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Author Topic: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)  (Read 233963 times)

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1100 on: May 16, 2019, 05:59:37 PM »
She blogged about that story here:
https://blogs.plos.org/models/how-soon-will-the-ice-apocalypse-come/
It's much quicker to read it than watch a freaking video.

She's clearly very smart with a PhD in particle physics. She's clearly an expert at physical modelling. What she appears to lack is training in the earth or ocean sciences. Brilliant physicists who are modelling experts may not have the same appreciation for how the earth works as someone who has done a large amount of field study. At least, that's my personal experience.

In my opinion, I concur that Tamsin Edwards is short on real world experience (& per Reply #1089 it appears that both David Pollard and Klaus Keller & others agree).  Furthermore, I repost A-Team's Reply #8 below:

"Quote
Tamsin Edwards is an apologist for climate risk denial.
Here is an amusing commentary on their low-ball Antarctic scenario from G Laden and RB Alley.

I did not care for the timing (as it undercut a good public outreach effort from E Holthaus) nor the self-promotional tone of the Guardian piece, nor the barrage of followup tweets, from a minor figure in climate science seemingly assuming a major role as media spokesperson.

I wonder if she will morph into another Dahl-Jensen, Judith Curry, Andrew Rifken, or Bjorn Lomberg, the last thing we need right now in communicating climate risk. Or maybe just naive (as only a scientist can be) to how the Guardian post will be utilized by industry to muddy the risk waters.

I located her researchgate page and the never--published, never-cited 2006 dissertation on Z bosons; this constant recitation of being a particle physicist despite never having worked in that area in a professional capacity. It's not a qualification any more than neurosurgery because the physics of climate change is entirely nineteenth century newtonian (outside a few things like isotopes).

http://gregladen.com/blog/2015/11/22/antarctic-ice-sheet-deterioration-study-left-out-important-factors/
http://www.annualreviews.org/doi/abs/10.1146/annurev-earth-060614-105344?journalCode=earth
http://www.annualreviews.org/doi/abs/10.1146/annurev-earth-060614-105344?journalCode=earth
https://www.researchgate.net/profile/Tamsin_Edwards/contributions
https://www-d0.fnal.gov/results/publications_talks/thesis/edwards/thesis.pdf

"An engineer, a theoretical physicist [ie TE], and a paleoclimatologist are at a wedding. There is a ice large sculpture of a swan on a flat topped table, for decoration. The three start a betting pool on how long it will take for the entire swan, which has already started to melt, to end up on the floor.

The engineer notices some of the meltwater dribbling off the back of the table. She places a set of beer mugs under the streams of water, and records how long it takes for a measured amount of liquid to accumulate. She uses this to generate a graph showing melting over time, estimating the volume of the swan by looking it up in his manual on Ice Sculpture Specifications, and suggests that it will take eleven hours.

The theoretical physicist estimates the volume of ice by assuming a spherical swan, measures the air temperature, and calculates the rate of conversion from ice to water using thermodynamics. He comes up with a different estimate, because the engineer forgot to account for density differences in ice vs water. He estimates that the swan will be entirely the floor in eight and a half hours.

The paleoclimatologist disagrees, and says, “It will take between one and three hours for that swan to be on the floor.”

“Why do you think that, you are clearly an idiot, and I am clearly a physicist, so I must be right!” says the theoretical physicist.

Just as the paleoclimatologist is about to answer, the already melting neck of the swan breaks, and the upper part of the neck and head fall backwards, knocking off one of the large wings. All of those pieces slide off the table and crash on the floor. The stress of the impact causes the second wing to break off, but it stays on the table, but it begins to slowly slide toward the edge, clearly about to fall off as well.

“Because,” the paleoclimatologist says. “Last wedding I went to, that happened.”"

See also:

Title: "Tamsin Edwards"

https://en.wikipedia.org/wiki/Tamsin_Edwards

Extract: "She will be a lead author for Chapter 9 (Ocean, cryosphere, and sea level change) of the sixth assessment report of the Intergovernmental Panel on Climate Change."
&

Title: "Working Group I contribution to the IPCC Sixth Assessment Report (AR6-WG1)"
https://archive.ipcc.ch/report/authors/report.authors.php?q=35&p=&p

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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1101 on: May 16, 2019, 06:06:37 PM »
I've learned a lot thanks to this topic, and my personal feeling is that future SLR is greatly underestimated due to uncertainties in the science behind it.

However most papers about marine ice sheet instabilities seem to be written by or referring to papers written by Pollard and DeConto. Is MISI/MICI type scenarios only a two man show and are their results approved or contested by other experts? I'm asking because I don't know and not to start a flame war :)

First, Pollard and DeConto are experts in MISI and include it in their MICI models.

Second, MICI research is not a two man show, as indicated by the following brief list of related references (however, MICI modeling is still maturing and has not yet been embraced by consensus climate science):


1.   Ben Seiyon Lee, Murali Haran, Robert Fuller, David Pollard, Klaus Keller (24 March 2019), "A Fast Particle-Based Approach for Calibrating a 3-D Model of the Antarctic Ice Sheet", arXiv:1903.10032v1

https://arxiv.org/abs/1903.10032

2.   David Pollard, Robert M. DeConto, Richard B. Alley (13 March 2018), "A continuum model of ice mélange and its role during retreat of the Antarctic Ice Sheet", Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2018-28

https://www.geosci-model-dev-discuss.net/gmd-2018-28/gmd-2018-28.pdf

3.   Tanja Schlemm and Anders Levermann (2018), "A simple stress-based cliff-calving law", The Cryosphere Discuss., https://doi.org/10.5194/tc-2018-205

https://www.the-cryosphere-discuss.net/tc-2018-205/tc-2018-205.pdf

4.   J. N. Bassis & C. C. Walker (23 November 2011), "Upper and lower limits on the stability of calving glaciers from the yield strength envelope of ice", Proceedings of the Royal Society A, https://doi.org/10.1098/rspa.2011.0422

https://royalsocietypublishing.org/doi/full/10.1098/rspa.2011.0422

5.   D. Pollard et al. (11 September 2018), "Estimating Modern Elevations of Pliocene Shorelines Using a Coupled Ice Sheet‐Earth‐Sea Level Model", JGR Earth Surface, https://doi.org/10.1029/2018JF004745

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JF004745

6.   Richard B. Alley (2019), "Is Antarctica Collapsing?", SciAm, Vol 320, No. 2,

https://www.scientificamerican.com/magazine/sa/2019/02-01/

7.   Byron R. Parizek et al. Ice-cliff failure via retrogressive slumping, Geology (2019). DOI: 10.1130/G45880.1

https://pubs.geoscienceworld.org/gsa/geology/article/569567/Icecliff-failure-via-retrogressive-slumping

8.   Edward Gasson, Robert M. DeConto, David Pollard and Richard H. Levy (2016), "Dynamic Antarctic ice sheet during the early to mid-Miocene", PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1516130113

http://www.pnas.org/content/113/13/3459

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vox_mundi

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1102 on: May 16, 2019, 06:33:44 PM »
24 Percent of West Antarctic Ice is Now Unstable: Study
https://phys.org/news/2019-05-percent-west-antarctic-ice-unstable.html

By combining 25 years of ESA satellite data, scientists have discovered that warming ocean waters have caused the ice to thin so rapidly that 24% of the glaciers in West Antarctica are now affected. 

... A team of researchers, led by Professor Andy Shepherd from the University of Leeds, found that Antarctica's ice sheet has thinned by up to 122 metres in places, with the most rapid changes occurring in West Antarctica where ocean melting has triggered glacier imbalance.

This means that the affected glaciers are unstable as they are losing more mass through melting and iceberg calving than they are gaining through snowfall.

The team found that the pattern of glacier thinning has not been static. Since 1992, the thinning has spread across 24% of West Antarctica and over the majority of its largest ice streams—the Pine Island and Thwaites Glaciers—which are now losing ice five times faster than they were at the start of the survey.



Time sequence of Antarctic glacier ice thickness change (left) and associated contribution to sea level rise (right) between 1992 and 2017. 

