08:21:57 PM
if you expand the edges of a bowl, it pushes the water higher (less volume inside)

This image from the linked open access paper indicates that the issue is somewhat complex.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on October 22, 2015, 02:11:44 AM
Miami-Dade Clerk Of Courts Calls For Sea-Level Rise Superfund
http://wlrn.org/post/miami-dade-clerk-courts-calls-sea-level-rise-superfund (http://wlrn.org/post/miami-dade-clerk-courts-calls-sea-level-rise-superfund)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on October 22, 2015, 11:48:24 AM
Perth's double whammy: as sea levels rise the city itself is sinking
http://www.theguardian.com/environment/2015/oct/22/perths-double-whammy-as-sea-levels-rise-the-city-itself-is-sinking (http://www.theguardian.com/environment/2015/oct/22/perths-double-whammy-as-sea-levels-rise-the-city-itself-is-sinking)
Quote
Growing demand for water in Perth has caused the city to sink at up to 6mm a year and could be responsible for an apparent acceleration in the rate of sea level rise, according to new research released by Curtin University.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on October 23, 2015, 05:16:31 PM
Miami-Dade Clerk Of Courts Calls For Sea-Level Rise Superfund
http://wlrn.org/post/miami-dade-clerk-courts-calls-sea-level-rise-superfund (http://wlrn.org/post/miami-dade-clerk-courts-calls-sea-level-rise-superfund)

On this thread, I have argued repeatedly that we are seriously underestimating the devastation that sea level rise will have on the global economy. I have argued that the wholesale destruction of property will actually result in the total collapse of the worldwide financial system that serves as the foundation of global capitalism. I will attempt to explain my point of view one more time and will use this linked article to make my point.

In the linked article the "Miami-Dade Clerk of Courts, Harvey Ruvin, sent a letter last week to South Florida members of Congress urging for the creation of a Federal Resiliency Superfund." He said that changes "in ocean levels threaten $6 trillion worth state property as well as the lives of the millions of South Floridians."

If you look at the picture at the top of the article, it conjures up a vision of Venice, buildings surrounded by water. This picture is not far from the truth as sea level rise will not result in the complete destruction of built structures. These magnificent structures will remain as monuments to our stupidity. Sewers are underground and it is estimated that a 1 meter rise in sea level over the current levels will render useless the waste water removal and treatment infrastructure in Dade County. The county will frequently and repeatedly be standing in a pool of raw sewage, rendering the county unfit for human habitation. Fresh water distribution is at risk as well but since water distribution is under pressure, it can withstand saltwater intrusion better than waste water infrastructure.

So why will this destruction of the built up wealth of $6 trillion damage the system of capitalism? It is not the structures themselves but the links these structures have with the financial system that will cause the damage. Mortgages and other debt issued against the value of this property will go into default. This debt has been packaged and sold into the financial markets and form the basis for pensions and wealth that is spread across the planet. The financial wealth that is supported by this debt is then borrowed against as well. The insurance and reinsurance industries are at risk as obligations against the physical structures and financial instruments will play havoc.

If you were paying attention in 2007, this is the process that nearly brought down the worldwide financial system. Only a coordinated effort by the banks of the entire developed world prevented this collapse as western nations flooded the system with an unprecedented amount of liquidity. This liquidity continues to prop up a still fragile financial system and the historically low interest rates are all the evidence that you need to realize that this excessive liquidity is still in the system.

So is a $6 trillion destruction of wealth really that large? Can that trigger the same kind of reaction in the financial markets that the destruction of wealth caused by the collapse of the housing bubble in 2007?

When the housing market bubble collapsed.....

http://fivethirtyeight.com/features/why-the-housing-bubble-tanked-the-economy-and-the-tech-bubble-didnt/ (http://fivethirtyeight.com/features/why-the-housing-bubble-tanked-the-economy-and-the-tech-bubble-didnt/)

"from 2007 to 2009, the value of real estate owned by U.S. households fell by nearly the same amount — $6 trillion"

Please keep in mind, that $6 trillion of real estate threatened by sea level rise is only in Florida. How many other coastal communities are at risk in the U.S.? How many globally?

The global financial system will not be able to withstand the devastation wrought by global warming and sea level rise is only one feature of global warming that will destroy the accumulated wealth in the system.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on October 23, 2015, 09:41:48 PM
SH @#449: 

Yes, but... I think you overlook the Time factor.

Cities will be destroyed at different times, at different rates, and for different reasons.  After a few such catastrophes, insurance companies and banks will rewrite their risk coverage requirements, denying coverage or loans unless vital infrastructure needs are addressed.*

There will be hard-hit areas as risks are adjusted and housing is abandoned, but it's difficult to imagine the crisis would hit planet-wide, all at once.


*Insurance co. sues Will County, 12 towns over flood damage
http://articles.chicagotribune.com/2014-04-29/news/ct-flooding-lawsuit-bolingbrook-plainfield-tl-0501-20140429_1_will-county-flood-damage-lawsuit (http://articles.chicagotribune.com/2014-04-29/news/ct-flooding-lawsuit-bolingbrook-plainfield-tl-0501-20140429_1_will-county-flood-damage-lawsuit)

Rise in government insurance rates to mirror rising waters, flood debt
https://www.washingtonpost.com/national/health-science/rise-in-government-insurance-rates-to-mirror-rising-waters-flood-debt/2015/03/28/8f9f17c6-d316-11e4-ab77-9646eea6a4c7_story.html (https://www.washingtonpost.com/national/health-science/rise-in-government-insurance-rates-to-mirror-rising-waters-flood-debt/2015/03/28/8f9f17c6-d316-11e4-ab77-9646eea6a4c7_story.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: ritter on October 23, 2015, 10:22:52 PM
SH @#449: 

Yes, but... I think you overlook the Time factor.

Cities will be destroyed at different times, at different rates, and for different reasons.  After a few such catastrophes, insurance companies and banks will rewrite their risk coverage requirements, denying coverage or loans unless vital infrastructure needs are addressed.*

There will be hard-hit areas as risks are adjusted and housing is abandoned, but it's difficult to imagine the crisis would hit planet-wide, all at once.


*Insurance co. sues Will County, 12 towns over flood damage
http://articles.chicagotribune.com/2014-04-29/news/ct-flooding-lawsuit-bolingbrook-plainfield-tl-0501-20140429_1_will-county-flood-damage-lawsuit (http://articles.chicagotribune.com/2014-04-29/news/ct-flooding-lawsuit-bolingbrook-plainfield-tl-0501-20140429_1_will-county-flood-damage-lawsuit)

Rise in government insurance rates to mirror rising waters, flood debt
https://www.washingtonpost.com/national/health-science/rise-in-government-insurance-rates-to-mirror-rising-waters-flood-debt/2015/03/28/8f9f17c6-d316-11e4-ab77-9646eea6a4c7_story.html (https://www.washingtonpost.com/national/health-science/rise-in-government-insurance-rates-to-mirror-rising-waters-flood-debt/2015/03/28/8f9f17c6-d316-11e4-ab77-9646eea6a4c7_story.html)

This all assumes that they can squeeze more blood from us turnips. Between health care insurance, auto insurance and other necessary insurances, year-over-year increases can only go so far before the mighty middle class can't support it anymore (Obamacare and the end of the automobile notwithstanding). Sure it won't hit everywhere at once. But it's already nibbling at our heals with an infrastructure in a pretty wretched state. It will be "interesting", to say the least.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on October 24, 2015, 07:26:01 PM
SH @#449: 

Yes, but... I think you overlook the Time factor.

Cities will be destroyed at different times, at different rates, and for different reasons.  After a few such catastrophes, insurance companies and banks will rewrite their risk coverage requirements, denying coverage or loans unless vital infrastructure needs are addressed.*

There will be hard-hit areas as risks are adjusted and housing is abandoned, but it's difficult to imagine the crisis would hit planet-wide, all at once.


*Insurance co. sues Will County, 12 towns over flood damage
http://articles.chicagotribune.com/2014-04-29/news/ct-flooding-lawsuit-bolingbrook-plainfield-tl-0501-20140429_1_will-county-flood-damage-lawsuit (http://articles.chicagotribune.com/2014-04-29/news/ct-flooding-lawsuit-bolingbrook-plainfield-tl-0501-20140429_1_will-county-flood-damage-lawsuit)

Rise in government insurance rates to mirror rising waters, flood debt
https://www.washingtonpost.com/national/health-science/rise-in-government-insurance-rates-to-mirror-rising-waters-flood-debt/2015/03/28/8f9f17c6-d316-11e4-ab77-9646eea6a4c7_story.html (https://www.washingtonpost.com/national/health-science/rise-in-government-insurance-rates-to-mirror-rising-waters-flood-debt/2015/03/28/8f9f17c6-d316-11e4-ab77-9646eea6a4c7_story.html)

The time it takes for Southeast Florida to become uninhabitable is irrelevant. During the collapse of  the housing bubble in 2007, no property became uninhabitable. The event was purely financial as the speculative construction industry, real estate investors, home owners trading up and the financial industry financing this run up in real estate prices suddenly all realized that the property they had invested in was horribly over valued. We still have not fully recovered and millions of  homeowners find themselves underwater (pun intended) on their mortgages.

Southeast Florida is experiencing just this kind of real estate bubble.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: GeoffBeacon on October 24, 2015, 08:57:01 PM
Care must be taken if we are to rebuild existing cities elswhere.

Currently,  providing the infrastructure to fit an extra person in a city creates about 100 tonnes of carbon dioxide. (e.g. building houses out of bricks and mortar, roads with concrete and tarmac and shops and offices with steel and concrete). And on a global scale the remaining carbon budget can be calculated as 115 tonnes CO2.

Clearly we must change the way we build. Wooden huts for everyone?

According to the Daily Mail (http://www.dailymail.co.uk/news/article-1393194/The-ultimate-downsize-Couple-ditch-2-500-sq-ft-home-belongings-live-mortgage-free-320-sq-ft-shack-son.html) they can be incredibly cheap!

Quote
Their house cost them less than $20,000 to make their home and they only pay $145 rent for the lot on which their shack and workshop stands.

No mortgages, no banking crisis.

A cheaper life would allow us to cut production. This is necessary to keep within the 2degC. ’

In an impressive interview Kevin Anderson says Climate targets ‘impossible’ unless rich cut emissions 10% a year. (https://youtu.be/fPbarwbiloE?t=86)

Using the Kaya identity carbon emmissions can be modelled as economic production multiplied by the carbon intensity of production. I have seen little evidence that carbon intensity can be cut that quickly so we need "de-growth".

Green growth (http://www.brusselsblog.co.uk/is-green-growth-a-fantasy/) for economies as a whole is a fantasy.

Can the financial system cope wth de-growth?

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on October 24, 2015, 09:34:32 PM


Can the financial system cope wth de-growth?

No.

The financial system which supports capitalism is absolutely dependent on an acceptable ROI which can only be attained when the economy grows. This is why capital investment collapses during severe recessions. Please keep in mind that the very definition of a recession is "degrowth". For us to enter into a new era of human civilization where degrowth is the long term norm (think perpetual recession), we will have to scrap capitalism as it is currently structured.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: GeoffBeacon on October 25, 2015, 01:59:14 PM
SH

I suppose "fiinancial system" was a rather loose term.

Why should "capitalism" fail if we

(1)tax the rich to reduce their pollution and
(2)give to the poor to stop them increasing theirs?


An international form of Hansen's Carbon Fee and Dividend (http://www.brusselsblog.co.uk/world-wide-carbon-fee-and-dividend/) would do that.

P.S. I looked up "de-growth" and found the Barcelona Declaration (http://www.barcelona.degrowth.org/Barcelona-2010-Declaration.119.0.html).  It's a bit wordy for me but does make some points. It ends
Quote
As the economy of wealthy parts of the world quietly contracts and our damage to the environment through new infrastructures and extraction activities is constrained, well-being will increase through public investments in low-cost social and relational goods.

Every new proposal generates several new objections and questions. We do not claim to have a recipe for the future, but we can no longer pretend that we can keep growing as if nothing has happened. The folly of growth has come to an end. The challenge now is how to transform, and the debate has just begun.

P.P.S. (A bit off-topic)
Who can take seriously someone from the soft sciences who references the second law of thermodynamics? e.g. the de-growth guru Nicholas_Georgescu-Roegen (http://https://en.wikipedia.org/wiki/)

Quote
The Entropy Law and the Economic Process, described by the Library Journal as "...a great seminal work that challenges economic analysis", is a wide-ranging technical and philosophical exposition which promotes the case that economic activity can not be adequately described without taking into account the implications of second law of thermodynamics

B/s or what?

P.P.S. Does "de-growth" need a separate thread?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: SteveMDFP on October 25, 2015, 06:13:12 PM


Can the financial system cope wth de-growth?

No.

The financial system which supports capitalism is absolutely dependent on an acceptable ROI which can only be attained when the economy grows. This is why capital investment collapses during severe recessions. Please keep in mind that the very definition of a recession is "degrowth". For us to enter into a new era of human civilization where degrowth is the long term norm (think perpetual recession), we will have to scrap capitalism as it is currently structured.
I don't think this is true at all.  Capitalism as a system has proven to be a robust way of organizing wealth, income, and power.  That isn't necessarily good, but we're discussing facts and analysis, not values.
Many places and many times have shown negative economic growth and/or economic stagnation.  Capitalist structures have not dissolved under such circumstances.   Sure, capitalism seeks everywhere to maximize wealth and income, but that doesn't mean the *system* falls apart when wealth and income decline.
How can this be?  If you own massive wealth, and potential investments everywhere are losing money, you still put your money into the economy or else inflation will eat away at your wealth faster than losses in poor investments.  You keep on playing the game, even as wealth might decrease year after year.
Similarly, if you're a worker facing falling wages, you don't stop working and starve, you keep on working.
Growth is simply not a necessary element for capitalism to continue to dominate.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on October 25, 2015, 08:49:21 PM
Geoff, good to see you still knocking around!

Pretty much all of economics as an academic discipline is based on misapplications of laws of physics. The earliest mathematically rigorous works on economics assumed that the laws of fluid dynamics (as they were understood at the time) could just be applied directly applied to money flow in an economy. Not only has this unsupported assumption never been reconsidered, the field of fluid dynamics itself soon moved beyond the model that the early economists relied on, but economics didn't even bother keeping up with the physics they were relying on.

So the field of economics is essentially an inappropriate application of a long-abandoned model of a sub-branch of physics.

(You are, of course, absolutely right about capitalism's reliance on growth. There may be an economic structure that can succeed with long-term de-growth and preserve a few elements of capitalism, but it will be fundamentally different from what most people think of as capitalism as they experience it today.)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: GeoffBeacon on October 26, 2015, 10:20:45 AM
wili

Thanks for your kind words.

I've not been away from the AF but mostly lurking.

Daily, this is my starting point for climate & related topics.
It is the most trustworthy, knowledgeable and up-to-date source I know.

Thanks to Neven.

P.S. I'll probably start a thread on de-growth.

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Neven on October 26, 2015, 11:05:40 AM
Thanks, Geoff.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: GeoffBeacon on October 26, 2015, 05:29:23 PM
I have started a new topic "Is de-growth necessary? Is it possible?" in "Policy and Solutions"
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on October 28, 2015, 02:46:55 PM
Rising Seas Pose Growing Flood Threat
A bipartisan group in the U.S. is attempting to raise awareness of sea level rise risks
Quote
Blackouts from hurricanes will be more common

The UCS report includes maps of projected flooding affecting large power substations and power plants in five major metropolitan regions: the Delaware Valley, southeastern Virginia, the South Carolina Low Country, southeastern Florida, and the central Gulf Coast.

In one example, if a Category 3 hurricane were to hit Virginia’s Tidewater region, 15 of the 18 major substations in Norfolk and nine of the 11 major substations in Hampton would be at risk of flooding, the report said.

“Between now and 2050—well within the lifetime of major equipment being installed today—an additional 13 major substations could face flood waters five to 10 feet deep, and an additional three could be exposed to depths of 10 to 15 feet,” it says.

In all five regions, 68 power plants and 415 major substations could be flooded by a Category 3 hurricane today unless protective actions are taken, UCS said.
http://www.scientificamerican.com/article/rising-seas-pose-growing-flood-threat/ (http://www.scientificamerican.com/article/rising-seas-pose-growing-flood-threat/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on October 31, 2015, 12:18:51 AM
NOAA paper on "nuisance flooding" of the U.S. coast.
Quote
During the 2014 meteorological year (May 2014 – Apr 2015), the mid‐Atlantic coast was most impacted. Between Sandy Hook, NJ and Savannah, GA long‐term accelerating trends continued unabated with several locations reporting 20 or more days of flooding and an increase from 2013.
http://www.noaanews.noaa.gov/stories2015/2014%20State%20of%20Nuisance%20Tidal%20Flooding.pdf (http://www.noaanews.noaa.gov/stories2015/2014%20State%20of%20Nuisance%20Tidal%20Flooding.pdf)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on October 31, 2015, 09:24:29 PM
King Tide combined with Sea Level Rise associated with the slowdown of the AMOC (Gulf Stream Current) produces record tidal gauge levels rivaling hurricane storm surges.

http://www.islandpacket.com/news/weather/article41526504.html (http://www.islandpacket.com/news/weather/article41526504.html)

Quote
Wheeler said the marina's staff is expecting the water level to again rise past the wharf wall Wednesday morning. High tide is at 9:48 a.m. Wednesday.

"It was pretty crazy," Wheeler said. "Usually when we get a full moon the water comes up to the edge of the wall but doesn't go over. Today it just kept coming."

Quote
"It was the biggest tide I've seen in 37 years here," he said. "It was crazy."

http://www.forbes.com/sites/ericmack/2015/10/29/are-flooding-and-crazy-king-tides-in-the-southeast-proof-of-climate-change/ (http://www.forbes.com/sites/ericmack/2015/10/29/are-flooding-and-crazy-king-tides-in-the-southeast-proof-of-climate-change/)

Quote
Tuesday morning’s high tide in Charleston, S.C. peaked at over eight-and-a-half feet — that’s a foot-and-a-half more than was predicted for the so-called “king tide” or normally occurring highest tide of the year.

Quote
in Savannah, Georgia, the water level crested at 10.43 feet, just shy of the record of 10.87 feet set when Hurricane Nine made landfall there in 1947
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on November 09, 2015, 10:49:49 PM
The linked Robert Scribbler article indicates that the combination of El Nino affects and King Tides will cause significant flooding this winter in US East Coast areas

http://robertscribbler.com/2015/11/06/the-frankentides-are-coming-us-east-coast-to-see-season-of-flooding-from-el-nino-sea-level-rise-this-winter/ (http://robertscribbler.com/2015/11/06/the-frankentides-are-coming-us-east-coast-to-see-season-of-flooding-from-el-nino-sea-level-rise-this-winter/)

Extract: "According to preliminary reports from NOAA, this Fall, Winter and Spring will likely bring an abnormal number of flooding tides to the US East Coast. These emperor and king tides are primarily driven by sea level rise — a knock on impact of human-forced warming. But during an El Nino year, as with this year, wind patterns along the East Coast tend to drive tides even higher. At El Nino times, lows tend to form off the US East Coast. These lows tend to generate a consistent northeasterly wind that pushes against the northward flow of the Gulf Stream. This action reduces the Gulf Stream’s ability to pull water away from our shores, and some of that water rebounds against the US East Coast."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on November 12, 2015, 10:03:05 PM
The attached Aviso plot of the sea level trend line through July 26 2016 indicates that sea level is trending higher than the trend line and by that date we had not yet reached peak El Nino conditions:

Date           Mean Sea Level (cm)
2015.463388 7.895294e-02
2015.490535 7.926799e-02
2015.517683 7.920715e-02
2015.544831 7.943782e-02
2015.571978 8.007446e-02
2015.599126 8.068274e-02
2015.626273 8.094006e-02
2015.653421 8.083496e-02
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on November 13, 2015, 12:20:13 PM
Good piece on Greenland, but also Antarctica, with Rignot, Joughin, Alley, Levermann and others:
http://www.nytimes.com/2015/11/15/magazine/the-secrets-in-greenlands-ice-sheets.html?smid=fb-share (http://www.nytimes.com/2015/11/15/magazine/the-secrets-in-greenlands-ice-sheets.html?smid=fb-share)

So will we have fast SLR, of very fast?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on November 13, 2015, 04:31:17 PM
Good piece on Greenland, but also Antarctica, with Rignot, Joughin, Alley, Levermann and others:
http://www.nytimes.com/2015/11/15/magazine/the-secrets-in-greenlands-ice-sheets.html?smid=fb-share (http://www.nytimes.com/2015/11/15/magazine/the-secrets-in-greenlands-ice-sheets.html?smid=fb-share)

So will we have fast SLR, of very fast?

Rignot cites a lower bound SLR by 2100 of 1.2m and he is working harm to try to define an upper bound (but he believes that it will be less than Hansen's value of 5m).
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Neven on November 14, 2015, 06:16:50 PM
Good piece on Greenland, but also Antarctica, with Rignot, Joughin, Alley, Levermann and others:
http://www.nytimes.com/2015/11/15/magazine/the-secrets-in-greenlands-ice-sheets.html?smid=fb-share (http://www.nytimes.com/2015/11/15/magazine/the-secrets-in-greenlands-ice-sheets.html?smid=fb-share)

So will we have fast SLR, of very fast?

Thanks, Lennart. Great article.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on November 15, 2015, 02:36:40 AM
North Topsail Beach, North Carolina, U.S.

How coastal real estate is being impacted by climate change
Quote
Englander expects that within a decade, perhaps as early as five years from now, awareness of sea level impacts on coastal real estate will spook the marketplace. Insurance premiums will spike, making mortgages unattainable for some. Property values will plunge, along with local tax revenues, making it harder for communities to adapt to new realities.

“People think this is an environmental issue, but it’s not. It’s an economic issue,” he said. “The people who own lots of real estate and finance it, they haven’t really thought this through yet.”

Those that have are quietly selling, Englander added. “They don’t want to make noise because they want to protect their property values. They want to sell high before the market notices.”
http://www.thestar.com/business/2015/11/14/how-coastal-real-estate-is-being-impacted-by-climate-change.html (http://www.thestar.com/business/2015/11/14/how-coastal-real-estate-is-being-impacted-by-climate-change.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on November 16, 2015, 05:14:45 AM
North Topsail Beach, North Carolina, U.S.

How coastal real estate is being impacted by climate change
Quote
Englander expects that within a decade, perhaps as early as five years from now, awareness of sea level impacts on coastal real estate will spook the marketplace. Insurance premiums will spike, making mortgages unattainable for some. Property values will plunge, along with local tax revenues, making it harder for communities to adapt to new realities.

“People think this is an environmental issue, but it’s not. It’s an economic issue,” he said. “The people who own lots of real estate and finance it, they haven’t really thought this through yet.”

Those that have are quietly selling, Englander added. “They don’t want to make noise because they want to protect their property values. They want to sell high before the market notices.”
http://www.thestar.com/business/2015/11/14/how-coastal-real-estate-is-being-impacted-by-climate-change.html (http://www.thestar.com/business/2015/11/14/how-coastal-real-estate-is-being-impacted-by-climate-change.html)

This has been my point all along. It will not take the actual destruction of coastal property to wreak havoc in our financial institutions as property values plummet.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on November 16, 2015, 04:38:21 PM
Good point, as usual, SH. The question is: How long it will take for the panic to set in?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on November 16, 2015, 10:13:14 PM
Egypt’s Nile River Delta Is Sinking Into the Sea
http://www.newsweek.com/egypts-nile-river-delta-sinking-sea-394268 (http://www.newsweek.com/egypts-nile-river-delta-sinking-sea-394268)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on November 18, 2015, 05:14:13 AM
Good point, as usual, SH. The question is: How long it will take for the panic to set in?

It's difficult to predict when a stampede will start but there will be no stopping it as emotions will take over. 
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: GeoffBeacon on November 22, 2015, 07:21:52 AM
I have just found:

https://www.bas.ac.uk/media-post/news-story-sea-level-rise-from-antarctic-collapse/ (https://www.bas.ac.uk/media-post/news-story-sea-level-rise-from-antarctic-collapse/)

Quote
Sea-level rise from Antarctic collapse may be slower than suggested

A new study by scientists in the UK and France has found that Antarctic ice sheet collapse will have serious consequences for sea level rise over the next two hundred years, though not as much as some have suggested.

This study, published this week in the journal Nature, uses an ice-sheet model to predict the consequences of unstable retreat of the ice, which recent studies suggest has begun in West Antarctica.

Via BBC podcast: http://www.bbc.co.uk/programmes/p0380gs8 (http://www.bbc.co.uk/programmes/p0380gs8)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: solartim27 on November 22, 2015, 08:05:41 AM
I have just found:
https://www.bas.ac.uk/media-post/news-story-sea-level-rise-from-antarctic-collapse/ (https://www.bas.ac.uk/media-post/news-story-sea-level-rise-from-antarctic-collapse/)
Previously discussed on another thread.  The et al on the authors gets muddled (It is a good interview though):
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on November 22, 2015, 01:15:24 PM
I have just found:
https://www.bas.ac.uk/media-post/news-story-sea-level-rise-from-antarctic-collapse/ (https://www.bas.ac.uk/media-post/news-story-sea-level-rise-from-antarctic-collapse/)
Previously discussed on another thread.  The et al on the authors gets muddled (It is a good interview though):

The other thread was the "Potential Collapse Scenario for the WAIS" thread in the Antarctica folder, and Lennart initiates the discussion in Reply #392.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on November 25, 2015, 01:10:49 AM
California coastal flooding from King tides.

This week’s king tides bring danger of flooding, glimpse of future
http://www.sfchronicle.com/science/article/This-week-s-king-tides-bring-danger-of-6652913.php (http://www.sfchronicle.com/science/article/This-week-s-king-tides-bring-danger-of-6652913.php)

Quote
@arasmusKTVU: .@Ca_king_tides warns this is what #SanFrancisco #Embarcadero will look like by 2100, w/sea level rise #kingtides [16-sec video:] https://t.co/ebQH03VeXF (https://t.co/ebQH03VeXF)

https://twitter.com/arasmusktvu/status/669209179865788416 (https://twitter.com/arasmusktvu/status/669209179865788416)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on November 25, 2015, 01:11:25 AM
The New Miami Beach Leader Facing Rising Seas
http://wlrn.org/post/new-miami-beach-leader-facing-rising-seas (http://wlrn.org/post/new-miami-beach-leader-facing-rising-seas)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on November 29, 2015, 04:28:25 PM
From Portland, Maine:

Sea Change: Rising sea levels should be a wake-up call
Quote
Even in calm weather, king tides are becoming problematic. When seawater first began bubbling up from storm sewers and forming briny puddles, officials called it “nuisance flooding.” Sneering at that language from “Roget’s Denial Thesaurus,” Jon Stewart put forward a few synonyms of his own – like “moisture inconvenience” or simply a “surprise pool party!”

Humor can help us contend with the sobering prognosis scientists now offer.
http://www.pressherald.com/2015/11/29/sea-change-rising-sea-levels-should-be-a-wake-up-call/ (http://www.pressherald.com/2015/11/29/sea-change-rising-sea-levels-should-be-a-wake-up-call/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Bruce Steele on December 05, 2015, 07:41:16 PM
Sea level gauges at San Diego, La Jolla, and Santa Barbara recorded the highest levels ever recorded to date at those stations. San Diego had flooding several miles inland as sea water surged into storm drains. Looks like we can add SanDiego to the list of U.S. cities with problems coming near term from sea level rise.

http://storms.ca.gov/docs/Record-Breaking-Sea-Levels-California.PDF (http://storms.ca.gov/docs/Record-Breaking-Sea-Levels-California.PDF)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: solartim27 on December 05, 2015, 08:52:52 PM
The San Diego flooding was several miles from the ocean, but only 1/2 mile from the bay, in one of the lowest areas of the city.  I was astonished at the height while walking over by the bay at the previous high tide.  Swam a mile last Wednesday, the water is chilly, but don't need a wetsuit yet, which is quite unusual, at least for me.
Sea level gauges at San Diego, La Jolla, and Santa Barbara recorded the highest levels ever recorded to date at those stations. San Diego had flooding several miles inland as sea water surged into storm drains. Looks like we can add SanDiego to the list of U.S. cities with problems coming near term from sea level rise.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: bligh8 on December 06, 2015, 07:40:27 AM
Residents resist tidal flooding, an increasing threat to the Jersey Shore.

Within the linked article there is a nice graph showing the increase in frequency
and degree of flooding.

On a personal note, friends of mine sold their lovely home in Bridgewater, NJ
To build their retirement home (very nice and expensive home) at the shore,
with a bulkhead 12inches above high tide. No matter what I said I could not dissuade
them from their pursuits.


http://www.app.com/story/news/local/land-environment/enviroguy/2015/11/24/residents-resist-tidal-flooding-increasing-threat-jersey-shore/75893620/ (http://www.app.com/story/news/local/land-environment/enviroguy/2015/11/24/residents-resist-tidal-flooding-increasing-threat-jersey-shore/75893620/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: oren on December 06, 2015, 10:05:02 AM
Residents resist tidal flooding, an increasing threat to the Jersey Shore.

Within the linked article there is a nice graph showing the increase in frequency
and degree of flooding.

On a personal note, friends of mine sold their lovely home in Bridgewater, NJ
To build their retirement home (very nice and expensive home) at the shore,
with a bulkhead 12inches above high tide. No matter what I said I could not dissuade
them from their pursuits.


http://www.app.com/story/news/local/land-environment/enviroguy/2015/11/24/residents-resist-tidal-flooding-increasing-threat-jersey-shore/75893620/ (http://www.app.com/story/news/local/land-environment/enviroguy/2015/11/24/residents-resist-tidal-flooding-increasing-threat-jersey-shore/75893620/)

That's a very good chart.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Bruce Steele on December 07, 2015, 12:22:37 AM
The Calif. King Tides expected for Jan. 21+22 might coincide with some El Nino rains , storm surge etc. Those of you on the U.S. West Coast might mark your calendars for a day at the beach !
There are several organized hikes for those days. If we do get some decent rains beforehand and a storm to push in some storm tides it should get interesting.

http://california.kingtides.net/ (http://california.kingtides.net/)

Bring your galoshes or knee waders.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on December 10, 2015, 02:18:11 PM
People told to stay indoors as Cumbrian village floods for second time
http://www.theguardian.com/environment/2015/dec/10/people-told-to-stay-indoors-as-cumbrian-village-floods-for-second-time (http://www.theguardian.com/environment/2015/dec/10/people-told-to-stay-indoors-as-cumbrian-village-floods-for-second-time)
Quote
Police have urged people to stay indoors after a Cumbrian village was flooded for the second time within a few days. The Liberal Democrat leader, Tim Farron, a local MP, said the government must learn that flooding is likely to become more frequent.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on December 12, 2015, 10:50:08 PM
Paleo evidence might guide our expectations for SLR. The picture is grim. I refer to three papers

1)Rohling(2007) doi:10.1038/ngeo.2007.28
2)Blanchon(2009) doi:10.1038/nature07933
3)Lambeck(2014) doi:10.1073/pnas.1411762111

Blanchon(2009) has a nice graf of SLR over the last 20 kyr in the supplementary which i attach.
I also attach two other grafs, one from each paper showing rates of SLR over the latest deglaciation and in the Eemian. The latter is a couple degrees warmer than the Holocene and might be an analog for the Anthropocene.  The jumps in sea level are episodic, the rates of rise jump to their maxima on century scale, if not faster. Sea level doesnt rise as an exponential would, with the greatest rises at the end; rather it goes in fits and starts, with SLR rates flickering between lows and highs over a couple orders of magnitude. This leads to far more damage early than the backloaded exponential would have you believe, and amplifies discounted damage costs, since discounting trivializes damages further in the future.

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: bligh8 on December 14, 2015, 12:05:47 PM
Thanks Sidd for adding clarity to the scenario of  SLR.
This makes sense as new mechanisms are added to a fragile situation
leading to acceleration in ice failure dynamics, as in when the January
zero degree isotherm moves across the broad area of the WAIS one could
add rain and hydro fracture as a new mechanism in that area, the results
would be as you described.

Fair Winds
Bligh
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 23, 2015, 12:21:13 AM
The attached NASA image of the Jason-2 Satellite Sea Level Residual for Dec 6 2015, shows that the current Super El Nino has raised sea level from the Eastern Equatorial region northward to the Southern tip of Baja California.  This raises the prospect that a northward traveling kelvin wave might reach California in time to reinforce the King Tides in late January 2016; which (if this scenario were to occur) would cause extensive local coastal flooding:
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sleepy on December 23, 2015, 05:41:24 AM
As I've heard deniers blaming El Nino, I would just like to add the comparison between SLR and MEI just to point out that it's not just ENSO. Picture attached.

None of the regulars in this thread needs the links, but I'll provide them for those who need them.
http://sealevel.colorado.edu/ (http://sealevel.colorado.edu/)
http://www.aviso.altimetry.fr/en/home.html (http://www.aviso.altimetry.fr/en/home.html)

New video from Aviso.
http://youtu.be/NNE6L82fv6w (http://youtu.be/NNE6L82fv6w)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 23, 2015, 05:10:36 PM
As I've heard deniers blaming El Nino, I would just like to add the comparison between SLR and MEI just to point out that it's not just ENSO.