Trends in Antarctic Ice Sheet Elevation and Mass, Geophysical Research Letters, 16 May 2019

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

‘Extraordinary Thinning’ of Ice Sheets Revealed Deep Inside Antarctica 
https://www.theguardian.com/environment/2019/may/16/thinning-of-antarctic-ice-sheets-spreading-inland-rapidly-study

... thinning of some ice streams had extended 300 miles inland along their 600-mile length. “More than 50% of the Pine Island and Thwaites glacier basins have been affected by thinning in the past 25 years. We are past halfway and that is a worry.” 
« Last Edit: May 16, 2019, 07:59:54 PM by vox_mundi »
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Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

gerontocrat

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1103 on: May 16, 2019, 09:10:11 PM »
By combining 25 years of ESA satellite data, scientists have discovered that warming ocean waters have caused the ice to thin so rapidly that 24% of the glaciers in West Antarctica are now affected. 
The Article is open access at ....
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL082182 - you can get to a word file from here,
and the pdf is at....
https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2019GL082182
Quote
Abstract
Fluctuations in Antarctic Ice Sheet elevation and mass occur over a variety of timescales, owing to changes in snowfall and ice flow. Here, we disentangle these signals by combining 25 years of satellite radar altimeter observations and a regional climate model. From these measurements, patterns of change that are strongly associated with glaciological events emerge. While the majority of the ice sheet has remained stable, 24% of West Antarctica is now in a state of dynamical imbalance. Thinning of the Pine Island and Thwaites glacier basins reaches 122 m in places, and their rates of ice loss are now five times greater than at the start of our survey. By partitioning elevation changes into areas of snow and ice variability, we estimate that East and West Antarctica have contributed ‐1.1±0.4 and +5.7±0.8 mm to global sea level between 1992 and 2017.

Some cool graphs in there.
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sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1104 on: May 16, 2019, 10:34:17 PM »
Re: MISI/MICI

Schoof has written the gospel on marine ice sheet instability, his 2007 paper is indispensable. The seminal paper on marine ice cliff instability was Bassis and Walker. Pollard and DiConto are the first (but not the only ones) to incorporate the latter into ice sheet models. 

sidd

Rich

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1105 on: May 17, 2019, 12:21:49 AM »
Is there any way to find out who nominated Tasmin Edwards to be a lead author on the AR6 regarding SLR? Her role smells very fishy to me.


b_lumenkraft

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1106 on: May 17, 2019, 05:40:38 AM »
Is there any way to find out who nominated Tasmin Edwards to be a lead author on the AR6 regarding SLR? Her role smells very fishy to me.

Sleepy answered here:

I am.

Nah, expert nominations are presented by Governments, Observer Organizations and IPCC Bureau members. They are requested to submit their nominations via their focal points, for Sweden it's Markku Rummukainen so there's one for each country.

There's a full list of 'everything' at ipcc.ch, well documented for everyone.

List >> https://archive.ipcc.ch/report/authors/report.authors.php?q=35&p&p

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1107 on: May 18, 2019, 05:40:56 PM »
Per the linked reference: "… people tend to use moral licensing (e.g., Mazar & Zhong, 2010), in which they believe that they can license themselves to act immorally after establishing moral credentials."  As consensus climate scientists are people, it seems likely that they use moral licensing to act immorally by discounting right-tailed climate risks, after establishing moral credentials by doing a lot of hard work on left-tailed and mean climate risks.  This is cognitive bias and poor science:

Mattias Holmgren et al. (2019), "Deceptive sustainability: Cognitive bias in people’s judgment of the benefits of CO2 emission cuts", Journal of Environmental Psychology, https://doi.org/10.1016/j.jenvp.2019.05.005

https://www.sciencedirect.com/science/article/pii/S0272494418306376

Abstract: "People’s beliefs in the actions necessary to reduce anthropogenic carbon dioxide (CO2) emissions are important to public policy acceptability. The current paper addressed beliefs concerning how periods of small emission cuts contribute to the total CO2 concentration in the atmosphere, by asking participants to rate the atmospheric CO2 concentration for various time periods and emission rates. The participants thought that a time period with higher emission rates combined with a period of lower emission rates generates less atmospheric CO2 in total, compared to the period with high emission rates alone – demonstrating a negative footprint illusion (Study 1). The participants appeared to base their CO2 estimates on the average, rather than on the accumulated sum, of the two periods’ emissions – i.e. an averaging bias (Study 2). Moreover, the effect was robust to the wordings of the problem presented to the participants (Study 3). Together, these studies suggest that the averaging bias makes people exaggerate the benefits of small emission cuts. The averaging bias could make people willing to accept policies that reduce emission rates although insufficiently to alleviate global warming."

Extract: "People tend to think that ‘climate friendly’ behaviors can compensate for less friendly behaviors (Kaklamanou et al., 2015, Sörqvist and Langeborg, 2019). For example, a common idea is that “I recycle - therefore I can take my car to work”. One possible explanation of these beliefs is that people try to find a balance between good and bad deeds (Sachdeva, Iliev, & Medin, 2009). In other words, people tend to use moral licensing (e.g., Mazar & Zhong, 2010), in which they believe that they can license themselves to act immorally after establishing moral credentials. This manifests in relationships between higher fuel efficiency and increased driving distance (Matiaske, Menges, & Spiess, 2012). Similarly, decreased water use due to a water saving campaign, is related to increased electricity usage (Tiefenbeck, Staake, Roth, & Sachs, 2013); and electric car owners generally feel less obliged to act environmental friendly compared to conventional car owners"
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Tom_Mazanec

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1108 on: May 18, 2019, 06:12:41 PM »
Since I have vehophobia, getting my more efficient car in 2011 did not increase my driving. My
SHARKS (CROSSED OUT) MONGEESE (SIC) WITH FRICKIN LASER BEAMS ATTACHED TO THEIR HEADS

sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1109 on: May 18, 2019, 11:09:26 PM »
Re: "As consensus climate scientists are people, it seems likely that they use moral licensing to act immorally by discounting right-tailed climate risks, after establishing moral credentials by doing a lot of hard work on left-tailed and mean climate risks. "

An example or three might be useful here.

Re: "The participants appeared to base their CO2 estimates on the average, rather than on the accumulated sum, of the two periods’ emissions – i.e. an averaging bias"

Any scientist who makes this arithmetic error is not worth the name.

sidd

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1110 on: May 19, 2019, 02:28:37 AM »
Re: "As consensus climate scientists are people, it seems likely that they use moral licensing to act immorally by discounting right-tailed climate risks, after establishing moral credentials by doing a lot of hard work on left-tailed and mean climate risks. "

An example or three might be useful here.

Re: "The participants appeared to base their CO2 estimates on the average, rather than on the accumulated sum, of the two periods’ emissions – i.e. an averaging bias"

Any scientist who makes this arithmetic error is not worth the name.

sidd

The cumulative climate risk includes consideration of the right-tail risk, but IPCC climate scientists intentionally discount the public communication these risks and prefer to discuss most likely (or mean) scenarios with both the public and decision makers.  Modern society was engineered with factors of safety to deal with right-tailed risk, but now it appears that both consensus climate scientist and the decision makers who listen to them have decided to ignore such factors of safety as we move rapidly forward to a potential MICI-type of the WAIS plausibly initiating sometime between 2030 and 2040.  And I strongly suspect that AR6 will discount such plausibility's due to such scientists as Edwards choosing to ignore such right-tail risks as the Antarctic ozone hole indirectly increasing the upwelling of warm CDW beneath key West Antarctic ice shelves; which is currently being observed to rapidly degrade all of the ice shelves in the ASE.

Edit: Another example of consensus climate scientist seriously discounting cumulative climate risks is how AR5 focuses on a mean value of ECS being about 3C this century; when eight of the most state-of-the-art ESMs contributing to AR6 have estimated mean values of ECS being above 5C this century.  Obviously, AR5 climate scientists were most likely ignoring cumulative ECS risk mechanisms (including right-tailed risks) that these current eight state-of-the-art ESMs have stopped ignoring.  Furthermore, I suspect that ESM estimates will not take seriously many potentially significant ice-climate feedback mechanisms before AR7 or AR8.
« Last Edit: May 19, 2019, 02:43:30 AM by AbruptSLR »
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Rich

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1111 on: May 19, 2019, 04:06:19 AM »
Would someone mind explaining the relationship between the ozone hole and CDW upwelling? I'd like to understand if someone is willing to spell it out.

Tor Bejnar

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1112 on: May 19, 2019, 05:02:29 AM »
Rich,
Go to the upper right corner of this web page and type "ozone" in the search field. Several postings that mention the word will be listed, and some of them may answer your question.  (Hope this is helpful.)
Arctic ice is healthy for children and other living things.

sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1113 on: May 19, 2019, 05:25:24 AM »
Re: "Obviously, AR5 climate scientists were most likely ignoring cumulative ECS risk mechanisms "

I will disagree. AR5 (as is happening in AR6) scientists are tasked to put together literature review of current science. They are not asked for their opinions on the literature, peer review occurs before publication. Accusing them of ignoring relevant literature is something  I will not do, since I have no evidence.  In the case of MICI, The Bassis and Walker paper came after the deadline for AR5.

sidd

Rich

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1114 on: May 19, 2019, 05:48:01 AM »
Re: "Obviously, AR5 climate scientists were most likely ignoring cumulative ECS risk mechanisms "

I will disagree. AR5 (as is happening in AR6) scientists are tasked to put together literature review of current science. They are not asked for their opinions on the literature, peer review occurs before publication. Accusing them of ignoring relevant literature is something  I will not do, since I have no evidence.  In the case of MICI, The Bassis and Walker paper came after the deadline for AR5.

sidd

Isn't it peculiar that Yasmin.Edwards is both the lead author on the section covering sea level rise AND submitting literature relevant to the same section which downplays the right tail risk?


sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1115 on: May 19, 2019, 09:34:52 AM »
Re: "Isn't it peculiar that Yasmin.Edwards is both the lead author on the section covering sea level rise AND submitting literature relevant to the same section which downplays the right tail risk? "

Not particularly. Agreed that her research is in conflict with other work. If you think that impedes her judgement, i will point out she has not the final word on what will go into AR6 SLR. It is a communal process.

The real fight comes over the executive summary, where countries like Bonesaw kingdom water the language.

But W(orking)G(roup)1 WG1 in the reports are quite clear. I think that AR6, like AR5, will be out of date by publication, but that is a different matter. Sorta like MICI with Bassis and Walker coming out shortly after the deadline for AR5.

As to the point made by AbruptSLR about CMIP6 models coming in hot for ECS: you cannot fault AR5 for ignoring CMIP6 models completed years later. AR5 was looking at CMIP5 results.

Also i think the name is "Tasmin Edwards"

sidd
« Last Edit: May 19, 2019, 09:41:04 AM by sidd »

Rich

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1116 on: May 19, 2019, 11:49:44 AM »
My bullshit detector is on high alert.

I'm not a trained scientist, just a critical thinker trying to make sense of the world.

We're experiencing a forward pulse in SLR in the present decade. GMSL according to NASA increased 36 mm in 54 months from 2011-2015. It paused (as expected) for the 2016 El Nino and resumed the 8mm / yr pace in 2017.

Where's all the new ocean water coming from? Increasingly from Greenland and Antarctica according to an abundance of scientific reports as well as steady increase in thermal expansion.

We're being exposed to corroborating warning signs all over about ice loss and have paleo climate evidence of rapid ice loss.

Then we have this person (Edwards)  with a questionable scientific fit for the position somehow being nominated to be a lead author for arguably the most politically controversial aspect of the AR6.

I'm not buying it. There are trillions of dollars of fossil fuel money at stake if the AR6 comes out and substantially raises SLR estimates. There is too much at stake for them not to try and manipulate process in their favor. This reeks.

Sleepy

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1117 on: May 19, 2019, 01:18:02 PM »
This reeks.
https://twitter.com/neilrkaye/status/1129467029495398400
2018 emissions are equal to 1751 to 1895 total emissions.
Image added below.

Or why not Eric Holthaus comment (that spurred the above):
270 → 280 ppm: ~5000 yrs
280 → 290: ~100
290 → 300: ~40
300 → 310: ~30
310 → 320: ~23
320 → 330: 12
330 → 340: 8
340 → 350: 6
350 → 360: 7
360 → 370: 6
370 → 380: 5
380 → 390: 5
390 → 400: 5
400 → 410: 4
410 → 415.7: 2

We are in a climate emergency.
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nukefix

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1118 on: May 19, 2019, 02:17:29 PM »
The word of the street seems to be that not all scientists are fully convinced that marine cliff instability will play out as current models predict. It would help if it could be observed to happen in nature.

Shared Humanity

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1119 on: May 19, 2019, 02:22:51 PM »
The word of the street seems to be that not all scientists are fully convinced that marine cliff instability will play out as current models predict. It would help if it could be observed to happen in nature.

It is happening at Jacobshavn.


Shared Humanity

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1120 on: May 19, 2019, 03:46:39 PM »
This is what it looks like...


AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1121 on: May 19, 2019, 07:04:08 PM »
Would someone mind explaining the relationship between the ozone hole and CDW upwelling? I'd like to understand if someone is willing to spell it out.

Rich,

The first image shows that the ozone hole over Antarctica deepens the upper atmospheric geopotential well, which then tightens the geopotential contours as shown in the second image.  These tighter geopotential contours cause the westerly winds that nearly continuously blow around the Southern Ocean to both accelerate and consequently to shift southward (like a spinning ice skater pulling inward [southward] her arms, causing her to spin faster).  This intensification, and southward shift, of the westerly winds, causes the associated circumpolar ocean surface currents to both accelerate and to be generated further to the south.  Furthermore, the Coriolis effect causes moving ocean currents (& all other moving objects) to deflect to the left in the Southern Hemisphere.  Thus, the faster westerly moving surface ocean currents deflect northward, which induces more upwelling of warm CDW onto the continental shelf where they advect with increasing frequency to beneath key Antarctic ice shelves.

Also, as shown in the third image, unlike the Arctic that has a convex geopotential height topology which tends to disperse local atmospheric methane concentrations; the Antarctic has a concave geopotential height topology which tends to concentrate any local methane emissions (see the fourth image and note that methane is lighter than air and thus floats upward).  Furthermore, the extreme cold over the East Antarctic reduces the rate of chemical oxidation of the methane to carbon dioxide thus resulting in a further concentration of methane in the troposphere over the South Pole.  However, as GHG contributes to the concavity of the geopotential height topology over Antarctica; this provides a positive feedback mechanism to further accelerate (or at least maintain) the velocity of the circumpolar winds, which should increase the circumpolar current velocity (as well as moving it to the south); which should push more warm CDW onto the Antarctic continental shelf thus causing more basal ice melting for local ice shelves; which reduces surface seawater salinity which causes more upwelling of warm CDW (by a different mechanism than that associated with the ozone hole).

Also, below I repost Reply #306:

The linked reference indicates that the projected increase (with continued global warming) of more frequent strong El Nino events combined with the projected increase in positive SAM, will significantly increase ice mass loss from the ASE, which will increase the risk of a collapse of the WAIS:

Deb, P., A. Orr, D. H. Bromwich, J. P. Nicolas, J. Turner, and J. S. Hosking, 2018: Summer drivers of atmospheric variability affecting ice shelf thinning in the Amundsen Sea Embayment, West Antarctica. Geophy. Res. Lett., 45. doi: 10.1029/2018GL077092.

http://polarmet.osu.edu/PMG_publications/deb_bromwich_grl_2018.pdf

Abstract:  "Satellite data and a 35-year hindcast of the Amundsen Sea Embayment summer climate using the Weather Research and Forecasting model are used to understand how regional and large-scale atmospheric variability affects thinning of ice shelves in this sector of West Antarctica by melting from above and below (linked to intrusions of warm water caused by anomalous westerlies over the continental shelf edge). El Niño episodes are associated with an increase in surface melt but do not have a statistically significant impact on westerly winds over the continental shelf edge. The location of the Amundsen Sea Low and the polarity of the Southern Annular Mode (SAM) have negligible impact on surface melting, although a positive SAM and eastward shift of the Amundsen Sea Low cause anomalous westerlies over the continental shelf edge. The projected future increase in El Niño episodes and positive SAM could therefore increase the risk of disintegration of West Antarctic ice shelves."

Extract: "Our study suggests that ASE ice shelves could experience an intensification of melt in the future from both above and below as a result of both regional and large-scale atmospheric changes, potentially increasing the risk of their disintegration, which in turn could potentially trigger a collapse of the West Antarctic ice sheet (DeConto & Pollard, 2016). To better understand this threat will require further detailed investigation of the impacts of ENSO, the polarity of the SAM, and the depth/location of the ASL on ASE ice shelves. Also necessary is improving the reliability of future projections, such as ENSO and its teleconnections, as well as the response of the SAM to recovery of the Antarctic ozone hole and increased greenhouse gas emissions (Polvani, Waugh, et al., 2011)."

Finally, see my comments in Reply #920.

ASLR
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1122 on: May 19, 2019, 08:14:10 PM »
As my last post ended by referring readers to Reply #920, here I repost Reply #921 so that readers cannot only understand not only that the increased upwelling of warm CDW contacts the seafloor of the Antarctic continental shelf, which can destabilize any methane hydrates there, but also that upwelling of the warm CDW splits with some of the flow headed southward (including to the ice shelves) and some headed northward:

Repost of Reply #921: "As a follow-on to my last post, I provide the two attached images of how warm CDW can contact marine sediment in the Southern Ocean that might contain methane hydrates (and the heat in the warm CDW may degrade any surface zone of methane hydrate in the contacted local seafloor).