Sleepy,
I am invariably impressed by the high-quality of your posts (which are based on sound facts & research). 

I concur that the relatively low current MEI values show that the atmosphere is providing relatively low forcing to move WWV in order to create the highest recorded Nino 3.4 values (see the attached image of Nino 3.4 vs the Warm Water Volume, WWV, transferred from the Eastern Eq. Pac. to the Western Eq. Pac); which indicates that our current high sea levels are due to a combination of moderate El Nino forcing and an increasing trend for climate change.

Many denialist, and many Pollyannas, fail to see that high Nino 3.4 values can act as a chaotic strange attractor to ratchet up many positive feedback mechanisms that will result in both higher global mean temperatures and higher Nino 3.4 temperatures.  A short list of such Nino 3.4 stimulated positive feedback mechanisms include:
- Stress on the Amazon Rainforest due to accelerated drought and wildfires.
- Increased probability of positive PDO values for years to come.
- Increased wildfires in many critical areas around the world including Indonesia.
- A reduction in low cloud cover and an increase in high cloud cover in the critical tropical belt.
- Accelerated ice mass loss from key WAIS marine glaciers.
- Warming of Alaska & Canada resulting in reduced local snow cover and reduced albedo.
- Etc.

Very Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sleepy on December 24, 2015, 06:44:37 AM
ASLR,
Thank you for you kind comment. I don't know about the quality of my posts, just trying to read and understand. I've had enough of people saying, -"ah, we've had mild winters in the past. Noone knows what the weather or the climate will do tomorrow." I heard that again this week.

Sure we know. We have known for a long, long time. Longer than I have lived, we should at least have started to listen in the eighties. I didn't.

But some things never change. Like those Donalds all over the planet, who like to decide what we should do or think. Those who have had the means to really make a difference and chose not to, they disturb me. But apart from my personal life, I can't do anything more than read. Lending a Danish sentence; Hvad gør vi nu lille du?

Therefore I'll end my little OT this Christmas Eve morning with Gasolin' and a quote from the lyrics at the end, they never made it in the states.
http://youtu.be/gQ5ZWxsjDKQ (http://youtu.be/gQ5ZWxsjDKQ)

Men så en dag gik jeg op til ministeren og sagde:
 Du der - få lige fødderne ned og ta' hatten af!
 Mand kan du ikke se at det hele er ved at gå
 fuldstændig agurk?!

 Så hvad gør vi nu din gamle skurk?

 Men han grinte bare og sagde:
 Dig, du kan sgu gå fanden i vold!
 Så det gør vi nu, lille du.
 Ja, vi gør!


That doesn't translate well. But I think you get the picture.
The social cost of carbon will be higher than today, thanks to those Donalds.

Merry Christmas.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 27, 2015, 07:21:55 PM
The linked article discusses how the climate change induced melting of glaciers is slightly slowing the Earth's rotation and is increasing "polar wander".  You can expect this effect to increase with continues sea level rise due to ice sheet mass loss with continued global warming:

http://www.climatecentral.org/news/glacial-melt-slowing-of-earths-rotation-19843 (http://www.climatecentral.org/news/glacial-melt-slowing-of-earths-rotation-19843)

Extract: "The driving force behind the modest but discernible changes in the Earth's rotation measured by satellites and astronomical methods is a global sea level rise fueled by an influx of meltwater into the oceans from glaciers, the researchers said.
"Because glaciers are at high latitudes, when they melt they redistribute water from these high latitudes towards lower latitudes, and like a figure skater who moves his or her arms away from their body, this acts to slow the rotation rate of the Earth," Harvard University geophysicist Jerry Mitrovica said.
The movement of ice and meltwater is also causing a slight migration of the Earth's axis, or north pole, in a phenomenon known as "polar wander," the researchers said.
"Imagine a figure skater who doesn't stick their arms straight out but rather sticks one at one angle and the other out at another angle. The figure skater will begin to wobble back and forth. This is the same thing as polar motion," Mitrovica said.
The research looked at the changes in the planet's rotation and axis in light of the world's sea level rise in the 20th century as a result of increasing global temperatures."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 30, 2015, 07:26:46 PM
The linked reference concludes that using current information and techniques it is impossible to rule-out a significant Antarctic contribution to Meltwater Pulse 1A (when sea levels rose approximately 4m per century).  While denialists may try to spin this to say that as we are not 95% certain that Antarctic marine glacial are unstable that we should assume that they are stable; however, I believe that such thinking is foolish, and that this analysis supports the idea that it is plausible that Antarctic marine glaciers could make a multi-meter contribution to SLR this century:

Jean Liu, Glenn A. Milne, Robert E. Kopp, Peter U. Clark & Ian Shennan (2015), "Sea-level constraints on the amplitude and source distribution of Meltwater Pulse 1A", Nature Geoscience, doi:10.1038/ngeo2616


http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2616.html (http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2616.html)


Abstract: "During the last deglaciation, sea levels rose as ice sheets retreated. This climate transition was punctuated by periods of more intense melting; the largest and most rapid of these—Meltwater Pulse 1A—occurred about 14,500 years ago, with rates of sea-level rise reaching approximately 4 m per century. Such rates of rise suggest ice-sheet instability, but the meltwater sources are poorly constrained, thus limiting our understanding of the causes and impacts of the event. In particular, geophysical modelling studies constrained by tropical sea-level records suggest an Antarctic contribution of more than seven metres, whereas most reconstructions from Antarctica indicate no substantial change in ice-sheet volume around the time of Meltwater Pulse 1A. Here we use a glacial isostatic adjustment model to reinterpret tropical sea-level reconstructions from Barbados, the Sunda Shelf and Tahiti. According to our results, global mean sea-level rise during Meltwater Pulse 1A was between 8.6 and 14.6 m (95% probability). As for the melt partitioning, we find an allowable contribution from Antarctica of either 4.1 to 10.0 m or 0 to 6.9 m (95% probability), using two recent estimates of the contribution from the North American ice sheets. We conclude that with current geologic constraints, the method applied here is unable to support or refute the possibility of a significant Antarctic contribution to Meltwater Pulse 1A."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 05, 2016, 04:38:48 PM
While this has already been discussed in the Greenland folder, it should be noted here that the firn in Greenland (and by extension in Antarctica) will hold less water than previously expected, so sea level rise will occur faster than previously expected:

Horst Machguth, Mike MacFerrin, Dirk van As, Jason E. Box, Charalampos Charalampidis, William Colgan, Robert S. Fausto, Harro A. J. Meijer, Ellen Mosley-Thompson & Roderik S. W. van de Wal (2016), "Greenland meltwater storage in firn limited by near-surface ice formation", Nature Climate Change, doi:10.1038/nclimate2899


http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2899.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2899.html)


Abstract: "Approximately half of Greenland’s current annual mass loss is attributed to runoff from surface melt. At higher elevations, however, melt does not necessarily equal runoff, because meltwater can refreeze in the porous near-surface snow and firn. Two recent studies suggest that all or most of Greenland’s firn pore space is available for meltwater storage, making the firn an important buffer against contribution to sea level rise for decades to come3. Here, we employ in situ observations and historical legacy data to demonstrate that surface runoff begins to dominate over meltwater storage well before firn pore space has been completely filled. Our observations frame the recent exceptional melt summers in 2010 and 2012, revealing significant changes in firn structure at different elevations caused by successive intensive melt events. In the upper regions (more than ~1,900 m above sea level), firn has undergone substantial densification, while at lower elevations, where melt is most abundant, porous firn has lost most of its capability to retain meltwater. Here, the formation of near-surface ice layers renders deep pore space difficult to access, forcing meltwater to enter an efficient surface discharge system and intensifying ice sheet mass loss earlier than previously suggested."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on January 05, 2016, 06:24:12 PM
Sea level rise, and decreasing availability of cool fresh water, also serve to make traditional fossil fuel and nuclear power plants obsolete.

Research out today maps where power plants around the world are most at risk from higher water temperatures and decreased water availability.
http://www.carbonbrief.org/map-where-climate-change-could-hit-electricity-production (http://www.carbonbrief.org/map-where-climate-change-could-hit-electricity-production)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 04, 2016, 09:33:55 AM


You can compare the attached Aviso plot of the sea level trend line through Oct 26 2015 to that shown in Reply #465 for July 26 2016. This indicates that sea level is trending high enough to change the slope of the trend line from 3.32 to 3.34mm/yr:

Date           Mean Sea Level (cm)
2015.599126 8.058987e-02
2015.626273 8.136587e-02
2015.653421 8.172501e-02
2015.680568 8.182677e-02
2015.707716 8.217352e-02
2015.734863 8.297785e-02
2015.762011 8.389317e-02
2015.789159 8.456793e-02
2015.816306 8.498810e-02
2015.843454 8.527852e-02
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 05, 2016, 08:35:38 PM
Scribbler has a discussion on the rapid acceleration of SLR from 2009 to October 2015 (at a rate of 5 mm/yr):

http://robertscribbler.com/2016/02/04/rapid-acceleration-in-sea-level-rise-from-2009-through-october-2015-global-oceans-have-risen-by-5-millimeters-per-year/ (http://robertscribbler.com/2016/02/04/rapid-acceleration-in-sea-level-rise-from-2009-through-october-2015-global-oceans-have-risen-by-5-millimeters-per-year/)

Extract: "Rapid Acceleration in Sea Level Rise — From 2009 Through October 2015, Global Oceans Have Risen by 5 Millimeters Per Year."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on February 05, 2016, 10:14:45 PM
Rietbroek(2016)  DOI: 10.1073/pnas.1519132113 discusses sea level budget closure. The figure for total SLR in the period 2002-2014 is 2.74 +/- 0.58 mm/yr. This is at the outer edge of the error bar for compatibility with AVISO or other satellite derived trends. More interestingly, the steric rise is found to be 1.38 +/- 0.16 mm/yr, much larger than previous estimates. They note:

"Another possibility is that the inversion scheme used here significantly underestimates the combined mass losses from the major ice sheets, glaciers, and hydrology. This leads to the larger steric trend, because the closure of the sea-level budget is respected in the inversion."

But they go on to note that their land ice mass waste trend "is consistent with published estimates of
mass loss in the ice sheets, glaciers, and hydrology."

They find a significant acceleration of GRIS mass waste.

Nice paper, but i imagine it is not the last word. I see that it was edited by Cazenave, who is a very sharp cookie. Don't miss the supplementaries.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on February 07, 2016, 07:19:47 PM
NASA study: glaciers outside of Greenland and Antarctica contributed one-third of the sea level rise during their study period -- matching the contribution from Greenland and Antarctica.

NASA Satellite Data Helps Pinpoint Glaciers' Role in Sea Level Rise
Quote
A new study of glaciers worldwide using observations from two NASA satellites has helped resolve differences in estimates of how fast glaciers are disappearing and contributing to sea level rise.

The new research found glaciers outside of the Greenland and Antarctic ice sheets, repositories of 1 percent of all land ice, lost an average of 571 trillion pounds (259 trillion kilograms) of mass every year during the six-year study period, making the oceans rise 0.03 inches (0.7 mm) per year. This is equal to about 30 percent of the total observed global sea level rise during the same period and matches the combined contribution to sea level from the Greenland and Antarctica ice sheets.
http://www.nasa.gov/topics/earth/features/glacier-sea-rise.html (http://www.nasa.gov/topics/earth/features/glacier-sea-rise.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 09, 2016, 02:21:11 AM
The linked reference emphasizes that climate change is not just a 21st century problem, but rather is a problem that will last for millennia as indicated by the attached image about SLR:

Peter U. Clark, Jeremy D. Shakun, Shaun A. Marcott, Alan C. Mix, Michael Eby, Scott Kulp, Anders Levermann, Glenn A. Milne, Patrik L. Pfister, Benjamin D. Santer, Daniel P. Schrag, Susan Solomon, Thomas F. Stocker, Benjamin H. Strauss, Andrew J. Weaver, Ricarda Winkelmann, David Archer, Edouard Bard, Aaron Goldner, Kurt Lambeck, Raymond T. Pierrehumbert & Gian-Kasper Plattner (2016), "Consequences of twenty-first-century policy for multi-millennial climate and sea-level change", Nature Climate Change, doi:10.1038/nclimate2923

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2923.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2923.html)

Abstract: "Most of the policy debate surrounding the actions needed to mitigate and adapt to anthropogenic climate change has been framed by observations of the past 150 years as well as climate and sea-level projections for the twenty-first century. The focus on this 250-year window, however, obscures some of the most profound problems associated with climate change. Here, we argue that the twentieth and twenty-first centuries, a period during which the overwhelming majority of human-caused carbon emissions are likely to occur, need to be placed into a long-term context that includes the past 20 millennia, when the last Ice Age ended and human civilization developed, and the next ten millennia, over which time the projected impacts of anthropogenic climate change will grow and persist. This long-term perspective illustrates that policy decisions made in the next few years to decades will have profound impacts on global climate, ecosystems and human societies — not just for this century, but for the next ten millennia and beyond."

Caption: " Past and future global average sea level (upper chart) and sea level change (lower chart), from 20,000 years ago to 10,000 years in the future. Future projections show four different emissions scenarios (figures on right-hand side show total cumulative carbon emissions). Inset maps show current (left) and future projected (right) ice coverage of Greenland and Antarctic ice sheets. Source: Clark et al. (2016)."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on February 09, 2016, 08:56:16 PM
The Guardian writes about the study ASLR exerpts in Reply #500 above:

Sea-level rise 'could last twice as long as human history'
Research warns of the long timescale of climate change impacts unless urgent action is taken to cut emissions drastically
Quote
Huge sea-level rises caused by climate change will last far longer than the entire history of human civilisation to date, according to new research, unless the brief window of opportunity of the next few decades is used to cut carbon emissions drastically.

Even if global warming is capped at governments’ target of 2C - which is already seen as difficult - 20% of the world’s population will eventually have to migrate away from coasts swamped by rising oceans. Cities including New York, London, Rio de Janeiro, Cairo, Calcutta, Jakarta and Shanghai would all be submerged.
http://www.theguardian.com/environment/2016/feb/08/sea-level-rise-could-last-twice-as-long-as-human-history (http://www.theguardian.com/environment/2016/feb/08/sea-level-rise-could-last-twice-as-long-as-human-history)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 12, 2016, 05:14:28 PM
The linked reference discusses how the period from 2002 to 2014 was dominated by La Nina behavior that lead to a decade of precipitation storing water on land (see image) thus slowing the observed rate of sea level rise by 0.71 ± 0.20 millimeters per year.  What the reference does not speculate on is that now that we are in a positive PDO phase this pattern is likely to flip resulting in a new trend line for SLR of about 3.34 + 0.71 = 4.05mm/year plus or minus (to get back to neutral) + 0.71 = 4.76 mm/year plus or minus for the duration of the positive PDO phase assuming that glacial and ice sheet contributions remain constant (which is not very likely):

J. T. Reager, A. S. Gardner, J. S. Famiglietti, D. N. Wiese, A. Eicker & M.-H. Lo (12 Feb 2016), "A decade of sea level rise slowed by climate-driven hydrology", Science, Vol. 351, Issue 6274, pp. 699-703, DOI: 10.1126/science.aad8386


http://science.sciencemag.org/content/351/6274/699 (http://science.sciencemag.org/content/351/6274/699)


Abstract: "Climate-driven changes in land water storage and their contributions to sea level rise have been absent from Intergovernmental Panel on Climate Change sea level budgets owing to observational challenges. Recent advances in satellite measurement of time-variable gravity combined with reconciled global glacier loss estimates enable a disaggregation of continental land mass changes and a quantification of this term. We found that between 2002 and 2014, climate variability resulted in an additional 3200 ± 900 gigatons of water being stored on land. This gain partially offset water losses from ice sheets, glaciers, and groundwater pumping, slowing the rate of sea level rise by 0.71 ± 0.20 millimeters per year. These findings highlight the importance of climate-driven changes in hydrology when assigning attribution to decadal changes in sea level."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sleepy on February 13, 2016, 06:49:45 AM
La Ninas are getting weaker and weaker, since 82-83. The PDO for January was 1.53 and we're now up to 25 consecutive moths with positive values. The first page at Aviso shows +3.35 mm/year (06 February 2016) but the real graph and data files were not updated. Image attached.
The latest SSW over the Arctic contributed to a huge impact on ASIE. Glaciers are now calving all year round. Etc, etc, etc.

It's more and more like travelling down a one-way road, without a turning space.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 13, 2016, 08:33:39 AM
La Ninas are getting weaker and weaker, since 82-83. The PDO for January was 1.53 and we're now up to 25 consecutive moths with positive values. The first page at Aviso shows +3.35 mm/year (06 February 2016) but the real graph and data files were not updated.

Sleepy,

Thanks for the updated Aviso image, and I note that the +3.35 mm/year is a linear regression over their entire data set.  Further, I note that in my Reply #502, I have corrected my math to show a PDO adjusted rate of +4.76mm/year. 

Finally, I remind readers that Scribbler has a discussion on the rapid acceleration of SLR from 2009 to October 2015 (at a rate of 5 mm/yr):

http://robertscribbler.com/2016/02/04/rapid-acceleration-in-sea-level-rise-from-2009-through-october-2015-global-oceans-have-risen-by-5-millimeters-per-year/ (http://robertscribbler.com/2016/02/04/rapid-acceleration-in-sea-level-rise-from-2009-through-october-2015-global-oceans-have-risen-by-5-millimeters-per-year/)

Extract: "Rapid Acceleration in Sea Level Rise — From 2009 Through October 2015, Global Oceans Have Risen by 5 Millimeters Per Year."

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wili on February 13, 2016, 08:23:27 PM
Apologies if this has already been posted somewhere:

http://www.carbonbrief.org/sea-level-research-says-only-a-brief-window-to-cut-emissions?utm_source=Daily+Carbon+Briefing&utm_campaign=585c34b9ac-cb_daily&utm_medium=email&utm_term=0_876aab4fd7-585c34b9ac-303429069 (http://www.carbonbrief.org/sea-level-research-says-only-a-brief-window-to-cut-emissions?utm_source=Daily+Carbon+Briefing&utm_campaign=585c34b9ac-cb_daily&utm_medium=email&utm_term=0_876aab4fd7-585c34b9ac-303429069)

Sea level research says only a ‘brief window’ to cut emissions

Quote
As global temperatures rise, scientists know that sea levels will follow suit. Today, global sea level is the topic of two new papers, both published in Nature Climate Change.

The first looks at Antarctica’s ice shelves – known as “gatekeepers of the ice” – and how much ice each one can afford to lose before opening the gates to more glacier flow into the oceans.

The second study focuses on how our greenhouse gas emissions today could lead to tens of metres of sea level rise that persist for hundreds of thousands of years.
Rapid thinning

An ice shelf forms when glaciers on land reach the coast and flow into the ocean. If the ocean is cold enough, this ice doesn’t melt. Instead it forms a permanently floating sheet of ice.

Ice shelves surround three-quarters of Antarctica. They can be as much as two kilometers thick and the largest – the Ross ice shelf – is roughly the same size as Spain.

These floating tongues of ice provide the important function of holding back – or “buttressing” – the flow of ice from the glaciers behind them into the ocean.

But many of Antarctica’s ice shelves are thinning rapidly. When an ice shelf thins, retreats or even collapses, it is less able to hold back the glaciers behind it, allowing more ice to flow from land and into the sea, and adding to sea levels. After the collapse of Larsen B ice shelf in West Antarctica in 2002, for example, some glaciers started flowing eight times faster.

The new paper estimates how much of each of Antarctica’s ice shelves can be lost without saying goodbye to this buttressing effect.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: GeoffBeacon on February 23, 2016, 10:41:38 AM
Kopp et. al Temperature-driven global sea-level variability in the Common Era (http://www.pnas.org/content/early/2016/02/17/1517056113)

Not as bad as we thought
Quote
Semiempirical 21st century projections largely reconcile differences between Intergovernmental Panel on Climate Change projections and semiempirical models.

Or is it?
Quote
However, both semi-empirical and process model-based projections may un-derestimate GSL rise if new processes not active in the calibration period and not well represented in process models [e.g., marine ice sheet instability in Antarctica (32)] become major factors in the 21st century.

The New York Times reported (http://www.nytimes.com/2016/02/23/science/sea-level-rise-global-warming-climate-change.html)
Quote
One of the authors of the new paper, Dr. Rahmstorf, had previously published estimates suggesting the sea could rise as much as five or six feet by 2100. But with the improved calculations from the new paper, his latest upper estimate is three to four feet.

That means Dr. Rahmstorf’s forecast is now more consistent with calculations issued in 2013 by the Intergovernmental Panel on Climate Change, a United Nations body that periodically reviews and summarizes climate research. That body found that continued high emissions might produce a rise in the sea of 1.7 to 3.2 feet over the 21st century.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on February 23, 2016, 11:31:42 AM
Also see Mengel et al 2016:
http://www.pnas.org/content/early/2016/02/17/1500515113 (http://www.pnas.org/content/early/2016/02/17/1500515113)

And Stefan Rahmstorf who connects the dots at RealClimate:
http://www.realclimate.org/index.php/archives/2016/02/millennia-of-sea-level-change/ (http://www.realclimate.org/index.php/archives/2016/02/millennia-of-sea-level-change/)

He also points to:
"two further new papers, also appearing in PNAS this week, by Gasson et al. and by Levy et al.. These papers look at the stability of the Antarctic Ice Sheet during the early to mid Miocene, between 23 and 14 million years ago. What is most relevant here is the advances in modelling the Antarctic ice sheet by including new mechanisms describing the fracturing of ice shelves and the breakup of large ice cliffs. The improved ice sheet model is able to capture the highly variable Antarctic ice volume during the Miocene; the bad news is that it suggests the Antarctic Ice Sheet can decay more rapidly than previously thought."

Gasson et al 2016 and Levy et al 2016 are being discussed in the Antarctica folder under the Potential WAIS Collapse thread. Gasson et al seem to find that about 10m of SLR in two centuries may be likely once WAIS collapse gets going, so maybe from around 2050 or so?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on February 23, 2016, 12:12:20 PM
Correction, I didn't read carefully enough: Gasson et al don't find 10m in two centuries, but in four, with about 6m in the first two and about 4m in the next two.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: tombond on February 25, 2016, 12:40:03 PM
Sea level rise for the whole of the 20th century was about 140mm (5.5 inches). 
See chart at
http://www.theguardian.com/environment/climate-consensus-97-per-cent/2016/feb/24/earth-is-warming-is-50x-faster-than-when-it-comes-out-of-an-ice-age (http://www.theguardian.com/environment/climate-consensus-97-per-cent/2016/feb/24/earth-is-warming-is-50x-faster-than-when-it-comes-out-of-an-ice-age)

NASA data shows that for the 21st century to November 2015 the sea level rise is already 64mm (2.5 inches) with 36mm (say 1.5 inches) occurring in just the past 5 years (since January 1st 2011) suggesting a large acceleration in sea level rise is currently under way.

See 'sea level' then ‘source files’ at http://climate.nasa.gov/ (http://climate.nasa.gov/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on February 28, 2016, 12:50:45 AM
neato keen.

http://noc.ac.uk/news/sea-level-mapped-from-space-gps-reflections (http://noc.ac.uk/news/sea-level-mapped-from-space-gps-reflections)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on February 28, 2016, 01:10:15 AM
one grain of sand at a time

http://www.mcclatchydc.com/news/nation-world/world/article61804767.html#emlnl=Evening_Newsletter (http://www.mcclatchydc.com/news/nation-world/world/article61804767.html#emlnl=Evening_Newsletter)

not so neato keen
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on March 02, 2016, 08:48:55 PM
Per the linked Aviso data, mean sea level increased over 1cm in 2015; which is about 3 times faster than the trend line value of +3.35mm/yr:

ftp://ftp.aviso.oceanobs.com/pub/oceano/AVISO/indicators/msl/MSL_Serie_MERGED_Global_IB_RWT_GIA_Adjust.txt


2015.001879 7.395465e-02
2015.029027 7.380310e-02
2015.056175 7.431604e-02
2015.083322 7.562385e-02
2015.110470 7.701932e-02
2015.137617 7.763227e-02
2015.164765 7.724165e-02
2015.191912 7.645551e-02
2015.219060 7.611650e-02
2015.246207 7.652439e-02
2015.273355 7.720411e-02
2015.300503 7.741302e-02
2015.327650 7.688440e-02
2015.354798 7.610278e-02
2015.381945 7.587687e-02
2015.409093 7.662098e-02
2015.436240 7.799320e-02
2015.463388 7.920639e-02
2015.490535 7.970721e-02
2015.517683 7.960347e-02
2015.544831 7.948334e-02
2015.571978 7.983224e-02
2015.599126 8.061223e-02
2015.626273 8.138412e-02
2015.653421 8.180773e-02
2015.680568 8.199674e-02
2015.707716 8.234852e-02
2015.734863 8.308320e-02
2015.762011 8.400241e-02
2015.789159 8.458516e-02
2015.816306 8.434915e-02
2015.843454 8.344596e-02
2015.870601 8.267728e-02
2015.897749 8.262383e-02
2015.924896 8.329785e-02
2015.952044 8.447426e-02
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on March 04, 2016, 05:13:32 PM
The linked (open access) reference provides support for the position that as Greenland ice sheet sustains surface melting, the surface darkens, which results in a positive feedback for more melting; which results in accelerating SLR:

Tedesco, M., Doherty, S., Fettweis, X., Alexander, P., Jeyaratnam, J., and Stroeve, J.: The darkening of the Greenland ice sheet: trends, drivers, and projections (1981–2100), The Cryosphere, 10, 477-496, doi:10.5194/tc-10-477-2016, 2016.


http://www.the-cryosphere.net/10/477/2016/ (http://www.the-cryosphere.net/10/477/2016/)

Abstract. The surface energy balance and meltwater production of the Greenland ice sheet (GrIS) are modulated by snow and ice albedo through the amount of absorbed solar radiation. Here we show, using space-borne multispectral data collected during the 3 decades from 1981 to 2012, that summertime surface albedo over the GrIS decreased at a statistically significant (99 %) rate of 0.02 decade−1 between 1996 and 2012. Over the same period, albedo modelled by the Modèle Atmosphérique Régionale (MAR) also shows a decrease, though at a lower rate ( ∼ −0.01 decade−1) than that obtained from space-borne data. We suggest that the discrepancy between modelled and measured albedo trends can be explained by the absence in the model of processes associated with the presence of light-absorbing impurities. The negative trend in observed albedo is confined to the regions of the GrIS that undergo melting in summer, with the dry-snow zone showing no trend. The period 1981–1996 also showed no statistically significant trend over the whole GrIS. Analysis of MAR outputs indicates that the observed albedo decrease is attributable to the combined effects of increased near-surface air temperatures, which enhanced melt and promoted growth in snow grain size and the expansion of bare ice areas, and to trends in light-absorbing impurities (LAI) on the snow and ice surfaces. Neither aerosol models nor in situ and remote sensing observations indicate increasing trends in LAI in the atmosphere over Greenland. Similarly, an analysis of the number of fires and BC emissions from fires points to the absence of trends for such quantities. This suggests that the apparent increase of LAI in snow and ice might be related to the exposure of a "dark band" of dirty ice and to increased consolidation of LAI at the surface with melt, not to increased aerosol deposition. Albedo projections through to the end of the century under different warming scenarios consistently point to continued darkening, with albedo anomalies averaged over the whole ice sheet lower by 0.08 in 2100 than in 2000, driven solely by a warming climate. Future darkening is likely underestimated because of known underestimates in modelled melting (as seen in hindcasts) and because the model albedo scheme does not currently include the effects of LAI, which have a positive feedback on albedo decline through increased melting, grain growth, and darkening.



See also:

https://www.washingtonpost.com/news/energy-environment/wp/2016/03/03/greenlands-vast-ice-sheet-is-getting-darker-heres-why-thats-really-bad-news/ (https://www.washingtonpost.com/news/energy-environment/wp/2016/03/03/greenlands-vast-ice-sheet-is-getting-darker-heres-why-thats-really-bad-news/)

Edit, see also:

https://eos.org/articles/faster-merging-snow-crystals-speed-greenland-ice-sheet-melting (https://eos.org/articles/faster-merging-snow-crystals-speed-greenland-ice-sheet-melting)

Extract: "A new study has found that the warming of Greenland is speeding changes to the crystalline structure of the fallen snow there in such a way that the snowpack more readily absorbs solar energy. This transformation, in turn, is contributing to more warming of the vast Greenland ice sheet, the researchers report, which further accelerates the transformation to more-heat-absorbent snow."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on March 04, 2016, 07:51:57 PM
One of the keys to Greenland albedo loss might be contained in this sentence:

"Changes in the abundances of light-absorbing algae and other organic material with warmer temperatures may also be contributing to declining albedo, particularly for the ice, but this is an essentially unstudied source of darkening."

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on March 14, 2016, 09:11:54 PM
The linked (open access) reference estimates that over 13 million continental US citizens may need to relocated due to SLR by 2100:

Mathew E. Hauer, Jason M. Evans and Deepak R. Mishra (14 MARCH 2016) , "Millions projected to be at risk from sea-level rise in the continental United States", Nature Climate Change,  DOI: 10.1038/NCLIMATE2961


http://www.nature.com/articles/nclimate2961.epdf?referrer_access_token=8UOrGZsIIykrT2EH_Auk1NRgN0jAjWel9jnR3ZoTv0NW5dzPCV1LQTM2JMQvXgeV5kcoIiVItcAo6QabUR9-178DTC5AmyL7sqoUXtYx2FydBJB3NZXi69rwMlAJSFnb4PbI1CrMlUnNDDLj1lRtE1FdsgdlaP7hfzAT8rce5yP_2UibeTtvtA4ujTyZbUPByzMHTNjjTGJZ8QEiLwK-0PCDzSfXGVWpXdchFnhL0A8Zlt-JZPnhT-fRsFjU3uw_&tracking_referrer=www.nytimes.com (http://www.nature.com/articles/nclimate2961.epdf?referrer_access_token=8UOrGZsIIykrT2EH_Auk1NRgN0jAjWel9jnR3ZoTv0NW5dzPCV1LQTM2JMQvXgeV5kcoIiVItcAo6QabUR9-178DTC5AmyL7sqoUXtYx2FydBJB3NZXi69rwMlAJSFnb4PbI1CrMlUnNDDLj1lRtE1FdsgdlaP7hfzAT8rce5yP_2UibeTtvtA4ujTyZbUPByzMHTNjjTGJZ8QEiLwK-0PCDzSfXGVWpXdchFnhL0A8Zlt-JZPnhT-fRsFjU3uw_&tracking_referrer=www.nytimes.com)

Abstract: "Sea-level rise (SLR) is one of the most apparent climate change stressors facing human society.  Although it is known that many people at present inhabit areas vulnerable to SLR, few studies have accounted for ongoing population growth when assessing the potential magnitude of future impacts. Here we address this issue by coupling a small-area population projection with a SLR vulnerability assessment across all United States coastal counties. We find that a 2100 SLR of 0.9 m places a land area projected to house 4.2 million people at risk of inundation, whereas 1.8 m affects 13.1 million people—approximately three times larger than indicated by current populations. These results suggest that the absence of protective measures could lead to US population movements of a magnitude similar to the twentieth century Great Migration of southern African-Americans. Furthermore, our population projection approach can be readily adapted to assess other hazards or to model future per capita economic impacts."

See also:
http://www.nytimes.com/2016/03/15/science/rising-sea-levels-global-warming-climate-change.html?_r=0 (http://www.nytimes.com/2016/03/15/science/rising-sea-levels-global-warming-climate-change.html?_r=0)

Extract: " For the study, the authors combined future population estimates with predicted sea-level rise, using data from the National Oceanic and Atmospheric Administration, to demonstrate that millions are at risk: 4.2 million if seas rise by three feet; 13.1 million with a six-foot increase, a high-end estimate."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on March 23, 2016, 09:17:30 PM
Bacteria could be speeding up the darkening of Greenland's ice
Greenland’s ice is melting, and scientists have discovered a photosynthesising microbe they believe to be responsible for accelerating the process
Quote
A single species of bacteria could be about to accelerate the melting of Greenland. A photosynthesising microbe from a genus called Phormidesmis has been identified as the guilty party behind the darkening of Greenland.

It glues soot and dust together to form a grainy substance known as cryoconite. As the surface darkens, the Greenland ice becomes less reflective, more likely to absorb summer sunlight and more likely to melt.

And, Dr Arwyn Edwards, a biologist at Aberystwyth University tells the Microbiology Society’s annual conference in Liverpool today, cryoconite holes now pockmark 200,000 square kilometres of the Greenland ice sheet.
...
Scientists have known about the cryoconite phenomenon for more than a century – the word was coined during an expedition to Greenland by Nils Adolf Erik Nordenskiöld in 1870 – but not the identity of the culprit. Britain’s Natural Environment Research Council has now put £2.4m into such research and working in Svalbard, Edwards and colleagues identified the species that triggers the process of microbial change on the ice sheet. They confirmed its presence in western Greenland and on the Petermann Glacier in north-west Greenland.