First, warm CDW water enter the Weddell Gyre from the north and then travels along the coast of the Queen Maud Land, as shown in the first image from the following website for the Andrex project that is actively monitoring this behavior:

http://www.noc.soton.ac.uk/ooc/PROJECTS/andrex/

The caption for the first image is:

"Schematic of the circulation in the Weddell Sea (in black). The red arrows represent the escape route from the Weddell Sea. The white arrows are the eastern branches of the Weddell Gyre."

Furthermore, if it is not clear, in the image the white arrows should indicate warm CDW entrained in the eastern end of the Weddell Gyre from the ACC to the north.

Second, upwelling of CDW can bring warm water in contact with the coastal seafloor as shown in the second image.

Edit:

The third image shows that in addition to the Weddell Gyre that is also the Ross Gyre and the Un-named Gyre that bring warm CDW into contact with the coastal seafloor in different parts of Antarctica."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1123 on: May 19, 2019, 08:28:42 PM »
Now that I have gone to all the trouble of discussing tropospheric geopotential height, GPH, in Reply #1121, this is likely a good spot to note that per the linked reference the Antarctic sea ice concentration, SIC, is affected by the Antarctic tropospheric GPH, so that minimum Antarctic SIC occurs when the depth of the tropospheric GPH over the South Pole deepens.  As increasing GHG concentrations deepen this tropospheric GPH this is not good if we continue following a BAU emissions scenario as a rapid reduction in Antarctic SIC would cause an ice-climate albedo flip mechanism that would have a positive feedback on further global warming:

Weihong Qian et al. (17 May 2019), "Antarctic sea‐ice variation associated with vertical geopotential height and temperature anomalies", International Journal of Climatology, https://doi.org/10.1002/joc.6161

https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/joc.6161

Abstract: "It is well‐known that the increasing zonal‐mean trend of sea‐ice concentration (SIC) surrounding Antarctica is up to 2015 so this paper first summarized this trend with opposing regional trends in each season along the latitude band 60°–70°S during 1979–2015. The surface wind trends can partly explain the observed regional SIC trends. By analyzing the surface wind, as well as the tropospheric geopotential height (GPH) and temperature trends, the study revealed that the increasing zonal‐mean SIC trend and opposing regional SIC trends surrounding Antarctica are vertically associated with GPH and temperature trends in the troposphere. This relationship is also found in extreme years for seven SIC minimum and four SIC maximum autumns from 1979 to 2015, particularly reconfirmed in the two SIC minimum autumns of 2017 and 2018, indicating that a positive regional SIC anomaly is vertically associated with an anomalously cold air mass centered around 850hPa in the troposphere which is located beneath a negative GPH anomaly at the upper troposphere, and vice versa."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1124 on: May 19, 2019, 08:43:08 PM »
In my last post I noted that a potential future deepening of the tropospheric geopotential well over the South Pole due to increasing GHG emissions may abruptly reduce future seasonal Antarctic sea ice concentrations; here I note that the linked reference indicates that an observed reduction in Arctic sea ice extent has contributed to a: 'reduction in northern mid-latitude 2-m temperature variability'.  Thus, it is reasonable to assume that potential future seasonal reductions in Antarctic sea ice area will likely lead to a reduction in southern mid-latitude 2-m temperature variability; with continued global warming:

Thomas W. Collow et al. (2019), "Reduction in northern mid-latitude 2-m temperature variability due to Arctic sea ice loss", Journal of Climate, https://doi.org/10.1175/JCLI-D-18-0692.1

https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0692.1

Abstract: "In this study, we investigate links between Arctic sea ice loss and the variability of 2-m temperatures over a 6-month period (November-April) over two domains centered over northern Eurasia and northern North America. Based on data from Climate Forecast System Reanalysis (CFSR), there has been an increase (a decrease) in recent seasonal temperature variability over Eurasia (North America), which can be attributed to cooling (warming) during the winter months. Decreases in the intraseasonal variability of temperature anomalies, however, are noted in both regions for the November-April period. This study investigates the role of different forcings on the changes seen in the reanalysis product using Atmospheric Model Intercomparison Project (AMIP) simulations forced with repeating sea surface temperature (SST), sea ice, and CO2 concentration relative to climatologies from two different base periods, 1981-1990 and 2005-2014. The seasonal temperature and intraseasonal anomaly variabilities are examined and we find that only the simulations with reduction in sea ice (2005-2014 base period sea ice concentration) produce significant decreases in intraseasonal temperature anomaly variability over these regions agreeing with the CFSR analysis. Runs that reduce sea ice also result in a significant decrease in the frequency and magnitude of extreme warm and cold temperature anomalies. It is proposed that the weakened latitudinal temperature gradient, resulting from decreased sea ice, leads to reduced meridional temperature advection variability, which in turn, contributes to the reduction in the variability of temperature anomalies."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1125 on: May 19, 2019, 08:55:16 PM »
As to my way of thinking, Arctic Amplification is a direct contributor to any potential future 'Ice Apocalypse', I note that the linked reference identifies transport patterns/mechanisms (see the attached image) of atmospheric moisture from extra tropical water vapor pools into the Arctic regions; and in my opinion, with continued global warming, the areas shown as 'more water vapor' are areas that will likely be subject to an abrupt transition from snowfall to rainfall; which will destabilize the local permafrost and contribute to thermal karst lake formation (and associated methane emissions):

Luis Gimeno et al. (16 May 2019), "Atmospheric moisture transport and the decline in Arctic Sea ice", WIREs Climate Change, https://doi.org/10.1002/wcc.588

https://onlinelibrary.wiley.com/doi/abs/10.1002/wcc.588

Abstract: "This article contains a review of the transport of moisture to the Arctic and its effect on Arctic Sea Ice Extent (SIE). The review includes a synthesis of our knowledge regarding the main sources supplying moisture to the Arctic, the changes experienced over the last few decades due to variations in the transport of moisture, the factors that control interannual variability, and the inherent contrast in the mechanisms related to the effect of changes in moisture transport on SIE in the Arctic. We note that the precise identification of the moisture sources for the Arctic depends both on the definition of the Arctic region itself and on the approach used to identify the sources, with the remote regions over the extratropical Atlantic and Pacific Oceans being universally important, as are some continental areas over Siberia and North America. This review also reaffirms the absence of any clear agreement regarding the trends in atmospheric moisture transport to the Arctic, and highlights discrepancies between different data sets and approaches in the quantification of moisture transport, implying that its long‐term impact on the intensification of the hydrological cycle in the Arctic remains unclear. We confirm the influence of the major modes of climate variability, planetary circulation patterns, and the changes in cyclonic activity in the variability of moisture transport to the Arctic. We reaffirm that the effect of moisture transport on the Arctic SIE through changes in humidity, cloud cover, and precipitation over the Arctic is a complex scientific problem that requires further detailed study over the decades to come, and we propose some important challenges for future research."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1126 on: May 20, 2019, 02:15:03 AM »
Re: "Obviously, AR5 climate scientists were most likely ignoring cumulative ECS risk mechanisms "

I will disagree. AR5 (as is happening in AR6) scientists are tasked to put together literature review of current science. They are not asked for their opinions on the literature, peer review occurs before publication. Accusing them of ignoring relevant literature is something  I will not do, since I have no evidence.  In the case of MICI, The Bassis and Walker paper came after the deadline for AR5.

sidd

I note that this forum is filled with tens of thousands of post documenting observed climate change's damaging impacts, yet there are virtually no significant carbon pricing programs implemented by world governments to date.  In my opinion this is partially due to the fact that AR5 issued a carbon budget based on left-tail assumptions about climate sensitivity including about ice-climate feedback mechanisms.  The AR5 carbon budgets (written by consensus climate scientists) tell decision makers that they have decades of time before it is too late to stay well below the 2C GMSTA target.  However, the two associated linked articles (parts 1 & 2); demonstrate that when the risks (probabilities times consequences) associated with worse plausible cases are considered, even very high social costs of carbon, SCC, are justified to be added to the prices of fossil fuels (preferably together with a UBI, or dividend, program).

Title: "On Buying Insurance, and Ignoring Cost-Benefit Analysis"

http://triplecrisis.com/on-buying-insurance-and-ignoring-cost-benefit-analysis/

Extract: "The damages expected from climate change seem to get worse with each new study. Reports from the IPCC and the U.S. Global Change Research Project, and a multi-author review article in Science, all published in late 2018, are among the recent bearers of bad news.

In fact, a crash program to decarbonize the economy is obviously the right answer. There are just a few things you need to know about the economics of climate policy, in order to confirm that Adam Smith and his intellectual heirs have not overturned common sense on this issue. Three key points are worth remembering.

For uncertain, extreme risks, policy should be based on the credible worst-case outcome, not the expected or most likely value. This is the way people think about insurance against disasters.

As the careful qualifications in the IPCC and other reports remind us, climate change could be very bad, surprisingly soon, but almost no one is willing to put a precise number or date on the expected losses.

One group does rush in where scientists fear to tread, guessing about the precise magnitude and timing of future climate damages: economists engaged in cost-benefit analysis (CBA).

The disastrous worst-case risks are all on the benefits, or avoided climate damages, side of the ledger. The scientific uncertainties about climate change concern the timing and extent of damages. Therefore, the urgency of avoiding these damages, or conversely the cost of not avoiding them, is intrinsically uncertain, and could be disastrously large."
&

Title: "Climate Damages: Uncertain but Ominous, or $51 per Ton?"

https://skepticalscience.com/climate-damages-51-per-ton.html

Abstract: "According to scientists, climate damages are deeply uncertain, but could be ominously large (see the previous post). Alternatively, according to the best-known economic calculation, lifetime damages caused by emissions in 2020 will be worth $51 per metric ton of carbon dioxide, in 2018 prices.
These two views can’t both be right. This post explains where the $51 estimate comes from, why it’s not reliable, and the meaning for climate policy of the deep uncertainty about the value of damages.

The “social cost of carbon” (SCC) is the value of present and future climate damages caused by a ton of carbon dioxide emissions.

Expected climate damages are uncertain over a wide range, including the possibility of disastrously large impacts. The SCC is a monetary valuation of expected damages per ton of carbon dioxide. Therefore, SCC values should be uncertain over a wide range, including the possibility of disastrously high values.

As explained in the previous post in this series, deep uncertainty about the magnitude and timing of risks stymies the use of cost-benefit analysis for climate policy. Rather, policy should be set in an insurance-like framework, focused on credible worst-case losses rather than most likely outcomes. Given the magnitude of the global problem, this means “self-insurance” – investing in measures that make worst cases less likely.

In short, we already know that doing everything on the least-cost emission reduction path will cost less, per ton of carbon dioxide, than worst-case climate damages.

That’s it: end of economic story about evaluating climate policy. We don’t need more exact, accurate SCC estimates; they will not be forthcoming in time to shape policy, due to the uncertainties involved. Since estimated worst-case damages are rising over time, while abatement costs (such as the costs of renewables) are falling, the balance is tipping farther and farther toward “do everything you can, now.” That was already the correct answer some years ago, and only becomes more correct over time."

ASLR
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1127 on: May 20, 2019, 02:32:12 AM »
I agree 110% ASLR.

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1128 on: May 20, 2019, 03:10:09 AM »
The word of the street seems to be that not all scientists are fully convinced that marine cliff instability will play out as current models predict. It would help if it could be observed to happen in nature.

nukefix,

While SH's posts demonstrates that no one questions the reality of ice cliff failures (such as those regularly observed for Jakobshavn), it seems that you are not only asking about well documented cases of marine ice cliff instability (MICI); but also whether current models of MICI can precisely determine a WAIS collapse scenario to the decadal-scale.

In this regards, no observed MICI event has been recorded my modern instruments (SH's recorded Jakobshavn's ice-cliff failure event was not an MICI event); however, the linked reference provides good documentation of a paleo-MICI event in Pine Island Bay from about 12.3kya to before 11.2kya (see the first attached image). 

You might say that a 1,100 yr MICI-event is a lot longer than the century-, to decadal-, scale MICI events projected by some recent MICI models.  Nevertheless, the second attached image shows that this 12.3kya to 11.2kya MICI event occurred between Meltwater Pulse (MWP) event 1A and MWP event 1B; both of which had ice mass loss rates comparable to those projected by Pollard & DeConto's MICI-model.

You might then say that the MICI-events associated with the MWP events shown in the second image involved different marine glaciers than exist in the WAIS today, and while that is true, if you search this thread (using the search function) for MICI, you while find a lot of references where MICI models have been calibrated against the paleo record for key interglacial periods over the past 3 million years, such as for the Pliocene when GMSTA was about 2C above pre-industrial.

You might then say that the peak periods for interglacials such as the Pliocene occurred over thousands of years, so this proves nothing.  But there is no recorded paleo warming rate as fast as we are currently experiencing, so if you demand an exact match for the projected WAIS MICI-event, then you will need to wait a few decades as we are current conducting a one of a kind experiment on Earth.

Wise et al. (2017), "Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks", Nature 550, 506-510, doi:10.1038/nature24458

https://www.nature.com/articles/nature24458

Abstract: "Marine ice-cliff instability (MICI) processes could accelerate future retreat of the Antarctic Ice Sheet if ice shelves that buttress grounding lines more than 800 metres below sea level are lost. The present-day grounding zones of the Pine Island and Thwaites glaciers in West Antarctica need to retreat only short distances before they reach extensive retrograde slopes. When grounding zones of glaciers retreat onto such slopes, theoretical considerations and modelling results indicate that the retreat accelerates. It is thought that MICI is triggered when this retreat produces ice cliffs above the water line with heights approaching about 90 metres. However, observational evidence confirming the action of MICI has not previously been reported. Here we present observational evidence that rapid deglacial ice-sheet retreat into Pine Island Bay proceeded in a similar manner to that simulated in a recent modelling study, driven by MICI. Iceberg-keel plough marks on the sea-floor provide geological evidence of past and present iceberg morphology, keel depth and drift direction. From the planform shape and cross-sectional morphologies of iceberg-keel plough marks, we find that iceberg calving during the most recent deglaciation was not characterized by small numbers of large, tabular icebergs as is observed today, which would produce wide, flat-based plough marks or toothcomb-like multi-keeled plough marks. Instead, it was characterized by large numbers of smaller icebergs with V-shaped keels. Geological evidence of the form and water-depth distribution of the plough marks indicates calving-margin thicknesses equivalent to the threshold that is predicted to trigger ice-cliff structural collapse as a result of MICI. We infer rapid and sustained ice-sheet retreat driven by MICI, commencing around 12,300 years ago and terminating before about 11,200 years ago, which produced large numbers of icebergs smaller than the typical tabular icebergs produced today. Our findings demonstrate the effective operation of MICI in the past, and highlight its potential contribution to accelerated future retreat of the Antarctic Ice Sheet."

ASLR
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1129 on: May 20, 2019, 03:53:01 AM »
Great study. Amazing how resourceful scientists can be to put two and two together.

The potential and appearance of the beginnings of a hockey stick rise in sea level is showing up.

Rich

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1130 on: May 20, 2019, 05:11:29 AM »
By the way, thank you ASLR for your explanation of the relationship between the ozone hole and CDW upwelling.

I was already familiar with the south polar wind and oceanic  circulation contracting, but your post certainly helped fill in some visualization of more attributes.

This isn't easy stuff to understand. I'm grateful to those willing to teach.

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1131 on: May 20, 2019, 06:04:07 AM »
Re: AR5 issued a carbon budget

What ? where ? AR5 uses RCPs which prescribe a concentration vs time for the atmosphere. AR5 says nothing about the anthro carbon budget that causes the RCP.

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1132 on: May 20, 2019, 07:54:55 AM »
Not explicitly but that's why we have NET's in the RCP's, I think Reto Knutti (& Rogelj) said this best back in 2015;
A global temperature target implies a CO2 "budget" or "quota", a finite
amount of CO2 that society is allowed to emit to stay below the target.
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1133 on: May 20, 2019, 08:30:09 AM »
AR5 says nothing about the anthro carbon budget that causes the RCP.

"Nothing" seems overstated: see for example figure SPM.10c below from the AR5 Synthesis Report, which shows carbon budgets for different temperature targets, in line with the references made by Sleepy. On p.19 the SPM says:
"Cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond. Limiting risks across RFCs would imply a limit for cumulative emissions of CO2. Such a limit would require that global net emissions of CO2 eventually decrease to zero and would constrain annual emissions over the next few decades (Figure SPM.10) (high confidence)."

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1134 on: May 20, 2019, 10:25:43 AM »
I thought the numbers in those AR5 graph showing anthro carbon emissions on the x axis were taken directly from the prescribed RCPs while the temperature rise and risk factors were from AR5 results ?

A much bigger issue is, as AbruptSLR has pointed out in this very thread, that feedbacks will probably increase atmospheric carbon load both in  CO2 and CH4 more than AR5 thought.

AR6 is going to use something called  "Shared Socioeconomic Pathways" (SSPs)

https://tntcat.iiasa.ac.at/SspDb/dsd?Action=htmlpage&page=about#v2

which seem prescribe land use changes and fluxes and a whole bunch of other things to drive CMIP6 models. But the SSPs were developed even before the deadline for AR6 papers. So i think they are already out of date.