“If we recognize ice species as a living landscape we can see that the microbes themselves are able to change the glacial surface,” Edwards said. “It’s only recently that we’ve begun to understand that these cryoconite holes are dynamic, changing in size and shape. Microbes are capable of ecosystem engineering and respond to changes in their environment all the time.”
https://www.theguardian.com/science/2016/mar/23/bacteria-speeding-up-darkening-greenlands-ice-climate-change (https://www.theguardian.com/science/2016/mar/23/bacteria-speeding-up-darkening-greenlands-ice-climate-change)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Steven on March 30, 2016, 08:36:32 PM
New paper by Robert DeConto and David Pollard:

Contribution of Antarctica to past and future sea-level rise (http://www.nature.com/articles/nature17145.epdf?referrer_access_token=FaIzUCFTOexRoQDY43bPXtRgN0jAjWel9jnR3ZoTv0M-pvJMg7VLINRa2mnTNsvXfjbAFNU4M9sSVFBNmnefzi_Tg5VLId6wPZa0y-lyfG-vEm6wcKjYMZNyVQpVGpxNuBQy2dtzpSq0NcRjB0jdNugzKU2KRX4P5kAvVABO4bobVehZVtXXvH_xPVB_Pb9hyLrFbV5Vi-6oiqRH2hl6CMVKe3xVfY-C8kdLeJD3hyeGP6RLPrByCSZtWhIuM-Ns&tracking_referrer=www.nytimes.com)

which suggests that "Antarctica has the potential to contribute more than a metre of sea-level rise by 2100 and more than 15 metres by 2500, if emissions continue unabated".

Quote
Abstract.

Polar temperatures over the last several million years have, at times, been slightly warmer than today, yet global mean sea level has been 6–9 metres higher as recently as the Last Interglacial (130,000 to 115,000 years ago) and possibly higher during the Pliocene epoch (about three million years ago). In both cases the Antarctic ice sheet has been implicated as the primary contributor, hinting at its future vulnerability.

Here we use a model coupling ice sheet and climate dynamics—including previously underappreciated processes linking atmospheric warming with hydrofracturing of buttressing ice shelves and structural collapse of marine-terminating ice cliffs—that is calibrated against Pliocene and Last Interglacial sea-level estimates and applied to future greenhouse gas emission scenarios. Antarctica has the potential to contribute more than a metre of sea-level rise by 2100 and more than 15 metres by 2500, if emissions continue unabated. In this case atmospheric warming will soon become the dominant driver of ice loss, but prolonged ocean warming will delay its recovery for thousands of years.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F04hBcnw.png&hash=c8888a99bae3338e4d1c8027c8e56f90)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on March 30, 2016, 10:20:37 PM
which suggests that "Antarctica has the potential to contribute more than a metre of sea-level rise by 2100 and more than 15 metres by 2500, if emissions continue unabated".

That is 1.05 +/-0.3m relative to 2000, which is already 0.2m above 1880 (it is nice that scientists keep re-zeroing so that they stay current).  So relative to 1880 we could be talking about up to 1.55m of SLR (without considering steric, glacial & GIS contributions).

See also:
http://theconversation.com/what-does-the-science-really-say-about-sea-level-rise-56807 (http://theconversation.com/what-does-the-science-really-say-about-sea-level-rise-56807)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on March 31, 2016, 03:20:47 AM
I find it interesting that their model actually shows net negative current SLR contributions from Antarctica and only positive contributions starting in 2050.  I guess the model is looking at a 3C rise in Antarctica Deep Water current starting sometime in 2035 or so.  Since recent satellite analysis shows net mass loss this seems to be a significant under-estimation.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on March 31, 2016, 04:26:22 AM
I find it interesting that their model actually shows net negative current SLR contributions from Antarctica and only positive contributions starting in 2050.  I guess the model is looking at a 3C rise in Antarctica Deep Water current starting sometime in 2035 or so.  Since recent satellite analysis shows net mass loss this seems to be a significant under-estimation.

As noted by sidd in the Antarctic folder, DeConto & Pollard (2016) know that their currently published findings are preliminary & incomplete as indicated by the following quote:


"In particular, the model lacks two-way coupling between the ice sheet and the ocean. This is especially relevant for RCP8.5, in which >1 Sv of freshwater and icebergs would be supplied to the Southern Ocean during peak retreat (Extended Data Fig. 8 ). Rapid calving and ice-margin collapse also implies ice mélange in restricted embayments that could provide buttressing and a negative feedback on retreat. The loss of ice mass would also have a strong effect on relative sea level at the margin owing to gravitational and solid-earth deformation effects [48], which could affect MISI and MICI dynamics because of their strong dependency on bathymetry. Future simulations should include coupling with Earth models that account for these processes."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Michael Hauber on March 31, 2016, 05:04:52 AM
RCP8.5 can only happen if the current explosive growth in renewable energy slams into a brick wall, and if there are no consequence of climate change that reduce our economic growth between now and 2100.  Under the much more reasonable RCP 4.5 the projection is for 40cm by 2100 (RCP4.5 still has more than half our energy from fossil fuels by 2100).  Add something for Greenland, and the IPCC 50cm for all other factors besides ice sheet collapse.  Perhaps we'll just barely reach 1 meter of SLR by 2100...

Under RCP 2.6 there is basically 0 contribution to SLR from Antarctica, even out to 2500.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on March 31, 2016, 07:47:34 AM
Mr. Mitchell has hit upon an important point. The DeConto models were initialized in 1950 and spun up with climate data. They show mass gain in antarctica until mid century, they are incorrect in that respect, we already see mass waste. But they are useful in the sense it shows 3/4 meter from antarctica in the last 50 years of the century, thats 15mm/yr. So, on my part, i wonder how many years to subtract, and how many mm/yr i want to add to their current model. And I do wonder if the melt layer feedback is already operating. They are smart people, they will put in the Hansen melt layer feedback soon, i am sure.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on March 31, 2016, 05:22:07 PM
RCP8.5 can only happen if the current explosive growth in renewable energy slams into a brick wall, and if there are no consequence of climate change that reduce our economic growth between now and 2100.  Under the much more reasonable RCP 4.5 the projection is for 40cm by 2100 (RCP4.5 still has more than half our energy from fossil fuels by 2100).  Add something for Greenland, and the IPCC 50cm for all other factors besides ice sheet collapse.  Perhaps we'll just barely reach 1 meter of SLR by 2100...

Under RCP 2.6 there is basically 0 contribution to SLR from Antarctica, even out to 2500.

Michael,

First we are currently following RCP 8.5 80-90%CL pathway.  Second, collapse of the key marine Antarctic glaciers mostly triggered by the subsurface ocean temperature offshore of West Antarctica circa 2040; which in-turn is driven by what is happening in the South Pacific, South Atlantic and Indian Oceans in the 2020 to 2030 timeframe.  Third, AR5 ESLD w.r.t. such issues as ECS and aerosol forcing and ice-climate interaction. Fourth, the preliminary findings of DeConto & Pollard (2016) show over twice the GMSL by 2100 as projected by AR5 for RCP 8.5.

Therefore, referring to AR5 projections should not given anyone any sense of comfort.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Steven on March 31, 2016, 07:33:51 PM
I find it interesting that their model actually shows net negative current SLR contributions from Antarctica and only positive contributions starting in 2050.  I guess the model is looking at a 3C rise in Antarctica Deep Water current starting sometime in 2035 or so.  Since recent satellite analysis shows net mass loss this seems to be a significant under-estimation.

That is discussed in the paper:

Quote
The CCSM4 simulations providing the model’s sub-ice-shelf melt
rates (Extended Data Fig. 5) underestimate the penetration of warm
Circum-Antarctic Deep Water into the Amundsen and Bellingshausen
seas observed in recent decades. As a result, the model fails to capture
recent, 21st-century thinning and grounding-line retreat
along the
southern Antarctic Peninsula and the Amundsen Sea Embayment.
Correcting for the ocean-model cool bias along this sector of coastline
improves the position of Pine Island and Thwaites grounding lines
relative to observations (Fig. 4h) and increases GMSL rise by 9 cm
at 2100
(mainly due to the accelerated retreat of Pine Island Glacier),
but the correction has little effect on longer timescales (Extended Data
Table 1).

(This quote is from page 4 of the DeConto & Pollard paper (http://www.nature.com/articles/nature17145.epdf?referrer_access_token=FaIzUCFTOexRoQDY43bPXtRgN0jAjWel9jnR3ZoTv0M-pvJMg7VLINRa2mnTNsvXfjbAFNU4M9sSVFBNmnefzi_Tg5VLId6wPZa0y-lyfG-vEm6wcKjYMZNyVQpVGpxNuBQy2dtzpSq0NcRjB0jdNugzKU2KRX4P5kAvVABO4bobVehZVtXXvH_xPVB_Pb9hyLrFbV5Vi-6oiqRH2hl6CMVKe3xVfY-C8kdLeJD3hyeGP6RLPrByCSZtWhIuM-Ns&tracking_referrer=www.nytimes.com).)

For the high emissions scenario (RCP8.5) their estimate for the Antarctic contribution to global mean sea level rise over the time period 2000-2100 is 1.05 +/- 0.30 m, without adjustment, and 1.14 +/- 0.36 m when adjusted as indicated in the above quote.  See Table 1 of the paper:


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FGegK1aX.png&hash=9473a968dc5840557b684a3af9b3aea9)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Steven on March 31, 2016, 07:49:28 PM
And I do wonder if the melt layer feedback is already operating.

I think that is unlikely.  E.g. see:

Quote
“The scale of the new freshwater input is small compared with snowfall or even rainfall in the Southern Ocean,” said Ted Scambos, senior research scientist at NSIDC. The Antarctic system has always experienced about 2,000 gigatons of melt annually, and the recent increases have only added about 150 gigatons. On top of that, the Southern Ocean annually receives about 20,000 to 40,000 gigatons of precipitation.
http://nsidc.org/icelights/2016/03/24/antarctic-sea-ice-an-update/ (http://nsidc.org/icelights/2016/03/24/antarctic-sea-ice-an-update/)

(This link is mainly about sea ice, but the "150 gigatons" per year refers to the loss of Antarctic land ice.)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on March 31, 2016, 10:07:07 PM
Quote
Under the much more reasonable RCP 4.5 the projection is for 40cm by 2100

RCP 4.5 is technically impossible now, the revisions to ECS and climate feedbacks make even RCP 6.0 nearly impossible at this point. 
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: ritter on March 31, 2016, 10:51:14 PM
Quote
Under the much more reasonable RCP 4.5 the projection is for 40cm by 2100

RCP 4.5 is technically impossible now, the revisions to ECS and climate feedbacks make even RCP 6.0 nearly impossible at this point.

Jai,

Can you expand on this a little, please?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on March 31, 2016, 11:30:14 PM
Re: melt feedback

As is pointed out by Fogwill(2015) DOI: 10.1002/2015EF000306 and others, the location of the extra melt input is important, it is not as though the melt is dispersed evenly over the Southern oceans. So a comparison to the volume of total southern ocean precipitation or total annual melt from all icebergs from antactica may not be appropriate.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on March 31, 2016, 11:54:27 PM
Here are two plots showing that we are well above the RCP 8.5 80% CL (for all GHGs) pathway.  Who knows what the future will hold.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Michael Hauber on April 01, 2016, 12:51:43 AM
Here are two plots showing that we are well above the RCP 8.5 80% CL (for GHG) pathway.  Who knows what the future will hold.

So you believe that the recent trends in total CO2 in the atmosphere is the best judge of the future Co2 pathways then?  In that case why don't you believe that current total SLR is the best judge of future SLR pathways?  Current SLR is just over 3mm a year, and has not sped up significantly over the last few decades (but has sped up over longer time frames).

Do you believe that we cannot get to the 40% or so level of renewable energy by 2100 to match RCP 4.5?  Renewable energy has grown quite rapidly over the last decade or so, but is still only a very small percentage of total energy.  Growth to date has not been enough to make a detectable difference in total Co2.  Just the same as growth in Antarctic ice loss has not been enough to make a detectable difference in global sea levels so far.  But in both cases future growth is likely to make a significant difference.

Do you believe that economic growth will continue without slow down right through to 2100 despite the consequences of climate change?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 01, 2016, 01:04:53 AM
Here are two plots showing that we are well above the RCP 8.5 80% CL (for GHG) pathway.  Who knows what the future will hold.

So you believe that the recent trends in total CO2 in the atmosphere is the best judge of the future Co2 pathways then? 

First, my post says: "Who knows what the future holds", but the second figure shows that following the current CoP21 pledges we will be emitting about 54 Gtons/yr of CO2-e though 2030. 

Second, the linked Kevin Anderson article notes that to avoid the 2C limit our remaining CO2 budget might be about 450 Gt.

http://www.skepticalscience.com/Anderson.html (http://www.skepticalscience.com/Anderson.html)

Extract: "Therefore, instead of a 1000 Gt CO2 budget, we might only have 450 Gt available for fossil-fuel energy emissions.”

Therefore, at 53 to 54 Gtons Co2-e per year, Anderson is indicating that we might only have 8.5 more years (plus an effective lag time of say 5.5 to 7.5 years for the emission period from 2016 to 2030) until 2030 to 2032 when we exceed the 2C limit (assuming an AR5 climate sensitivity, and assuming a GWP100 for methane of 34, while GWP20 for methane is 105).

Edit: Further, I note that during the late Eemian (that DeConto & Pollard 2016 also modeled) the GMST was between 2 to 3C above pre-industrial
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Michael Hauber on April 01, 2016, 01:07:56 AM
I find it interesting that their model actually shows net negative current SLR contributions from Antarctica and only positive contributions starting in 2050.  I guess the model is looking at a 3C rise in Antarctica Deep Water current starting sometime in 2035 or so.  Since recent satellite analysis shows net mass loss this seems to be a significant under-estimation.

The last paragraph in the Future Simulations section explains that the CCSM4 simulations that they use underestimate the penetration of warm water underneath the ice sheets.  A correction for this factor yields improved match to current observations and increases sea levels in 2100 by 9 cm.  Their simulations find that warm water is important for early ice sheet melt, but in future decades melting from above becomes the most important factor as the globe warms up enough for significant areas of surface melting. 
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Michael Hauber on April 01, 2016, 01:20:47 AM

Second, the linked Kevin Anderson article notes that to avoid the 2C limit our remaining CO2 budget might be about 450 Gt.

http://www.skepticalscience.com/Anderson.html (http://www.skepticalscience.com/Anderson.html)

Extract: "Therefore, instead of a 1000 Gt CO2 budget, we might only have 450 Gt available for fossil-fuel energy emissions.”

Therefore, at 53 to 54 Gtons Co2-e per year, Anderson is indicating that we might only have 8.5 more years (plus an effective lag time of say 5.5 to 7.5 years for the emission period from 2016 to 2030) until 2030 to 2032 when we exceed the 2C limit (assuming an AR5 climate sensitivity, and assuming a GWP100 for methane of 34, while GWP20 for methane is 105).

And that is relevant to whether 4.5 or 8.5 is the more likely future how?

I think its obvious that 4.5 is far more likely, and the projection in the DeConto and Pollard paper is for 40cm (due to Antarctica only) by 2100 under that scenario.  While it is indeed a preliminary modelling result which may go up or down in the future, it looks far more detailed and realistic than anything else I've seen on this topic.  It makes Hansen's paper look like a joke in comparison.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 01, 2016, 01:36:36 AM

And that is relevant to whether 4.5 or 8.5 is the more likely future how?


The point is that once you get to late Eemian temperatures (2 to 3C above pre-industrial) the WAIS surface ice starts to melt so hydrofracturing starts.  Your opinion that RCP 4.5 is most likely, is just that, your opinion.  My point is that cliff failures and hydrofracturing could begin in key coastal regions of the WAIS as early at 2030- 2035, and that DeConto & Pollard 2016 are not final ice mass loss estimates as they do not include many different considerations including:

- Positive ice-climate feedback (ala Hansen et al 2016)
- Use of a much finer mesh particularly in the Amundsen Sea Embayment area (which has increased ice mass loss in other models).
- Their paleo ice cliff and hydrofracturing calibrations most likely (appropriately) err on the side of least drama, ESLD, as: (a) the bed topology is smoother now than in paleo times; and (b) with the modern radiative forcing increasing at a rate over 10-times that of the PETM, the net positive feedbacks could accelerate faster than calibrated.
- The Byrd Subglacial Basin has an unusually high geothermal basal heat value that could accelerate ice mass loss.
- Their model spins-up from 1950 with negative ice mass contribution from the Antarctic Ice Sheet, AIS, to SLR (due to snowfall); while in actuality the AIS is currently contributing to SLR.
- They focus on ice mass loss from land based ice, while currently the ice mass loss from Antarctic ice shelves is dominate (& does not contribute to SLR) and is already triggering the ice-climate feedback (ala Hansen et al 2016).
- We are currently in a 20 to 30-year climate phase with a positive PDO which should make El Ninos more intense and more frequent than for the average climate state.  In general terms El Ninos telecommunicate more energy to the Bellingshausen & Amundsen Sea marine glaciers via both the ocean & the atmosphere).
- They ignore the recent evidence that ECS may be between 4 and 4.5C.
- I suspect that they ignore the influence of the extant ozone hole over Antarctica.
- They do not capture the consideration that as the Antarctic sea ice extant increases (with increased ice mass loss discharge into the ocean), more snow will fall on the sea ice rather than on the land.
 
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on April 01, 2016, 05:07:27 AM
"It makes Hansen's paper look like a joke ..."

I differ. Hansen is no joke, and to me, DeConto strengthens the case for Hansen. As I have pointed out in the WAIS collapse thread and elsewhere, DeConto is merely 50 yrs behind Hansen for his 8.5 scenario. DeConto cannot capture present mass waste without imposing a 3C warming of ASE with his ocean model, and i submit that the model is deficient in the way Hansen points out, that the mixed layer is too deep and stratification due to melt is not well represented.  DeConto has no melt feedback yet, although his melt flux is comparable.

Hansen I think has a more realistic ocean and DeConto has the ice sheet model, which Hansen lacks. I think when they put these together, the result will be closer to Hansen.

We shall see whether ocean forcing will tip the balance before the Mercer 0C midsummer isotherm arrives but I fear so.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sleepy on April 01, 2016, 07:21:01 AM
Here are two plots showing that we are well above the RCP 8.5 80% CL (for GHG) pathway.  Who knows what the future will hold.

So you believe that the recent trends in total CO2 in the atmosphere is the best judge of the future Co2 pathways then?  In that case why don't you believe that current total SLR is the best judge of future SLR pathways?  Current SLR is just over 3mm a year, and has not sped up significantly over the last few decades (but has sped up over longer time frames).

Do you believe that we cannot get to the 40% or so level of renewable energy by 2100 to match RCP 4.5?  Renewable energy has grown quite rapidly over the last decade or so, but is still only a very small percentage of total energy.  Growth to date has not been enough to make a detectable difference in total Co2.  Just the same as growth in Antarctic ice loss has not been enough to make a detectable difference in global sea levels so far.  But in both cases future growth is likely to make a significant difference.

Do you believe that economic growth will continue without slow down right through to 2100 despite the consequences of climate change?
Why not look at right now and the most successful nation within the EU? Sweden now has 52.1% renewables in energy consumption and we met our 2020 target back in 2013.
http://ec.europa.eu/eurostat/documents/2995521/6734513/8-10032015-AP-EN.pdf/3a8c018d-3d9f-4f1d-95ad-832ed3a20a6b (http://ec.europa.eu/eurostat/documents/2995521/6734513/8-10032015-AP-EN.pdf/3a8c018d-3d9f-4f1d-95ad-832ed3a20a6b)

But our total emissions per capita is still increasing, because we travel more in our cars, we buy more of them and our new ecofuel is diesel, we fly more, we eat more meat, we use more energy and all of that is projected to increase. When it comes to heating our homes we are trending downwards though, since we are helped by warmer winters...

The social cost of carbon will be very high, since that seems to be the typical cost of happiness?
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.footprintnetwork.org%2Fimages%2Farticle_uploads%2Fhappinessfinal.jpg&hash=4697745c625da2b3b79e52d3b7f5feb1)
Unsurprisingly, the disturbing picture that emerges from the graph is that a high Ecological Footprint is the typical cost of happiness. In this year’s ranking, Denmark was No. 1, followed by Switzerland, Iceland, Norway, Finland, Canada, the Netherlands, New Zealand, Australia and Sweden. Most have strong social safety nets and high Ecological Footprints.
http://www.footprintnetwork.org/en/index.php/blog/af/imagine_happiness_treading_lightly_on_the_earth (http://www.footprintnetwork.org/en/index.php/blog/af/imagine_happiness_treading_lightly_on_the_earth)

We are nothing but Shiny Happy People. What we are doing right now using Sweden as an example, can't get us to RCP4.5. But I would love to see some facts and figures that changes my opinion. I really do.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 01, 2016, 05:30:01 PM
The linked article emphasizes that the DeConto & Pollard (2016) is only a preliminary and partial scenario for likely future SLR, as for instance it does not consider the worst case dynamic SLR contribution from Greenland's ice sheet; which according to Eric Rignot might bring the total SLR by 2100 up to about 10-ft (3m).  Also, I note that such large changes in ice sheet mass also induce a "finger print" effect on relative SLR, which could make local RSLR still higher:

http://thinkprogress.org/climate/2016/03/31/3765266/coastal-cites-carbon-pollution/ (http://thinkprogress.org/climate/2016/03/31/3765266/coastal-cites-carbon-pollution/)

Extract: "To be clear, though, the five to six feet of sea level rise is not the worst-case scenario. For instance, it doesn’t include a more dynamic modeling of what will happen to Greenland’s ice sheet.
For a “worse-case scenario,” NASA scientist Eric Rignot directs us to the study he coauthored with James Hansen and others. That study posits 10 feet of sea level rise by 2100 is possible. But, again, it doesn’t provide a physical mechanism for how that much ice-melt could occur that fast, so some scientists tend to view it as unrealistic."

Edit: Also, for what it is worth, ice mass loss from the GIS & AIS can interact creating a positive feedback via the ocean (there is a thread in the Antarctic folder on this topic).
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on April 01, 2016, 07:36:58 PM
Let us remember what RCP 4.5 actually means.

RCP 4.5 is the emissions pathway that, if the IPCC estimates of GHG atmospheric contribution to radiative forcing are correct, will produce 4.5 watts per meter squared of radiative forcing by 2100.

Currently the IPCC holds that, in 2011, the global GHG radiative forcing was 2.83 watts per meter squared. 

It is very likely that we are above 3.0 now even by their calculations - with about 1.5 watts per meter squared currently being offset by anthropogenic aerosols (with some studies showing values as high as 2.37 watts per meter squared).  This means that we are likely already at a net 4.5 watts per meter squared.

Since they did not include permafrost decomposition in their calculation,

since they did not project widescale destruction of tropical and boreal forests by fire in their estimation-leading to significantly increased emissions,

since they expect a future Atmospheric Fraction (AF) of residual emissions (emissions less any GHGs captured by the biosphere and removed from the atmosphere by natural sources) - even though many future AF models have as much variance in outcomes as the entirety of the emissions contained in the RCP 8.5 scenario,

since they DO include massive amounts of carbon capture and sequestration in their estimates of future emissions pathways,

Since we are still building coal power plants and (even more so) shifting to shale natural gas as a 'bridge fuel' even though it has a higher warming potential than Coal on a 50-year timeline,

since they do not include the albedo effects of an ice-free arctic september in 2025 - leading to much more rapid frozen soils emissions and (though not within the definition of radiative forcing) an additional 3.0 watts per meter squared of albedo effect (globally averaged) by 2050.

Then RCP 4.5 is technically impossible. 

even looking strictly at per unit anthropogenic emissions reductions, the reliance on a CCS miracle makes these equally technically impossible, whatever the actual anthropogenic impacts on the earths radiative budget (on a per unit scale) are.

--------------
2.37 watts per meter squared aerosol study (high end estimation) https://www.researchgate.net/profile/Hua_Zhang35/publication/291949505_The_updated_effective_radiative_forcing_of_major_anthropogenic_aerosols_and_their_effects_on_global_climate_at_present_and_in_the_future/links/56aeb89408ae28588c61e660.pdf (https://www.researchgate.net/profile/Hua_Zhang35/publication/291949505_The_updated_effective_radiative_forcing_of_major_anthropogenic_aerosols_and_their_effects_on_global_climate_at_present_and_in_the_future/links/56aeb89408ae28588c61e660.pdf)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 02, 2016, 12:54:30 AM
I agree with jai that without major application of NET (negative emissions technology) that achieving RCP 4.5 is impracticable.  Furthermore, the first & second attached images indicate that without future assumed ratcheting (which assume such large scale use of NET) the current CoP21 INDCs will result in about 3.7C increase using AR5 assumptions; which is close to the RCP 6.0 response.

While I sincerely hope that CoP21 works, I think that it is important to consider the case that RCP 8.5 (8.5 watts/sq m of radiative forcing by 2100) might actually be the pathway we follow no matter what our good intensions are (I note that INDCs are voluntary; that the GOP has promised to cancel US contributions to CoP21 if they get the White House; that current international trade agreements ban the use of subsidies for renewable energy technology; that tracking GHG emissions is difficult & people cheat; and that the future assumed ratcheting may never be agreed to).  Therefore, I offer the following reasons (in addition to jai's) that we might reach 8.5 watts per sq m of radiative forcing by 2100:

1. The third image shows that the largest reason for continued BAU emissions is growth of per capita worldwide.  Thus even if we build more renewables it will likely me that we just consume more, rather than that we will cut GHG emissions.
2. By 2100 we might have 12 Billion people on Earth and food production to feed these people is already driving current methane and nitrous oxide emissions to record high levels.
3. ECS may already be 4.3C (as indicated by recent paleo-evidence).
4. Accelerating net positive feedback mechanisms could make the effective ECS as high as 5C by 2100.
5. The Hansen et al 2016 identified ice-climate positive feedback could temporarily raise the effective ECS well above 6C by 2100.
6. As discussed in the "Conservative Scientists and its Consequences" thread many of the authors of the RCP pathways now acknowledge that they are 10 to 15% too low.
7. The ocean heat content is currently abnormally high due to 20 years of negative PDO.
8. If the WAIS collapses a lot of methane hydrates would be destabilized.
9. The Southern Ocean is current absorbing high levels of CO2 but with continued warming and ocean acidification it could both vent CO2, and experience a plankton die-off that would both further reduce CO2 absorption & would reduce DMS emissions that currently cause negative aerosol forcing.
10. Currently, high CO2 concentrations are driving a bloom of plant growth, but with more warming this trend could reverse (due to plants sensitivity to heat & slow ability to adapt).
11. The tropical rainforests around the world are all near tipping points.
12. The RCP scenarios use a GWP for methane that is too low.
13. Wildfires & pests could destroy large areas of boreal forests and their associated BVOCs & SOAs.
14. TCR is dependent on GHG emission rates and if the combination of anthropogenic and natural (say due to increase soil microbe activity) emission rates increase the TCR will increase (as we are currently at a low point for TCR.

While none of these points prove that we will continue to follow a RCP 8.5 pathway (which we are currently following), they do indicate that we may need to be lucky to avoid following this pathway.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: oren on April 02, 2016, 09:16:50 AM
ASLR and all the resident experts - I assume that the IPCC not  only created charts for the future emissions pathways, but also has somewhere a chart of the expected concentrations of each GHG that should result from each emissions scenario.
As quantifying actual emissions is difficult and approximate, but measuring actual concentrations in the atmosphere is relatively straightforward, I would like to see what the IPCC expected for these concentrations and compare it to reality. This should uncover not just discrepancies between their assumed emission pathways and actual emissions, as ASLR showed a few posts ago, but should also uncover discrepancies between their estimate of other emission sources and sinks, and actual reality.
So can anyone post such a chart, assuming it exists?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: S.Pansa on April 02, 2016, 09:37:15 AM
Hi Oren,

perhaps the RC-Database (http://tntcat.iiasa.ac.at:8787/RcpDb/dsd?Action=htmlpage&page=compare) is what you are looking for?
You can select regions, scenarios and in point (3) also GHG emissions and concentrations. The projected concentrations can be found under "Climate indicators".
For 2020 for instance the projected CO2 numbers are:
RCP 2.6 - 412
RCP 4.5 - 411
RCP 6.0 - 409
RCP 8.5 - 416

More interesting perhaps the CO2-eq projections for 2020:

RCP 2.6 - 471
RCP 4.5 - 472
RCP 6.0 - 469
RCP 8.5 - 483

The actual CO2-eq concentration for 2014 was 481 (http://www.esrl.noaa.gov/gmd/aggi/aggi.html)


Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on April 02, 2016, 01:42:14 PM
CO2e link see the table at the end
http://www.esrl.noaa.gov/gmd/aggi/aggi.html (http://www.esrl.noaa.gov/gmd/aggi/aggi.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on April 02, 2016, 02:06:49 PM
ASLR

Quote
Hansen et al 2016 identified ice-climate positive feedback could temporarily raise the effective ECS well above 6C by 2100

Was he the lead on this? I can't find the paper.  link?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on April 02, 2016, 02:10:14 PM
Hansen et al 2016:
http://www.atmos-chem-phys.net/16/3761/2016/acp-16-3761-2016.html (http://www.atmos-chem-phys.net/16/3761/2016/acp-16-3761-2016.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 02, 2016, 04:01:58 PM
Hi Oren,

perhaps the RC-Database (http://tntcat.iiasa.ac.at:8787/RcpDb/dsd?Action=htmlpage&page=compare) is what you are looking for?

Alternately (with a different interface), you can find the same RCP data at the following Potsdam link:

http://www.pik-potsdam.de/~mmalte/rcps/ (http://www.pik-potsdam.de/~mmalte/rcps/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 02, 2016, 04:08:16 PM
ASLR

Quote
Hansen et al 2016 identified ice-climate positive feedback could temporarily raise the effective ECS well above 6C by 2100

Was he the lead on this? I can't find the paper.  link?

While Lennart provided the correct link to Hansen et al (2016); Hansen has discussed this concept for several years now as indicate by the attached image (Fig 7 of Hansen & Sato 2012) & the following references:

Figure 7 from Hansen & Sato (2012) is based on empirical interpretation of paleo-evidence discussed in Hansen et al (2011), see both references below.

Hansen, J.E., and M. Sato, 2012: Paleoclimate implications for human-made climate change. In Climate Change: Inferences from Paleoclimate and Regional Aspects. A. Berger, F. Mesinger, and D. Šijački, Eds. Springer, pp. 21-48, doi:10.1007/978-3-7091-0973-1_2.

Hansen, J., M. Sato, P. Kharecha, and K. von Schuckmann, 2011: Earth's energy imbalance and implications. Atmos. Chem. Phys., 11, 13421-13449, doi:10.5194/acp-11-13421-2011.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 02, 2016, 05:07:10 PM
The linked article by Kolbert confirms that we only need to stay on a CO₂-e BAU pathway for a few more decades and the WAIS might contribute about 1m to SLR by 2100:

http://www.newyorker.com/news/daily-comment/climate-catastrophe-coming-even-sooner (http://www.newyorker.com/news/daily-comment/climate-catastrophe-coming-even-sooner)

Extract: "When DeConto and Pollard revised their model to account for this possibility, the results, as the Times put it, were “striking.” The revised model could account for earlier sea-level rises. More significantly, it suggested that what had happened then could easily happen again. The researchers concluded that just a few more decades of “unabated” carbon emissions could result in more than three feet of sea-level rise from WAIS by the end of this century. (The over-all rise would be much greater, as ice would also be lost from Greenland and from mountain glaciers.) Over the longer term, melt from Antarctica could raise sea levels by fifty feet."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 02, 2016, 06:37:57 PM
ASLR and all the resident experts - I assume that the IPCC not  only created charts for the future emissions pathways, but also has somewhere a chart of the expected concentrations of each GHG that should result from each emissions scenario.
As quantifying actual emissions is difficult and approximate, but measuring actual concentrations in the atmosphere is relatively straightforward, I would like to see what the IPCC expected for these concentrations and compare it to reality. This should uncover not just discrepancies between their assumed emission pathways and actual emissions, as ASLR showed a few posts ago, but should also uncover discrepancies between their estimate of other emission sources and sinks, and actual reality.
So can anyone post such a chart, assuming it exists?

While both S.Pansa and I have provided links to RCP databases, the linked article confirms what I have already said, that the RCP pathways underestimate radiative forcing scenarios (& and should be revised for AR6):

The linked, open access, reference indicates that if the AR5 global mean surface temperature, GMST, projections had not adopted procedures (w.r.t. carbon cycles) that err on the side of least drama, they would have projected higher values of GMST, with wider ranges of uncertainty, as illustrated by the attached plot with the caption cited below:

Bodman, R. W., Rayner, P. J. and Jones, R. N. (2016), "How do carbon cycle uncertainties affect IPCC temperature projections?",  Atmosph. Sci. Lett., doi: 10.1002/asl.648

http://onlinelibrary.wiley.com/doi/10.1002/asl.648/abstract (http://onlinelibrary.wiley.com/doi/10.1002/asl.648/abstract)

Abstract: "Carbon cycle uncertainties associated with the Intergovernmental Panel on Climate Change temperature-change projections were treated differently between the Fourth and Fifth Assessment Reports as the latter focused on concentration- rather than emission-driven experiments. Carbon cycle feedbacks then relate to the emissions consistent with a particular concentration. A valuable alternative is to include all uncertainties in a single step from emissions to temperatures. We use a simple climate model with an observationally constrained parameter distribution to explore the carbon cycle and temperature-change projections, simulating the emission-driven Representative Concentration Pathways. The resulting range of uncertainty is a somewhat wider and asymmetric likely range (biased high)."

Caption: "Plume plots for ΔGMT change projections 2000–2100, ∘C relative to 1986–2005. MAGICC results with carbon cycle temperature feedbacks on (CC-on) and switched off (CC-off) (a) RCP2.6, (b) RCP4.5, (c) RCP6.0 and (d) RCP8.5. Shaded regions indicate the 67% confidence interval for CC-on (green) and CC-off (blue), with median results as solid green and dashed blue lines, respectively."

Edit: See also:

Joeri Rogelj, Michiel Schaeffer, Pierre Friedlingstein, Nathan P. Gillett, Detlef P. van Vuuren, Keywan Riahi, Myles Allen & Reto Knutti (2016), "Differences between carbon budget estimates unraveled", Nature Climate Change, Volume: 6, Pages: 245–252, DOI: 10.1038/NCLIMATE2868

http://www.nature.com/nclimate/journal/v6/n3/full/nclimate2868.html (http://www.nature.com/nclimate/journal/v6/n3/full/nclimate2868.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on April 02, 2016, 08:19:21 PM
Math error alert

It is very likely that we are above 3.0 now even by their calculations - with about 1.5 watts per meter squared currently being offset by anthropogenic aerosols (with some studies showing values as high as 2.37 watts per meter squared).  This means that we are likely already at a net 4.5 watts per meter squared.

Correction to the above,

As measured from pre-industrial abundances of GHGs in the earths atmosphere the radiative forcing value of energy re-radiated down to planet earth is indeed about 3 watts per meter squared by the IPCC adopted methodology.  The aerosol value subtracts from this value and is not added to provide a total radiative forcing value of 4.5 Watts per meter squared.  The GHG forcing value would still be only 3 watts per meter squared.

However, since the earth has warmed since pre-industrial times the amount of blackbody radiation emitted has also increased and this would together (with aerosols, changes in albedo and GHG radiative forcing-including lapse rate) produce the net top of atmosphere radiation imbalance (TOA).  This value is empirically determined by the study of gains in Ocean Heat Content using the ARGO buoy network and has shown to be somewhere greater than 1 watt per meter squared  (first quarter global ocean heat content increases in 2016 are pending release from NODC)  over the last 2 years, (~1.2 Watts per meter squared).

So, this tells me that the 3 Watts per meter squared for GHG is underestimated and, if the 2.73 watts per meter squared of aerosol forcing is correct, then the GHG forcing amount is significantly underestimated by the IPCC.

-------------------

in looking for ASLRs james hansen paper I came across this one:
https://www.researchgate.net/profile/Karina_Schuckmann/publication/292188056_An_imperative_to_monitor_Earth's_energy_imbalance/links/56b8724a08ae44bb330d223b.pdf (https://www.researchgate.net/profile/Karina_Schuckmann/publication/292188056_An_imperative_to_monitor_Earth's_energy_imbalance/links/56b8724a08ae44bb330d223b.pdf)

An imperative to monitor Earth’s energy imbalance
K. von Schuckmann1,2*, M.D. Palmer3 , K.E. Trenberth4, A. Cazenave5,6, D. Chambers7 , N. Champollion6, J. Hansen8, S.A. Josey9 , N. Loeb10, P.-P. Mathieu11, B. Meyssignac5 and M. Wild12

abstract:
The current Earth’s energy imbalance (EEI) is mostly caused by human activity, and is driving global warming. The absolute value of EEI represents the most fundamental metric defining the status of global climate change, and will be more useful than using global surface temperature. EEI can best be estimated from changes in ocean heat content, complemented by radiation measurements from space. Sustained observations from the Argo array of autonomous profiling floats and further development of the ocean observing system to sample the deep ocean, marginal seas and sea ice regions are crucial to refining future estimates of EEI. Combining multiple measurements in an optimal way holds considerable promise for estimating EEI and thus assessing the status of global climate change, improving climate syntheses and models, and testing the effectiveness of mitigation actions. Progress can be achieved with a concerted international effort.

the following graphic (from the paper) shows clear correlation to ARGO 0-2000 meter depth ocean heat content to TOA
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on April 03, 2016, 04:00:48 PM
An easy read explaining the Antarctic ice crisis, for those who don't like graphs and charts.  ;)

Climate Catastrophe, Coming Even Sooner?
http://www.newyorker.com/news/daily-comment/climate-catastrophe-coming-even-sooner (http://www.newyorker.com/news/daily-comment/climate-catastrophe-coming-even-sooner)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on April 03, 2016, 04:22:07 PM
But for those who like the maths...  ;)
Size of a photon versus the size of a CO2 molecule:

It's the Number Density Not the Mixing Ratio
http://rabett.blogspot.com/2016/04/its-number-density-not-mixing-ratio.html (http://rabett.blogspot.com/2016/04/its-number-density-not-mixing-ratio.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 04, 2016, 07:23:54 PM
But for those who like the maths...  ;)
Size of a photon versus the size of a CO2 molecule:

It's the Number Density Not the Mixing Ratio
http://rabett.blogspot.com/2016/04/its-number-density-not-mixing-ratio.html (http://rabett.blogspot.com/2016/04/its-number-density-not-mixing-ratio.html)

It does seem silly to me that the IPCC issues Likelihood Scales (first image) and even probability density functions for GMSL by 2100 for RCP 8.5 (see second & third images); when findings like DeConto & Pollard (2016) can dramatically change these probabilities (and the IPCC only addresses such abrupt possible changes with a footnote).
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 04, 2016, 08:10:05 PM
Here is a nice SLR overview by Rignot up to the DeConto & Pollard (2016) paper with ice cliffs and hydrofracturing:

Eric Rignot (AGU Dec 2015)
https://www.youtube.com/watch?v=3p9uRxX95f4 (https://www.youtube.com/watch?v=3p9uRxX95f4)

With a hat-tip to Lennart van der Linde, the following provides a nice overview of DeConto & Pollard's work including ice cliffs and hydrofracturing:

Robert DeConto (New Zealand, SCARS)
https://www.youtube.com/watch?v=jK_8Pfo6wRk (https://www.youtube.com/watch?v=jK_8Pfo6wRk)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 05, 2016, 06:11:36 PM
While it is pleasant to think that society will reduce its radiative forcing footprint sufficiently to avoid abrupt sea level rise this century, if DeConto & Pollard (2016) are close to being right (and we follow a BAU pathway for several more decades) then we should start to think now what that means.  Two less obvious impacts are that:
(a) While it takes centuries to millennia to build beaches, they can be inundated and eroded (everywhere in the world at once) in decades, as indicated in the first image.  This also applies to river deltas and to barrier islands.
(b) Seawater intrusion into the groundwater can extend for many miles (kilometers) inland, and few locations can afford well points to control this intrusion as shown in the second image for Southern Florida.  This intrusion not only affect water from wells, but also corrodes buried utilities.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on April 06, 2016, 02:27:06 AM
Director Josh Fox, (Gasland, Gasland II) has a new documentary film “How to Let Go of the World and Love All the Things Climate Can’t Change,” which he is screening tonight here in Miami.

How to keep caring when it’s ‘staggeringly too late’ to stop climate change
Quote
What does this film set out to do?

When you’re dealing with climate change, I think there’s sort of a tennis match that happens, sort of ping-ponging back and forth between despair and denial. One minute you think there’s no way to solve this problem and the next minute you’re just suppressing and denying it. And that is the problem right now with why we’re not acting on climate. I think when you go through the despair and you go through all the emotions and difficulties of it, you can still come out the other side.

Rather than a stale, scientific presentation of this subject, this is an emotional roller coaster ride. It takes you through the fear and the horror and then comes out the other side and on the other side is all the things that we can do, all the things that are worth saving. Those are civic virtues, courage, innovation, creativity, human rights, democracy, civil disobedience. There are things within human beings that are so strong that no storm can take them away. That is what’s on the other side of delving into the climate problem.

I think we avoid the climate problem a lot unless it’s right in our face and you know this film sort of says, “This is another way to deal with this.”
https://thenewtropic.com/how-to-let-go-of-the-world/
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on April 06, 2016, 02:56:25 AM
New web portal shines beacon on rising seas
Quote
Sea level rise is a critical global issue affecting millions across our planet. A new Web portal developed by NASA’s Jet Propulsion Laboratory, Pasadena, California, gives researchers, decision makers and the public alike a resource to stay up to date with the latest developments and scientific findings in this rapidly advancing field of study.

The portal, “Sea Level Change: Observations from Space,” is online at:

https://sealevel.nasa.gov/

The portal’s key features include:

- “Understanding Sea Level,” a summary of decades of scientific research that has shaped our knowledge of sea level rise: its causes, including a warming, expanding ocean and melting ice on land; projections of future sea level rise; and ways in which humanity might adapt, largely drawn from NASA data.

- An interactive data analysis tool, launching in mid-2016, that will allow direct access to NASA datasets on sea level. Users will be able to manipulate these datasets to automatically generate charts, graphs and maps of sea surface height, temperature and other factors. The analysis tool will also allow users to make forecasts of future conditions, as well as “hindcasts” -- retroactive calculations of past trends and conditions.

- News highlights and feature stories with strong visual elements that explore the findings of sea level researchers in detail.

- An extensive library of published papers on sea level-related topics, hyperlinked to individual citations throughout “Understanding Sea Level.”

- A multimedia section with dynamic still and video imagery, and a glossary of sea level terms.

- A “frequently asked questions” section maintained by sea level scientists. Users can submit questions to scientists and data managers.

The website is optimized for most mobile devices, including smartphones and tablets.
http://climate.nasa.gov/news/2425/ (http://climate.nasa.gov/news/2425/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 13, 2016, 05:54:06 PM
Humans are already responsible for 2/3rds of SLR, and we have yet started experiencing rapid ice melt contributions:

http://www.climatecentral.org/news/pollution-key-driver-late-20th-century-sea-rise-20232 (http://www.climatecentral.org/news/pollution-key-driver-late-20th-century-sea-rise-20232)

Extract: "New computer modeling has shown that human influences were responsible for two-thirds of sea level rise from 1970 to 2005. By contrast, natural forces were responsible for about two-thirds of the rise in sea levels detected from 1900 to 1950."

See also:
http://news.nationalgeographic.com/2016/04/160412-ice-sheet-collapse-antarctica-sea-level-rise/ (http://news.nationalgeographic.com/2016/04/160412-ice-sheet-collapse-antarctica-sea-level-rise/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Greenbelt on April 13, 2016, 11:36:39 PM
http://www.insurancejournal.com/news/national/2016/04/12/405089.htm (http://www.insurancejournal.com/news/national/2016/04/12/405089.htm)

RIMS 2016: Sea Level Rise Will Be Worse and Come Sooner
By Don Jergler | April 12, 2016
Margaret Davidson, NOAA’s senior advisor for coastal inundation and resilience science and services, and Michael Angelina, executive director of the Academy of Risk Management and Insurance, offered their take on climate change data in a conference session titled “Environmental Intelligence: Quantifying the Risks of Climate Change.”

RIMS16_conference
Davidson said recent data that has been collected but has yet to be made official indicates sea levels could rise by roughly 3 meters by 2050-2060, far higher and quicker than current projections. Until now most projections have warned of seal level rise of up to 4 feet by 2100.

...

Davidson said recent data that has been collected but has yet to be made official indicates sea levels could rise by roughly 3 meters or 9 feet by 2050-2060, far higher and quicker than current projections. Until now most projections have warned of seal level rise of up to 4 feet by 2100.

These new findings will likely be released in the latest sets of reports on climate change due out in the next few years.

“The latest field data out of West Antarctic is kind of an OMG thing,” she said.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 15, 2016, 10:31:18 PM
http://www.insurancejournal.com/news/national/2016/04/12/405089.htm (http://www.insurancejournal.com/news/national/2016/04/12/405089.htm)

Davidson said recent data that has been collected but has yet to be made official indicates sea levels could rise by roughly 3 meters by 2050-2060, far higher and quicker than current projections. Until now most projections have warned of seal level rise of up to 4 feet by 2100.

The linked 2014 Climate Central article provides a rough idea of what impact a 3m SLR by 2050 would have on the lower 48 US States:

http://www.climatecentral.org/news/us-with-10-feet-of-sea-level-rise-17428 (http://www.climatecentral.org/news/us-with-10-feet-of-sea-level-rise-17428)

Extract: "More than half of the area of 40 large cities (population over 50,000) is less than 10 feet above the high tide line, from Virginia Beach and Miami (the largest affected), down to Hoboken, N.J. (smallest). Twenty-seven of the cities are in Florida, where one-third of all current housing sits below the critical line — including 85 percent in Miami-Dade and Broward counties. Each of these counties is more threatened than any whole state outside of Florida – and each sits on bedrock filled with holes, rendering defense by seawalls or levees almost impossible.
By the metric of most people living on land less than 10 ft above the high tide line, New York City is most threatened in the long run, with a low-lying population count of more than 700,000. Sixteen other cities, including New Orleans, La.; Norfolk, Va.; Stockton, Calif.; Boston, Mass.; St. Petersburg, Fla.; and Jacksonville, Fla.; are on the list of places with more than 100,000 people below the line. (Much of New Orleans is already below sea level, but is protected at today’s level by levees.)"

See also:
http://www.climatecentral.org/what-we-do/our-programs/sea-level-rise (http://www.climatecentral.org/what-we-do/our-programs/sea-level-rise)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on April 16, 2016, 01:55:34 AM
Below is a map of the geology of South Florida. Dade and Broward Counties, where most of residents live, sits over a large oolite formation. The other image is a sample of this rock.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on April 17, 2016, 12:17:03 AM
Here's the image of the Florida rock that shocked me. :o
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on April 17, 2016, 12:24:28 AM
Sinking Atlantic Coastline Meets Rapidly Rising Seas
Quote
Geological changes along the East Coast are causing land to sink along the seaboard. That’s exacerbating the flood-inducing effects of sea level rise, which has been occurring faster in the western Atlantic Ocean than elsewhere in recent years.

New research using GPS and prehistoric data has shown that nearly the entire coast is affected, from Massachusetts to Florida and parts of Maine.

Land subsidence and sea level rise are worsening flooding in Annapolis, Md., and elsewhere along the East Coast.

The study, published this month in Geophysical Research Letters, outlines a hot spot from Delaware and Maryland into northern North Carolina where the effects of groundwater pumping are compounding the sinking effects of natural processes. Problems associated with sea level rise in that hot spot have been — in some places — three times as severe as elsewhere.
http://www.climatecentral.org/news/sinking-atlantic-coastline-meets-rapidly-rising-seas-20247 (http://www.climatecentral.org/news/sinking-atlantic-coastline-meets-rapidly-rising-seas-20247)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 17, 2016, 09:01:20 AM
The linked article entitled " No Way to Slow Down: Silence Howling in Antarctica", was written by Dr Ricky Rood, a professor at Michigan U, and the notes come from the recent climate change course that he taught and focuses on the irreversible ice mass loss from the WAIS:
https://www.wunderground.com/blog/RickyRood/no-way-to-slow-down-silence-howling-in-antarctica (https://www.wunderground.com/blog/RickyRood/no-way-to-slow-down-silence-howling-in-antarctica)
Extract: "

* It will be difficult to avoid a world that is four degrees warmer.
* We have, in fact, underestimated the impacts of warming.
* We have some control over how fast and how far the warming will go.
* We are committed to irreversible changes, for example, sea-level rise.
* We can “cope” with this. We must. There is opportunity.

I felt that one of the most defining new science-based results was the evidence of loss of some of the West Antarctic Glaciers."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on April 20, 2016, 12:50:39 AM
Miami-Dade flooding to increase as engineers start identifying miles of risky U.S. coast
Quote
> New study projects up to eight times as much flooding in county by 2045

> Based on most recent U.S. Army Corps of Engineers projections

> Corps to assess risks on 10,000 miles of vulnerable shoreline

With sea rise projections growing ever grimmer — the latest predicts up to eight times as much flooding around Miami-Dade County by 2045 — the U.S. Army Corps of Engineers has launched an ambitious plan to come up with a comprehensive assessment of risks that could easily run into the billions of dollars.

Covering 10,000 miles of vulnerable shoreline from North Carolina to Mississippi, the study for the first time tries to unify what has so far been a patchwork of sea rise assessments.
...
In the most recent study of South Florida sea rise, researchers with the Union of Concerned Scientists used the Corps’ revised 2015 calculations for sea rise and found that far more swaths of Miami-Dade County will flood than under a projection they developed only a year earlier with more conservative estimates. The group focused on five cities — Miami, Miami Beach, Key Biscayne, Hialeah and Coral Gables — and found the number of projected floods rose from 45 a year to 80 with a 10-inch rise in sea levels by 2030.
http://www.miamiherald.com/news/local/environment/article72070677.html (http://www.miamiherald.com/news/local/environment/article72070677.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on April 20, 2016, 07:56:00 AM
Why, clearly, we have identified the source of the problems.

Studies cause problems. In the last thirty years, every time scientists and engineers have looked at the situation, they have found future problems. We would be much happier if they had not, after all, what have the coming generations done for us ?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 20, 2016, 05:13:47 PM
Why, clearly, we have identified the source of the problems.

Studies cause problems. In the last thirty years, every time scientists and engineers have looked at the situation, they have found future problems. We would be much happier if they had not, after all, what have the coming generations done for us ?

And now just so that everyone will have enough to eat, the "studies" want us all to become vegan.  Forget future generations, why should meat eaters make an effort just so that those already living can stay alive?

http://www.carbonbrief.org/feeding-the-world-can-we-preserve-forests-go-organic-and-eat-meat (http://www.carbonbrief.org/feeding-the-world-can-we-preserve-forests-go-organic-and-eat-meat)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: opensheart on April 25, 2016, 10:58:17 PM
I'm afraid someday many of the powers that be will follow that logic.   
Stop measuring or keeping track of climate change.
Destroy all records.   Slience those who know too much.

What ever the future climate becomes
 that is the way it always was...

Someday the surviving humans will have to do an archaeological dig to discover the climate was once very different.   And they will have to  come up with their own explanations.   
"Those ancient people must have done something really bad for the gods to have curse them so."   A second fall from the garden of Eden perhaps?

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: DoomInTheUK on April 26, 2016, 10:56:40 AM
opensheart - I would agree with that with one caveat. When the moving baseline issue moves too fast, it can't be hidden. We're already in a state of change whereby people are noticing that things aren't like they used to be. As we get further down this path the rate of change will increase.
Soon it will be impossible to hide it as major changes will be on a decadal timescale, and I have socks older than that!
Once you start getting over half a meter of sea level rise per year, it's a bit tricky to pass it off as normal.

I suppose you can wait until everyone is dead that remembers when the world wasn't in a constant state of flux, and so now change is the new normal. But society doesn't do well with change like that, so I don't think there will be that many people left to govern.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 05, 2016, 05:42:00 PM
Per the attached AVISO plot & the following AVISO data (with sea level change on the plot in centimeters and the data in meters) through February 12 2016, after a brief dip, sea level increased to an all time high:

2016.006339 8.136694e-02
2016.033487 8.215760e-02
2016.060634 8.362668e-02
2016.087782 8.522942e-02
2016.114929 8.662768e-02
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 05, 2016, 06:44:14 PM
They say 3.37 mm/yr from 1993-2015.
Do they also give the averages over 1993-2004 and 2004-2015? Or even over intervals of 5-6 yrs?
It would be good to know if and how much acceleration can be observed on such short timescales.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: S.Pansa on May 05, 2016, 06:58:01 PM
The trend for the Jason-2 time period from ~2009 - today is +4.4mm/yr it seems. You can get it from here (http://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level/products-images.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 05, 2016, 07:31:03 PM
The following image also comes from the link provided by S.Pansa; indicating to me that satellite performance can degrade with the age of the satellite, making me lean towards the Jason-2 measurements:
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: RaenorShine on May 10, 2016, 10:57:33 AM
And so it begins....

http://www.theguardian.com/environment/2016/may/10/five-pacific-islands-lost-rising-seas-climate-change (http://www.theguardian.com/environment/2016/may/10/five-pacific-islands-lost-rising-seas-climate-change)

Quote
Five Pacific islands lost to rising seas as climate change hits

Six more islands have large swaths of land, and villages, washed into sea as coastline of Solomon Islands eroded and overwhelmed

Five tiny Pacific islands have disappeared due to rising seas and erosion, a discovery thought to be the first scientific confirmation of the impact of climate change on coastlines in the Pacific, according to Australian researchers.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 12, 2016, 08:42:22 PM
The attached U of Colorado SLR plot (edited on May 6 2016) shows that the sea level has fluctuated back up to close to its El Nino peak:
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on May 13, 2016, 05:43:10 AM
http://e360.yale.edu/feature/abrupt_sea_level_rise_realistic_greenland_antarctica/2990/ (http://e360.yale.edu/feature/abrupt_sea_level_rise_realistic_greenland_antarctica/2990/)

has a quote from DeConto

"We’re talking about centimeters per year. That’s really tough. At that point your engineering can’t keep up; you’re down to demolition and rebuilding"

He forgot to insert "cleanup" in there between demolition and rebuilding. This will be a huge effort, civil engineering and hydrology are the careers for the next century. It is a losing battle, but rich cities like NY will spend billions on it.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 15, 2016, 11:13:16 AM
The linked article (& associated map) addresses the changes in sea level (in meters) from March 3 to April 2 2016 as measured by Sentinel-3a (red is positive & blue is negative).

http://www.bbc.com/news/science-environment-36255957 (http://www.bbc.com/news/science-environment-36255957)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: RaenorShine on May 16, 2016, 11:25:22 AM
http://www.bbc.co.uk/news/world-36299541 (http://www.bbc.co.uk/news/world-36299541)

Quote
Billion people face global flooding risk by 2060, charity warns

A British aid charity is warning that by 2060 more than a billion people worldwide will live in cities at risk of catastrophic flooding as a result of climate change.

A study by Christian Aid says the US, China and India are among the countries most threatened.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: DoomInTheUK on May 16, 2016, 05:21:25 PM
The attached U of Colorado SLR plot (edited on May 6 2016) shows that the sea level has fluctuated back up to close to its El Nino peak:

I know it borders on cherry-picking, but that graph certainly looks like it has a worrying kink around 2011. I'll give it a few more years before I get excited, but it's certainly another thing on my list of 'things to keep an eye on'.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 16, 2016, 06:37:55 PM
The attached U of Colorado SLR plot (edited on May 6 2016) shows that the sea level has fluctuated back up to close to its El Nino peak:

I know it borders on cherry-picking, but that graph certainly looks like it has a worrying kink around 2011. I'll give it a few more years before I get excited, but it's certainly another thing on my list of 'things to keep an eye on'.

As noted in Reply #571 since 2009 the Jason-2 observations show a trend for SLR with a slope of +4.4 mm/yr; which does looks like a bifurcation to me.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: crandles on May 17, 2016, 12:10:57 AM
2010/11 had quite strong La Nina and recent very stong El Nino could make it important to adjust for ENSO if you are going to use a short trend like from 2010 onward. 2009/10 did have an El Nino making 2009 a good bit better but still looks to be some scope for ENSO to be distorting short trend values.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on May 17, 2016, 12:25:35 PM
All the values you are writing which are in the range of mm are average year averaged on ten years is it ?
Because as AbruptSLR posted the average year is more of the centimetre kind.
ftp://ftp.aviso.oceanobs.com/pub/oceano/AVISO/indicators/msl/MSL_Serie_MERGED_Global_IB_RWT_GIA_Adjust.txt
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: DoomInTheUK on May 17, 2016, 12:51:50 PM
@Laurent - there's too much noise to take any period much less than 10 years. Yes, that does mean that if the rate is increasing (and it almost certainly is) then the trend rate will be low.

I think we can be pretty confident that in another 10 years the trend will be above 4.4, but the trend really does need to be that long to help remove the noise.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on May 17, 2016, 01:15:27 PM
I do not say it is wrong just that we tend to say it is the average for this or this year, but it is not, it is the average year averaged on ten year which should be mentioned because a layman would think it is the average year which is not ! That is important to be precise for public communication but more importantly if we want to have an idea where we are heading that does not fit a fair estimation. I agree with you we need that ten year averaged but something is missing, we should find something, I don't know what... ?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: DoomInTheUK on May 17, 2016, 02:07:08 PM
I think the confusion comes with the term "Trend".

I've just had several goes at:

a) defining where the issue lies.
b) wondering what I'm talking about.

Maybe we could settle on the use of yearly-average and trend-average to help distinguish between the two.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on May 17, 2016, 03:10:04 PM
yearly average sounds good for the name !
But not enough, as you say it the yearly average is what we use but just it doesn't define the trend when there is so much difference between the yearly average and the year average. That difference is not only the noise as you said it. There is a trend that we do not catch here, and it is what the people want to know, they are trusting on specialists, so should we go on as it is... I don't think so. May be it is too complex to describe so that should be said regularly (to the public).
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: DoomInTheUK on May 17, 2016, 03:57:18 PM
The trouble with a yearly rate is that it can change quite a lot. If we said that 2017 had an increase of only 2 mm, the public might think it's all OK. 2018 might then 'rebound' with 6 mm and everyone expects us to be under water in the next 5 years.

The problem is that we're trying to smooth (trend) a bumpy curve (yearly values). The end of the curve (i.e. current yearly rate) will almost always be higher than the smoothed value.

There again, almost no-one seems to care anyway. I've even been told, you can't be that accurate as waves are bigger than 4 mm so it doesn't matter.

Life would be so much easier without the general public.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on May 17, 2016, 05:56:57 PM
Yes, the public wish for a stable economy (that is totally normal) and the blindness that follow must be slightly (to say the least) be shaken. I think the problem is that we use the past to say the trend but the tools that we are using to determine the trend are obsolete, they do not fit. That is the problem, no scientist alone, should take the burden of putting forward something closer to the reality, but any scientist can push for something different, the linear thinking is over. A consensus should emerge fast !
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on May 17, 2016, 07:10:34 PM
Coastal Flooding Will Hit World’s Biggest Polluters Hardest
http://www.huffingtonpost.com/entry/biggest-polluters-climate-change-flooding_us_573a007ee4b08f96c183b311?ir=Green&section=us_green&utm_hp_ref=green (http://www.huffingtonpost.com/entry/biggest-polluters-climate-change-flooding_us_573a007ee4b08f96c183b311?ir=Green&section=us_green&utm_hp_ref=green)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on May 18, 2016, 12:54:17 AM
is it just me, or have fluctuations around the mean trend increased in sea level rise ? Some of those represnt huge transfers of water from sea to and from land thru precip events. I keep thinking of phase transitions, critical slowdowns, and increased correlation length/duration but i cant quite put my finger on it.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 18, 2016, 01:05:49 AM
is it just me, or have fluctuations around the mean trend increased in sea level rise ? Some of those represnt huge transfers of water from sea to and from land thru precip events. I keep thinking of phase transitions, critical slowdowns, and increased correlation length/duration but i cant quite put my finger on it.

I think that the fluctuations are probably getting greater, both because El Ninos and La Nina events are becoming more extreme and because global warming is bifurcating away from a linear trend line.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: DoomInTheUK on May 18, 2016, 11:19:51 AM
Also don't forget that Sea Level Rise is as chaotic as global warming. Just as we see the Arcrtic warm much faster than the rest of the world, then sea level rise will affect some places a lot quicker/harder than others.

Very few places will experience the 'average' rise for either temperature or sea level rise.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on May 19, 2016, 08:02:20 PM
Australia to Lay Off Leading Scientist on Sea Levels
http://www.nytimes.com/2016/05/18/world/australia/australia-to-lay-off-leading-scientist-on-sea-levels.html?partner=rss&emc=rss&_r=0 (http://www.nytimes.com/2016/05/18/world/australia/australia-to-lay-off-leading-scientist-on-sea-levels.html?partner=rss&emc=rss&_r=0)

Quote
SYDNEY — A pre-eminent scientist in the field of rising global sea levels has been given notice of his dismissal as part of deep cuts at Australia’s national science agency that will reduce the country’s role in global climate research.

The scientist, John Church, confirmed Tuesday that he was one of 275 scientists whom the agency, the Commonwealth Scientific and Industrial Research Organization, or Csiro, said would be laid off.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on May 30, 2016, 09:55:06 PM
An ancient city, now hidden beneath the waves off the coast of Tanzania.

The Atlantis of Africa May Be Hiding Near a New Private Island Retreat
https://www.bloomberg.com/news/articles/2016-05-26/the-lost-city-of-rhapta-may-have-been-discovered-near-thanda-island (https://www.bloomberg.com/news/articles/2016-05-26/the-lost-city-of-rhapta-may-have-been-discovered-near-thanda-island)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Dundee on May 30, 2016, 10:42:02 PM
If you are in the mood for irony, look carefully at the coral in the "underwater look at the north wall" in the Bloomberg article referred by Sigmetnow.

Look like anything published recently re: the Great Barrier Reef?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on June 06, 2016, 10:06:57 PM
A Tax On Rising Sea Levels Is Making Waves In The San Francisco Bay
The regional tax would help all the communities around the Bay lower their risk of flooding by restoring wetlands. Can everyone work together to make it happen?
Quote
Developers and corporations do have a clear interest in these plans. A report by the San Francisco Public Press found at least $21 billion in housing and commercial developments, including tech campuses, the new stadium for the Golden State Warriors, and San Francisco’s ferry terminal will be vulnerable to flooding over the next century, as sea-level rise pushes flood waters from storms up to eight feet above today’s high-tide line.
http://www.fastcoexist.com/3060581/a-tax-on-rising-sea-levels-is-making-waves-in-the-san-francisco-bay (http://www.fastcoexist.com/3060581/a-tax-on-rising-sea-levels-is-making-waves-in-the-san-francisco-bay)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on June 10, 2016, 01:02:07 AM
Bay Area Voters Agreed To First-Of-Its Kind Climate Adaptation Tax
Quote
The Bay Area has long been a bastion of environmental action, but this week locals outdid themselves when they approved an unprecedented, first-of-its kind tax to remove pollution from their bay and create habitats to fight sea level rise.

With more than 65 percent approval, Measure AA is the first region-wide local tax San Francisco Bay voters have passed, the Associated Press reported Wednesday. Aside from pollution removal projects, the tax will fund nature-based flood protections through wetlands, and habitat restoration along the Bay’s edge and creeks. In doing so, it will nearly double the 40,000 acres of tidal marsh that remain there. The San Francisco Bay area had 200,000 acres of wetlands before the gold rush kicked off development.
http://thinkprogress.org/climate/2016/06/09/3786580/bay-area-sea-level-rise-tax-approved/ (http://thinkprogress.org/climate/2016/06/09/3786580/bay-area-sea-level-rise-tax-approved/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 11, 2016, 07:27:26 PM
The linked article discusses how recent massive storms are washing city pollution into the oceans.  Can you image the impact on the oceans when we combine abrupt SLR together with more frequent/intense future storms.  Every coastal city and port in the world might pump massive amounts of debris and pollution directly into the ocean within a few short decades.  If/when such a thing happens we will learn to our communal regret just how dependent on the oceans were are for life support:

https://theconversation.com/massive-storms-are-pumping-pollution-into-our-oceans-time-to-clean-up-our-cities-60551

Extract: "Stormwater is a mixture of rain and any dissolved or solid pollutants carried along with it. The excess water flowing along streets and gutters picks up litter, oil and grease, and metals. Run-off from parks and gardens introduces fertilisers, pathogens, pesticides and soil.

In Sydney Harbour it has been estimated that more than two-thirds of the pollutants entering the waterway do so via stormwater drains, creating hotspots of pollution with concentrations 20 times higher than natural levels. More than 80% of the city’s catchment is covered by concrete, increasing the volumes of stormwater run-off.

When stormwater reaches a waterway it represents a significant ecological risk. Together with international colleagues, we have been investigating the impact of stormwater pollution on ecological communities large and small, including changes to the number of species, nutrient cycling, and the release of toxic compounds such as ammonia, nitrous oxide and hydrogen sulphide."

Edit: Just think how much city debris the Fukushima tsunami pulled into the Pacific Ocean from just one event.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on June 11, 2016, 08:30:52 PM
The linked article discusses how recent massive storms are washing city pollution into the oceans.  ...