The things are out of date when published. My larger point is, that is not the fault of the IPCC but rather the procedure. They need to publish updates yearly, but they haven't the budget for it. Sad, innit ?

sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1135 on: May 20, 2019, 11:21:20 AM »
I thought the numbers in those AR5 graph showing anthro carbon emissions on the x axis were taken directly from the prescribed RCPs while the temperature rise and risk factors were from AR5 results ?

A much bigger issue is, as AbruptSLR has pointed out in this very thread, that feedbacks will probably increase atmospheric carbon load both in  CO2 and CH4 more than AR5 thought.

AR6 is going to use something called  "Shared Socioeconomic Pathways" (SSPs)

https://tntcat.iiasa.ac.at/SspDb/dsd?Action=htmlpage&page=about#v2



which seem prescribe land use changes and fluxes and a whole bunch of other things to drive CMIP6 models. But the SSPs were developed even before the deadline for AR6 papers. So i think they are already out of date.

The things are out of date when published. My larger point is, that is not the fault of the IPCC but rather the procedure. They need to publish updates yearly, but they haven't the budget for it. Sad, innit ?

sidd

not sad but planned
There is a principle which is a bar against all information, which cannot fail to keep a man in everlasting ignorance. That principle is contempt prior to investigation. - Herbert Spencer

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1136 on: May 20, 2019, 04:55:52 PM »
The linked reference documents the disturbing trend for ice mass loss in the WAIS and for the Thwaites Glacier in particular.

Andrew Shepherd et al. (16 May 2019), "Trends in Antarctic Ice Sheet Elevation and Mass", Geophysical Research Letters, https://doi.org/10.1029/2019GL082182

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL082182

Abstract
Fluctuations in Antarctic Ice Sheet elevation and mass occur over a variety of timescales, owing to changes in snowfall and ice flow. Here, we disentangle these signals by combining 25 years of satellite radar altimeter observations and a regional climate model. From these measurements, patterns of change that are strongly associated with glaciological events emerge. While the majority of the ice sheet has remained stable, 24% of West Antarctica is now in a state of dynamical imbalance. Thinning of the Pine Island and Thwaites glacier basins reaches 122 m in places, and their rates of ice loss are now five times greater than at the start of our survey. By partitioning elevation changes into areas of snow and ice variability, we estimate that East and West Antarctica have contributed ‐1.1±0.4 and +5.7±0.8 mm to global sea level between 1992 and 2017.

Key Points
•   We combine satellite radar altimetry and a regional climate model to separate changes in Antarctic elevation into snow and ice contributions
•   Between 1992 and 2017, ice thinning has grown in extent to include 24% of West Antarctica, and reaches 122 metres in places
•   Ice losses from Pine Island and Thwaites Glaciers have risen fivefold. East and West Antarctica have contributed 4.6±1.2 mm to sea level
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1137 on: May 20, 2019, 05:28:02 PM »
Re: AR5 issued a carbon budget

What ? where ? AR5 uses RCPs which prescribe a concentration vs time for the atmosphere. AR5 says nothing about the anthro carbon budget that causes the RCP.

sidd

IPCC's AR5 explicitly calculates a Carbon Budget and in doing so they use TCR (transient climate response) values, and they ignore uncertainties in estimating TCR such as cloud feedback uncertainty.  The first linked article by Zeke Hausfather, points out (as discussed earlier in this thread) that the IPCC updated this carbon budget in the SR15 report.

Title: "Analysis: Why the IPCC 1.5C report expanded the carbon budget"

https://www.carbonbrief.org/analysis-why-the-ipcc-1-5c-report-expanded-the-carbon-budget

Extract: "The newly published Intergovernmental Panel on Climate Change’s (IPCC) special report on 1.5C (SR15) significantly expands the budget for a 66% chance of avoiding 1.5C to the equivalent of 10 years of current emissions. This compares to the IPCC’s fifth assessment report (AR5), which put it at around three years.

Based on estimates made in the IPCC’s fifth assessment report (AR5), there would be around 120 gigatonnes of CO2 (GtCO2) remaining from the beginning of 2018 – or around three years of current emissions – for a 66% chance of avoiding 1.5C warming. For a 50/50 chance of exceeding 1.5C, the remaining budget was a modestly larger 268GtCO2 – or around seven years of current emissions.

The IPCC’s new SR15 significantly revises these numbers. It raises the budget for a 66% of avoiding 1.5C to 420GtCO2 – or 10 years of current emissions. Similarly, the budget for a 50/50 chance of exceeding 1.5C is increased to 580GtCO2 – 14 years of current emissions.

Even the revised 1.5C carbon budget is unlikely to be the end of the debate, however, given a number of large remaining uncertainties. These include:
•   The precise meaning of the 1.5C target.
•   Disagreement about what “surface temperature” actually refers to.
•   The definition of the “pre-industrial” period.
•   What observational temperature datasets should be used.
•   What happens to non-CO2 factors that influencing the climate.
•   Whether Earth-system feedbacks like melting permafrost are taken into account."

See also:

https://www.carbontracker.org/carbon-budgets-explained/

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Ken Feldman

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1138 on: May 20, 2019, 06:32:47 PM »
The word of the street seems to be that not all scientists are fully convinced that marine cliff instability will play out as current models predict. It would help if it could be observed to happen in nature.

It is happening at Jacobshavn.

Yet once MICI started, it didn't destroy the entire glacier.  In fact Jacoshavn is growing again.

https://www.cbsnews.com/news/glacier-growing-melting-jakobshavn-glacier-in-greenland-is-growing-again-a-new-nasa-study-finds/

Quote
Six years ago, the Jakobshavn glacier was retreating about 1.8 miles and thinning nearly 130 feet annually but it started growing again at about the same rate in the past two years, according to a study in Monday's Nature Geoscience. Study authors and outside scientists think this is temporary.

"That was kind of a surprise. We kind of got used to a runaway system," said Geological Survey of Denmark and Greenland ice and climate scientist Jason Box. "The good news is that it's a reminder that it's not necessarily going that fast. But it is going."




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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1139 on: May 20, 2019, 06:42:41 PM »
The fact that there aren't ice cliffs taller than 100 meters is well established by observations.  The controversial part of the MICI hypothesis is that once it starts in Antarctica, it will continue and destroy the West Antarctic ice sheet within decades.  There are modeling studies that support both sides of the argument. 

Tasmin Edwards is only one of a dozen authors of that chapter for the AR6.  A scientist who has published with DeConto, Nicholas Golledge, is another lead author of that chapter. 
(Here's a link to the paper they both contributed to:  https://www.pnas.org/content/113/13/3453)

There are three chapter lead authors and two review editors that will be responsible for the executive summary and final text of the chapter.

It's interesting to note that Golledge and Edwards were co-authors on paper in 2019.  This may forshadow what we see in AR6:

https://www.nature.com/articles/s41586-019-0889-9

Quote
Global environmental consequences of twenty-first-century ice-sheet melt
Nicholas R. Golledge, Elizabeth D. Keller, Natalya Gomez, Kaitlin A. Naughten, Jorge Bernales,
Luke D. Trusel & Tamsin L. Edwards

Quote
Government policies currently commit us to surface warming of three to four degrees Celsius above pre-industrial levels by 2100, which will lead to enhanced ice-sheet melt. Ice-sheet discharge was not explicitly included in Coupled Model Intercomparison Project phase 5, so effects on climate from this melt are not currently captured in the simulations most commonly used to inform governmental policy. Here we show, using simulations of the Greenland and Antarctic ice sheets constrained by satellite-based measurements of recent changes in ice mass, that increasing meltwater from Greenland will lead to substantial slowing of the Atlantic overturning circulation, and that meltwater from Antarctica will trap warm water below the sea surface, creating a positive feedback that increases Antarctic ice loss. In our simulations, future ice-sheet melt enhances global temperature variability and contributes up to 25 centimetres to sea level by 2100. However, uncertainties in the way in which future changes in ice dynamics are modelled remain, underlining the need for continued observations and comprehensive multi-model assessments.

Quote
Recent research suggests that tipping points in parts of the West Antarctic Ice Sheet may have already been passed11,12. Coastal flooding events in low-latitude areas will probably double in frequency by 2050 if sea-level rise reaches 0.1–0.2 m above present13, with less-developed small island nations likely to experience the greatest local climate changes if the Paris targets are not met14. The consequences of predicted future changes in the Earth system will therefore be societally and economically important, but will be spatially variable, and the spread of future sea-level-rise scenarios remains large owing to uncertainties in the processes that are likely to control future ice-sheet retreat15. Even within climatologies that are consistent with the Paris targets there is a likelihood of at least 0.5 m of global-mean sea-level rise by 210016.