Also, severe storms can cause raw or partially-treated sewage to be discharged into the ocean from overloaded sanitary sewer systems.  From the 2016 Atlantic Hurricane thread:


St. Petersburg Pumping Sewage into Bay as Tropical Storm Colin Flooding Continues
Flooding from Tropical Storm Colin is quite literally making a mess of the Tampa Bay area.
Quote
St. Petersburg officials told the Associated Press that the city will be pumping partially treated sewage into the bay after rainwater infiltrated leaky sewer pipes and overloaded the system. According to the National Weather Service, much of the Tampa Bay area still had standing water as of Wednesday morning.

St. Petersburg Public Works Administrator Claude Tankersley said the sewage will be pumped by pipe about a quarter of a mile into the bay, and the Florida Department of Environmental Protection has been notified of the discharge.
...
Lowe said residents and businesses should not takes showers or baths, do laundry, wash dishes or engage in "any other use of water that enters the sanitary sewer system."

https://weather.com/safety/hurricane/news/tropical-storm-colin-flooding-impacts-news
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on June 18, 2016, 02:52:39 AM
In 100 Years, $77 Billion Worth Of San Francisco Property Could Be Underwater
Rethinking a city for new coastlines that don't exist yet
http://www.fastcoexist.com/3060770/in-100-years-77-billion-of-san-francisco-property-could-be-underwater (http://www.fastcoexist.com/3060770/in-100-years-77-billion-of-san-francisco-property-could-be-underwater)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 19, 2016, 04:12:09 PM
The linked reference provides evidence that indeed the rate of GMSL rise has been accelerating recently.  Not only does this mean that sea level will be higher in the future, but also that Hansen's ice-climate feedback is beginning:

P. J. Watson (16 June 2016), "A new perspective on global mean sea-level (GMSL) acceleration", Geophysical Research Letters, DOI: 10.1002/2016GL069653


http://onlinelibrary.wiley.com/doi/10.1002/2016GL069653/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2016GL069653/abstract)

Abstract: "The vast body of contemporary climate change science is largely underpinned by the premise of a measured acceleration from anthropogenic forcings evident in key climate change proxies – greenhouse gas emissions, temperature and mean sea-level. By virtue, over recent years, the issue of whether or not there is a measurable acceleration in global mean sea-level has resulted in fierce, widespread professional, social and political debate. Attempts to measure acceleration in global mean sea-level (GMSL) have often used comparatively crude analysis techniques providing little temporal instruction on these key questions. This work proposes improved techniques to measure real-time velocity and acceleration based on five GMSL reconstructions spanning the time frame from 1807-2014 with substantially improved temporal resolution. Whilst this analysis highlights key differences between the respective reconstructions, there is now more robust, convincing evidence of recent acceleration in the trend of GMSL."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on June 25, 2016, 06:19:05 PM
Climate Change Could Put Major Boston Landmarks Under Water
City’s temps could climb past 90 degrees 1 in 4 days a year
http://boston.curbed.com/2016/6/23/12011916/climate-change-boston-landmarks (http://boston.curbed.com/2016/6/23/12011916/climate-change-boston-landmarks)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 28, 2016, 05:15:04 PM
The linked article discusses how bad SLR could get:

https://www.washingtonpost.com/news/capital-weather-gang/wp/2016/05/20/10-things-you-should-know-about-sea-level-rise-and-how-bad-it-could-be/ (https://www.washingtonpost.com/news/capital-weather-gang/wp/2016/05/20/10-things-you-should-know-about-sea-level-rise-and-how-bad-it-could-be/)

Extract: "Sea level rise has been in the news a lot lately. Recent research has raised concerns about the possible collapse of the West Antarctic Ice Sheet and how this could double sea level rise projections for 2100.
Sea level rise is potentially one of the most damaging results of climate change, but few people understand its risks. Its impacts — financial and otherwise — will spread far from the coasts.
Here are 10 things you should know about sea level rise, what causes it and how bad it might get."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 12, 2016, 11:40:42 PM
Here is a high-resolution study on ice mass loss from the GIS:


Malcolm McMillan et al (9 July 2016), "A high-resolution record of Greenland mass balance", Geophysical Research Letters, DOI: 10.1002/2016GL069666

http://onlinelibrary.wiley.com/doi/10.1002/2016GL069666/abstract?campaign=agupersonalchoice (http://onlinelibrary.wiley.com/doi/10.1002/2016GL069666/abstract?campaign=agupersonalchoice)

Abstract: "We map recent Greenland Ice Sheet elevation change at high spatial (5 km) and temporal (monthly) resolution using CryoSat-2 altimetry. After correcting for the impact of changing snowpack properties associated with unprecedented surface melting in 2012, we find good agreement (3 cm/yr bias) with airborne measurements. With the aid of regional climate and firn modeling, we compute high spatial and temporal resolution records of Greenland mass evolution, which correlate (R = 0.96) with monthly satellite gravimetry and reveal glacier dynamic imbalance. During 2011–2014, Greenland mass loss averaged 269 ± 51 Gt/yr. Atmospherically driven losses were widespread, with surface melt variability driving large fluctuations in the annual mass deficit. Terminus regions of five dynamically thinning glaciers, which constitute less than 1% of Greenland's area, contributed more than 12% of the net ice loss. This high-resolution record demonstrates that mass deficits extending over small spatial and temporal scales have made a relatively large contribution to recent ice sheet imbalance."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 15, 2016, 05:08:12 PM
The linked article notes that currently some of the world's largest cities are sinking faster than the oceans are currently rising.  Some people will take this to mean that they can continue to discount the importance of anthropogenic eustatic SLR; others will realize that this means that such cities (like New Orleans) will be in trouble sooner than the average coastal cities, and will draw-down limited national resource will fighting a losing battle. This may likely leave cities with a fighting chance (like New York) without sufficient national support to adequately defend themselves:

https://eos.org/features/global-risks-and-research-priorities-for-coastal-subsidence

Extract: "Some of the world's largest cities are sinking faster than the oceans are rising. Humans are part of the problem …"
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 22, 2016, 11:46:09 AM
The linked article discusses the second phase of the Mass Balance Inter-comparison Exercise (IMBIE) project focused on better documentation of ice sheet contributions to GSLR.

Edit: I note that this type of study typically combines multiple sources of measurements as if they might all be equally correct; while I prefer ice sheet mass loss scenarios such as those developed by Rignot as he seems to better understand the importance of the various factors contributing to such scenarios (especially upper bound scenarios):

Briggs, K. H., et al. (2016), Charting ice sheet contributions to global sea level rise, Eos, 97, doi:10.1029/2016EO055719. Published on 18 July 2016

https://eos.org/project-updates/charting-ice-sheet-contributions-to-global-sea-level-rise

Abstract: "In 2012, the first community assessment of ice mass losses from Antarctica and Greenland demonstrated confidence in our estimates, showing that measurements based on data from different classes of satellite sensors agreed with one another and that the combined rate of loss had tripled over the previous 2 decades. Now, we’ve begun a second phase of this assessment, with an open call for participation and an ambitious schedule to deliver annual updates."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on August 08, 2016, 11:57:27 PM
The linked reference address means to more precisely determine sea-level during MIS 5e:

Rovere, A.; Raymo, M., E.; Vacchi, M.; Lorscheid, T.; Stocchi, P.; Gómez-Pujol, L.; Harris, D., L.; Casella, E.; O’Leary, M., J.; and Hearty, P., J. (2016), "The analysis of Last Interglacial (MIS 5e) relative sea-level indicators: Reconstructing sea-level in a warmer world",  Earth-Science Reviews, 159: 404-427; doi:10.1016/j.earscirev.2016.06.006

http://www.sciencedirect.com/science/article/pii/S0012825216301246 (http://www.sciencedirect.com/science/article/pii/S0012825216301246)

Abstract: "The Last Interglacial (MIS 5e, 128–116 ka) is among the most studied past periods in Earth's history. The climate at that time was warmer than today, primarily due to different orbital conditions, with smaller ice sheets and higher sea-level. Field evidence for MIS 5e sea-level was reported from thousands of sites, but often paleo shorelines were measured with low-accuracy techniques and, in some cases, there are contrasting interpretations about paleo sea-level reconstructions. For this reason, large uncertainties still surround both the maximum sea-level attained as well as the pattern of sea-level change throughout MIS 5e. Such uncertainties are exacerbated by the lack of a uniform approach to measuring and interpreting the geological evidence of paleo sea-levels. In this review, we discuss the characteristics of MIS 5e field observations, and we set the basis for a standardized approach to MIS 5e paleo sea-level reconstructions, that is already successfully applied in Holocene sea-level research. Application of the standard definitions and methodologies described in this paper will enhance our ability to compare data from different research groups and different areas, in order to gain deeper insights into MIS 5e sea-level changes. Improving estimates of Last Interglacial sea-level is, in turn, a key to understanding the behavior of ice sheets in a warmer world."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: iamlsd on August 09, 2016, 01:08:39 PM
I have a look at the NASA Sea Level Change Page now and again and I think the Global Mean Sea Level has moved up from 3.4 to 3.5 since I last looked (but it could be my memory failing :) Also a good article on how persistent low pressure and a change in wind patterns could be having a dramatic local affect on sea levels North Eastern coast of the US.

https://sealevel.nasa.gov/news/52/neglected-effects-might-influence-sea-level
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: tombond on August 09, 2016, 02:54:21 PM
I have a look at the NASA Sea Level Change Page now and again and I think the Global Mean Sea Level has moved up from 3.4 to 3.5

The most interesting change is the doubling of annual sea level rise in the second decade of this century.  In the last five years (since January 2011) sea level rise has averaged 6mm per year reflecting the rapid acceleration of polar sheet ice melt.

Sea level was +40mm in January 2011 and is +73mm in April 2016, giving a rise of 33mm in 5.4 years or 6mm per year.  Raw data found at;

ftp://podaac.jpl.nasa.gov/allData/merged_alt/L2/TP_J1_OSTM/global_mean_sea_level/GMSL_TPJAOS_199209_201605.txt

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Darvince on August 09, 2016, 02:56:54 PM
Does anyone know of data for sea level rise that uses the normal date system instead of decimal fractions of a year?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wehappyfew on August 09, 2016, 05:57:06 PM


The most interesting change is the doubling of annual sea level rise in the second decade of this century.  In the last five years (since January 2011) sea level rise has averaged 6mm per year reflecting the rapid acceleration of polar sheet ice melt.

Sea level was +40mm in January 2011 and is +73mm in April 2016, giving a rise of 33mm in 5.4 years or 6mm per year.  Raw data found at;

ftp://podaac.jpl.nasa.gov/allData/merged_alt/L2/TP_J1_OSTM/global_mean_sea_level/GMSL_TPJAOS_199209_201605.txt (http://ftp://podaac.jpl.nasa.gov/allData/merged_alt/L2/TP_J1_OSTM/global_mean_sea_level/GMSL_TPJAOS_199209_201605.txt)

I think it is a mistake to attribute the higher trend to increased melt. More important in the short term (and 5 years is very short term) is the ENSO correlation:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fsealevel.colorado.edu%2Ffiles%2F2016_rel3%2Fsl_mei.png&hash=cc6a3d2c11b7ffa78b669802259766c2)

The 2011 to 2016 period starts at the strongest La Nina and ends on the 2nd Strongest El Nino. This has a huge impact on rainfall patterns and land storage of water. More rain over the tropical land areas in La Nina, more rain over ocean during El Nino (and corresponding drought over South America and tropical Oceania).

Better to draw a trend line through points of similar ENSO values: 2006, 2009, 2012, 2014, for example. These points define a trend that is only a little steeper than the long term trend line.

Wait until the current transition to neutral or weak El Nino bottoms out. Compare 2016/17 sea level values to 2013 and 2008 values. Then draw a trend line through those points. I predict that trend line will be far less than 6mm/yr, but it could still be a little larger than the current long term trend of 3.4 mm/yr.

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on August 10, 2016, 07:38:32 PM
The linked reference indicates that the 1991 Mt. Pinatubo eruption suppressed subsequent sea level rise, but that this effect was not considered by Large Ensemble (LE) climate models (see attached plots) and thus we can expect the rate of SLR to accelerate in the near-term as the Mt. Pinatubo effect dissipates:

Fasullo, J.T., Nerem, R.S. & Hamlington, B. (August 10, 2016), "Is the detection of accelerated sea level rise imminent?", Scientific Reports 6, No. 31245, doi: 10.1038/srep31245.

http://www.nature.com/articles/srep31245 (http://www.nature.com/articles/srep31245)

See also:

http://www.wired.co.uk/article/climate-change-sea-level-rise (http://www.wired.co.uk/article/climate-change-sea-level-rise)

Extract: "Recent reports that suggest sea levels aren't rising as fast as expected – and may even be dropping – could be inaccurate, according to new research.
Experts from the National Center for Atmospheric Research (NCAR) have discovered that the 1991 eruption of Mount Pinatubo in the Philippines could have masked the true reading, and this could have dire consequences for the future.
Satellite observations, which began in 1993, show that the rate of sea level rise has held fairly steady at about 3 millimeters per year. However, these records began soon after the eruption, which temporarily cooled the planet, causing sea levels to drop.
The new study finds that the lower starting point effectively distorts the calculation of sea level rise acceleration for the last couple of decades. It also lends support to projections that show the rate of sea level rise escalating over time as the climate warms.
"When we used climate model runs designed to remove the effect of the Pinatubo eruption, we saw the rate of sea level rise accelerating in our simulations," said NCAR scientist John Fasullo, who led the study. "Now that the impacts of Pinatubo have faded, this acceleration should become evident in the satellite measurements in the coming decade, barring another major volcanic eruption.""
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on August 10, 2016, 08:46:47 PM
The linked reference indicates that the 1991 Mt. Pinatubo eruption suppressed subsequent sea level rise, but that this effect was not considered by Large Ensemble (LE) climate models

Great Find as always, I was not sure to put this into SLR or Conservative Scientists threads since the projections to 2020 are much lower than I expect we will find
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on August 10, 2016, 09:49:58 PM
The linked reference indicates that the 1991 Mt. Pinatubo eruption suppressed subsequent sea level rise, but that this effect was not considered by Large Ensemble (LE) climate models

Great Find as always, I was not sure to put this into SLR or Conservative Scientists threads since the projections to 2020 are much lower than I expect we will find

Frequently it is a challenge to decide where to post links to new research, so I will re-post this info over in the Conservative Scientists thread as well.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on September 07, 2016, 09:28:58 PM
Here is an article on the possible impacts of SLR on NYC:

http://nymag.com/daily/intelligencer/2016/09/new-york-future-flooding-climate-change.html?mid=nymag_press (http://nymag.com/daily/intelligencer/2016/09/new-york-future-flooding-climate-change.html?mid=nymag_press)

Extract: "Even locals who believe climate change is real have a hard time grasping that their city will almost certainly be flooded beyond recognition."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on September 21, 2016, 05:51:08 PM
Great article on Scherer paper today in the Washington Post.  By adding key ice sheet collapse mechanisms to their model, researchers have found significant east Antarctica ice sheet collapse (as well as full west collapse) during the Pliocene (see associated image below)

(https://img.washingtonpost.com/wp-apps/imrs.php?src=https://img.washingtonpost.com/news/energy-environment/wp-content/uploads/sites/43/2016/09/pliocene-antarctica.jpg&w=1484)

article here:

https://www.washingtonpost.com/news/energy-environment/wp/2016/09/20/scientists-may-have-just-solved-a-riddle-about-antarctica-and-youre-not-going-to-like-the-answer (https://www.washingtonpost.com/news/energy-environment/wp/2016/09/20/scientists-may-have-just-solved-a-riddle-about-antarctica-and-youre-not-going-to-like-the-answer)

Quote
The new study suggests otherwise. In the Pliocene — and especially the mid-Pliocene warm period, when atmospheric carbon dioxide was at about the level where it is now, 400 parts per million, but global temperatures were 1 or 2 degrees Celsius warmer than at present — the model not only collapses the entirety of West Antarctica (driving some 10 feet of global sea-level rise) but also shows the oceans eating substantially into key parts of East Antarctica. In particular, the multi-kilometer thick ice that currently fills the extremely deep Aurora and Wilkes basins of the eastern ice sheet retreats inland for hundreds of miles — which would have driven global seas to a much higher level than a West Antarctic collapse alone.

referenced paper found here:  http://www.nature.com/articles/ncomms12957 (http://www.nature.com/articles/ncomms12957)

Windblown Pliocene diatoms and East Antarctic Ice Sheet retreat

    Reed P. Scherer

Abstract

Marine diatoms in tillites along the Transantarctic Mountains (TAMs) have been used to suggest a diminished East Antarctic Ice Sheet (EAIS) during Pliocene warm periods. Updated ice-sheet modelling shows significant Pliocene EAIS retreat, creating marine embayments into the Wilkes and Aurora basins that were conducive to high diatom productivity and rapid accumulation of diatomaceous sediments. Here we show that subsequent isostatic uplift exposed accumulated unconsolidated marine deposits to wind erosion. We report new atmospheric modelling utilizing Pliocene climate and derived Antarctic landscapes indicating that prevailing mid-altitude winds transported diatoms towards the TAMs, dominantly from extensive emerged coastal deposits of the Aurora Basin. This result unifies leading ideas from competing sides of a contentious debate about the origin of the diatoms in the TAMs and their link to EAIS history, supporting the view that parts of the EAIS are vulnerable to relatively modest warming, with possible implications for future sea-level rise.

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on September 21, 2016, 06:34:52 PM
Thanks for the tip, jai!
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on September 21, 2016, 06:35:21 PM
jai,

A great (& disturbing) catch, particularly as Robert M. DeConto, David Pollard & Richard B. Alley are co-authors and must have used hydrofracturing and cliff failure mechanisms in their models.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on October 15, 2016, 06:50:11 PM
Changing from disbelief/denial  to  bargaining/reaching for a miracle.

The $50 billion plan to save Louisiana's coast gets a rewrite
Quote
Gov. John Bel Edwards made clear that the 2017 master plan – and its reshuffling of which restoration and levee projects are included and are built during its early years – will represent a new, aggressive phase of Louisiana's efforts to create a sustainable coast, sustainable economy and sustainable coastal communities.

"Simply put, I didn't become governor to watch south Louisiana wash away," Edwards told attendees at a June gathering of scientists, activists and public officials working on restoration. "We've only got a short amount of time to get this right. We're going to do that. We're going to rise to the challenge. We're going to be successful."
http://www.nola.com/environment/index.ssf/2016/10/louisiana_coastal_flood_protection_plan.html (http://www.nola.com/environment/index.ssf/2016/10/louisiana_coastal_flood_protection_plan.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on October 15, 2016, 07:26:09 PM
Changing from disbelief/denial  to  bargaining/reaching for a miracle.

The $50 billion plan to save Louisiana's coast gets a rewrite

The linked video summarizes a few of the well known challenges that Louisiana faces when trying to "save" their coastline:

http://www.businessinsider.com/every-map-louisiana-lie-2016-10 (http://www.businessinsider.com/every-map-louisiana-lie-2016-10)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on November 01, 2016, 03:28:00 AM
The linked reference and associated NASA articles indicate that global tide gauges are likely located around the world in positions that underestimate the rate of mean global sea level rise:

P. R. Thompson, B. D. Hamlington, F. W. Landerer & S. Adhikari (9 October 2016), "Are long tide gauge records in the wrong place to measure global mean sea level rise?", Geophysical Research Letters, DOI: 10.1002/2016GL070552

http://onlinelibrary.wiley.com/doi/10.1002/2016GL070552/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2016GL070552/abstract)

Abstract: "Ocean dynamics, land motion, and changes in Earth's gravitational and rotational fields cause local sea level change to deviate from the rate of global mean sea level rise. Here we use observations and simulations of spatial structure in sea level change to estimate the likelihood that these processes cause sea level trends in the longest and highest-quality tide gauge records to be systematically biased relative to the true global mean rate. The analyzed records have an average twentieth century rate of approximately 1.6 mm/yr, but based on the locations of these gauges, we show that the simple average underestimates the twentieth century global mean rate by 0.1 ± 0.2 mm/yr. Given the distribution of potential sampling biases, we find that <1% probability that observed trends from the longest and highest-quality tide gauge records are consistent with global mean rates less than 1.4 mm/yr."


Se the linked NASA article and the attached associated image:

http://climate.nasa.gov/news/2504/historical-records-may-underestimate-sea-level-rise/ (http://climate.nasa.gov/news/2504/historical-records-may-underestimate-sea-level-rise/)

Extract: "A new NASA and university study using NASA satellite data finds that tide gauges — the longest and highest-quality records of historical ocean water levels — may have underestimated the amount of global average sea level rise that occurred during the 20th century.

A research team led by Philip Thompson, associate director of the University of Hawaii Sea Level Center in the School of Ocean and Earth Science and Technology, Manoa, evaluated how various processes that cause sea level to change differently in different places may have affected past measurements. The team also included scientists from NASA’s Jet Propulsion Laboratory, Pasadena, California, and Old Dominion University, Norfolk, Virginia.

“It’s not that there’s something wrong with the instruments or the data,” said Thompson, “but for a variety of reasons, sea level does not change at the same pace everywhere at the same time. As it turns out, our best historical sea level records tend to be located where 20th century sea level rise was most likely less than the true global average.”

One of the key processes the researchers looked at is the effect of “ice melt fingerprints,” which are global patterns of sea level change caused by deviations in Earth’s rotation and local gravity that occur when a large ice mass melts. To determine the unique melt fingerprint for glaciers, ice caps and ice sheets, the team used data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites on Earth’s changing gravitational field, and a novel modeling tool (developed by study co-author Surendra Adhikari and the JPL team) that simulates how ocean mass is redistributed due to ice melting.

One of the most fascinating and counter-intuitive features of these fingerprints is that sea level drops in the vicinity of a melting glacier, instead of rising as might be expected. The loss of ice mass reduces the glacier’s gravitational influence, causing nearby ocean water to migrate away. But far from the glacier, the water it has added to the ocean causes sea level to rise at a much greater rate.

During the 20th century, the dominant locations of global ice melt were in the Northern Hemisphere. The results of this study showed that many of the highest-quality historical water level records are taken from places where the melt fingerprints of Northern Hemisphere sources result in reduced local sea level change compared to the global average. Furthermore, the scientists found that factors capable of enhancing sea level rise at these locations, such as wind or Southern Hemisphere melt, were not likely to have counteracted the impact of fingerprints from Northern Hemisphere ice melt.

The study concludes it is highly unlikely that global average sea level rose less than 5.5 inches (14 centimeters) during the 20th century. The most likely amount was closer to 6.7 inches (17 centimeters).

“This is really important, because it provides answers to the question about how melt fingerprints and the influence of wind on ocean circulation affect our ability to estimate past sea level rise,” said Thompson. “These results suggest that our longest records are most likely to underestimate past global mean change and allow us to establish the minimum amount of global sea level rise that could have occurred during the last century.”"
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on November 08, 2016, 07:42:30 PM
To me the linked reference entitled: "Coastal sea level rise with warming above 2 °C", errs on the side of least drama by minimizing the risk of the WAIS collapsing & by assuming AR5 values for climate sensitivity.  Nevertheless, it does indicate that without rapidly implemented mitigation measures we may reach the 2C level by 2040 (using ESLD assumptions) which may result in significant levels of SLR (even when minimizing the risks of WAIS contributions this century):

Svetlana Jevrejeva, Luke P. Jackson, Riccardo E. M. Riva, Aslak Grinsted, and John C. Moore (2016), "Coastal sea level rise with warming above 2 °C", PNAS, doi: 10.1073/pnas.1605312113

http://www.pnas.org/content/early/2016/11/02/1605312113 (http://www.pnas.org/content/early/2016/11/02/1605312113)

Abstract: "Two degrees of global warming above the preindustrial level is widely suggested as an appropriate threshold beyond which climate change risks become unacceptably high. This “2 °C” threshold is likely to be reached between 2040 and 2050 for both Representative Concentration Pathway (RCP) 8.5 and 4.5. Resulting sea level rises will not be globally uniform, due to ocean dynamical processes and changes in gravity associated with water mass redistribution. Here we provide probabilistic sea level rise projections for the global coastline with warming above the 2 °C goal. By 2040, with a 2 °C warming under the RCP8.5 scenario, more than 90% of coastal areas will experience sea level rise exceeding the global estimate of 0.2 m, with up to 0.4 m expected along the Atlantic coast of North America and Norway. With a 5 °C rise by 2100, sea level will rise rapidly, reaching 0.9 m (median), and 80% of the coastline will exceed the global sea level rise at the 95th percentile upper limit of 1.8 m. Under RCP8.5, by 2100, New York may expect rises of 1.09 m, Guangzhou may expect rises of 0.91 m, and Lagos may expect rises of 0.90 m, with the 95th percentile upper limit of 2.24 m, 1.93 m, and 1.92 m, respectively. The coastal communities of rapidly expanding cities in the developing world, and vulnerable tropical coastal ecosystems, will have a very limited time after midcentury to adapt to sea level rises unprecedented since the dawn of the Bronze Age."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on November 26, 2016, 05:26:48 PM
Bill McKibben:  Believe it or not, BP is sponsoring art exhibit entitled 'Sunken Cities.' This isn't even irony, it's just a raised corporate middle finger

As new cities are added, the waters in the @britishmuseum Great Court spread. BP = sea level rise = #SunkenCities @350 @GreenpeaceUK

https://twitter.com/billmckibben/status/802539750028611584

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: bligh8 on November 27, 2016, 04:15:47 PM
Perils of Climate Change Could Swamp Coastal Real Estate

In the linked reference there are some interesting noted changes within the real estate, insurance and banking
Industries related to the threat of increasing encroachment of Sea Water.

Extract:

State lawmakers in Massachusetts and New Jersey are pushing to impose new rules on real estate agents and others, obligating them to disclose climate-related damage like previous flooding.
Banks and insurers need to protect their collateral and investors more by improving their methods for estimating climate-change risks and creating more standardized rules for reporting them publicly, economists warn.
In April, Sean Becketti, the chief economist for Freddie Mac, the government-backed mortgage giant, issued a dire prediction. It is only a matter of time, he wrote, before sea level rise and storm surges become so unbearable along the coast that people will leave, ditching their mortgages and potentially triggering another housing meltdown — except this time, it would be unlikely that these housing prices would ever recover.


http://www.nytimes.com/2016/11/24/science/global-warming-coastal-real-estate.html (http://www.nytimes.com/2016/11/24/science/global-warming-coastal-real-estate.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on November 27, 2016, 04:42:49 PM
Miami-Dade Clerk Of Courts Calls For Sea-Level Rise Superfund
http://wlrn.org/post/miami-dade-clerk-courts-calls-sea-level-rise-superfund (http://wlrn.org/post/miami-dade-clerk-courts-calls-sea-level-rise-superfund)

On this thread, I have argued repeatedly that we are seriously underestimating the devastation that sea level rise will have on the global economy. I have argued that the wholesale destruction of property will actually result in the total collapse of the worldwide financial system that serves as the foundation of global capitalism. I will attempt to explain my point of view one more time and will use this linked article to make my point.

In the linked article the "Miami-Dade Clerk of Courts, Harvey Ruvin, sent a letter last week to South Florida members of Congress urging for the creation of a Federal Resiliency Superfund." He said that changes "in ocean levels threaten $6 trillion worth state property as well as the lives of the millions of South Floridians."

If you look at the picture at the top of the article, it conjures up a vision of Venice, buildings surrounded by water. This picture is not far from the truth as sea level rise will not result in the complete destruction of built structures. These magnificent structures will remain as monuments to our stupidity. Sewers are underground and it is estimated that a 1 meter rise in sea level over the current levels will render useless the waste water removal and treatment infrastructure in Dade County. The county will frequently and repeatedly be standing in a pool of raw sewage, rendering the county unfit for human habitation. Fresh water distribution is at risk as well but since water distribution is under pressure, it can withstand saltwater intrusion better than waste water infrastructure.

So why will this destruction of the built up wealth of $6 trillion damage the system of capitalism? It is not the structures themselves but the links these structures have with the financial system that will cause the damage. Mortgages and other debt issued against the value of this property will go into default. This debt has been packaged and sold into the financial markets and form the basis for pensions and wealth that is spread across the planet. The financial wealth that is supported by this debt is then borrowed against as well. The insurance and reinsurance industries are at risk as obligations against the physical structures and financial instruments will play havoc.

If you were paying attention in 2007, this is the process that nearly brought down the worldwide financial system. Only a coordinated effort by the banks of the entire developed world prevented this collapse as western nations flooded the system with an unprecedented amount of liquidity. This liquidity continues to prop up a still fragile financial system and the historically low interest rates are all the evidence that you need to realize that this excessive liquidity is still in the system.

So is a $6 trillion destruction of wealth really that large? Can that trigger the same kind of reaction in the financial markets that the destruction of wealth caused by the collapse of the housing bubble in 2007?

When the housing market bubble collapsed.....

http://fivethirtyeight.com/features/why-the-housing-bubble-tanked-the-economy-and-the-tech-bubble-didnt/ (http://fivethirtyeight.com/features/why-the-housing-bubble-tanked-the-economy-and-the-tech-bubble-didnt/)

"from 2007 to 2009, the value of real estate owned by U.S. households fell by nearly the same amount — $6 trillion"

Please keep in mind, that $6 trillion of real estate threatened by sea level rise is only in Florida. How many other coastal communities are at risk in the U.S.? How many globally?

The global financial system will not be able to withstand the devastation wrought by global warming and sea level rise is only one feature of global warming that will destroy the accumulated wealth in the system.

I argued this point over a year ago. The global system of Capitalism and the financial markets that support it are simply not capable of withstanding the damage that AGW will wreak on it. The costs of mitigation as governments attempt to save the wealth of the system that our cities and infrastructure represent will overwhelm their capacity to budget and pay for them. The financial crisis spurred by the near collapse of the housing market in the U.S. will look laughable compared to the approaching financial crisis. The response will be the same. As Capitalism teeters on the brink governments will engage in a quick, coordinated response. It will simply fail as the magnitude of the disaster overwhelms our attempts to save the system.

Simply to provide some background, perhaps to cause others to consider the accuracy of my admittedly personal viewpoint, I have an Economics degree and MBA (Specialization in Finance) from the University of Chicago.

(edit: This education and the knowledge acquired in a 40 year business career has served me well. By the beginning of 2008, I had nearly completely exited equity markets with less than 10% of my investments remaining in stock. (I saw the crash coming, the root cause, massive amounts of debt.) I began reentering equity markets in 2010 and my overall portfolio has nearly doubled since 2007.)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on November 28, 2016, 01:26:52 AM
The entire east coast is under attack and we are going to lose.

http://www.msn.com/en-us/news/technology/sands-end/ar-AAkpaBJ?li=BBnb7Kz&ocid=mailsignout (http://www.msn.com/en-us/news/technology/sands-end/ar-AAkpaBJ?li=BBnb7Kz&ocid=mailsignout)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: oren on November 29, 2016, 08:13:32 AM
The entire east coast is under attack and we are going to lose.

http://www.msn.com/en-us/news/technology/sands-end/ar-AAkpaBJ?li=BBnb7Kz&ocid=mailsignout (http://www.msn.com/en-us/news/technology/sands-end/ar-AAkpaBJ?li=BBnb7Kz&ocid=mailsignout)
Interesting article. Another one of the hidden ways that humanity is using the planet non-sustainably.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Pmt111500 on November 29, 2016, 09:57:53 AM
en.m.wikipedia.org/wiki/MOSE_Project attempts to do the impossiböe. Much better would be to just reinforce the buildings so Venice would become the first monument of AGW. If they want to preserve the buildings too I guess a monumental project of building a new Venice up 20 m could be started. Same goes for Amsterdam and a few other cities round the globe. The relocation of harbours is of course also a gargantuan task for future generations, but the land aquisition from suitable locations could be started now.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 12, 2016, 01:33:06 AM
The linked reference evaluates the implications of more accurately considering a 3-D viscoelastic Earth models as opposed to the less accurate assumption of elastic response on the sea-level fingerprint implications of an abrupt collapse of the WAIS.  Their findings conclude that "… when viscous effects are included, the peak sea-level fall predicted in the vicinity of WAIS during a melt event will increase by ~25% and ~50%, relative to the elastic case, for events of duration 25 years and 100 years, respectively."  This is important w.r.t. global sea level rise as the further the local sea-level drops around West Antarctica, the higher sea level will raise at distance away from West Antarctica.

Carling C. Hay, Harriet C. P. Lau, Natalya Gomez, Jacqueline Austermann, Evelyn Powell, Jerry X. Mitrovica, Konstantin Latychev, and Douglas A. Wiens (2016), "Sea-level fingerprints in a region of complex Earth structure: The case of WAIS", Journal of Climate, DOI: http://dx.doi.org/10.1175/JCLI-D-16-0388.1 (http://dx.doi.org/10.1175/JCLI-D-16-0388.1)


http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0388.1 (http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0388.1)


Abstract: "Sea-level fingerprints associated with rapid melting of the West Antarctic Ice Sheet (WAIS) have generally been computed under the assumption of a purely elastic response of the solid Earth. We investigate the impact of viscous effects on these fingerprints by computing gravitationally self-consistent sea-level changes that adopt a 3-D viscoelastic Earth model in the Antarctic region consistent with available geological and geophysical constraints. In West Antarctica, the model is characterized by a thin (~65 km) elastic lithosphere and sub-lithospheric viscosities that span three orders of magnitude, reaching values as low as ~4 × 1018 Pa s beneath WAIS. Our calculations indicate that sea-level predictions in the near field of WAIS will depart significantly from elastic fingerprints in as little as a few decades. For example, when viscous effects are included, the peak sea-level fall predicted in the vicinity of WAIS during a melt event will increase by ~25% and ~50%, relative to the elastic case, for events of duration 25 years and 100 years, respectively. Our results have implications for studies of sea-level change due to both ongoing mass loss from WAIS over the next century and future, large scale collapse of WAIS on century-to-millennial time scales."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: GeoffBeacon on December 15, 2016, 08:04:38 PM
I'm trying to get clear in my mind the effect of short term climate forcers (SLCFs), e.g. methane and black carbon. The effect on sea-levels is one aspect.

Taking as an example, methane emitted between 50 and 40 years ago, the surface temperature rise caused now is more-or-less zero as the extra heat will have dissipated by radiation to space & etc.

However, I'd like to know more details. For example will that burst of heating have contributed to sea-level rise? Alsowill that effect, if any,  have been reversed (all or in part) as its effect on surface temperature disappears?

Are there any good references?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 15, 2016, 10:24:12 PM
Taking as an example, methane emitted between 50 and 40 years ago, the surface temperature rise caused now is more-or-less zero as the extra heat will have dissipated by radiation to space & etc.

However, I'd like to know more details. For example will that burst of heating have contributed to sea-level rise? Alsowill that effect, if any,  have been reversed (all or in part) as its effect on surface temperature disappears?

Geoff,

As mankind's radiative planetary forcing is not in balance (see the first image from March 2015), and the various Earth Systems can show different degrees of non-linearity at different times, the answers to your questions depend on what type of accounting system (first in, first out or first in, last out) that you want to use for determining impacts and responsibility (see the second image that hints at social justice and carbon budgets).

Thus one simple-minded example of estimating the sea level rise impacts of methane emissions from 40 to 50 years ago would be to take the third image of observed SLR (including this period) and linearly pro-rate the area under the radiative forcing curve (in this period) for methane as compared to the area under the total radiative forcing curve (in this period) shown on the fourth image.

However, in my next post I discuss some more complex issues that might change the estimate, depending on how much responsibility you care to recognize.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 15, 2016, 10:52:22 PM
Geoff,

As a follow-up to my last post, if you chose to accept the legal argument that one is responsible for turning the world over to the next generation with its systems in-balance then you might want to consider some of the following issues in determining impacts of a methane emission 40 to 50 years ago:

1.  The first image illustrates the logarithmic relationship of GHG concentrations (x) vs GMSTA (y); thus your methane emission 40 to 50-years ago is logarithmically worse (w.r.t. GMSTA) than such emissions today (so do you want to acknowledge responsibility for being an early emitter?).

2.  The second image shows both the AR4 (lower curve) and the AR5 (upper curve) GWP for methane; while the AGGI plot in my last post assumes the AR4 GWP it is out of date and should be updated to the AR5 curve which indicates a GWP of about 50 to 60 for methane over a 50-year period, so your assumption that your past methane emissions have all dissipated (w.r.t. atmosphere heat) is not correct.

3.  The third image show the AR5 GWP and GTP (see note below) for methane, which indicates a GTP50 of about 14, so you need to ask yourself if you are concerned about atmosphere heat content or only global mean surface temperature anomalies.

4.  The fourth image shows Pollard, et al's estimate for the timing of sea level rise contribution from Antarctica assuming continued BAU forcing and cliff failure and hydrofracturing response.  So you need to ask yourself, since your methane forcing was not in equilibrium to make room for the next generation, do you bear any responsibility for such potential future abrupt SLR.

5.  I could make similar points about TCR, ECS and ESS, but you get the idea.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 15, 2016, 11:10:37 PM
5.  I could make similar points about TCR, ECS and ESS, but you get the idea.

Geoff,

In case you haven't read any of my posts on climate sensitivity, I briefly note that:

A. Climate sensitivity is a function of temperature (see the first plot where ECS increases with GMST, as determined by paleo data);

B.  Climate sensitivity depends on how many earth systems one believes will exceed their various tipping points in the near future (see the second image of methane emissions projected to occur from thermokarst lakes following a BAU pathway);

C.  How response you care to believe that the climate is to radiative forcing (see the third image from the Ringberg 2015 workshop on climate sensitivity); and

D.  Where you accept that Lorenz attractors (such as the ENSO) can progressively ratchet-up Earth Systems to progressively higher degrees of activity with continued radiative forcing.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: GeoffBeacon on December 16, 2016, 01:38:23 AM
Thanks ALSR

I'm working my way through your replies.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: TerryM on December 16, 2016, 03:16:56 AM
A Question Re. Methane (CH4)


Both Shindell and IPCC 2007 attempt to give the Global Warming Potential (GWP) for a mass of CH4 compared to the same mass of Carbon Dioxide, (CO2). Both give figures that they believe are viable IF NO FURTHER CH4 IS RELEASED DURING THE TIME FRAME STUDIED.


Ie, if a given amount of CH4 is released, then, using Shindell's figures we should experience ~130 times as much warming effect, for ~ 7 years, as a similar amount of CO2 being released at that moment.
If any additional CH4 should find it's way into the atmosphere during that ~7 yr, period, the whole red line needs to be moved to the right along the X axis.
How far, (how many years) the red line must shift will depend on the amount of CH4 released within our 7 year window, Even if the release is not able to fully make up for the amount lost over time, causing the Parts Per Million. (PPM) to drop, the red line still needs to be pushed to the right.


If this is correct we will always find ourselves at the far left of the chart, and at the highest multiplier given.
[size=78%] [/size]
Again, the multipliers given are only accurate if no further atmospheric release occurs. Since we can't foresee a future without CH4 emissions, the warming effect will always be at least as high as
the most recent PPM multiplied be the shortest timespan multiplier.


Terry
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on December 16, 2016, 07:26:32 AM
Re:methane

This probably belongs in a separate thread, but doi:10.1038/NCLIMATE2998 is useful especially in regard to the difference between pulse and sustained emissions. I attach fig 2.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on December 16, 2016, 08:51:58 AM
Re: post on nov 27 by bligh8 referring to freddie mac april call

its at
http://www.freddiemac.com/finance/report/20160426_lifes_a_beach.html (http://www.freddiemac.com/finance/report/20160426_lifes_a_beach.html)

"In the housing crisis, a significant share of borrowers continued to make their mortgage payments even though the values of their homes were less than the balances of their mortgages. It is less likely that borrowers will continue to make mortgage payments if their homes are literally underwater."

"Or, alternatively, will the value of the house—and all the houses around it—plunge the first time a lender refuses to make a mortgage on a nearby house or an insurer refuses to issue a homeowner's policy? Or will the trigger be one or two homeowners who decide to sell defensively?"

game of chicken.

has links to flood maps. the new ones have real estate types squawking loud and long.

sidd
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: skanky on December 16, 2016, 11:01:47 AM
The second part of this post will be of interest to people here: http://planet3.org/2016/12/15/day-4-at-agu-productive-self-doubt-and-healthy-retraction/ (http://planet3.org/2016/12/15/day-4-at-agu-productive-self-doubt-and-healthy-retraction/)
I expect more details, and maybe even the talks, will be availble on the AGU site.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: GeoffBeacon on December 16, 2016, 02:07:06 PM
sidd

It was the article you quote by Allen et. al. that prompted me to ask the question. However "New use of global warming potentials to compare cumulative and short-lived climate pollutants (http://www.nature.com/nclimate/journal/v6/n8/full/nclimate2998.html)" is concerned with strategies "to limit [surface?] warming to 2°C".

If a proportion of the heat stored due to SLCF warming is stored in the deep ocean, it does not contribute to surface warming but does have consequences for sea level. I wanted to know how big this effect might be - and if there were other serious effects that can show themselves independently of the target to keep surface warming below a given level.


ALSR

(Still thinking about your posts but..)

Yes. My "assumption that [my example of] past methane emissions have all dissipated" after 50 years was incorrect but with GTP down to 14 from an initial 120 the effects on surface temperature is falling quite fast and after 100 years it's all but disappeared.

However, some of the heat has warmed the ocean and melted some land based ice, raising sea level.  This is not something that I noticed  in Allen et. al. at first - although they do say

Quote
Some contributions to the rate of sea-level rise also scale with integrated climate forcing.
How big are these contributions?

I often read Myles Allen as saying "No need to worry much about SLCF - yet".

Is my impression incorrect?

If so, is he correct?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 16, 2016, 04:27:05 PM
ALSR

(Still thinking about your posts but..)

Yes. My "assumption that [my example of] past methane emissions have all dissipated" after 50 years was incorrect but with GTP down to 14 from an initial 120 the effects on surface temperature is falling quite fast and after 100 years it's all but disappeared.

However, some of the heat has warmed the ocean and melted some land based ice, raising sea level.  This is not something that I noticed  in Allen et. al. at first - although they do say

Quote
Some contributions to the rate of sea-level rise also scale with integrated climate forcing.
How big are these contributions?

I often read Myles Allen as saying "No need to worry much about SLCF - yet".

Is my impression incorrect?

If so, is he correct?


Geoff,
I cannot answer your questions in an exact manner, but if you assume that Allen et. al. (2016) are telling decision makers that they can discount the importance of acting immediately on reducing anthropogenic SLCP emissions, then to me this is clearly an incorrect interpretation, even though in the attached figure they provide new dotted curves for both GWP & GTP for both methane and black carbon that are lower than those posted in AR5.  The correct interpretation is that one cannot make appropriate policy decisions without the projections of the best Earth Systems Models, ESMs, such as ACME (whose Phase I results should be available in 2017), for reasons including those that you posted and because we do not know which radiative forcing pathway that decision makers will take us down.

Myles R. Allen, Jan S. Fuglestvedt, Keith P. Shine, Andy Reisinger, Raymond T. Pierrehumbert and Piers M. Forster ; New use of global warming potentials to compare cumulative and short-lived climate pollutants; Nature Climate Change (2016) doi:10.1038/nclimate2998

http://www.nature.com/nclimate/journal/v6/n8/full/nclimate2998.html (http://www.nature.com/nclimate/journal/v6/n8/full/nclimate2998.html)

Extract: "Parties to the United Nations Framework Convention on Climate Change (UNFCCC) have requested guidance on common greenhouse gas metrics in accounting for Nationally determined contributions (NDCs) to emission reductions. Metric choice can affect the relative emphasis placed on reductions of ‘cumulative climate pollutants’ such as carbon dioxide versus ‘short-lived climate pollutants’ (SLCPs), including methane and black carbon. Here we show that the widely used 100-year global warming potential (GWP100) effectively measures the relative impact of both cumulative pollutants and SLCPs on realized warming 20–40 years after the time of emission. If the overall goal of climate policy is to limit peak warming, GWP100 therefore overstates the importance of current SLCP emissions unless stringent and immediate reductions of all climate pollutants result in temperatures nearing their peak soon after mid-century, which may be necessary to limit warming to “well below 2 °C” . The GWP100 can be used to approximately equate a one-off pulse emission of a cumulative pollutant and an indefinitely sustained change in the rate of emission of an SLCP. The climate implications of traditional CO2-equivalent targets are ambiguous unless contributions from cumulative pollutants and SLCPs are specified separately."


Caption: "This image is from the Nature Climate Change paper that proposes new ways of treating short lived climate pollutants when assessing the impact on future warming. In the graphic, global warming potential (GWP) and global temperature-change potential are shown as a function of the time horizon. a, Values for methane. b, Values for combined organic and black carbon. Solid lines show metrics calculated using current IPCC response functions; dotted blue lines show the impact of varying the climate response time. Dotted black lines show the value of GWP100. Courtesy: authors and Nature Climate Change."

I will make a few more comments in a follow-on post.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 16, 2016, 04:35:52 PM
Geoff,

The linked BBC article is entitled: "Methane surge needs 'urgent attention'", and it indicates that scientists need to re-focus on identifying the various sources and sinks for atmospheric methane (see attached images); however, such information and that provided by Allen et. al. (2016) err on the side of least drama for reasons including: 

(a) the authors state that the GWP100 for methane is about 30 whereas AR5 indicates that it is 34;

(b) the authors downplay the importance of likely future increases in natural methane emissions from high latitude soils and thermokarst lakes; as well as from the coming degradation of tropical rainforests; and

(c) the authors note the uncertainties associated changes (reductions) in the atmospheric hydroxyl reduction of methane; however, they treat this like a reduction in a methane sink; when in actuality this process increases the GWP of all of the current and future atmospheric methane so the effective GWP100 for methane through 2100 is likely well above 34 (see the following Wikilink to learn about GWP).

https://en.wikipedia.org/wiki/Global_warming_potential (https://en.wikipedia.org/wiki/Global_warming_potential)


http://www.bbc.com/news/science-environment-38285300 (http://www.bbc.com/news/science-environment-38285300)

Extract: ""Methane has many sources, but the culprit behind the steep rise is probably agriculture," Prof Jackson told BBC News.
"We do see some increased fossil fuel emissions over the last decade, but we think biological sources, and tropical sources, are the most likely."
Agricultural sources would include cattle and other ruminants, as well as rice paddies.
Emissions from wetlands are almost certainly a significant part of this story as well. But so too could be the role played by the chemical reactions that normally remove methane from the atmosphere.
One of the most important of these is the destruction process involving the so-called hydroxyl radical.
The concentration of this chemical species in the atmosphere might also be changing in some way.
According to the ERL editorial, there needs to be a particular push on understanding such methane "sinks".
CH4 is about 30 times better than CO2, over a century timescale, at trapping heat in the atmosphere."


See also the linked Vox article is entitled: "Methane levels in the atmosphere are now rising at their fastest pace in decades".
http://www.vox.com/energy-and-environment/2016/12/12/13915950/methane-atmosphere-rise-agriculture (http://www.vox.com/energy-and-environment/2016/12/12/13915950/methane-atmosphere-rise-agriculture)

The following two references were cited in the articles cited previously in this post:

M Saunois, R B Jackson, P Bousquet, B Poulter and J G Canadell (12 December 2016), "The growing role of methane in anthropogenic climate change", Environmental Research Letters, Volume 11, Number 12,  doi:10.1088/1748-9326/11/12/120207.


http://iopscience.iop.org/article/10.1088/1748-9326/11/12/120207 (http://iopscience.iop.org/article/10.1088/1748-9326/11/12/120207)

Abstract: "Unlike CO2, atmospheric methane concentrations are rising faster than at any time in the past two decades and, since 2014, are now approaching the most greenhouse-gas-intensive scenarios. The reasons for this renewed growth are still unclear, primarily because of uncertainties in the global methane budget. New analysis suggests that the recent rapid rise in global methane concentrations is predominantly biogenic-most likely from agriculture-with smaller contributions from fossil fuel use and possibly wetlands. Additional attention is urgently needed to quantify and reduce methane emissions. Methane mitigation offers rapid climate benefits and economic, health and agricultural co-benefits that are highly complementary to CO2 mitigation."

Also see:
Saunois, M., Bousquet, P., Poulter, B., Peregon, A., Ciais, P., Canadell, J. G., Dlugokencky, E. J., Etiope, G., Bastviken, D., Houweling, S., Janssens-Maenhout, G., Tubiello, F. N., Castaldi, S., Jackson, R. B., Alexe, M., Arora, V. K., Beerling, D. J., Bergamaschi, P., Blake, D. R., Brailsford, G., Brovkin, V., Bruhwiler, L., Crevoisier, C., Crill, P., Covey, K., Curry, C., Frankenberg, C., Gedney, N., Höglund-Isaksson, L., Ishizawa, M., Ito, A., Joos, F., Kim, H.-S., Kleinen, T., Krummel, P., Lamarque, J.-F., Langenfelds, R., Locatelli, R., Machida, T., Maksyutov, S., McDonald, K. C., Marshall, J., Melton, J. R., Morino, I., Naik, V., O'Doherty, S., Parmentier, F.-J. W., Patra, P. K., Peng, C., Peng, S., Peters, G. P., Pison, I., Prigent, C., Prinn, R., Ramonet, M., Riley, W. J., Saito, M., Santini, M., Schroeder, R., Simpson, I. J., Spahni, R., Steele, P., Takizawa, A., Thornton, B. F., Tian, H., Tohjima, Y., Viovy, N., Voulgarakis, A., van Weele, M., van der Werf, G. R., Weiss, R., Wiedinmyer, C., Wilton, D. J., Wiltshire, A., Worthy, D., Wunch, D., Xu, X., Yoshida, Y., Zhang, B., Zhang, Z., and Zhu, Q.: The global methane budget 2000–2012, Earth Syst. Sci. Data, 8, 697-751, doi:10.5194/essd-8-697-2016, 2016.


http://www.earth-syst-sci-data.net/8/697/2016/ (http://www.earth-syst-sci-data.net/8/697/2016/)

Abstract. The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH4 over the past decade. Emissions and concentrations of CH4 are continuing to increase, making CH4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH4 sources that overlap geographically, and from the destruction of CH4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (∼ biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models, inventories and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations).

For the 2003–2012 decade, global methane emissions are estimated by top-down inversions at 558 Tg CH4 yr−1, range 540–568. About 60 % of global emissions are anthropogenic (range 50–65 %). Since 2010, the bottom-up global emission inventories have been closer to methane emissions in the most carbon-intensive Representative Concentrations Pathway (RCP8.5) and higher than all other RCP scenarios. Bottom-up approaches suggest larger global emissions (736 Tg CH4 yr−1, range 596–884) mostly because of larger natural emissions from individual sources such as inland waters, natural wetlands and geological sources. Considering the atmospheric constraints on the top-down budget, it is likely that some of the individual emissions reported by the bottom-up approaches are overestimated, leading to too large global emissions. Latitudinal data from top-down emissions indicate a predominance of tropical emissions (∼ 64 % of the global budget, < 30° N) as compared to mid (∼ 32 %, 30–60° N) and high northern latitudes (∼ 4 %, 60–90° N). Top-down inversions consistently infer lower emissions in China (∼ 58 Tg CH4 yr−1, range 51–72, −14 %) and higher emissions in Africa (86 Tg CH4 yr−1, range 73–108, +19 %) than bottom-up values used as prior estimates. Overall, uncertainties for anthropogenic emissions appear smaller than those from natural sources, and the uncertainties on source categories appear larger for top-down inversions than for bottom-up inventories and models.

The most important source of uncertainty on the methane budget is attributable to emissions from wetland and other inland waters. We show that the wetland extent could contribute 30–40 % on the estimated range for wetland emissions. Other priorities for improving the methane budget include the following: (i) the development of process-based models for inland-water emissions, (ii) the intensification of methane observations at local scale (flux measurements) to constrain bottom-up land surface models, and at regional scale (surface networks and satellites) to constrain top-down inversions, (iii) improvements in the estimation of atmospheric loss by OH, and (iv) improvements of the transport models integrated in top-down inversions. The data presented here can be downloaded from the Carbon Dioxide Information Analysis Center (http://doi.org/10.3334/CDIAC/GLOBAL_METHANE_BUDGET_2016_V1.1 (http://doi.org/10.3334/CDIAC/GLOBAL_METHANE_BUDGET_2016_V1.1)) and the Global Carbon Project.

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 16, 2016, 06:45:02 PM
Due to political pressure Alley typically errs on the side of least drama; however, he is well aware that DeConto's projected SLR contributions from Antarctic would result in significantly higher SLR by 2100 than the 2 m that he acknowledges in the linked reference:

Michael Oppenheimer & Richard B. Alley (16 Dec 2016), "How high will the seas rise?" Science, Vol. 354, Issue 6318, pp. 1375-1377, DOI: 10.1126/science.aak9460. 

http://science.sciencemag.org/content/354/6318/1375 (http://science.sciencemag.org/content/354/6318/1375)


Summary: "Recent estimates suggest that global mean sea level rise could exceed 2 m by 2100. These projections are higher than previous ones and are based on the latest understanding of how the Antarctic Ice Sheet has behaved in the past and how sensitive it is to future climate change. They pose a challenge for scientists and policy-makers alike, requiring far-reaching decisions about coastal policies to be made based on rapidly evolving projections with large, persistent uncertainties. An effective approach to managing coastal risk should couple research priorities to policy needs, enabling judicious decision-making while focusing research on key questions."

See also the following linked article entitled: "The maddening, uncertain reality of sea-level rise".

http://www.vox.com/energy-and-environment/2016/12/16/13971720/sea-level-rise-uncertainty-climate (http://www.vox.com/energy-and-environment/2016/12/16/13971720/sea-level-rise-uncertainty-climate)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on December 16, 2016, 08:40:02 PM
Ever paper and website I can find about methane (CH₄) attribute rapid increases to something other than fossil fuels.


It should be noted that the recent isotopic studies involved that came to this conclusion (increased tropical wetland emissions since 2007) neglected to observe that there was a striking decline in the OH oxidation sink in the upper Troposphere, leading to a false signal of increased lower isotopic methane abundances.  There is likely more fossil fuel emissions than these recent studies are indicating.

That being said, fugitive methane leaks from improperly sealed legacy wells are a primary cause of aquifer contamination.  It should be noted that, on a 200-year timeline, the failure rate of ALL capped wells (even the most resilient) is 100%

however, I must ask that you move these posts to the (no offense meant!) :-)  'stupid questions' thread,  http://forum.arctic-sea-ice.net/index.php/topic,143.0.html (http://forum.arctic-sea-ice.net/index.php/topic,143.0.html)  or maybe the methane threads under 'science'  this post has nothing to do with sea level rise.

thanks!
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: GeoffBeacon on December 16, 2016, 10:31:14 PM
ASLR

Thanks again. I'm worrying that this is getting a bit off-topic for this thread - only slightly because SLCF does contribute to sea-level rise through atmospheric warming and the dark snow effect. (But should this be in another thread?) You say
Quote
I cannot answer your questions in an exact manner, but if you assume that Allen et. al. (2016) are telling decision makers that they can discount the importance of acting immediately on reducing anthropogenic SLCP emissions, then to me this is clearly an incorrect interpretation...
My impression is that Myles Allen and Ray Pierrehumbert have been downplaying the role of SLCF, particularly methane, for some time but it may not be obvious in this paper. Actually, I read it last week and it did make some things clearer to me. It is well written.

However, I have worried about their apparent leniency on methane for a few years now. See "Now CO2 is short lived, cows really are bad (http://www.brusselsblog.co.uk/now-co2-is-short-lived-cows-really-are-bad/). (I'm a bit embarrassed by the title.) Here I quote Pierrehumbert as saying in  Losing time not buying time (http://www.realclimate.org/index.php/archives/2010/12/losing-time-not-buying-time/)

Quote
Suppose we are outrageously successful, and knock down anthropogenic methane emissions to zero, which would knock back atmospheric methane to a pre-industrial concentration of around 0.8 ppm… This gives us a one-time cooling of 0.4°C.
And
Quote
… since methane responds within a decade to emissions reductions, we still get the full climate benefit of reducing methane even if the actions are deferred to 2040.
In The exit strategy (2009) (http://www.nature.com/climate/2009/0905/full/climate.2009.38.html), Myles Allen and others said
Quote
Short-term measures that reduce 2020 emissions of potent but short-lived gases but commit to greater emissions of CO2 overall could actually be counterproductive.
Strictly this is correct. “Reduce methane emissions to go easy on carbon dioxide emissions” is dangerous but it has the worrying implication “Concentrate on carbon dioxide, go easy on methane” – a message that may have been transmitted to UK Government Departments. In a reply to me, David Mackay, then Chief Scientist at DECC, wrote “[there is the] competing argument from Myles Allen et. al. that methane has too ‘high’ a rating ”. Myles may have been technically correct in some sense but the wrong message may have been received by the policy makers.

In Cutting soot and methane distracts from 2C goal, says Oxford scientist (https://www.carbonbrief.org/cutting-soot-and-methane-distracts-from-2c-goal-says-oxford-scientist), Carbon Brief reported

Quote
Most countries are focusing on reducing CO2 and [methane and soot] at the same time. But a new policy paper by Myles Allen, professor of geosystem science at the Oxford Martin School at the University of Oxford, says that reducing [methane and soot] while CO2 emissions are still rising could make it more difficult to hit the 2C goal.


Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 17, 2016, 01:15:32 AM
ASLR

Thanks again. I'm worrying that this is getting a bit off-topic for this thread - only slightly because SLCF does contribute to sea-level rise through atmospheric warming and the dark snow effect. (But should this be in another thread?) You say

Geoff,

As jai started this threads and believes that we should stay focused on SLR instead of methane impacts, I recommend that we move the discussion to the thread entitled: "Methane leaks could negate climate benefits of US natural gas boom", as in my opinion Myles Allen is likely downplaying the impacts of methane in order to take pressure off the shale gas industry.

https://forum.arctic-sea-ice.net/index.php/topic,354.0.html

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on December 17, 2016, 03:52:33 PM
Re: post on nov 27 by bligh8 referring to freddie mac april call

its at
http://www.freddiemac.com/finance/report/20160426_lifes_a_beach.html (http://www.freddiemac.com/finance/report/20160426_lifes_a_beach.html)

"In the housing crisis, a significant share of borrowers continued to make their mortgage payments even though the values of their homes were less than the balances of their mortgages. It is less likely that borrowers will continue to make mortgage payments if their homes are literally underwater."

"Or, alternatively, will the value of the house—and all the houses around it—plunge the first time a lender refuses to make a mortgage on a nearby house or an insurer refuses to issue a homeowner's policy? Or will the trigger be one or two homeowners who decide to sell defensively?"

game of chicken.

has links to flood maps. the new ones have real estate types squawking loud and long.

sidd


Home prices behave just like any other item we purchase but we act as if this is not the case. And it is absolutely necessary that we treat this purchase differently than buying, say, a carton of milk. If we didn't the home real estate market would disappear instantly.

Both homes and milk are consumed but we treat homes as a capital investment and the informed consumer makes their decision based on expectations going out to their personal event horizon (How long do they expect to own their home and what will the value of this property be when I sell?) If milk futures are expected to drop dramatically, we're still going to buy that gallon of milk. Conversely, if milk prices are expected to rise dramatically, we won't likely go out and buy more milk than we need but this is exactly what we do for homes. People buy homes to consume and as an investment. It is the rare consumer of homes that makes their purchase by comparing the relative costs of renting or buying a comparable dwelling.

As soon as the investment potential declines or disappears for homes in a region, the demand and prices for these homes will plummet. When this happens, banks won't issue mortgages, insurance companies won't insure properties from loss and consumers won't buy them. So, how much is a home worth that you can't sell?

The answer is not as simple as it would seem. Certainly a perfectly fine dwelling, located in a nice neighborhood that will likely be abandoned within a decade is worth something. The answer is that this home is no longer an investment but its value is based on it being treated as a consumable. How much per month does it cost to live in this pretty nice house (Just look at those granite counter tops!) in an attractive neighborhood. Supply and demand will still determine the value of these homes but the value will be based on what it can be rented for and how long you expect to be able to rent it.

Do you want an accurate market assessment of the egregious impacts of AGW on regional housing markets? Do you want to anticipate what communities will be abandoned first? Follow the change in purchase/rent ratios. Individual consumers will make personal decisions based on their knowledge about a local market. If they expect home prices to stagnate or decline but still need (It's where they work.) or want (What a beautiful place to retire!) to live in the community they will choose to rent. In the aggregate, these individual decisions will be a highly predictive tool.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on December 25, 2016, 11:33:35 PM
"To be or not the be …" is not the only question; there is also: "How soon and how fast"?  I am concerned that if we do not properly address the later questions then the climate change impacts that society faces will be greater than then otherwise could be.

Soheil Shayegh, Juan Moreno-Cruz, Ken Caldeira. Adapting to rates versus amounts of climate change: a case of adaptation to sea-level rise. Environmental Research Letters, 2016; 11 (10): 104007 DOI: 10.1088/1748-9326/11/10/104007

http://iopscience.iop.org/article/10.1088/1748-9326/11/10/104007/meta;jsessionid=2A4CF29FADA7A9B74E6A877ECE51DCEE.ip-10-40-1-105 (http://iopscience.iop.org/article/10.1088/1748-9326/11/10/104007/meta;jsessionid=2A4CF29FADA7A9B74E6A877ECE51DCEE.ip-10-40-1-105)

Abstract: "Adaptation is the process of adjusting to climate change in order to moderate harm or exploit beneficial opportunities associated with it. Most adaptation strategies are designed to adjust to a new climate state. However, despite our best efforts to curtail greenhouse gas emissions, climate is likely to continue changing far into the future. Here, we show how considering rates of change affects the projected optimal adaptation strategy. We ground our discussion with an example of optimal investment in the face of continued sea-level rise, presenting a quantitative model that illustrates the interplay among physical and economic factors governing coastal development decisions such as rate of sea-level rise, land slope, discount rate, and depreciation rate. This model shows that the determination of optimal investment strategies depends on taking into account future rates of sea-level rise, as well as social and political constraints. This general approach also applies to the development of improved strategies to adapt to ongoing trends in temperature, precipitation, and other climate variables. Adaptation to some amount of change instead of adaptation to ongoing rates of change may produce inaccurate estimates of damages to the social systems and their ability to respond to external pressures."

See the associated article entitled: "How fast will we need to adapt to climate change?"

https://www.sciencedaily.com/releases/2016/10/161004113130.htm (https://www.sciencedaily.com/releases/2016/10/161004113130.htm)

Summary: "What would we do differently if sea level were to rise one foot per century versus one foot per decade? Until now, most policy and research has focused on adapting to specific amounts of climate change and not on how fast that climate change might happen. Using sea-level rise as a case study, researchers have developed a quantitative model that considers different rates of sea-level rise, in addition to economic factors, and shows how consideration of rates of change affect optimal adaptation strategies.


See also:
http://phys.org/news/2016-10-fast-climate.html (http://phys.org/news/2016-10-fast-climate.html)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Buddy on January 16, 2017, 07:36:55 PM
Anyone know of a more RECENT reading on sea level rise than July 30, 2016?  I was looking for something near the end of 2016.



Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 16, 2017, 07:55:45 PM
Buddy,

Here is a plot of the Jason-2 satellite SLR measurements to Oct 22 2016 per Aviso:

http://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level/products-images.html (http://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level/products-images.html)

Best,
ASLR
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Buddy on January 16, 2017, 08:00:47 PM
Quote
Here is a plot of the Jason-2 satellite SLR measurements to Oct 22 2016 per Aviso:/quote]

AbruptSLR...thank you much :)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: DrTskoul on January 20, 2017, 03:04:05 AM
Study of past warming signals major sea level rise ahead (https://m.phys.org/news/2017-01-major-sea.html)

http://science.sciencemag.org/cgi/doi/10.1126/science.aai8464 (http://science.sciencemag.org/cgi/doi/10.1126/science.aai8464)

Quote
.. The findings in the journal Science show that ocean surface temperatures during the Earth's last warm period, some 125,000 years ago, were remarkably similar to today.

But what concerns scientists is that sea level back then was 20-30 feet (six to nine meters) above what it is today...
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on January 20, 2017, 04:52:23 PM
New worst-case scenario by NOAA for global (and regional) sea level rise:
https://tidesandcurrents.noaa.gov/publications/techrpt83_Global_and_Regional_SLR_Scenarios_for_the_US_final.pdf

For RCP8.5 they estimate a 0.1% chance of 2.5m in 2100 and 9.7m in 2200, with from 2150 to 2200 an average rise of 84 cm per decade.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: longwalks1 on January 21, 2017, 08:28:40 PM
I can't help but be sarcastic about the "US_final.pdf" part of the url.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 23, 2017, 01:13:48 AM
Study of past warming signals major sea level rise ahead (https://m.phys.org/news/2017-01-major-sea.html)

http://science.sciencemag.org/cgi/doi/10.1126/science.aai8464 (http://science.sciencemag.org/cgi/doi/10.1126/science.aai8464)

Quote
.. The findings in the journal Science show that ocean surface temperatures during the Earth's last warm period, some 125,000 years ago, were remarkably similar to today.

But what concerns scientists is that sea level back then was 20-30 feet (six to nine meters) above what it is today...

Here is any image of the submerged lands (in red) 125,000 years ago
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: DrTskoul on January 23, 2017, 01:41:03 AM
What is depicted by red?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on January 23, 2017, 01:59:11 AM
What is depicted by red?