Quote
Our results arise from an experimental set-up that (1) is underpinned by time-varying multi-parameter present-day measurements (Fig 1), (2) predicts twenty-first-century ice-sheet mass loss in areas where recent thinning has been greatest (Fig. 3) and (3) allows more extreme Antarctic scenarios such as warm interglacial conditions of the early to mid-Pliocene to be reproduced (Extended Data Fig. 3). In addition, by using a parameterization that includes sub-grid melting at glacial grounding lines (Methods), our model produces a sea-level contribution from the Antarctic Ice Sheet of 0.14 m by 2100, which compares favourably with the mode (0.15 m; 90% probability interval, 0.09–0.39 m) for the same scenario derived from a reanalysis of previous simulations20 in which marine ice-cliff instability is excluded39. Further, the timing of a positive Antarctic sea-level contribution is almost identical in our study and the reanalysis39, with both identifying the emergence of a clear signal during the middle of the century.

Quote
Our model does not include the mechanics of ice-shelf hydrofracture or cliff failure20, which might hasten retreat. However, it is our contention that such processes are unlikely to be important during this century; this is based on three lines of evidence. First, by incorporating ice–ocean–atmosphere feedbacks, our simulations predict substantial atmospheric cooling over mid- to high southern latitudes (Extended Data Fig. 1b), which will offset approximately 0.5–3.5 °C of the atmospheric warming predicted by CMIP5 models (Extended Data Fig. 2c, d) and thus reduce melt. Second, although we do not have data from warmer-than-present conditions, contemporary observations show that surface melt has been a normal component of Antarctic ice shelves in the recent past, without it having led to shelf breakup47,48. Third, simulations of future surface melting across Antarctic ice shelves using regional climate models such as RACMO2.1 (ref. 49) and CMIP5 general circulation models50 predict far lower melt quantities than the simulations of ref. 20. If such high melt is necessary to induce continent-wide hydrofracture, then these other models would imply that more extreme atmospheric warming than predicted for 2100 may be necessary to trigger widespread ice-shelf collapse.

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1140 on: May 20, 2019, 07:51:02 PM »
The word of the street seems to be that not all scientists are fully convinced that marine cliff instability will play out as current models predict. It would help if it could be observed to happen in nature.

It is happening at Jacobshavn.

Yet once MICI started, it didn't destroy the entire glacier.  In fact Jacoshavn is growing again.

https://www.cbsnews.com/news/glacier-growing-melting-jakobshavn-glacier-in-greenland-is-growing-again-a-new-nasa-study-finds/

Quote
Six years ago, the Jakobshavn glacier was retreating about 1.8 miles and thinning nearly 130 feet annually but it started growing again at about the same rate in the past two years, according to a study in Monday's Nature Geoscience. Study authors and outside scientists think this is temporary.

"That was kind of a surprise. We kind of got used to a runaway system," said Geological Survey of Denmark and Greenland ice and climate scientist Jason Box. "The good news is that it's a reminder that it's not necessarily going that fast. But it is going."

As shown in the first image there are multiple factors contributing to where Jakobshavn undergoes an ice cliff failure, or not, including: bedslope, water depth, ice cliff freeboard height, hydrofracturing, hardness/softness of the basal ice, gravitational driving force etc.

The second image shows a highly simplified image giving ice cliff failure criteria a freeboard above 90 to 100m and a submerged cliff face height of over about 800m.

The third and fourth images show that the ice cliff face for Jakobshavn was (until recently) retreating up a prograde bedslope so that as it retreated it became more stable.  Furthermore, and increase in basal meltwater volume would contribute to an advance of the ice face, which would reduce the height of the ice face, including the freeboard height; which would also serve to stabilize the ice face against cliff failures.

If for any reason the ice cliff face retreats upstream of point A15 in the fourth image, then the negative bedslope would likely trigger an MICI mechanism for tens of kilometer of ice face retreat.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1141 on: May 20, 2019, 09:54:13 PM »
I think that it is useful to periodic post updates on our emissions/GMSTA status.  In that regard:

The first image shows that the weekly average of the Mauna Loa CO2 concentration was about 415ppm for the week of May 12 to 18, 2019.

The second image shows the per NOAA (which assumes a 100-year GWP for methane of 25) that for 2018 the CO2-equiv was just below 500ppm.

The third image shows NOAA's AGGI index increased by 1.8% in 2018 from 2017.

The fourth image shows that based on GISTEMP information thru the end of April 2019, that Gavin Schmidt projects that GMSTA above the late 19th century will likely be well about 1C.

All of this indicates that 2018 was a BAU year for anthropogenic radiative forcing.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1142 on: May 20, 2019, 10:05:54 PM »
Quote
Our model does not include the mechanics of ice-shelf hydrofracture or cliff failure20, which might hasten retreat. However, it is our contention that such processes are unlikely to be important during this century; this is based on three lines of evidence. First, by incorporating ice–ocean–atmosphere feedbacks, our simulations predict substantial atmospheric cooling over mid- to high southern latitudes (Extended Data Fig. 1b), which will offset approximately 0.5–3.5 °C of the atmospheric warming predicted by CMIP5 models (Extended Data Fig. 2c, d) and thus reduce melt. Second, although we do not have data from warmer-than-present conditions, contemporary observations show that surface melt has been a normal component of Antarctic ice shelves in the recent past, without it having led to shelf breakup47,48. Third, simulations of future surface melting across Antarctic ice shelves using regional climate models such as RACMO2.1 (ref. 49) and CMIP5 general circulation models50 predict far lower melt quantities than the simulations of ref. 20. If such high melt is necessary to induce continent-wide hydrofracture, then these other models would imply that more extreme atmospheric warming than predicted for 2100 may be necessary to trigger widespread ice-shelf collapse.

Consensus climate scientists are free to make any assumptions that they want to make to justify that their models do not consider either ice shelf-hydrofracturing or ice cliff failure mechanisms, and then to publish probabilities based on their simplified models; but that does not mean that nature will conform to the assumptions of said consensus climate scientists.  Furthermore, I have previously posted information indicating that the ice shelves in the ASE are rapidly deteriorating without any hydrofracturing, and if the current rate of ASE ice shelf degradation continues for the next one to two decades, MICI-mechanisms maybe initiated for several key ASE marine glaciers without the need for any significant hydrofracturing.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1143 on: May 20, 2019, 11:28:54 PM »
Re: Carbon budgets

Mr. van der Linde included a vesrion of a figure from AR5 SPM,  which occurs in two places in the SPM. The caption for the version on pg 26 includes the sources for budgets.


"Figure SPM.5 |  (a) Emissions of carbon dioxide (CO2) alone in the Representative Concentration Pathways (RCPs) (lines) and the associated scenario categories used in WGIII (coloured areas show 5 to 95% range). The WGIII scenario categories summarize the wide range of emission scenarios published in the scientific literature and are defined on the basis of CO2-eq concentration levels (in ppm) in 2100. The time series of other greenhouse gas emissions are shown in Box 2.2, Figure 1. (b) Global mean surface temperature increase at the time global CO2 emissions reach a given net cumulative total, plotted as a function of that total, from various lines of evidence. Coloured plume shows the spread of past and future projections from a hierarchy of climate-carbon cycle models driven by historical emissions and the four RCPs over all times out to 2100, and fades with the decreasing number of available models. Ellipses show total anthropogenic warming in 2100 versus cumulative CO2 emissions from 1870 to 2100 from a simple climate model (median climate response) under the scenario categories used in WGIII. The width of the ellipses in terms of temperature is caused by the impact of different scenarios for non-CO2 climate drivers. The filled black ellipse shows observed emissions to 2005 and observed temperatures in the decade 2000–2009 with associated uncertainties. {Box 2.2, Figure 1; Figure 2.3)

The first sentence states that fossil carbon emission estimates are taken from the RCPs and WGIII scenarios, which in turns are used to drive CMIP5 models.

sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1144 on: May 20, 2019, 11:57:48 PM »
Bamber et al 2019 shows results below of structured expert judgement on global sea level rise projections:
https://www.pnas.org/content/early/2019/05/14/1817205116

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1145 on: May 21, 2019, 01:51:49 AM »
Re: Carbon budgets

Rogelj et al (2016) recommend a much more stringent guidelines than the AR5 carbon budget for staying below 2C.