The land that was submerged 125,000 years ago that are not yet submerged today; but by extension may well be submerged (either just submerged or very substantially submerged) sometime in the future.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: magnamentis on January 23, 2017, 11:55:24 AM
i think that at same temps there was more land submerged because it took much longer for the temps to rise, hence in the process give more time for the ice to melt.

this time the warming process is significantly faster which leaves the SLR behind but there is no doubt IMO that it will catch up eventually and probably with force, means very quickly (abruptly LOL) as compared to past occurrences.

in short, i think that it's the speed of events that explain the difference of lower sea levels at same temps.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on February 10, 2017, 05:35:48 PM
A new study looks at regional sea level rise impacts in North America, using the projections from the U.S. National Climate assessment they find that some communities in the North East will experience tidal flooding up to 3 times per week by 2040.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0170949 (http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0170949)

Sea level rise drives increased tidal flooding frequency at tide gauges along the U.S. East and Gulf Coasts: Projections for 2030 and 2045

    Kristina A. Dah et al

Abstract

Tidal flooding is among the most tangible present-day effects of global sea level rise. Here, we utilize a set of NOAA tide gauges along the U.S. East and Gulf Coasts to evaluate the potential impact of future sea level rise on the frequency and severity of tidal flooding. Using the 2001–2015 time period as a baseline, we first determine how often tidal flooding currently occurs. Using localized sea level rise projections based on the Intermediate-Low, Intermediate-High, and Highest projections from the U.S. National Climate Assessment, we then determine the frequency and extent of such flooding at these locations for two near-term time horizons: 2030 and 2045. We show that increases in tidal flooding will be substantial and nearly universal at the 52 locations included in our analysis. Long before areas are permanently inundated, the steady creep of sea level rise will force many communities to grapple with chronic high tide flooding in the next 15 to 30 years.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on February 11, 2017, 07:19:12 PM
Article based on the PLOS ONE study described in comment #657:

Coastal Cities Could Flood Three Times a Week by 2045
Quote
The lawns of homes purchased this year in vast swaths of coastal America could regularly be underwater before the mortgage has even been paid off, with new research showing high tide flooding could become nearly incessant in places within 30 years.

Such floods could occur several times a week on average by 2045 along the mid-Atlantic coastline, where seas have been rising faster than nearly anywhere else, and where lands are sagging under the weight of geological changes.

Washington and Annapolis, Md. could see more than 120 high tide floods every year by 2045, or one flood every three days, according to the study, published last week in the journal PLOS ONE. That’s up from once-a-month flooding in mid-Atlantic regions now, which blocks roads and damages homes.

“The flooding would generally cluster around the new and full moons,” said Erika Spanger-Siegfried, a Union of Concerned Scientists analysts who helped produce the new study. “Many tide cycles in a row would bring flooding, this would peter out, and would then be followed by a string of tides without flooding.”

The analysis echoed findings from previous studies, though it stood out in part because of its focus on impacts that are expected within a generation — instead of, say, by the end of the century....
http://www.climatecentral.org/news/coastal-cities-flood-three-times-a-week-2045-21153 (http://www.climatecentral.org/news/coastal-cities-flood-three-times-a-week-2045-21153)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on February 16, 2017, 06:34:45 PM
heinrich events were caused by warming oceans, not air as previously thought and the implications for Thwaites and PIG are devastating.

https://www.sciencedaily.com/releases/2017/02/170215131551.htm (https://www.sciencedaily.com/releases/2017/02/170215131551.htm)

Quote
"We're seeing ocean warming in those region and we're seeing these regions start to change. In that area, they're seeing ocean temperature changes of about 2.7 degrees Fahrenheit," Bassis said. "That's pretty similar magnitude as we believe occurred in the Laurentide events, and what we saw in our simulations is that just a small amount of ocean warming can destabilize a region if it's in the right configuration, and even in the absence of atmospheric warming."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on February 22, 2017, 01:06:25 AM
The linked article is entitled: "Think States Alone Can't Handle Sea Level Rise?  Watch California".

https://www.wired.com/2017/02/think-states-alone-cant-handle-sea-level-rise-watch-california/ (https://www.wired.com/2017/02/think-states-alone-cant-handle-sea-level-rise-watch-california/)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on March 13, 2017, 10:16:33 PM
Abadie et al 2016:
http://journal.frontiersin.org/article/10.3389/fmars.2016.00265/full (http://journal.frontiersin.org/article/10.3389/fmars.2016.00265/full)

Climate Risk Assessment under Uncertainty: An Application to Main European Coastal Cities

Abstract:
This paper analyses the risk of extreme coastal events in major European coastal cities using a stochastic diffusion model that is calibrated with the worst case emission scenario from the Intergovernmental Panel for Climate Change (IPCC), i.e., the representative concentration pathway (RCP) 8.5. The model incorporates uncertainty in the sea-level rise (SLR) distribution. Expected mean annual losses are calculated for 19 European coastal cities, together with two risk measures: the Value at Risk (VaR) and the Expected Shortfall (ES). Both measures are well-known in financial economics and enable us to calculate the impact of the worst SLR paths under uncertainty. The results presented here can serve as valuable inputs for cities in deciding how much risk they are willing to accept, and consequently how much adaptation they need depending on the risk aversion of their decision-makers.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Archimid on March 15, 2017, 10:46:15 PM
My apologies for the duplicate thread. I couldn't find this thread so I started a new one. I'll repost the contents of the other thread here.

This is a thread to post links to real world examples of the impacts of sea level rise. Sea level rise is no longer a future threat. It is a clear and present danger.

I'll start with this:

USA – Louisiana Wetlands Struggling With Sea-Level Rise 4 Times the Global Average

http://floodlist.com/america/usa/louisiana-wetlands-sea-level-rise (http://floodlist.com/america/usa/louisiana-wetlands-sea-level-rise)

Extract:
Quote
The study by researchers in Tulane’s Department of Earth and Environmental Sciences and published in the open-access journal Nature Communications shows that the rate of sea-level rise in the region over the past six to 10 years amounts to half an inch per year on average
.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Archimid on March 15, 2017, 10:47:10 PM
SeaIceSailor posted the following in the closed thread:

A few months old report but kind of fits, the text of the link is a good summary

https://www.scientificamerican.com/article/sea-level-rise-swallows-5-whole-pacific-islands/# (https://www.scientificamerican.com/article/sea-level-rise-swallows-5-whole-pacific-islands/#)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on March 16, 2017, 04:10:02 PM
Vousdoukas et al 2017, Extreme sea levels on the rise along Europe's coasts:
http://onlinelibrary.wiley.com/doi/10.1002/2016EF000505/full (http://onlinelibrary.wiley.com/doi/10.1002/2016EF000505/full)

Abstract
Future extreme sea levels (ESLs) and flood risk along European coasts will be strongly impacted by global warming. Yet, comprehensive projections of ESL that include mean sea level (MSL), tides, waves, and storm surges do not exist. Here, we show changes in all components of ESLs until 2100 in view of climate change. We find that by the end of this century, the 100-year ESL along Europe's coastlines is on average projected to increase by 57 cm for Representative Concentration Pathways (RCP)4.5 and 81 cm for RCP8.5. The North Sea region is projected to face the highest increase in ESLs, amounting to nearly 1 m under RCP8.5 by 2100, followed by the Baltic Sea and Atlantic coasts of the UK and Ireland. Relative sea level rise (RSLR) is shown to be the main driver of the projected rise in ESL, with increasing dominance toward the end of the century and for the high-concentration pathway. Changes in storm surges and waves enhance the effects of RSLR along the majority of northern European coasts, locally with contributions up to 40%. In southern Europe, episodic extreme events tend to stay stable, except along the Portuguese coast and the Gulf of Cadiz where reductions in surge and wave extremes offset RSLR by 20–30%. By the end of this century, 5 million Europeans currently under threat of a 100-year ESL could be annually at risk from coastal flooding under high-end warming. The presented dataset is available through this link: http://data.jrc.ec.europa.eu/collection/LISCOAST. (http://data.jrc.ec.europa.eu/collection/LISCOAST.)

Plain Language Summary
Future extreme sea levels and flood risk along European coasts will be strongly impacted by global warming. Here, we show changes in all acting components, i.e., sea level rise, tides, waves, and storm surges, until 2100 in view of climate change. We find that by the end of this century the 100-year event along Europe will on average increase between 57 and 81 cm. The North Sea region is projected to face the highest increase, amounting to nearly 1 m under a high emission scenario by 2100, followed by the Baltic Sea and Atlantic coasts of the UK and Ireland. Sea level rise is the main driver of the changes, but intensified climate extremes along most of northern Europe can have significant local effects. Little changes in climate extremes are shown along southern Europe, with the exception of a projected decrease along the Portuguese coast and the Gulf of Cadiz, offseting sea level rise by 20–30%. By the end of this century, 5 million Europeans currently under threat of a 100-year coastal flood event could be annually at risk from coastal flooding under high-end warming.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Archimid on March 20, 2017, 03:33:58 PM
Nothing new for those on the know, but still nice video.


Sea level rise: Miami and Atlantic city fight to stay above water – video:

https://www.theguardian.com/us-news/video/2017/mar/20/sea-level-rise-miami-and-atlantic-city-fight-to-stay-above-water-video (https://www.theguardian.com/us-news/video/2017/mar/20/sea-level-rise-miami-and-atlantic-city-fight-to-stay-above-water-video)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Jontenoy on March 20, 2017, 03:45:48 PM
Hi All
This is my first blog on your wonderful site which I have been watching for nearly a year.
Today NASA announced that Greeland and Antarctic are losing 400 gigatons of ice / year. I have just calculated this as giving 2.38 mm / year height increase. Water thermal expansion + glacial and other surface ice would be in addition to this (also aquafier surface pumping). Does this seem a bit high ?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: solartim27 on March 20, 2017, 04:07:49 PM
Does this seem a bit high ?
Nope
https://forum.arctic-sea-ice.net/index.php/topic,874.msg99463.html#msg99463
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on March 20, 2017, 05:42:16 PM
Yes, it does sound too high.
NASA said on March 15th:
https://sealevel.nasa.gov/news/76/grace-mission-15-years-of-watching-water-on-earth

"Since GRACE launched, its measurements show Greenland has been losing about 280 gigatons of ice per year on average — a bit less than twice the weight of Mt. Everest — and Antarctica has lost slightly under 120 gigatons a year."

So the 400 gigatons/yr is for Greenland and Antarctica combined, not separately. This means 1.11 mm/yr of SLR from both ice sheets combined, not 2.38 mm/yr.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on March 21, 2017, 03:25:18 PM
Atlantic City and Miami Beach: two takes on tackling the rising waters
Sea level rise is making floods more common and as the New Jersey resort braces for the next Sandy, the well-heeled Florida city is throwing money at the problem
Quote
“We can have floods at the drop of a hat,” Burke said. “Without even realizing we’re going to have them. It’ll be raining and within seconds you’ll see flooding in the street. You don’t read about it in the paper. You don’t hear about it on the radio or television. You just have water that just comes up and if you don’t have warning and move your car, you have water in the car.”

These flooding events have increased seven-fold in Atlantic City since the 1950s, according to the National Oceanic and Atmospheric Administration, and are spurred by rainfall or simply a spring tide abetted by unhelpful gusts of wind. ...
https://www.theguardian.com/us-news/2017/mar/20/atlantic-city-miami-beach-sea-level-rise (https://www.theguardian.com/us-news/2017/mar/20/atlantic-city-miami-beach-sea-level-rise)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: rboyd on March 21, 2017, 05:40:12 PM
A single section of the article sums things up so well

"Retreat isn’t on the agenda, but as in Atlantic City there’s an equity issue at play. The affluent can afford to raise their homes, lobby for sea walls and water pumps, and stay in a nice hotel if it all gets a bit much".

The rich/affluent can afford to insulate themselves in the short term, so that they can live as they have become accustomed to, including low taxes and "small government". Of course the longer-term may be a lot quicker in coming than they expect (e.g. Hansen's ice sheet melt doubling rates). Should be spending their money to get a climate activist in the White House and as Governor of Florida, and accepting a high (realistic) social cost of carbon reflected in carbon taxes.

Also should read "Nature is putting retreat on the agenda", but as soon as we accept that all that expensive real estate will lose value very fast. The banks would take a huge hit.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on March 22, 2017, 04:10:12 PM
The linked article is entitled: "Ice cap in place for millions of years is on track to vanish"; & it states that the loss of small glaciers, like Barnes Ice Cap, will likely accelerate in the near future thus accelerating sea level rise.

http://www.eenews.net/stories/1060051765 (http://www.eenews.net/stories/1060051765)

Extract: "Global warming is causing significant melting throughout the region and will claim the last remnants of a massive ice sheet that once covered all of North America and that remained stable for 2,000 years, according to findings published yesterday in Geophysical Research Letters, a journal of the American Geophysical Union. The Barnes Ice Cap, which is about the size of Delaware and is located on Baffin Island in the Canadian Arctic, is likely to disappear even if humanity curtails its combustion of fossil fuels at levels not currently expected, even under the most conservative estimations.

All of those suggest a much higher sea level in the near future. Sea-level rise is now coming from small glaciers, such as the Barnes Ice Cap, as well as the expansion of the sea as it gets warmer. But that could quickly change if the current level of warming is observed, Miller said."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Dry_Land_Is_Not_A_Myth on March 24, 2017, 02:02:17 AM
Newbie here,
What are the best places to view sea level rise data? I've been looking at http://sealevel.colorado.edu/ (http://sealevel.colorado.edu/) . Anyone know of real time measurements or more than 2-3 monthly updates? Relatedly, it seems like sealevel.colorado should have updated by now. Anyone know if it's still ongoing? 
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Neven on March 24, 2017, 07:33:37 AM
Welcome to the ASIF, Dry_Land_Is_Not_A_Myth, our profile has been released.

As for our question, I also watch the University of Colorado graph (occasionally), but I would expect there are others as well.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wehappyfew on March 24, 2017, 02:20:31 PM
Welcome DLiNaM,

My new favorite SLR viewer is here:

http://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level/products-images.html (http://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level/products-images.html)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Laurent on March 26, 2017, 06:26:27 PM
Jontenoy, the rumor I hear is that 1mm of SLR is 360GT of ice melted without Thermal expansion. Sounds nearly ok if I calculate with my big fingers.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Bill Fothergill on March 29, 2017, 02:48:46 PM
Newbie here,
What are the best places to view sea level rise data? I've been looking at http://sealevel.colorado.edu/ (http://sealevel.colorado.edu/) . Anyone know of real time measurements or more than 2-3 monthly updates? Relatedly, it seems like sealevel.colorado should have updated by now. Anyone know if it's still ongoing?
You can also try the NASA vital signs pages...
https://climate.nasa.gov/vital-signs/sea-level/

This has recently updated, and it appears we will soon have a new record for Mean Sea Level Rise (MSLR).

Early March 2016 saw a value of 88.5mm above baseline. After falling back to 83.2mm by mid August, it has started to climb rapidly again. The latest value (Jan 4th 2017) is 88.2mm, or just 0.3mm below the record. MSLR is showing little, or no, sign of slowing.

Hi All
This is my first blog on your wonderful site which I have been watching for nearly a year.
Today NASA announced that Greeland and Antarctic are losing 400 gigatons of ice / year. I have just calculated this as giving 2.38 mm / year height increase. Water thermal expansion + glacial and other surface ice would be in addition to this (also aquafier surface pumping). Does this seem a bit high ?
Here's the arithmetic needed to do the calculation. (NB I rounded certain values, and ignored the differing densities of fresh water and sea water.)

1 litre (10x10x10 cm) of water has a mass of ~ 1kg
1 cubic metre of water therefore has a mass of ~ 1 tonne
1 cubic km of water therefore has a mass of ~ 1 Gigatonne (Gt)

The surface area of the planet is ~ 511 million sq kms
The oceanic surface area is approx 70% of this, or ~ 358 million sq kms

1Gt of melted ice (1 cubic km) spread over this oceanic surface would equate to an increase in sea level of (1/358,000,000 kms) or (1/358 millimetres)

400Gt of melted ice would therefore equate to 400/358 millimetres, which is ~ 1.12mm
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Archimid on April 06, 2017, 03:05:49 AM
Miami's fight against sea level rise

http://www.bbc.com/future/story/20170403-miamis-fight-against-sea-level-rise (http://www.bbc.com/future/story/20170403-miamis-fight-against-sea-level-rise)

Extract:
Quote
Just down the coast from Donald Trump's weekend retreat, the residents and businesses of south Florida are experiencing regular episodes of water in the streets. In the battle against rising seas, the region – which has more to lose than almost anywhere else in the world – is becoming ground zero.

I thought this article had great imagery.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: jai mitchell on April 06, 2017, 03:25:03 AM
Dr. Eric Rignot gave a captivating lecture on projections of sea level rise here:

https://www.youtube.com/watch?v=AAPPq43iRLs (https://www.youtube.com/watch?v=AAPPq43iRLs)

5 min highlight of his talk here:

https://www.youtube.com/watch?v=u3ivlofypzE (https://www.youtube.com/watch?v=u3ivlofypzE)

very interesting to hear how the discussion within the IPCC has changed and how they are still discussing this issue as though we have not already locked in 3 meters of SLR by 2100.  In addition, the projections of 8-9 meters of locked in sea level rise under 2C is not on 2,000 year time lines but rather closer to 200 years.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: DrTskoul on April 08, 2017, 03:33:52 AM
Rising Waters Threaten China’s Rising Cities (https://www.nytimes.com/interactive/2017/04/07/world/asia/climate-change-china.html?hp&action=click&pgtype=Homepage&clickSource=story-heading&module=second-column-region&region=top-news&WT.nav=top-news)

Quote
The rising South China Sea and the overstressed Pearl River network lie just a meter or so below much of this new multitrillion-dollar development — and they are poised to drown decades of progress, scrambling global supply chains and raising prices on a world of goods like smartphones, T-shirts, biopharmaceuticals and even the tiny springs inside your ballpoint pens.

As always, climate change works like an opportunistic pathogen, worsening existing woes, not acting alone. This can make it hard to pin down, easy to dismiss. Notoriously, China today is crippled by air pollution, linked to local emissions from coal-fired power plants, steel factories and cars. New research shows that rising temperatures and stagnant air resulting from climate change — caused largely by worldwide emissions of carbon dioxide — are exacerbating China’s smog crisis, which has contributed to millions of premature deaths.

The Chinese government has become an outspoken voice on climate change. President Xi Jinping, who is meeting this week with President Trump, has urged the signatories of the 2015 Paris climate accord to follow through on their pledge, while state-run Chinese media has criticized the Trump administration for “brazenly shirking its responsibility on climate change.”

China is now the world leader in domestic investment in renewable energy, and over the past decade the central authorities in Beijing have made environmental performance a higher priority for civil servants. But stronger mandates haven’t yet overcome the pace of expansion, a decentralized fiscal system, lax enforcement and a culture that frequently pits growth against green. The country continues to consume as much coal as the rest of the world combined, and to increase its steel capacity.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on April 08, 2017, 01:51:12 PM
Le Bars et al 2017, A high-end sea level rise probabilistic projection including rapid Antarctic ice sheet mass loss:
http://iopscience.iop.org/article/10.1088/1748-9326/aa6512 (http://iopscience.iop.org/article/10.1088/1748-9326/aa6512)

Abstract
The potential for break-up of Antarctic ice shelves by hydrofracturing and following ice cliff instability might be important for future ice dynamics. One recent study suggests that the Antarctic ice sheet could lose a lot more mass during the 21st century than previously thought. This increased mass-loss is found to strongly depend on the emission scenario and thereby on global temperature change. We investigate the impact of this new information on high-end global sea level rise projections by developing a probabilistic process-based method. It is shown that uncertainties in the projections increase when including the temperature dependence of Antarctic mass loss and the uncertainty in the Coupled Model Intercomparison Project Phase 5 (CMIP5) model ensemble. Including these new uncertainties we provide probability density functions for the high-end distribution of total global mean sea level in 2100 conditional on emission scenario. These projections provide a probabilistic context to previous extreme sea level scenarios developed for adaptation purposes.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on April 08, 2017, 10:25:31 PM
Worst-case sea level rise estimates in 2100 by Le Bars et al 2017: 2-3m (RCP8.5) & 1-2m (RCP4.5). This could imply 4-5m in 2200, even with pretty strong mitigation. All the more reason, if that was still needed, to make sure the Paris Agreement is implemented and warming kept well below 2C.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: TerryM on April 08, 2017, 11:00:41 PM
Worst-case sea level rise estimates in 2100 by Le Bars et al 2017: 2-3m (RCP8.5) & 1-2m (RCP4.5). This could imply 4-5m in 2200, even with pretty strong mitigation. All the more reason, if that was still needed, to make sure the Paris Agreement is implemented and warming kept well below 2C.


How???


Terry
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on April 08, 2017, 11:32:40 PM
How? Good question. Kevin Anderson for one proposes system change and a Marshall Plan style approach:
https://www.youtube.com/watch?v=jIODRrnHQxg&feature=youtu.be (https://www.youtube.com/watch?v=jIODRrnHQxg&feature=youtu.be)

Not likely we'll succeed, but maybe not completely impossible either, yet.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: sidd on April 09, 2017, 08:00:41 AM
I think Greenland will melt in place, but not catastrophically. I think WAIS will go, catastrophically. The only question in my mind is timescale. Every indication is decades, not centuries. When global SLR hits 10mm/yr i think people might wake up. Especially since so many live so close to the ocean.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on April 09, 2017, 09:48:44 AM
How???

If not thru system change, then maybe thru making 2020 the global climate turning point, as proposed by Michael Mann, Stefan Rahmstorf, Anders Levermann and others:
http://time.com/4731632/climate-change-2020-trump/ (http://time.com/4731632/climate-change-2020-trump/)

The report is by Carbon Tracker, Climate Action Tracker, PIK and Yale, with a preface by Rahmstorf & Levermann:
http://www.mission2020.global/2020TheClimateTurningPoint.pdf (http://www.mission2020.global/2020TheClimateTurningPoint.pdf)

Yes we can, can't we?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: oren on April 09, 2017, 10:24:29 AM
The sad thing is that we certainly can, but we won't  :'(
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on April 09, 2017, 11:06:37 AM
we won't  :'(

Can you be absolutely 100% sure of this?
It may not be likely, but who knows we'll surprise ourselves.
We won't know unless we try.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: oren on April 09, 2017, 11:56:47 AM
Of course, there is always hope and I'm not saying we shouldn't try. Just that my assessed probability is low, and it saddens me.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on April 09, 2017, 12:23:03 PM
I share your realism and grief.

And yet, or better, because of that, we need all the optimism and hope and moral and creative strength we can find within and among ourselves, to mobilize society to act with the necessary speed and power, as shown so well by Al Gore in his 2016 Ted-talk in Vancouver:
https://www.youtube.com/watch?v=u7E1v24Dllk (https://www.youtube.com/watch?v=u7E1v24Dllk)

Political will is a renewable resource.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on April 09, 2017, 03:38:57 PM
I think Greenland will melt in place, but not catastrophically. I think WAIS will go, catastrophically. The only question in my mind is timescale. Every indication is decades, not centuries. When global SLR hits 10mm/yr i think people might wake up. Especially since so many live so close to the ocean.

Sea level rise will most certainly cause people living along the SE coast of Florida to wake up but it will be to pack their suitcases, load their cars and drive away from their worthless homes for the last time. It will be left to the policy makers to decide what to do with all of these built structures.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: gerontocrat on April 09, 2017, 04:05:34 PM
I think Greenland will melt in place, but not catastrophically. I think WAIS will go, catastrophically. The only question in my mind is timescale. Every indication is decades, not centuries. When global SLR hits 10mm/yr i think people might wake up. Especially since so many live so close to the ocean.

Sea level rise will most certainly cause people living along the SE coast of Florida to wake up but it will be to pack their suitcases, load their cars and drive away from their worthless homes for the last time. It will be left to the policy makers to decide what to do with all of these built structures.

There are many places where sea level rise is and has been at or above 10mm p.a., due to accompanying land subsidence. See below (but don't tell scott pruitt as this epa page talks about climate change).

https://www.epa.gov/climate-impacts/climate-impacts-coastal-areas (https://www.epa.gov/climate-impacts/climate-impacts-coastal-areas)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on April 09, 2017, 11:28:48 PM
The question is what DeConto & Pollard 2016 means for the SLR-probability estimates of NOAA 2017:
https://tidesandcurrents.noaa.gov/publications/techrpt83_Global_and_Regional_SLR_Scenarios_for_the_US_final.pdf

Le Bars et al 2017 give estimates for RCP8.5 and RCP4.5, but what about RCP2.6? Does DeConto & Pollard for example imply a 4% chance of 1m or more in 2100 and 3m or more in 2200? So about double the risk compared to the estimates in tables 4 and 5 of NOAA 2017 below?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Buddy on April 16, 2017, 06:30:24 PM
What is sea level going to do in the coming months and next several years?  Here is one possible look.....

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on April 16, 2017, 06:37:47 PM
What is sea level going to do in the coming months and next several years?  Here is one possible look.....

So that would be almost a doubling of the rate of SLR? From about 3 mm/yr to almost 6 mm/yr...
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Buddy on April 16, 2017, 08:29:57 PM
Quote
So that would be almost a doubling of the rate of SLR? From about 3 mm/yr to almost 6 mm/yr...

As those immortal words say....."it is, what it is."  We have formed a "channel with more slope to it" starting in about 2010.  That is what HAS ALREADY HAPPENED.  The only thing I have done is to "connect the dots".

UNFORTUNATELY.....the "fundamentals" of (1) increasing RATE of atmospheric temperatures, and (2) increased melting of the ice sheets (3) increasing CO2 and methane, etc...........SUPPORT the "technical view" of the chart itself (again....the FUNDAMENTLS form the chart....not the other way around).

The rate of sea level rise as noted by Dr. Hansen in his research has a good chance of being attained....and THAT will be a LOT MORE than 6 mm per year (20 inches per decade....2 INCHES PER YEAR if my memory is correct).   Of course....we're a long ways from that RIGHT NOW....but since we are accelerating, I'm afraid that is going to be all too achievable.

Don't look behind....LOOK AHEAD.

 

 
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: oren on April 16, 2017, 08:30:52 PM
What is sea level going to do in the coming months and next several years?  Here is one possible look.....
Buddy I must say these blue and red straight "trend" lines sure look like cherry-picking. I too fear that there has been some acceleration in SLR in the last few years, but this chart does not show a doubling. The 2010 low was not representative of the previous trend, but its biggest negative anomaly instead. The data points since around 2014/2015 that are above the black trend line are interesting and disturbing but not long enough to form a certain signal.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 16, 2017, 08:44:09 PM
Per the attached Jason-2 SLR series from July 17 2008 to Dec 30 2016, the recent trend line has a slope of at least 4.44 mm/yr
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Buddy on April 16, 2017, 09:37:39 PM
Quote
Buddy I must say these blue and red straight "trend" lines sure look like cherry-picking. I too fear that there has been some acceleration in SLR in the last few years, but this chart does not show a doubling. The 2010 low was not representative of the previous trend, but its biggest negative anomaly instead. The data points since around 2014/2015 that are above the black trend line are interesting and disturbing but not long enough to form a certain signal.

Yes....I can certainly accept that critique.  Changes in TREND are a tricky thing.....because you never know until AFTER they happen.  And differentiating between (1) short term, and (2) intermediate term is fraught with pot holes.

But think about 2 things:

(1) I was ONLY pointing WHAT ALREADY HAS HAPPENED....and what MIGHT HAPPEN over the coming decade or so.  Yes....it is DEFINITELY short term.  Could it just be a short term "blip"....and then head back DOWN to the LONGER TERM TREND LINE?  Sure....it could.

(2) I happen to think that many if not MOST climate scientists have underestimated many things within the climate change realm because they have a CONSERVATIVE BIAS. I think we have begun to see that OVER CONSERVATIVE BIAS come to light over the past few years.....and I think it will continue to "unwind" as accelerating physics play out.

One DISADVANTAGE I have is that I am NOT a "trained scientist".....let alone a trained CLIMATE SCIENTIST.  So that is a disadvantage.

One ADVANTAGE I have is that I am NOT a "trained scientist".....let along a trained CLIMATE SCIENTIST.

Yes....it cuts BOTH WAYS.  I am NOT "weighed down" by looking too closely at every twig and leaf....but instead am looking CLOSELY AT THE BIGGER PICTURE and then "drilling down" to see why "things are happening" on a larger scale (yes....drilling down into what CLIMATE SCIENTSTS are finding).

I have but two simple goals:  (1) Look to see WHAT IS ACTUALLY HAPPENING, and then (2) Look ahead to see where we are likely headed over the next decade and DECADES....and communicate that to others.

We'll see how the sea level plays out over the next 5 years or more....but I DO believe we are in an "accelerating pattern" that will play out over time.....  In the case of sea level rise....within the new "channel" that has been established.

NOTE:  I have input a zig-zag "black line" which shows the SHORT TERM "legs" within the LONGER INTERMEDIATE TERM CHANNEL UP.

Fundamentally.....I believe there will be MORE to come at HIGHER LEVELS of melt in future decades.










Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on April 21, 2017, 05:32:11 AM
The following link leads to a report entitled: "Rising Seas in California – An Update on Sea-Level Rise Science", and includes input by Rob DeConto & Claudia Tebaldi (& see the associated image).

http://www.opc.ca.gov/webmaster/ftp/pdf/docs/rising-seas-in-california-an-update-on-sea-level-rise-science.pdf (http://www.opc.ca.gov/webmaster/ftp/pdf/docs/rising-seas-in-california-an-update-on-sea-level-rise-science.pdf)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Archimid on April 21, 2017, 03:21:49 PM
State of emergency declared for Louisiana coast by Gov. John Bel Edwards

http://www.nola.com/environment/index.ssf/2017/04/state_of_emergency_louisiana_coast.html (http://www.nola.com/environment/index.ssf/2017/04/state_of_emergency_louisiana_coast.html)

Quote
Gov. John Bel Edwards on Wednesday (April 19) officially declared Louisiana's coastal land loss an emergency, a move he hopes will expedite a host of restoration projects mired in federal permitting. "The Louisiana coast is in a state of crisis that demands immediate and urgent action to avert further damage to one of our most vital resources," he said.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: gerontocrat on April 21, 2017, 03:52:54 PM
On the left the official Louisiana Coastline; on the right reality.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: TerryM on April 21, 2017, 04:51:54 PM
A Democratic governor asks a Republican President for funds to help with problems due to climate change.
A Rabbi, a Priest, and a Reverend walk into a bar.


Which will elicit more laughs?


Terry
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on April 22, 2017, 03:11:42 PM
Simple little article making a simple little point....the financial system, the foundation of capitalism, will not be able to withstand the impact of rising sea levels in southeast Florida and this little story will be playing out across the country and world.

https://www.bloomberg.com/news/features/2017-04-19/the-nightmare-scenario-for-florida-s-coastal-homeowners (https://www.bloomberg.com/news/features/2017-04-19/the-nightmare-scenario-for-florida-s-coastal-homeowners)

The difference between this unavoidable financial catastrophe from the housing crisis that tanked the world economy in 2007 is that there will be no recovery of the housing prices.

And this ignores completely the disastrous effects of other climate destruction of the real economy.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on May 18, 2017, 07:50:06 PM
While the linked reference may well err on the side of least drama it is a good first effort to quantify the impacts of potential abrupt sea level rise associated with ice-cliff failure and hydrofracting mechanisms:

Kopp et. al. (2017) "Implications of ice-shelf hydrofracturing and ice-cliff collapse mechanisms for sea-level projections", arXiv:1704.05597v1

https://arxiv.org/pdf/1704.05597.pdf

Abstract: "Probabilistic sea-level projections have not yet integrated insights from physical ice-sheet models representing mechanisms, such as ice-shelf hydrofracturing and ice-cliff collapse, that can rapidly increase ice-sheet discharge. Here, we link a probabilistic framework for sealevel projections to a small ensemble of Antarctic ice-sheet (AIS) simulations incorporating these physical processes to explore their influence on projections of global-mean sea-level (GMSL) and relative sea-level (RSL) change. Under high greenhouse gas emissions (Representative Concentration Pathway [RCP] 8.5), these physical processes increase median projected 21st century GMSL rise from ~80 cm to ~150 cm. Revised median RSL projections would, without protective measures, by 2100 submerge land currently home to > 79 million people, an increase of ~25 million people. The use of a physical model, rather than simple parameterizations assuming constant acceleration, increases sensitivity to forcing: overlap between the central 90% of the frequency distributions for 2100 for RCP 8.5 (93–243 cm) and RCP 2.6 (26–98 cm) is minimal. By 2300, the gap between median GMSL estimates for RCP 8.5 and RCP 2.6 reaches > 10 m, with median RSL projections for RCP 8.5 jeopardizing land now occupied by ~900 million people (vs. ~80 million for RCP 2.6). There is little correlation between the contribution of AIS to GMSL by 2050 and that in 2100 and beyond, so current sea-level observations cannot exclude future extreme outcomes. These initial explorations indicate the value and challenges of developing truly probabilistic sea-level rise projections incorporating complex ice-sheet physics."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on May 18, 2017, 11:03:14 PM
While the linked reference may well err on the side of least drama it is a good first effort to quantify the impacts of potential abrupt sea level rise associated with ice-cliff failure and hydrofracting mechanisms.

Thanks for the reference ASLR. Table 1 below, from Kopp et al 2017, shows the estimates with and without including the results of DC 16 (DeConto & Pollard 2016). RCP4.5 still has a 5% chance of 4.55m in 2200, and RCP2.6 a 5% chance of 2.06m in 2200.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Dry_Land_Is_Not_A_Myth on May 19, 2017, 01:29:40 AM
What do the column labels mean (50, 17-83, 5-95, 1-99, 99.9)?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: oren on May 19, 2017, 07:49:32 AM
What do the column labels mean (50, 17-83, 5-95, 1-99, 99.9)?
Probability ranges.
Edit: Actually explained at the bottom of the table.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 07, 2017, 07:41:44 PM
New analysis on SLR (see image):

Sönke Dangendorf, Marta Marcos, Guy Wöppelmann, Clinton P. Conrad, Thomas Frederikse, and Riccardo Riva (2017, "Reassessment of 20th century global mean sea level rise", PNAS, doi: 10.1073/pnas.1616007114

http://www.pnas.org/content/114/23/5946.short (http://www.pnas.org/content/114/23/5946.short)

Abstract: "The rate at which global mean sea level (GMSL) rose during the 20th century is uncertain, with little consensus between various reconstructions that indicate rates of rise ranging from 1.3 to 2 mm⋅y−1. Here we present a 20th-century GMSL reconstruction computed using an area-weighting technique for averaging tide gauge records that both incorporates up-to-date observations of vertical land motion (VLM) and corrections for local geoid changes resulting from ice melting and terrestrial freshwater storage and allows for the identification of possible differences compared with earlier attempts. Our reconstructed GMSL trend of 1.1 ± 0.3 mm⋅y−1 (1σ) before 1990 falls below previous estimates, whereas our estimate of 3.1 ± 1.4 mm⋅y−1 from 1993 to 2012 is consistent with independent estimates from satellite altimetry, leading to overall acceleration larger than previously suggested. This feature is geographically dominated by the Indian Ocean–Southern Pacific region, marking a transition from lower-than-average rates before 1990 toward unprecedented high rates in recent decades. We demonstrate that VLM corrections, area weighting, and our use of a common reference datum for tide gauges may explain the lower rates compared with earlier GMSL estimates in approximately equal proportion. The trends and multidecadal variability of our GMSL curve also compare well to the sum of individual contributions obtained from historical outputs of the Coupled Model Intercomparison Project Phase 5. This, in turn, increases our confidence in process-based projections presented in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on June 08, 2017, 02:45:55 PM
U.S.:  Report: Sea rise means more tidal flooding this year for New Jersey Shore
Quote
...
The NOAA data show that even without an El Niño, three of the local locations examined, Atlantic City and Sandy Hook in New Jersey and Philadelphia, have all shown a continual increase in nuisance flooding over the last 50 years.

“What I see for Atlantic City and Sandy is an acceleration in the number of days per year in high-tide flooding,” said NOAA’s Billy Sweet, one of the report’s authors. “It’s growing by leaps and bounds. That’s a concern, because ultimately this trend is going to have to be reconciled locally.”
...
http://www.philly.com/philly/health/report-sea-rise-means-more-tidal-flooding-this-year-for-jersey-shore-20170607.html (http://www.philly.com/philly/health/report-sea-rise-means-more-tidal-flooding-this-year-for-jersey-shore-20170607.html)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Archimid on June 12, 2017, 12:09:05 AM
Fantastic video, like all of Vice's reports. Great imagery and sound bites.

Shane Smith Investigates The True Cost of Climate Denial (VICE on HBO: Season 5, Episode 1)

https://youtu.be/9suO4jrwfDE

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on June 12, 2017, 04:45:06 PM
U.S.:  Resettling climate refugees from Louisiana
Quote
In January, the Department of Housing and Urban Development announced grants totaling $1 billion in 13 states to help communities adapt to climate change, by building stronger levees, dams and drainage systems.

One of those grants, $48 million for Isle de Jean Charles, is something new: the first allocation of federal tax dollars to move an entire community struggling with the impacts of climate change. The divisions the effort has exposed and the logistical and moral dilemmas it has presented point up in microcosm the massive problems the world could face in the coming decades as it confronts a new category of displaced people who have become known as climate refugees....
https://www.nytimes.com/2016/05/03/us/resettling-the-first-american-climate-refugees.html (https://www.nytimes.com/2016/05/03/us/resettling-the-first-american-climate-refugees.html)

Electrek says:
Quote
Resettling the First American ‘Climate Refugees’ – $48 million for Isle de Jean Charles, is something new: the first allocation of federal tax dollars to move an entire community struggling with the impacts of climate change – This is the definition of an externality. Fossil fuel sources were just given an extra $50 million for free. Taken from the American tax payer. This is part of the $5.3 trillion a year fossil fuels get annually.
https://electrek.co/2017/06/12/egeb-german-citizens-energy-company-omnio-sungrow-floating-solar-schneiderman/ (https://electrek.co/2017/06/12/egeb-german-citizens-energy-company-omnio-sungrow-floating-solar-schneiderman/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on June 14, 2017, 01:07:19 PM
Trump Tells Mayor Of Sinking U.S. Island Not To Worry About Climate Change
Scientists predict rising seas will soon swamp Virginia’s Tangier Island. The president doesn’t seem to believe it.
Quote
WASHINGTON — President Donald Trump, apparently confirming his disregard for the risks of global climate change, reportedly told the mayor of a small Chesapeake Bay island that could soon disappear to erosion and rising seas that there’s no cause for concern.

Trump phoned James “Ooker” Eskridge, the mayor of Tangier, Virginia, on Monday, a few days after CNN aired a story about the impacts of climate change on the island in the middle of the bay, The Daily Times in Salisbury, Maryland, reports.

Trump “said not to worry about sea-level rise,” Eskridge told the newspaper. “He said, ‘Your island has been there for hundreds of years, and I believe your island will be there for hundreds more.’”

It’s a bold claim, even for a longtime climate-change nonbeliever who has dismissed the phenomenon as “bullshit” and a Chinese “hoax.”

Since 1850, nearly 70 percent of Tangier’s landmass has been lost, according to a 2015 study by U.S. Army Corps of Engineers scientists. Those scientists predict that in as little as 25 years, erosion and rising seas will sink much of the remaining land, forcing residents to abandon their island homes....
http://www.huffingtonpost.com/entry/trump-tangier-island-mayor-climate-change_us_59406a8ce4b09ad4fbe3fa03 (http://www.huffingtonpost.com/entry/trump-tangier-island-mayor-climate-change_us_59406a8ce4b09ad4fbe3fa03)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: pileus on June 14, 2017, 11:15:18 PM
Trump Tells Mayor Of Sinking U.S. Island Not To Worry About Climate Change
Scientists predict rising seas will soon swamp Virginia’s Tangier Island. The president doesn’t seem to believe it.
Quote
WASHINGTON — President Donald Trump, apparently confirming his disregard for the risks of global climate change, reportedly told the mayor of a small Chesapeake Bay island that could soon disappear to erosion and rising seas that there’s no cause for concern.

Trump phoned James “Ooker” Eskridge, the mayor of Tangier, Virginia, on Monday, a few days after CNN aired a story about the impacts of climate change on the island in the middle of the bay, The Daily Times in Salisbury, Maryland, reports.

Trump “said not to worry about sea-level rise,” Eskridge told the newspaper. “He said, ‘Your island has been there for hundreds of years, and I believe your island will be there for hundreds more.’”

It’s a bold claim, even for a longtime climate-change nonbeliever who has dismissed the phenomenon as “bullshit” and a Chinese “hoax.”

Since 1850, nearly 70 percent of Tangier’s landmass has been lost, according to a 2015 study by U.S. Army Corps of Engineers scientists. Those scientists predict that in as little as 25 years, erosion and rising seas will sink much of the remaining land, forcing residents to abandon their island homes....
http://www.huffingtonpost.com/entry/trump-tangier-island-mayor-climate-change_us_59406a8ce4b09ad4fbe3fa03 (http://www.huffingtonpost.com/entry/trump-tangier-island-mayor-climate-change_us_59406a8ce4b09ad4fbe3fa03)

Was just about to post this.  It's a great example of Trump encountering a very specific implication of not only climate change impact but also scientifically based geologic processes.  He fails on both subject areas.

The lower Chesapeake Bay has been undergoing subsidence for thousands of years, and that whole region will be among the first in the US to be devastated by rising sea levels given the exiting geologic factors.

Have visited Tangier several times.  Beautiful area, very rough and ready, salt of the earth people.  Poor folk are being fed lies by their mayor and Trump.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on June 20, 2017, 06:07:53 PM
New York City Planners With Sandy Nightmares Say Barrier May Come Too Late
Quote
The warming Atlantic Ocean has raised the risk of another Hurricane Sandy. And still, trillions of dollars of real estate and infrastructure near the shores of New York City and northern New Jersey remain vulnerable to devastation.

A storm-surge barrier similar to those in Louisiana and parts of Europe might protect the area, but politicians have questioned its $30 billion cost, effectiveness and environmental impact. A group of scientists, planners and property owners is urging the U.S. Army Corps of Engineers to accelerate its study of the project. It may take another hurricane to speed up the process....
https://www.bloomberg.com/news/articles/2017-06-20/nyc-planners-with-sandy-nightmares-say-barrier-may-come-too-late (https://www.bloomberg.com/news/articles/2017-06-20/nyc-planners-with-sandy-nightmares-say-barrier-may-come-too-late)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Dry_Land_Is_Not_A_Myth on June 21, 2017, 03:08:49 PM
(https://www.aviso.altimetry.fr/fileadmin/images/data/Products/indic/msl/MSL_Serie_MERGED_Global_AVISO_GIA_Adjust_SerieReference.png)

Latest MSL data from March 2017. Any thoughts/explanations on why MSL has been flat for over a year? Seems incredulous due to all the melting of Greenland and Antarctica? Could it be related to in the influx of colder water reducing the thermal expansion effects?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: wehappyfew on June 21, 2017, 03:48:01 PM
El Nino changes precipitation patterns. Less rain over South America, more over the ocean. Sea level rises.

Neutral/weak La Nina since mid 2016 = more rain over land, sea level rise is temporarily paused.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: rboyd on June 21, 2017, 05:24:28 PM
You can see the relative flat-lining after the 1998 El Nino. Interesting that apart from that El Nino the trend does not have that much noise/variability in it until 2010, then it gets much noisier. Perhaps with more and more water vapour in the atmosphere we should expect this?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: oren on June 21, 2017, 05:29:13 PM
It's basically reversion to mean, post el-nino. But perhaps there's also the higher Greenland mass balance this year due to more autumn snows?
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 21, 2017, 06:03:10 PM
Latest MSL data from March 2017. Any thoughts/explanations on why MSL has been flat for over a year? Seems incredulous due to all the melting of Greenland and Antarctica? Could it be related to in the influx of colder water reducing the thermal expansion effects?

While I concur with the posts from wehappyfew, rboyd & oren; scale can also clarify what is happening.  The attached Jason-2 sea level time series thru May 2017 shows a trend line slope of 4.41 mm/yr; vs the trend line slope that you showed of 3.28 mm/yr.  This difference shows the contribution of meltwater, but you do not notice it in your post because you are distracted by ENSO induced fluctuations between varying rainfall patterns between land and ocean and also ENSO induced fluctuations between heat absorbed by the ocean (the ocean absorbs more heat energy during a La Nina and less heat during an El Nino).
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: bbr2314 on June 22, 2017, 07:49:09 AM
(https://www.aviso.altimetry.fr/fileadmin/images/data/Products/indic/msl/MSL_Serie_MERGED_Global_AVISO_GIA_Adjust_SerieReference.png)

Latest MSL data from March 2017. Any thoughts/explanations on why MSL has been flat for over a year? Seems incredulous due to all the melting of Greenland and Antarctica? Could it be related to in the influx of colder water reducing the thermal expansion effects?
This might have something to do with it.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.dmi.dk%2Fuploads%2Ftx_dmidatastore%2Fwebservice%2Fb%2Fm%2Fs%2Fd%2Fe%2Faccumulatedsmb.png&hash=c506c3e5b9cf54923934d197b30960fc)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on June 27, 2017, 07:40:58 AM
Chen et al 2017, The increasing rate of global mean sea-level rise during 1993–2014:
https://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3325.html (https://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3325.html)

Abstract
Global mean sea level (GMSL) has been rising at a faster rate during the satellite altimetry period (1993–2014) than previous decades, and is expected to accelerate further over the coming century. However, the accelerations observed over century and longer periods have not been clearly detected in altimeter data spanning the past two decades. Here we show that the rise, from the sum of all observed contributions to GMSL, increases from 2.2 ± 0.3 mm yr−1 in 1993 to 3.3 ± 0.3 mm yr−1 in 2014. This is in approximate agreement with observed increase in GMSL rise, 2.4 ± 0.2 mm yr−1 (1993) to 2.9 ± 0.3 mm yr−1 (2014), from satellite observations that have been adjusted for small systematic drift, particularly affecting the first decade of satellite observations. The mass contributions to GMSL increase from about 50% in 1993 to 70% in 2014 with the largest, and statistically significant, increase coming from the contribution from the Greenland ice sheet, which is less than 5% of the GMSL rate during 1993 but more than 25% during 2014. The suggested acceleration and improved closure of the sea-level budget highlights the importance and urgency of mitigating climate change and formulating coastal adaption plans to mitigate the impacts of ongoing sea-level rise.

Also see:
https://theconversation.com/contributions-to-sea-level-rise-have-increased-by-half-since-1993-largely-because-of-greenlands-ice-79175?utm_source=twitter&utm_medium=twitterbutton (https://theconversation.com/contributions-to-sea-level-rise-have-increased-by-half-since-1993-largely-because-of-greenlands-ice-79175?utm_source=twitter&utm_medium=twitterbutton)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on June 27, 2017, 03:10:34 PM
The mass contributions to GMSL increase from about 50% in 1993 to 70% in 2014 with the largest, and statistically significant, increase coming from the contribution from the Greenland ice sheet, which is less than 5% of the GMSL rate during 1993 but more than 25% during 2014.

Ice mass loss from WAIS has the potential to accelerate much faster than from the Greenland ice sheet.  We should find-out just how fast this acceleration will be in the next two to three decades.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 12, 2017, 10:09:43 PM
Here is what Rotterdam is doing to prepare for coming sea level rise:

"The Dutch Have Solutions to Rising Seas. The World Is Watching."

https://www.nytimes.com/interactive/2017/06/15/world/europe/climate-change-rotterdam.html (https://www.nytimes.com/interactive/2017/06/15/world/europe/climate-change-rotterdam.html)

Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 18, 2017, 12:14:44 AM
The linked article indicates that a satellite snafu masked the true rate of increase of SLR:

Jeff Tollefson (17 July 2017), "Satellite snafu masked true sea-level rise for decades", Nature, 547, Pages: 265–266, doi:10.1038/nature.2017.22312

http://www.nature.com/news/satellite-snafu-masked-true-sea-level-rise-for-decades-1.22312 (http://www.nature.com/news/satellite-snafu-masked-true-sea-level-rise-for-decades-1.22312)

Extract: "Revised tallies confirm that the rate of sea-level rise is accelerating as the Earth warms and ice sheets thaw.

In an analysis published in Geophysical Research Letters in April, Cazenave’s team tallied up the various contributions to sea-level rise, including expansion resulting from warming ocean waters and from ice melt in places such as Greenland. Their results suggest that the satellite altimetry measurements were too high during the first six years that they were collected; after this point, scientists began using TOPEX/Poseidon's back-up sensor. The error in those early measurements distorted the long-term trend, masking a long-term increase in the rate of sea-level rise."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on July 18, 2017, 05:48:14 PM
While the timeframe in the linked article may be too slow by a factor of about 2, it nevertheless, provides a nice summary of some of the key SLR risks that we are facing from the Antarctic Ice Sheet:

Title: "Antarctic Tipping Points for a Multi-Metre Sea Level Rise"

http://www.resilience.org/stories/2017-01-26/antarctic-tipping-points-for-a-multi-metre-sea-level-rise/ (http://www.resilience.org/stories/2017-01-26/antarctic-tipping-points-for-a-multi-metre-sea-level-rise/)

Extract:
•   "The Amundsen Sea sector of the West Antarctic Ice Sheet has most likely been destabilized and ice retreat is unstoppable for the current conditions.
•   No further acceleration in climate change is necessary to trigger the collapse of the rest of the West Antarctic Ice Sheet on decadal time scales.
•   Antarctica has the potential to contribute more than a metre of sea-level rise by 2100.
•   A large fraction of West Antarctic basin ice could be gone within two centuries, causing a 3–5 metre sea level rise.
•   Mechanisms similar to those causing deglaciation in West Antarctica are now also found in East Antarctica.
•   Partial deglaciation of the East Antarctic ice sheet is likely for the current level of atmospheric carbon dioxide, contributing to 10 metres of more of sea level rise in the longer run, and 5 metres in the first 200 years."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Shared Humanity on July 19, 2017, 04:30:50 PM
The linked article indicates that a satellite snafu masked the true rate of increase of SLR:

Jeff Tollefson (17 July 2017), "Satellite snafu masked true sea-level rise for decades", Nature, 547, Pages: 265–266, doi:10.1038/nature.2017.22312

http://www.nature.com/news/satellite-snafu-masked-true-sea-level-rise-for-decades-1.22312 (http://www.nature.com/news/satellite-snafu-masked-true-sea-level-rise-for-decades-1.22312)

Extract: "Revised tallies confirm that the rate of sea-level rise is accelerating as the Earth warms and ice sheets thaw.

In an analysis published in Geophysical Research Letters in April, Cazenave’s team tallied up the various contributions to sea-level rise, including expansion resulting from warming ocean waters and from ice melt in places such as Greenland. Their results suggest that the satellite altimetry measurements were too high during the first six years that they were collected; after this point, scientists began using TOPEX/Poseidon's back-up sensor. The error in those early measurements distorted the long-term trend, masking a long-term increase in the rate of sea-level rise."

"Nerem's team calculated that the rate of sea-level rise increased from around 1.8 millimetres per year in 1993 to roughly 3.9 millimetres per year today as a result of global warming."

This rate of increase can be seen as a 2 mm increase in the rate of sea-level rise in the past 2 decades or it can be seen as a doubling in the rate of sea level rise in the past 2 decades. How it is viewed can have dramatic implications on the anticipated increase in sea level by the end of the century.

"If sea-level rise continues to accelerate at the current rate, Nerem says, the world’s oceans could rise by about 75 centimetres over the next century. That is in line with projections made by the Intergovernmental Panel on Climate Change in 2013."

And this projection of 75 centimeters by 2100 indicates that the research team believes that the rate of increase is linear, essentially rising by 2 millimeters every 2 decades. I did a back of the envelope calculation (literally back of the envelope calculation with a pencil) and, using a 2 millimeter rate of increase over 2 decades  and starting at 4 millimeter rate in 2020, sea levels will rise an additional 64 centimeters by 2100.

Perhaps the research team is right and the rate of increase is linear. I don't have the annual measures to evaluate but, instinctively, I am troubled by this assumption of a linear rate of increase. All across the planet, we are watching individual processes accelerate at an exponential rate (glacier speeds and melt, ice sheet melt, atmospheric warming, methane increases etc.). It seems counter intuitive to think that sea level rise which, in a sense, is capturing the impact of all of these accelerating trends would result in a linear increase in the rate of sea level rise.

If we, instead, interpret this essentially 2 millimeter increase over 2 decades as a doubling of the rate of increase and project this doubling of the rate of increase to persist, my back of the envelope calculation suggests an additional 178 centimeters of sea level rise by 2100. IMHO, this is a far better projection.

(Feel free to perform your own calculations. I am an old man with declining faculties, using a dirty envelope and a blunt pencil.)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: rboyd on July 20, 2017, 06:51:29 AM
If we, instead, interpret this essentially 2 millimeter increase over 2 decades as a doubling of the rate of increase and project this doubling of the rate of increase to persist, my back of the envelope calculation suggests an additional 178 centimeters of sea level rise by 2100. IMHO, this is a far better projection.

(Feel free to perform your own calculations. I am an old man with declining faculties, using a dirty envelope and a blunt pencil.)

The end result is very dependent upon the doubling time, if its closer to a doubling each decade (as could be the case as the WAIS and Greenland accelerate as proposed by Hansen) then the multiples of 178.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Coffee Drinker on July 21, 2017, 08:03:23 AM
So many coastal areas will be flooded and still people buy seafront property like there is no tomorrow. At least insurance companies become aware of this and already increase their flood risk premiums.

Me and my wife just withdrew an offer for our new house as it is in a 5% (5% flood risk per year) zone. Better safe than sorry. The real estate agent was a bit surprised when I explained her our concerns with global warming and sea level rise. Oh well.

My personal fear is not so much the immediate flooding but the loss of value in the future and problem to sell it again. In 10 years it may be in the 20% flood zone and in 30 years it may get flooded each year.

I know this is not really scientific contribution but global warming has already real consequences and affects our decisions. And I think when people feel the consequences at their own property or finances they will finally wake up. So far global warming is too abstract for most normal folks to really care.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Lennart van der Linde on July 26, 2017, 09:35:12 AM
Tamino on accelerating SLR, according to tide gauge and satellite data:
https://tamino.wordpress.com/2017/07/25/sea-level-rise-has-accelerated/

"How fast, you may ask, is the estimated trend since 1993 according to these tide-gauge-based data? It’s 3.56 mm/yr, even larger than the estimated rate from satellite data... Do bear in mind that the difference (from the satellite-based estimate) isn’t statistically significant. Essentially, they agree (certainly within their uncertainty limits)."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on August 14, 2017, 04:21:48 PM
Many people think that SLR is a concern of the future, but 25 million people around the world have already been displaced due to SLR and should the WAIS reach a tipping point circa 2040-2060 ASLR could make matters (including climate refugees, see the linked article) a lot worse than currently projected:

Title: "Refugees of a different kind are being displaced by rising seas — and governments aren't ready"

https://www.cnbc.com/2017/08/11/climate-change-refugees-grapple-with-effects-of-rising-seas.html (https://www.cnbc.com/2017/08/11/climate-change-refugees-grapple-with-effects-of-rising-seas.html)

Extract: "Increasingly, the phenomenon of rising sea levels has amplified fears over climate refugees — individuals forced to leave their homes due to changing environmental conditions in their respective homelands. Climate watchers estimate that at least 26 million people around the world have already been displaced, and that figure could balloon to 150 million by 2050, according to the Worldwatch Institute."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: rboyd on August 14, 2017, 08:21:30 PM
In the richer nations the issue is that we treat property as a financial asset, against which we borrow huge amounts of money. The vast majority of bank lending is against property. Once perceptions change, and they tend to 'tip' surprisingly fast, that collateral will lose most of its value and large chunks of the banking systems in many countries will be insolvent.

Once perceptions of 1 to 3 feet within 30-50 years get into people's minds large chunks of many cities will fall heavily in price. Many decades before the actual waters engulf the properties. Add the odd hurricane hitting a major city and it could turn into a financial stampede for the exits.
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on August 15, 2017, 08:45:45 PM
"The Trump administration is acting very rashly in part out of the desire to undo a climate measure under the Obama administration," he said. "This is an enormous mistake that is disastrous for taxpayers. The (Obama) rule would have saved billions of dollars over time."

Trump to revoke Obama-era flood risk building standards
Quote
U.S. President Donald Trump will revoke an Obama-era executive order on Tuesday that required strict building standards for government-funded projects to reduce exposure to increased flooding from sea level rise, sources said. ...
http://mobile.reuters.com/article/amp/idUSKCN1AV1ZI (http://mobile.reuters.com/article/amp/idUSKCN1AV1ZI)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on August 18, 2017, 11:49:13 PM
Scribbler discusses present (and near present) SLR risks due to contributions from Antarctica and Greenland over the coming 1 to multiple decades.  While generally presenting a reasonable picture, this article ESLD with regards to at least:

- Scribbler cites NOAA's 2016 490 ppm CO₂-eq value without correcting for the GWP100 of methane; which had he done so would give a value of 521 ppm.

- Scribbler does not discuss the bi-polar seesaw mechanism that can accelerate marine glacial ice mass loss (particularly in the WAIS) on a decadal timeframe but which is poorly represented in the CMIP5 projections.

- Scribbler does not cite the recent research that indicates that since 1750 global warming has sequestered substantial amount of heat content in the Southern Ocean at a water depth conducive for accelerating ice mass loss from marine glaciers (particularly in West Antarctica).

- Scribbler does not cite that beginning in the 1970's the ozone hole over Antarctica accelerated the circumpolar winds to a near optimal velocities for advecting CDW towards the grounding lines of associated marine glaciers and that as the ozone hole has begun to heal itself, the concurrent increase in GHG concentrations has kept the circumpolar wind velocities within the optimal range for such advection:

The Present Threat to Coastal Cities From Antarctic and Greenland Melt

https://robertscribbler.com/2017/08/18/the-present-threat-to-coastal-cities-from-antarctic-and-greenland-melt/

Extract: "With global temperatures now exceeding 1 C and with these temperatures likely to exceed 1.5 C within the next two decades, it is certain that broader heat-based stresses to these various glacial systems will increase. And we are likely to see coincident melt rate acceleration as more glaciers become less stable. The result is that coastal flooding conditions will tend to follow a worsening trend — with the most vulnerable regions like the U.S. Gulf and East Coasts feeling the impact first. Unfortunately, there is risk that this trend will include the sudden acceleration of various glaciers into the ocean, which will coincide with rapid increases in global rates of sea level rise. In other words, the trend for sea level rise is less likely to be smooth and more likely to include a number of melt pulse spikes.

Such an overall trend including outlier risks paints a relatively rough picture for coastal city planners in the 1-3 decade timeframe. But on the multi-decade horizon there is a rising risk that sudden glacial destabilization — first in Greenland and West Antarctica and later in East Antarctica will put an increasing number of coastal cities permanently under water."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on August 19, 2017, 08:13:21 PM
Miami Taxpayers Asked to Foot the Bill to Protect the City from Climate Change
Quote
Miami is among the U.S. cities most vulnerable to rising seas due to climate change, and city officials estimate that they may have to spend at least $900 million in the coming decades to upgrade the city’s flood prevention and drainage systems to keep the Atlantic Ocean at bay.

City officials don’t know exactly where all the money will come from, but in November the city will ask voters to approve a $400 million general obligation bond—new property taxes that will start chipping away at the cost of shoring up the city against the ravages of climate change. ...
https://www.climateliabilitynews.org/2017/08/16/miami-florida-climate-change-sea-level-rise-adaptation/ (https://www.climateliabilitynews.org/2017/08/16/miami-florida-climate-change-sea-level-rise-adaptation/)
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on August 20, 2017, 01:16:40 AM
The linked July 14, 2017 article entitle: "ADB warns climate change 'disastrous' for Asia"; indicates that a BAU approach to climate change would be disastrous for Asia (particularly w.r.t. SLR and storm surge, as indicated by the attached image showing the coastal population [in millions per country in the year 2000] subject inundation by 2100 following an ESLD IPCC BAU scenario):

https://phys.org/news/2017-07-asia-dire-future-toll-climate.html

Extract: "A business-as-usual approach to climate change will be "disastrous" for Asia, undoing much of the phenomenal economic growth that has helped it make vast inroads against poverty, the Asian Development Bank said in a report released Friday

While a 2 degrees Celsius rise will be difficult to manage, "one can assume that a 4 degrees Celsius increase would lead to humanitarian disasters in many nations and result in unmanageable migration flows or locked-in populations", the report said.

Asia as a whole would see sea levels rise by 1.4 metres (4.6 feet) within this century, nearly twice the projected increase under the Paris deal, and face more destructive cyclones, it said."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on August 23, 2017, 05:53:15 PM
SLR is not uniform around the planet and the linked reference provides updated insight on this 'fingerprint' effect based on GRACE gravity data:

Chia-Wei Hsu & Isabella Velicogna (22 August 2017), "Detection of Sea Level Fingerprints derived from GRACE gravity data." Geophysical Research Letters, DOI: 10.1002/2017GL074070

http://onlinelibrary.wiley.com/doi/10.1002/2017GL074070/abstract?utm_content=bufferda45e&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://onlinelibrary.wiley.com/doi/10.1002/2017GL074070/abstract?utm_content=bufferda45e&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Abstract: "Mass changes of ice sheets, glaciers, ice caps, land water hydrology, atmosphere, and ocean cause a non-uniform sea level rise due to the gravitational and self-attraction and loading effects, called sea level fingerprints (SLF). SLF have been previously derived from a combination of modeled and observed mass fluxes from the continents into the ocean. Here, we derive improved SLF from time series of time-variable gravity data from the GRACE mission for April 2002-October 2014. We evaluate the GRACE-derived SLF using Ocean Bottom Pressure (OBP) data from stations in the tropics, where OBP errors are the lowest. We detect the annual phase of the SLF in the OBP signal and separate it unambiguously from the barystatic sea level (BSL) at two stations. At the basin scale, the SLF explain a larger fraction of the variance in steric-corrected altimetry than the BSL, which has implications for evaluating mass transport between ocean basins."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on November 05, 2017, 02:29:08 PM
From Miami to Shanghai: 3°C of warming will leave world cities below sea level
An elevated level of climate change would lock in irreversible sea-level rises affecting hundreds of millions of people, Guardian data analysis shows
Quote
Hundreds of millions of urban dwellers around the world face their cities being inundated by rising seawaters if latest UN warnings that the world is on course for 3C of global warming come true, according to a Guardian data analysis.

Famous beaches, commercial districts and swaths of farmland will be threatened at this elevated level of climate change, which the UN warned this week is a very real prospect unless nations reduce their carbon emissions.

Data from the Climate Central group of scientists analysed by Guardian journalists shows that 3C of global warming would ultimately lock in irreversible sea-level rises of perhaps two metres. Cities from Shanghai to Alexandria, and Rio to Osaka are among the worst affected. Miami would be inundated - as would the entire bottom third of the US state of Florida. ...
https://www.theguardian.com/cities/2017/nov/03/miami-shanghai-3c-warming-cities-underwater
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: AbruptSLR on November 11, 2017, 06:40:27 PM
The linked reference indicates that prior estimate of the SLR rate from 1958 to 2014 of 1.3 +/- 0.1 mm/yr was too low by about 0.2 mm/yr.  These values clearly ignore GIA (see below), and they do not emphasize the cumulative impact of the 0.07 mm/sq yr acceleration; which per the University of Colorado gives a SLR rate of 3.4 +/- 0.4 mm/yr value from 1993 thru 2016 (see the first image); and which per the Jason-2 satellite reading give a SLR rate of 4.4 1mm/yr from 2008 thru the end of February 2017 (see the second image):

Thomas Frederikse, Svetlana Jevrejeva, Riccardo E.M. Riva & Sönke Dangendorf (10 November 2017), "A consistent sea-level reconstruction and its budget on basin and global scales over 1958-2014", Journal of Climate, https://doi.org/10.1175/JCLI-D-17-0502.1

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-17-0502.1?utm_content=buffer005d8&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract: "Different sea-level reconstructions show a spread in sea-level rise over the last six decades and it is not yet certain whether the sum of contributors explains the reconstructed rise. Possible causes for this spread are, amongst others, vertical land motion at tide-gauge locations and the sparse sampling of the spatially-variable ocean. To assess these open questions, reconstructed sea level and the role of the contributors are investigated on a local, basin, and global scale. High-latitude seas are excluded. Tide-gauge records are combined with observations of vertical land motion, independent estimates of ice-mass loss, terrestrial water storage, and barotropic atmospheric forcing in a self-consistent framework to reconstruct sea-level changes on basin and global scales, which are compared to the estimated sum of contributing processes. For the first time, it is shown that for most basins, the reconstructed sea-level trend and acceleration can be explained by the sum of contributors, as well as a large part of the decadal variability. The sparsely-sampled South Atlantic Ocean forms an exception. The global-mean sea-level reconstruction shows a trend of 1.5±0.2 mm/y over 1958-2014 (1σ), compared to 1.3±0.1 mm/y for the sum of contributors. Over the same period, the reconstruction shows a positive acceleration of 0.07±0.02 mm/y2, which is also in agreement with the sum of contributors, which shows an acceleration of 0.07±0.01 mm/y2. Since 1993, both reconstructed sea level and the sum of contributors show good agreement with altimetry estimates."

Note per the CU Sea Level Research Group at the University of Colorado:
"Glacial isostatic adjustment is comparatively a much shorter-term process (although still measured in thousands of years), and it does have a minor effect on ocean basin size. The current effect has been estimated to be -0.3 mm/yr of equivalent sea level rise due to increasing ocean basin size. This effect is corrected in the satellite altimeter global mean sea level time series and contributes 0.3 mm/yr to the estimated global mean sea level."
Title: Re: Sea Level Rise and Social Cost of Carbon
Post by: Sigmetnow on November 22, 2017, 06:41:13 PM
Ice Apocalypse
Rapid collapse of Antarctic glaciers could flood coastal cities by the end of this century.
By Eric Holthaus   on Nov 21, 2017
Quote
The glaciers of Pine Island Bay are two of the largest and fastes