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 unravelled", Nature Climate Change, 6, 245–252, doi:10.1038/nclimate2868

http://www.nature.com/nclimate/journal/v6/n3/full/nclimate2868.html?WT.feed_name=subjects_climate-change-mitigation&foxtrotcallback=true

Abstract: "Several methods exist to estimate the cumulative carbon emissions that would keep global warming to below a given temperature limit. Here we review estimates reported by the IPCC and the recent literature, and discuss the reasons underlying their differences. The most scientifically robust number — the carbon budget for CO2-induced warming only — is also the least relevant for real-world policy. Including all greenhouse gases and using methods based on scenarios that avoid instead of exceed a given temperature limit results in lower carbon budgets. For a >66% chance of limiting warming below the internationally agreed temperature limit of 2 °C relative to pre-industrial levels, the most appropriate carbon budget estimate is 590–1,240 GtCO2 from 2015 onwards. Variations within this range depend on the probability of staying below 2 °C and on end-of-century non-CO2 warming. Current CO2 emissions are about 40 GtCO2 yr−1, and global CO2 emissions thus have to be reduced urgently to keep within a 2 °C-compatible budget."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1146 on: May 21, 2019, 02:59:55 AM »
How far are we away from proof of concept with MICI? It seems like we are making heaps of progress with measuring the topography beneath the ice and water temperature / salinity / depth.

I'm anticipating the day when scientists can tell us that a specific retrograde grounding line has been breached and warm water is at the base of an 800+ meter deep ice cliff so we can all follow along in real time.

Correct me if I'm wrong, but I think MICI would be a function of the speed at which the warm water lifts the ice off the bedrock. The surface ice instability kicks in when the base begins to float, no?

I realize that these are very remote places which makes observation challenging but there is also huge public interest. Any ice gurus know when we'll hit an important grounding line?

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1147 on: May 21, 2019, 04:03:17 AM »
Sea Level Rise Could Be Much Larger Than Expected 
https://www.bbc.com/news/science-environment-48337629

Scientists believe that global sea levels could rise far more than predicted, due to accelerating melting in Greenland and Antarctica,

The long-held view has been that the world's seas would rise by a maximum of just under a metre by 2100.

This new study, based on expert opinions, projects that the real level may be around double that figure.

In the researchers' view, if emissions continue on the current trajectory then the world's seas would be very likely to rise by between 62-238cm by 2100. This would be in a world that had warmed by around 5C - one of the worst case scenarios for global warming.

"For 2100, the ice sheet contribution is very likely in the range range of 7-178cm but once you add in glaciers and ice caps outside the ice sheets and thermal expansion of the seas, you tip well over two metres," said lead author Prof Jonathan Bamber from the University of Bristol.

... According to the authors, this scenario would have huge implications for the planet.

They calculate that the world would lose an area of land equal to 1.79 million square kilometres - equivalent to the size of Libya.

Much of the land losses would be in important food growing areas such as the delta of the Nile. Large swathes of Bangladesh would be very difficult for people to continue to live in. Major global cities, including London, New York and Shanghai would be under threat.

"To put this into perspective, the Syrian refugee crisis resulted in about a million refugees coming into Europe," said Prof Bamber.

"That is about 200 times smaller than the number of people who would be displaced in a 2m sea-level rise."


----

Ice sheet contributions to future sea-level rise from structured expert judgment 
https://www.pnas.org/content/early/2019/05/14/1817205116
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Sleepy

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1148 on: May 21, 2019, 04:41:00 AM »
v_m, LvdL already posted that twice in here.

Edit; adding this tweet by Aslan Grinsted and the graph for RCP8.5 (RCP4.5 in the tweet).
https://twitter.com/AGrinsted/status/1130819798634573824
« Last Edit: May 21, 2019, 05:40:08 PM by Sleepy »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1149 on: May 21, 2019, 07:29:15 PM »
... However, my general point is that a some portion of the changes in the magnetic pole can be associated with changes in the rotational pole (the attached image illustrates how fast this is currently changing), due to changes in the magma flow associated with ice mass redistribution.  Furthermore, my point is that due to the current exceptionally high rate of anthropogenic forcing and the bipolar seesaw mechanism that possible abrupt changes in ice mass loss can make faster changes in tectonic behavior than observed in the paleorecord.

https://forum.arctic-sea-ice.net/index.php/topic,2205.50.html

ASLR"

The first image shows the southern supercontinent Gondwana about 183million year ago at the point of the initial breakup of the supercontinent.  The second image highlights the Euler geometry of hexagons and pentagons bounded by the supercontinent rupture lines that define the lines of minimum energy required to break apart the supercontinent.  These two images illustrate the origins of the area known as the South Atlantic Anomaly – an expanse of the field currently stretching from Chile to Zimbabwe, as discussed in the reference linked (and the last two images) below.  The Hare et al. (2018) linked open access reference indicates that this region is likely a key area of the Earth core-mantle boundary that is likely in the process of triggering a flip in the Earth's magnetic poles.

Vincent J. Hare et al. (15 February 2018), "New Archeomagnetic Directional Records From Iron Age Southern Africa (ca. 425–1550 CE) and Implications for the South Atlantic Anomaly", GRL, DOI: 10.1002/2017GL076007

http://onlinelibrary.wiley.com/doi/10.1002/2017GL076007/full

Abstract: "The paucity of Southern Hemisphere archeomagnetic data limits the resolution of paleosecular variation models. At the same time, important changes in the modern and historical field, including the recent dipole decay, appear to originate in this region. Here a new directional record from southern Africa is presented from analysis of Iron Age (ca. 425–1550 CE) archeological materials, which extends the regional secular variation curve back to the first millennium. Previous studies have identified a period of rapid directional change between 1225 and ∼1550 CE. The new data allow us to identify an earlier period of relatively rapid change between the sixth and seventh centuries CE. Implications for models of recurrent flux expulsion at the core-mantle boundary are discussed. In addition, we identify a possible relationship of changes recorded in these African data with archeomagnetic jerks."

See also:

Title: "A Mysterious Anomaly Under Africa Is Radically Weakening Earth's Magnetic Field"

https://www.sciencealert.com/something-mysterious-under-southern-africa-dramatically-weakening-earth-s-magnetic-field-south-atlantic-anomaly

Extract: "This could be precursor to Earth's poles swapping places.

The region that concerns scientists the most at the moment is called the South Atlantic Anomaly – a huge expanse of the field stretching from Chile to Zimbabwe. The field is so weak within the anomaly that it's hazardous for Earth's satellites to enter it, because the additional radiation it's letting through could disrupt their electronics.

… the artefacts revealed that the weakening in the South Atlantic Anomaly isn't a standalone phenomenon of history.

Similar fluctuations occurred in the years 400-450 CE, 700-750 CE, and 1225-1550 CE – and the fact that there's a pattern tells us that the position of the South Atlantic Anomaly isn't a geographic fluke.

"We're getting stronger evidence that there's something unusual about the core-mantel boundary under Africa that could be having an important impact on the global magnetic field," Tarduno says.

The current weakening in Earth's magnetic field – which has been taking place for the last 160 years or so – is thought to be caused by a vast reservoir of dense rock called the African Large Low Shear Velocity Province, which sits about 2,900 kilometres (1,800 miles) below the African continent.

"It is a profound feature that must be tens of millions of years old," the researchers explained in The Conversation last year.

"While thousands of kilometres across, its boundaries are sharp."

This dense region, existing in between the hot liquid iron of Earth's outer core and the stiffer, cooler mantle, is suggested to somehow be disturbing the iron that helps generate Earth's magnetic field.

There's a lot more research to do before we know more about what's going on here.

As the researchers explain, the conventional idea of pole reversals is that they can start anywhere in the core – but the latest findings suggest what happens in the magnetic field above us is tied to phenomena at special places in the core-mantle boundary."

Is it possible that the new subsea volcanic activity east of Mayotte Island is geodynamically associated with the: 'Anomaly Under Africa' which 'Is Radically Weakening Earth's Magnetic Field'?

Title: "The volcanic-tectonic crisis of 2018 east of Mayotte, Comoros islands" by Lemoine et al. (2019):

https://eartharxiv.org/d46xj/

See also:

Title: "Strange waves rippled around Earth. Now we may know why."

https://www.nationalgeographic.com/science/2019/05/strange-waves-rippled-around-earth-may-know-why/

Extract: "Now, researchers may have at last found the source of the unexpected activity: the birth of a submarine volcano some 31 miles off Mayotte's eastern shore. Sitting about two miles underwater, the baby volcano stretches nearly half a mile high and extends up to three miles across.

Even back then, the experts' conclusion was that the quakes and strange seismic signal were likely related to the movement of molten rock. Perhaps the earthquake swarm was the result of magma squishing through the subsurface, and the low-frequency rumble was caused by waves resonating in a collapsing magma chamber.

The link to volcanic activity gained further support from a preprint study posted to the EarthArxiv server in February 2019. That research pinned the swarm on a massive magma chamber starting to drain, in what could be the largest off-shore submarine volcanic event yet documented."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson