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Lennart van der Linde

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Re: Sea Level Rise Projections and Maps
« Reply #50 on: September 04, 2013, 01:39:44 PM »
Ah, so Pfeffer's position does not even differ so much from Hansen's after all :)

Another point made by Hansen, the possibility of 'scientific reticence' and/or a 'Millikan Effect', or maybe also a scientific inclination to 'err on the side of least drama' (Rysse et al 2012) rather than being accused of/for 'crying wolf':
http://www.columbia.edu/~jeh1/mailings/2012/20121226_GreenlandIceSheetUpdate.pdf

Hansen even resorts to literary tactics in trying to make his point:
http://www.giss.nasa.gov/research/briefs/hansen_12/

And Rysse et al 2012:
http://www.wageningenur.nl/upload/24618685-3919-475e-a59c-823e90376072_erring.pdf

Maybe there could also be an effect that scientists, being human, can sometimes be frightened by possible conclusions from their work?

AbruptSLR

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Re: Sea Level Rise Projections and Maps
« Reply #51 on: September 04, 2013, 04:13:41 PM »
Lennart,

All that I can say is that when a multinational oil/gas company wants to drill in deep offshore water (such as BP in the Gulf of Mexico), they are required to conduct, and submit for review, a detailed hazard analysis of worst case scenarios.  However, when modern society wants to conduct a one of a kind experiment on the Earth's climatic system, that could result in billions of deaths in the next hundred years or so, there is no requirement to perform a hazard analysis, or to take precautions; all that most people think that they need to do is to look around and to see if they are doing as well as their neighbors; and if so, most people think that things are as they should be.

Best,
ASLR
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JimD

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Re: Sea Level Rise Projections and Maps
« Reply #52 on: September 04, 2013, 05:44:10 PM »
Lennart

I am finished working through the RealClimatre posts by Ramsdorf and the comments and I either did not find an answer to your question or I did not understand it when it went by.  The following comment to the post is the closest I found to anything providing a clue.

Quote
...Some good news: Not much additional response in SLR until 650 ppm. “sea level stays more or less constant for CO2 changes between 400 and 650 parts per million and it is only for CO2 levels above 650 parts per million that the researchers again saw a strong sea level response for a given CO2 change.”

This indicates the relative stability of the East Antarctic Ice Sheet. However, I don’t think we should take this as an excuse for burning fossil fuels up to 650 ppm, as the additional forcing will probably cause a faster rate of sea level rise.

where the poster was talking about paleo records which indicate that slr is not linear with rising CO2 but, for some reason, stalls out for a time between 400-650 and then takes off again.  This is very strange to me and I wonder if you or ASLR know what could cause such a result.  It seems to defy physics.  I am wondering if they made a mistake. 

But the post brought up the question in my mind that if the paleo records (which are not perfect and have their own issues, but are still real data) show a non-continuous rise in slr (speeds up , slows down, speeds back up) due to rising CO2 levels and the various forms of modeling assume a more linear steady state rise then perhaps this difference would also result in different answers.  Do you think that could be part of the answer?

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Lennart van der Linde

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Re: Sea Level Rise Projections and Maps
« Reply #53 on: September 04, 2013, 06:10:39 PM »
ASLR, agreed on the need for hazard analysis.

Jim, that's based on Foster & Rohling, I think. It is indeed intriguing.

There could be some 'hysteresis' in the response of EAIS, as Jim Hansen agrees, but he questions if it is as strong as Foster & Rohling seem to find. However, the hysteresis that F&R find, still seems to be significantly smaller than the hysteresis observed in traditional ice sheet models.

One difference between Hansen and F&R seems to be that Hansen thinks CO2-levels between 60 and 10 million years ago were lower than F&R assume. This seems to be a real open question in paleo studies.

As mentioned before, there are reasons to think that at least part of EAIS will respond earlier and stronger to global warming than previously thought. So, this potential or probable hysteresis may delay SLR from say 20-35m, but our problems with SLR (not to mention other effects of warming which may be even more urgent) will start long before we've reached 20m, and that may already be (largely) locked in, although we may still be able to strongly slow the rate of the rise and limit it to maybe 10-15m in the long run, if we're lucky.

Other than that, I'm just a lay-man and not nearly enough of an expert to really understand the potential causes for this apparently plausible (to scientists) hysteresis-property of EAIS.

AbruptSLR

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Re: Sea Level Rise Projections and Maps
« Reply #54 on: September 05, 2013, 12:12:24 AM »
In reponse to Jim's question, I do not know the answer but I offer the following points:

(1) Paleo data is generally in climatic equalibrium which means that at a CO2 concentration of 400ppm, the corresponding sea level in the past could be 8 to 12m higher than today (as we are far from equalibrium now).  This implies that in the past at 400ppm all of the unstable parts of the WAIS, the EAIS and the GIS (and Mountain Glaciers) could have melted; leaving only the stable parts of the EAIS and of the GIS to contribute further SLR; which might take more forcing.

(2) We need to remember that the continents were in different configurations in the distant past, so the Earth System Sensitivity was different in the past than today, so we cannot directly compare the impact of past CO2 concentrations on todays conditions.

(3) It is possible that to melt stable parts of the EAIS and the GIS might require an equable climate condition; which might require a certain threshold level of CO2 to engage.
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Lennart van der Linde

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Re: Sea Level Rise Projections and Maps
« Reply #55 on: September 05, 2013, 02:18:39 PM »
Thanks to this good find by Artful Dodger we can now read the full paper by Meehl et al (2012), Relative outcomes of climate change mitigation related to global temperature versus sea-level rise:
http://robinlea.com/pub/nclimate/nclimate1529.html

Supplementary info here:
http://www.nature.com/nclimate/journal/v2/n8/extref/nclimate1529-s1.pdf

Lennart van der Linde

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Re: Sea Level Rise Projections and Maps
« Reply #56 on: September 05, 2013, 02:43:50 PM »
ASLR,

The differing past configurations of the continents indeed make it more difficult to determine and compare earth system sensitivities then and now. It still seems an open question however, how big the impact of continental drift etc on these sensitivities has been. I think arguments have been made (again by Jim Hansen, among others) that CO2 is by far the most dominant influence on climate on the time scales of millions of years.

So we can't be sure, but maybe the influence of continental drift in the sense you mention has been limited. It's influence on CO2 in the atmosphere may be more important by speeding up or slowing down vulcanism and weathering processes (thru uplift or subsidence of mountain ranges for example).

If you know scientists/papers which strongly argue differently, I would be interested to learn more.

Foster & Rohling conclude that 400 ppm seems correlated to past sea levels about 24m (-15/+7m) higher than today, with an 84% chance that at this CO2-level it will rise at least 9m in the long run. So a SLR somewhere between 10-30m seems quite possible, although the higher values may be less likely than the lower ones, if I understand correctly.

Their findings have probably not (yet?) been checked for glacial isostatic adjustment, so maybe that could also change them somewhat? I will see if I can find out more on that.

Lennart van der Linde

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Re: Sea Level Rise Projections and Maps
« Reply #57 on: September 05, 2013, 03:26:51 PM »
Some more relevant quotes from Foster & Rohling:

"The compiled CO2 and sea-level records cover about two thirds of the last 40 My, but not in a continuous fashion (Fig. 2), and we restrict our selection to the time periods with the highest density of data for both sea-level and CO2. Although other variables and boundary conditions that influence ice growth/retreat also may have changed between the time intervals (e.g., ocean gateway configurations, continental positions, and orography), we focus here on establishing the first-order relationships and accept that these may be refined further by future studies."

"There is a clearly sigmoidal relationship between sea level and climate forcing by CO2. Moreover, there is a striking similarity between data from different time periods and those generated by different techniques (e.g., Fig. 3A). This overall agreement implies that this relationship is robust and reflects the fundamental behavior of the Cenozoic climate system, despite some significant changes in boundary conditions (e.g., closing of the Panama Gateway since the Pliocene, closure of Tethys since the Miocene)."

"In the Pleistocene (CO2 < 280 ppm), there is no evidence of hysteresis beyond a few thousand years; intervals with increasing and decreasing CO2 give a similar sea-level response (Fig. 1), as also was elaborated for the relationship between sea level and temperature in that period (9). Similarly, for the Miocene (CO2 < 450 ppm), there is no evidence of hysteresis within a temporal resolution of ~300,000 y (Fig. 2). Conversely, the Eocene–Oligocene data show some suggestion of hysteresis (SI CO2 and Sea-Level Estimates and Fig. S3). As yet, this remains insufficiently defined, but it concerns only times with CO2 > 800 ppm (Fig. S3)."

"This assessment (Fig. 3B) clearly reveals a sea-level “plateau” at around 22 m between CO2 levels of about 400 and 650 ppm, with average 68% confidence limits for this interval of +13/−12 m, which covers sea-level values that might be expected in the absence of GrIS and WAIS [+14 m (31)], although within the bounds of uncertainty, we cannot rule out that there was an additional component of mass reduction in the EAIS at these midlevel CO2 values (18, 32). Based on the probability maximum and full contributions from GrIS and WAIS, this may have been equivalent to about 10 m of sea-level rise."

"Our observed long-term relationship between sea level and CO2 forcing reaffirms the importance of CO2 as a main driver of changes in the Earth’s climate over the past 40 My."

"We observe a lack of long-term sea-level response for CO2 levels between about 650 and 400 ppm. This suggests that during these times, very little continental ice grew (or retreated); presumably CO2 was too high, hence the climate too warm to grow more continental ice after the “carrying capacity” of the EAIS had been reached (Fig. 3A). It also suggests that 300–400 ppm is the approximate threshold CO2 value for retreat and growth, respectively, of WAIS and GrIS (and possibly a more mobile portion of EAIS). Sea levels of 20–30 m above the present during the Pliocene and Miocene, when CO2 was largely between 400 and 280 ppm, are thought to predominantly reflect mass changes in the GrIS and WAIS (26, 31). However, recent records proximal to the Antarctic ice sheet indicate that some portion [maybe as much as 10 m sea-level equivalent (26, 34)] of the EAIS also retreated during these warm periods (26, 35)."

"Although the overall shape of our ln(CO2/C0):SL relationship is similar to that inferred using inverse modeling of the benthic foraminiferal δ18O record (39), our compilation places the transition from a nonglaciated to fully glaciated EAIS at considerably higher CO2 (650–1,000 ppm CO2 vs. their 380–480 ppm CO2; Fig. 3C)."

"Because it is constrained by real-world observations of the Earth system, our relationship inherently includes all feedbacks and processes that contribute to sea-level change. It also appears to be largely independent of other boundary condition changes and therefore may be used with confidence to determine a likely estimate for sea level if theEarth system were to reach equilibrium with modern or future CO2 forcing. Given the present-day (AD 2011) atmospheric CO2 concentration of 392 ppm, we estimate that the long-term sea level will reach +24 +7/−15 m (at 68% confidence) relative to the present. This estimate is an order of magnitude larger than current projections for the end of this century [up to 2 m; best estimate, 0.8 m (41)] and seems closer to the worst-case long-term sea-level projection portrayed by Meehl et al. (1)."

AbruptSLR

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Re: Sea Level Rise Projections and Maps
« Reply #58 on: September 05, 2013, 03:42:52 PM »
Lennart,
In response to your questions please briefly scan through replies #55 to 68 and #71 to 73, and then focus on the reference discussed in reply #74, which cites a consistent 5oC temperature difference for the same atmospheric CO₂ concentrations between modern and early Eocene conditions, per the following link:

http://forum.arctic-sea-ice.net/index.php/topic,130.50.html

Also, note that per reply # 31 in the following link, during the early Eocene, the bed of the West Antarctic was above modern sea level; which implies that equable climate conditions may have been required to keep glaciers from forming in this area as well prior to 32 MYA.


http://forum.arctic-sea-ice.net/index.php/topic,314.0.html#lastPost

Best,
ASLR
« Last Edit: September 05, 2013, 04:38:34 PM by AbruptSLR »
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Lennart van der Linde

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Re: Sea Level Rise Projections and Maps
« Reply #59 on: September 05, 2013, 04:43:30 PM »
ASLR,

Thanks for the references, that I've only scanned quickly so far. So maybe the past continental configuration is a much more important factor after all, in contrast to what Hansen and Rohling seem to think. I will need some time to study your references and see what I can understand :)

Cheers!
Lennart

Lennart van der Linde

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Re: Sea Level Rise Projections and Maps
« Reply #60 on: September 05, 2013, 05:42:12 PM »
Reading the full Meehl et al (2012) paper shows that their worst-case SLR-scenario for 2100 is about 145cm and for 2300 it's around 960 cm. See their figure 3 again, attached below.

As they say in the paper:
"These values inform the upper range of the shading in Fig. 3 that encompasses the larger estimates. But the limit of the higher end of the shading is depicted as being indistinct to reflect that these are only estimates. There is no real way of knowing if these higher total sea-level rise values are credible, or if higher or lower values are more likely."

From eye-balling the figure itself it looks as if these estimates have uncertainty ranges up to almost 2m for 2100, almost 6m for 2200 and almost 12m for 2300, of course bearing the above quote in mind.

AbruptSLR

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Re: Sea Level Rise Projections and Maps
« Reply #61 on: September 05, 2013, 05:50:31 PM »
Lennart,

While you study the references that I cited; remember that Hansen et al expect that the "slow response" feedback mechanisms (e.g.: "albedo flip", collapse of the WAIS, etc.) will occur more quickly than assumed by the references that I gave.  Therefore, I am not saying that Hansen et al are wrong, but rather that there is some climate state threshold that must be crossed before the world slips into an equable climate, where relatively low Global Mean Temperatures can result in high sea levels.

Personnally, I am concerned that when the modern climate condition is forced by between 800 to 1,000 ppm CO2 equivalent (note that I include the carbon dioxide equivalent of a significant increase of methane say from the permafrost or marine methane hydrates in these concentration values), that we might then collapse into an equable climate with one single atmospheric Hadley Cell, and a very high risk of abrupt SLR, for several centuries to come as occurred in MeltPulse 1A (no matter what the current GCM projections imply).

Best,
ASLR
« Last Edit: September 05, 2013, 06:31:25 PM by AbruptSLR »
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AbruptSLR

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Re: Sea Level Rise Projections and Maps
« Reply #62 on: September 06, 2013, 06:59:51 PM »
In my initial response to JimD on this matter, I incorrectly stated that Pfeffer et al's 2008 initial ice mass loss values from the Amundsen Sea sector may need to be increased by 25% due to GIA corrections.  While the actual amount of the GIA correction is in dispute, if the following reference is correct, then the Pfeffer et al 2008 values may need to be increased by 40% (not 25%):


An investigation of Glacial Isostatic Adjustment over the Amundsen Sea sector, West Antarcticaby: A. Groh; H. Ewert, M. Scheinert, M. Fritsche, A. Rülke, A. Richter, R. Rosenau, R. Dietrich
http://dx.doi.org/10.1016/j.gloplacha.2012.08.001

Abstract
"The present study focuses on the Amundsen Sea sector which is the most dynamical region of the Antarctic Ice Sheet (AIS). Based on basin estimates of mass changes observed by the Gravity Recovery and Climate Experiment (GRACE) and volume changes observed by the Ice, Cloud and Land Elevation Satellite (ICESat), the mean mass change induced by Glacial Isostatic Adjustment (GIA) is derived. This mean GIA-induced mass change is found to be 34.1 ± 11.9 Gt/yr, which is significantly larger than the predictions of current GIA models. We show that the corresponding mean elevation change of 23.3 ± 7.7 mm/yr in the Amundsen Sea sector is in good agreement with the uplift rates obtained from observations at three GPS sites. Utilising ICESat observations, the observed uplift rates were corrected for elastic deformations due to present-day ice-mass changes. Based on the GRACE-derived mass change estimate and the inferred GIA correction, we inferred a present-day ice-mass loss of − 98.9 ± 13.7 Gt/yr for the Amundsen Sea sector. This is equivalent to a global eustatic sea-level rise of 0.27 ± 0.04 mm/yr. Compared to the results relying on GIA model predictions, this corresponds to an increase of the ice-mass loss or sea-level rise, respectively, of about 40%."

Note that in the Antarctic folder, the "Surge" thread and the "Tectonic" threads both have additional discussion on this matter.
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JimD

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Re: Sea Level Rise Projections and Maps
« Reply #63 on: September 06, 2013, 07:59:32 PM »
ASLR  thanks.  You and Lennart have helped me learn about this far more than I anticipated.

When one looks at all the papers we have been discussing above it seems as if the general consensus is that a collapse of the PIGS/Thwaites complex will not happen soon enough to impact the 2100 numbers significantly (depending on what significant means to each author).  Your last post indicates that we could add 40% to the Pheffer numbers for Antarctica but that would still leave us under 3m total slr in 2100 correct?

So I guess this leaves me with a question about how soon/fast the west Antarctic could destabilize and how fast of a rise in sea level that could result from that.  I have spent some time reading about this question and I have not come up with a suitable set of scientific papers which contain projections.   In your first post in Hazard Analysis for Pig/Thwaites you indicate that you expect them to be in collapse sometime in the 2050/60 timeframe. When you finish this analysis are you intending to make slr projections for 2100 and other times along the lines of what the authors above have done?
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AbruptSLR

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Re: Sea Level Rise Projections and Maps
« Reply #64 on: September 06, 2013, 11:06:05 PM »
Jim,

The general opinion at the moment (per NOAA) is that the WAIS will not collapse this century, and that by 2100 SLR will be between 1 to 7-ft, with a most probable value of about 4-ft (1.22m); and NOAA's position is that the user of their SLR guidance needs to decide for themselves how much risk they do, or do not want to take, as it is currently not possible to predict SLR by 2100, and some researchers such as James Hansen have not back away from their earlier estimates of about 5m of SLR by 2100 (assuming the WAIS does collapse by then).

Regarding whether I am going to pull my numerous posts together into my own SLR projection, I have already done so in the "Philosphical" thread in the Antarctic folder, but I attach one version of this projection here (for the record), and all of my posts in the Antarctic folder since creating my SLR projection, are intended to provide additional support that this worst case projection is credible.  In the attached figure:

(a) SBEHA is my "Scenario Based Engineering Hazard Assessment" for use as a "Maximum Credible SLR Event" by 2100, which is intended as a worst case resiliency case for infrastructure (engineering) planning;

(b) RSLR in this figure is the relative SLR for California, while eustatic is the mean global SLR by 2100;

(c) RP&V is: 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

(d) the percentages give are for radiative forcing Confidence Levels of the RCP 8.5, which is taken as the worst case forcing scenario.


Editorial Note: The attached figure assumes that the atmospheric circulation will not transition to that for an equable climate before 2200.  However, I have provided some discussion in the Antarctic folder indicating that if we stay on the RCP 8.5 95% CL path that we currently are on, then Earth might transition to a stable equable climate pattern circa 2100; which would in my opinion continue the abrupt SLR trend beyond 2100 until eustatic sea level has risen by about 216-ft (66 m) sometime around 3200.
« Last Edit: September 06, 2013, 11:52:28 PM by AbruptSLR »
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Lennart van der Linde

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Re: Sea Level Rise Projections and Maps
« Reply #65 on: September 19, 2013, 03:20:49 PM »
Two quotes from the new paper by Hansen et al 2013 that are particularly noteworthy, at least to me, living in Holland:
http://m.rsta.royalsocietypublishing.org/content/371/2001/20120294.full.pdf

“The empirical data support a high sensitivity of the sea level to global temperature change, and they provide strong evidence against the seeming lethargy and large hysteresis effects that occur in at least some ice sheet models [p.22].”

“The amount of CO2 required to melt most of Antarctica in the MMCO [Middle Miocene Climatic Optimum, about 16 million years ago] was only approximately 450–500 ppm, conceivably only about 400 ppm. These CO2 amounts are smaller than suggested by ice sheet/climate models, providing further indication that the ice sheet models are excessively lethargic, i.e. resistant to climate change [p.23].”

So we could be very close to melting all of the ice on Earth, resulting in about 70m of SLR. Maybe that would take as little as a few millennia and could be very hard to stop, if we don't succeed in decarbonizing our economy very fast and/or in geoengineering our way out of this prospect. About 10m of SLR, including contributions from EAIS, could be possible in the coming three centuries, which may be inevitable in the longer term anyhow, but could still be slowed down substantially by fast decarbonization.

How Holland and the world could or would adapt to 10m of SLR over the coming centuries is an interesting question, but it looks like it would be a lot more expensive than rapidly decarbonizing. Which of course would also mitigate the need for adaptation to earlier and maybe even more urgent pressures, like food and water shortages, heat waves, droughts, fires, storms, floods, diseases, migration and conflicts over all kinds of resources.

Shared Humanity

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Re: Sea Level Rise Projections and Maps
« Reply #66 on: September 19, 2013, 06:25:38 PM »
"How Holland and the world could or would adapt to 10m of SLR over the coming centuries is an interesting question....."

In the most recent National Geographic, there is a nice article on the impact of sea level rise.

http://ngm.nationalgeographic.com/2013/09/rising-seas/folger-text

The author spent quite a bit of time in Holland to get a sense of how the most skilled nation in the world is currently battling this rise. If you read the article, "a recent Dutch study predicted that the Netherlands could engineer solutions at a manageable cost to a rise of as much as five meters, or 16 feet."

Keep in mind this is a wealthy country with a great deal of expertise in dealing with the sea. Most other nations will not be able to deal with such a rise and, for some areas such as Florida, there are simply no solutions that will prevent the complete evacuation of the southern 1/3 of the state, including Miami. In fact most of South Florida will lose its source of drinking water with a sea level rise of 2 feet as sea water poisons all current sources of fresh water.

Lennart van der Linde

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Re: Sea Level Rise Projections and Maps
« Reply #67 on: September 19, 2013, 10:11:17 PM »
Very nice article indeed. I'll have to find out which recent report said about 5m of SLR would still be manageable for the Netherlands. Sounds like the number I've heard before, but have never really seen the underlying reasoning for.

We had a new Delta Committee a few years ago, who assumed the worst-case would be a little over 1m of SLR by 2100 and about 3.5m by 2200. That seem like underestimates for worst-cases by now.

I live and work in The Hague myself. For planning the municipality uses 60cm by 2100 and 120cm by 2200 as SLR-scenarios. Way too low in my opinion, but so far I see little willingness to consider higher scenarios, like the NOAA worst-case scenario of 2m by 2100.

Lennart van der Linde

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Re: Sea Level Rise Projections and Maps
« Reply #68 on: September 20, 2013, 03:43:31 PM »
The following two papers give further support to the apparent vulnerability of the EAIS at current CO2-levels and the high probability of at least 17m of SLR in the long term if we don't manage to reduce these levels.

Dwyer & Chandler 2009, Phil. Trans. R. Soc.;
Mid-Pliocene sea level and continental ice volume based on coupled benthic Mg/Ca palaeotemperatures and oxygen isotopes:
http://rsta.royalsocietypublishing.org/content/367/1886/157.full.pdf+html

ABSTRACT:
"Ostracode magnesium/calcium (Mg/Ca)-based bottom-water temperatures were combined with benthic foraminiferal oxygen isotopes in order to quantify the oxygen isotopic composition of seawater, and estimate continental ice volume and sea-level variability during the Mid-Pliocene warm period, ca 3.3–3.0 Ma. Results indicate that, following a low stand of approximately 65 m below present at marine isotope stage (MIS) M2 (ca 3.3 Ma), sea level generally fluctuated by 20–30 m above and below a mean value similar to presentday sea level. In addition to the low-stand event atMIS M2, significant low stands occurred at MIS KM2 (K40 m), G22 (K40 m) and G16 (K60 m). Six high stands ofC10 m or more above present day were also observed; four events (C10, C25,C15 and C30 m) from MIS M1 to KM3, a high stand of C15 m at MIS K1, and a high stand of C25 m at MIS G17. These results indicate that continental ice volume varied significantly during the Mid-Pliocene warm period and that at times there were considerable reductions of Antarctic ice."

Kenneth G. Miller, James D. Wright, James V. Browning, Andrew Kulpecz, Michelle Kominz, Tim R. Naish, Benjamin S. Cramer, Yair Rosenthal, W. Richard Peltier and Sindia Sosdian 2012, Geology;
High tide of the warm Pliocene: Implications of global sea level for Antarctic deglaciation:
http://geology.rutgers.edu/images/Publications_PDFS/Miller_2012.pdf

ABSTRACT:
"We obtained global sea-level (eustatic) estimates with a peak of ∼22 m higher than present for the Pliocene interval 2.7–3.2 Ma from backstripping in Virginia (United States), New Zealand, and Enewetak Atoll (north Pacific Ocean), benthic foraminiferal δ18O values, and Mg/Ca-δ18O estimates. Statistical analysis indicates that it is likely (68% confidence interval) that peak sea level was 22 ± 5 m higher than modern, and extremely likely (95%) that it was 22 ± 10 m higher than modern. Benthic foraminiferal δ18O values appear to require that the peak was <20–21 m. Our estimates imply loss of the equivalent of the Greenland and West Antarctic ice sheets, and some volume loss from the East Antarctic Ice Sheet, and address the long-standing controversy concerning the Pliocene stability of the East Antarctic Ice Sheet."

So this last study indicates there seems to be about 84% chance that sea level will rise at least 17m in the long term, if current CO2 levels are not reduced over the coming centuries.

Anne

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Coastal erosion
« Reply #69 on: October 05, 2013, 04:19:55 PM »
Coastal erosion is happening unexpectedly fast as the buffer zone of sea ice and permafrost declines. This threatens not only habitations but also onshore gas and oil infrastructure.

Quote
ABSTRACT
Permafrost coasts make up to 34 per cent of the world's coastlines. Erosion of these coasts currently averages 0.5 m a-1, which is similar to or greater than rates observed in temperate regions. The erosion rate has risen on the Arctic coast of Alaska during the first decade of the 21st century as the minimum sea ice extent has declined. Increasing erosion leads to higher engineering and relocation costs for coastal villages (US$140 million for Kivalina alone to adapt and eventually relocate), and to greater quantities of organic carbon contained in permafrost being released to the near-shore zone (up to 46.5 Tg a-1). Modelling of coastal erosion has begun to include permafrost-specific components such as block failure. The absence of basic information on Arctic coasts that would be provided by a dedicated observing network, especially on lithified coasts, has hindered the development of a system model with predictive capability.

Recent Progress Regarding Permafrost Coasts
H. Lantuit*, P. P. Overduin, S. Wetterich

LRC1962

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Re: Sea Level Rise Projections and Maps
« Reply #70 on: October 07, 2013, 06:57:48 AM »
Came across this page: http://ngm.nationalgeographic.com/2013/09/rising-seas/uneven-impacts-map
Granted NG is not a scientific pear review publication but they do generally do good reporting.
http://ngm.nationalgeographic.com/2013/09/rising-seas/uneven-impacts-map shows impacts based on 4ft rise by 2100. The scary part is that there are those on the ground reporting from both Greenland and Antarctica that are saying it could easily be by 2050. Not only that, every time a new study gets completed from these ice sheets they seem to come to the same conclusion: Its worse then we thought it would be.
"All truth passes through three stages: First, it is ridiculed; Second,  it is violently opposed; and Third, it is accepted as self-evident."
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Re: Sea Level Rise Projections and Maps
« Reply #71 on: December 04, 2013, 07:18:46 PM »
http://www.jamstec.go.jp/jamstec-e/iugg/htm/abstract/abst/jsm04/018042-2.html


Experts say the IPCC underestimated future sea level rise


Quote
It looks like past IPCC predictions of sea level rise were too conservative; things are worse than we thought.

(Somehow I feel like I've heard that last phrase before, someplace...)

Quote
That is the takeaway message from a new study out in Quaternary Science Reviews and from updates to the IPCC report itself. The new study, which is also discussed in depth on RealClimate, tries to determine what our sea levels will be in the future. What they found isn't pretty...

the authors took a different approach. They decided to ask the scientists themselves. What do they think sea level rise will be by 2100 and 2300 under different greenhouse gas scenarios? The authors found 360 sea-level experts through a literature survey. They then worked to find contact information for these scientists and finally, they sent a questionnaire. After receiving 90 expert judgments from 18 countries, the results were tallied. So, what do experts think?


...According to the more likely higher emission scenario, the results are 0.7–1.2 meters (2.3–3.9 feet) by 2100 and 2.0–3.0 meters (6.5–9.8 feet) by 2300. These are significantly larger than the predictions set forth in the recently published IPCC AR5 report. They reflect what my colleagues, particularly scientists at NOAA, have been telling me for about three years.

"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

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Re: Sea Level Rise Projections and Maps
« Reply #72 on: December 04, 2013, 08:45:49 PM »
Wili

These numbers from that survey are right in line with our discussions in this thread.  While the IPCC numbers are conservative as would be expected given the process they work under, the numbers put forth in the studies we identified and from statements by recognized experts fell pretty much exactly where this survey landed.  So there is no surprise here is there?
We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

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Re: Sea Level Rise Projections and Maps
« Reply #73 on: December 04, 2013, 11:13:59 PM »
The State of California is estimating a 1.0 to 1.4 meter sea level rise by 2100.

edited to add: Wrong link, Wili.

wili

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Re: Sea Level Rise Projections and Maps
« Reply #74 on: December 05, 2013, 12:13:41 AM »
Ooops, sorry. http://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/dec/04/experts-ipcc-underestimated-sea-level-rise

Yeah, I think this is just new reporting on a report that we've already discussed.

Sorry. Not feeling great today. Posting while sick apparently can lead to as many gaffs as posting drunk (don't both, I must confess).

Best to all,
Dohboi
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

Lennart van der Linde

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Re: Sea Level Rise Projections and Maps
« Reply #75 on: December 05, 2013, 10:58:03 AM »
John Abraham writes in the Guardian and on Skeptical Science:

"According to the best case scenario (humans take very aggressive action to reduce greenhouse gases), the experts think sea level rise will likely be about 0.4–0.6 meters (1.3–2.0 feet) by 2100 and 0.6–1.0 meters (2.0–3.3 feet) by 2300. According to the more likely higher emission scenario, the results are 0.7–1.2 meters (2.3–3.9 feet) by 2100 and 2.0–3.0 meters (6.5–9.8 feet) by 2300."

This is what these experts as a group think likely. But what do they think is possible? What could be the worst case?

According to one of the authors, Stefan Rahmstorf, about half of these experts think there's a 5% chance that SLR by 2300 could be more than 4 meters in a worst-case scenario (whereas 3.8 meters seems to be about the worst-case according to IPCC AR5, chapter 13, figure 13.13).

Four of this half think there's a 5% chance it could be more than 9 meters. Three of these four think it could be more than 10 meters. Two of these three think it could be more than 12 meters. And one of these two thinks it could be even more than 15 meters by 2300 (see Rahmstorf's inline response to my comment 9 at the RealClimate post).

So should citizens and policy makers make decisions based on the likely range, or on the worst-case in the possible range?

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Re: Sea Level Rise Projections and Maps
« Reply #76 on: December 05, 2013, 05:03:43 PM »
Quote
...
So should citizens and policy makers make decisions based on the likely range, or on the worst-case in the possible range?

This is a difficult question and one we all wrestle with all the time here on the forum.  It certainly generates some of the more pointed discussions.

In a perfect world we could perform a rigorous risk analysis and agree to take action based upon what the numbers (so to speak) say.  We all know that is not going to happen for a variety of reasons.  Politics, money to be made, and the frailty of human nature among them.  But one absolutely critical key in making such a risk analysis is that an agreed set of experts would have to evaluate the outliers to make a determination that their estimates were sound enough to be considered in the analysis.  I don't mean to impugn the scientists who made the high estimates here, but any time you have big outliers there is the possibility of some kind of error or that a bias has crept into the analysis.  Keep the AMEG in mind when thinking about this type of issue.   

But we at the working level are already past the above issue from a practical standpoint.  Sea rise level rise is going to be catastrophic even if it is 'only' 1.5m in 2100 and 3 m by 2300.  To me at least, it gets down to arguing, in a policy sense, about how many devils one can fit on the head of a pin.  The devils have already arrived so prevention is not the issue nor is how many actually fit.

Perhaps a better strategy at this point would be to accept the median estimate and 'fully accept' its implications and propose actions based upon those numbers and what they mean.  For example at 1.5 m sea level rise Bangladesh will functionally cease to exist.  So it is time for activists to initiate the process of proposing the migration and relocation of the bulk of the population to India and Burma.  Convene a formal conference between the three countries under the sponsorship of the UN to determine where these people will live and how much they will pay the Indians and Burmese for the right to resettle in their territory.  Do not wait for the Indians to agree to show up.  Just start and they will react you can be sure.  At the same time the Dutch and other locals in northern Europe initiate the process for determining how to resettle the residents of those areas which will no longer be viable post 2100.  Organize it and start paying for it now.  The same for the  various low island countries of the Indian and Pacific Oceans.  None of the receiving locals are going to want to have anything to do with this process now or in the future.  Do not give them a choice.  Start without them.  Invite them to provide input at all stages but make it clear this is going to happen and the sooner everyone gets involved the better it will work out.

Preempt the certain to happen delaying political process by saying this is going to happen and we are starting planning now.  India has to absorb Bangladesh.  Sorry guys but that is just the way it is so deal with it starting now.  Other Europeans are going to have to accept their lowland neighbors, etc.  Drop any pretense of discussion on possibilities and just say they are coming so let us manage the process starting now.  This would, of course, cause a huge hew and cry and result in all sorts of threats and demands. But it would start the process of getting results.  As long as we put the argument among the scientists on what the eventual sea level rise is going to be on the front burner we will make no progress on actual actions.  Not that the argument has no meaning, but that the argument is well enough settled at this point that we leave the devils on the pin discussion to the experts and the rest of us get to work with planning for the inevitable.

There should be a organization in the US which guides the discussion of when we stop public infrastructure investment in low lying areas of Florida (especially Miami), Louisiana, New York/New Jersey and so on.  NO more public money goes to upgrading utilities, roads, bridges, ports, you name it.  Plan for when maintenance will cease and for when utilities will be turned off in specific areas.  When do we abandon.   No federal insurance or insurance guarantees, no disaster money for storm or sea level rise damage. You want to stay there you pay for it all out of your own pocket.  The insurance companies are eventually going to be all over this type of issue in the wealthy countries and when that happens the business interests are going to try and use their political influence to arrange for the taxpayers to provide backup for their private investments (just like the banking/investment fiasco we are stuck with).  We the citizens have to preempt such actions and the way to do it is to force the issue.

How's that for my first cup of coffee  ;D

 

We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

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Re: Sea Level Rise Projections and Maps
« Reply #77 on: December 05, 2013, 05:24:30 PM »
How's that for my first cup of coffee  ;D

You seem to get much better caffeine mileage than I do. What's the secret?

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Re: Sea Level Rise Projections and Maps
« Reply #78 on: December 05, 2013, 05:40:10 PM »
I was taught to make coffee by an old cowboy.  He drank 12 cups a day.  I am a wimp in comparison.
We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

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Re: Sea Level Rise Projections and Maps
« Reply #79 on: December 05, 2013, 06:07:09 PM »
Jim,
In Holland planners now assume a worst-case of 60 cm in 2100 and 120 cm in 2200, based on IPCC 2007. They know it could be worse, but at this point we don't insure ourselves against that risk. The Dutch Delta Committee considers 130 cm by 2100 and 4 m by 2200 as the worst-case (including subsidence). They think we could adapt to such rises.

Our Environmental Assessment Agency and Delft University think we can adapt to 1.5 meter/century for at least four centuries. They consider this as a worst-case, even though the main adviser to the Delta Committee say there's a significant risk of more than 1.5 meter/century. The risks for Bangladesh and other countries are not being seriously considered. It seems this is the case in other rich countries as well.

So to me it seems relevant, for both the Dutch situation and the world, if several experts think the risks are higher than IPCC thinks. Of course it would be nice to know who those experts are and how sound their judgement is. And we should definitely start doing all the things you suggest. But I think the scientific debate on the risks is more than discussing how many angels fit on the pin of a needle.

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Re: Sea Level Rise Projections and Maps
« Reply #80 on: December 05, 2013, 06:34:47 PM »
How's that for my first cup of coffee  ;D

Nice post, Jim. One of my issues with planning for sea level rise is which event horizon do we plan for? It's not as if we hit 1.5 meters at 2100 and then it stops. Do we really want to rebuild coastal infrastructure every 85-100 years? I don't think so. So then there is the issue, as you raise for Bangladesh, or orderly retreat. Just using the US as an example, how do we get the citizen fired up about absorbing the ocean-side population of Florida? These are just colossally huge problems.

edited to untangle my quotation....
« Last Edit: December 05, 2013, 07:31:14 PM by ritter »

JimD

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Re: Sea Level Rise Projections and Maps
« Reply #81 on: December 05, 2013, 06:53:10 PM »
Lennart

If the Dutch planners think that they can adapt to 1.5m per century rise they are a bold lot.  A rational consideration of the state that humanity is likely to be in circa 2100 and even more by 220 hundred indicates to me that they have their heads stuck into the dikes a bit too far.  Since a dramatically shrinking population and a collapsing global economy are highly probable by 2100 exactly how do they expect to pay for that adaptation and perform the work needed?

I do not mean to say that the scientific goal of ascertaining the likely sea level rise numbers and eventual equilibrium temperatures are not important.  But, from a practical perspective of get something done in time to make some kind of measurable difference for the survivors of this coming disaster, we have plenty enough data in hand already and the consensus projections are more than adequate to justify taking actions independent of what the governments are doing.   

As seen in Holland, politics will always minimize the danger and delay action as long as possible while the politicians wait for public consensus to reach the point that a political calculation says it is time to jump in front of the crowd and lead it where it is going.  The time for that kind of patience is long past. 
We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

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Re: Sea Level Rise Projections and Maps
« Reply #82 on: December 05, 2013, 07:02:07 PM »
I think nobody can project accurately the sea level at more than...let's say 20 years !
Why ? because we are on an exponential curve, because the past has never encountered such CO2 levels changes !
I have been to see a speech from michel Galliot (ONERC) he was speaking in the name of the IPCC saying that :
1) in 120 years the CO2 level would be back again to present level (if we stop emissions).
(I don't know the answer but it is obviously completely wrong, I am not certain but it would be a minima 500 years and more, certainly 5000 years (do you have data or accurate info ? IPCC?)
2 ) If Antarctica would melt completely it would be at max 30 meters
(Well a basic calculation base on 30 million km3 storage show it would be around 84 meters (Let's say around 63 as I have heard) but that does not include the thermal expansion that is 50 % of the sea level rise so 63 + 7 + 70 = 140 meters ouaouh That does not include the isostatic rebound of the Antarctica continental floor and the informations that I have show that around 70 millions years ago the sea level was 300 meters above ! What do you think ? )
3) well he was also saying that the scientist gather themselves on their free time and therefore their conclusions cannot be challenged !
4) That the end of the arctic would be for 2050 ! (Changing from 2100 6 years ago without apologize)
5) That if we reduce by 4 our emissions everything would be fine !
6) A woman told him about a study published in "National Geographic" saying the CO2 would be back in a few thousand years, but he dismissed the study straight away saying only IPCC was right ( I did just shut up but complained by mail to the organisation after that...they don't want to hear... I am not from IPCC you know)

If you have some links on the 5th IPCC report that match or not is speech, I would have something to argue with !
The max change rate was around 4 cm/year 14.000 years ago, I really think we can expect more !
« Last Edit: December 05, 2013, 07:24:00 PM by Laurent »

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Re: Sea Level Rise Projections and Maps
« Reply #83 on: December 05, 2013, 07:02:49 PM »
Nice post, Jim. One of my issues with planning for sea level rise is which event horizon do we plan for? It's not as if we hit 1.5 meters at 2100 and then it stops. Do we really want to rebuild coastal infrastructure every 85-100 years? I don't think so. So then there is the issue, as you raise for Bangladesh, or orderly retreat. Just using the US as an example, how do we get the citizen fired up about absorbing the ocean-side population of Florida? These are just colossally huge problems.

That is exactly the idea.  Trying to precipitate an orderly retreat.  The attempt might well fail but the alternative certainly will fail.

If we wait until the Bangladeshi's start moving over the Indian border in mass the almost certain result will be genocide.  If we hit the Indians along the head with "They are coming to live with you and let's figure out how to manage that." then it will trigger all sorts of anguish and perhaps get some better result than just mass murder.  I am certain that one of their first responses will be that you Americans (and Europeans) made this problem so you take care of them.  A fair point that most Americans are unwitting of I would guess.  Best start arguing now is the way I look at it.
We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

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Re: Sea Level Rise Projections and Maps
« Reply #84 on: December 05, 2013, 07:40:22 PM »
I am certain that one of their first responses will be that you Americans (and Europeans) made this problem so you take care of them.  A fair point that most Americans are unwitting of I would guess.  Best start arguing now is the way I look at it.

I believe there was just recently a breakdown in climate negotiations precisely because wealthy nations didn't want to compensate developing nations for past emissions. I will admit that looking at the adaptation concept from a world-wide perspective is just too mind boggling for me. I get all cross eyed just thinking about how to get meaningful action at our federal level!

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Re: Sea Level Rise Projections and Maps
« Reply #85 on: December 05, 2013, 08:05:43 PM »
Jim,
I agree there's enough reason for action even under IPCC consensus likely ranges. The powers that be, however, still are not willing to take this action. Maybe they need even more reason for concern...

As to the fate of the Bangladeshi: India has already built a fence on the border to keep them out. I don't know how effective that fence will be once they really start moving.

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Re: Sea Level Rise Projections and Maps
« Reply #86 on: December 05, 2013, 09:47:04 PM »
How's that for my first cup of coffee  ;D

Just using the US as an example, how do we get the citizen fired up about absorbing the ocean-side population of Florida? These are just colossally huge problems.

edited to untangle my quotation....

I vote we accept only the residents from Florida who have expressed concern about AGW. For the global warming deniers in Florida, we give them rowboats.

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Re: Sea Level Rise Projections and Maps
« Reply #87 on: December 05, 2013, 09:55:08 PM »
Quote
...
So should citizens and policy makers make decisions based on the likely range, or on the worst-case in the possible range?

Perhaps a better strategy at this point would be to accept the median estimate and 'fully accept' its implications and propose actions based upon those numbers and what they mean.  For example at 1.5 m sea level rise Bangladesh will functionally cease to exist.  So it is time for activists to initiate the process of proposing the migration and relocation of the bulk of the population to India and Burma.  Convene a formal conference between the three countries under the sponsorship of the UN to determine where these people will live and how much they will pay the Indians and Burmese for the right to resettle in their territory.

How's that for my first cup of coffee  ;D

And why exactly should this orderly relocation be to India and Burma? Given that the western world  is primarily responsible for global warming, shouldn't this relocation be to Europe and North America?

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Re: Sea Level Rise Projections and Maps
« Reply #88 on: December 05, 2013, 11:33:45 PM »
Laurent. Am I reading that graph correctly, Santa Catarina 40m - Sunda/Vietnam shelf 140m slr?

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Re: Sea Level Rise Projections and Maps
« Reply #89 on: December 06, 2013, 08:58:22 AM »
I do not see -40m for Santa Catarina !
Yes -140m for Sunda/Vietnam shelf 21.000 thousands years ago, it is generally said that see level was -120 meters below 20.000 years ago.
You have to keep in mind that graph as many others do soften the datas ! It is certainly more bumpy than that on a short scale.
I join a graph taken from the thesis of a student named Alix lombard.
« Last Edit: December 06, 2013, 09:11:49 AM by Laurent »

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Re: Sea Level Rise Projections and Maps
« Reply #90 on: December 06, 2013, 05:03:30 PM »
And why exactly should this orderly relocation be to India and Burma? Given that the western world  is primarily responsible for global warming, shouldn't this relocation be to Europe and North America?

Oh exactly, exactly!  Thus my statement above

Quote
If we wait until the Bangladeshi's start moving over the Indian border in mass the almost certain result will be genocide.  If we hit the Indians along the head with "They are coming to live with you and let's figure out how to manage that." then it will trigger all sorts of anguish and perhaps get some better result than just mass murder.  I am certain that one of their first responses will be that you Americans (and Europeans) made this problem so you take care of them.  A fair point that most Americans are unwitting of I would guess.  Best start arguing now is the way I look at it.

I am thinking here in the global activist non-government role, not from the American preference.  Governments are so complacent and unlikely to act in a timely fashion they need to be preempted.  One of the best ways to get large numbers of people involved in the process is to start promoting a solution which will outrage a big group of people and several governments.  Just flat out promoting that India needs to plan to absorb Bangladesh should fit that bill in spades.  Start a big fight and then compromise towards an equitable solution.  But force people to get involved.  Maybe 350.org could get some traction out of starting to promote that the US needs to start making plans to absorb 30-50 million immigrants since we are insisting on destroying the climate (course some of my neighbors might shoot them too  :o ).

If we just cruise along until the problem is no longer theoretical and action has to be taken in the near-term we have the disaster I was trying to avoid.  Some form of genocide.  It will probably happen anyway but it seems worthwhile to try and trigger the orderly retreat as Ritter phrased it.

I must admit that I am not optimistic that any solution to very large mass migrations will ever be found.  But not trying to work that problem and just waiting for the consequences of when the train sails off into the chasm where the bridge used to be seems sort of ...immoral?...unethical?
We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

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Re: Sea Level Rise Projections and Maps
« Reply #91 on: February 06, 2014, 06:09:00 PM »
Interesting article about what the UK is doing (or not doing as the case may be) about dealing with sea level rise.

http://www.newstatesman.com/politics/2014/02/protecting-farms-or-front-rooms-impossible-dilemma-climate-change-forces-upon-us
We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

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Re: Sea Level Rise Projections and Maps
« Reply #92 on: February 06, 2014, 07:27:36 PM »
Just flat out promoting that India needs to plan to absorb Bangladesh should fit that bill in spades.

Considering they're building a bloody great fence and beefing up their military - I think it fair to speculate India not only already realises this but has decided how it's going to approach it. Pretty much in the same way as the US approaches the border with Mexico.

I must admit that I am not optimistic that any solution to very large mass migrations will ever be found.  But not trying to work that problem and just waiting for the consequences of when the train sails off into the chasm where the bridge used to be seems sort of ...immoral?...unethical?

If population is too high, is it ethical to officiously strive to preserve life though? Is it ethical to try to absorb large numbers of people at the risk of those in the region they are moving into? If by trying to preserve too many people you threaten or damage the prospects for people indefinitely into the future, is that any more moral?

Now, if you were suggesting we take the more culpable people out of the nations most responsible for causing these problems, dump them in Bangladesh - and move the least culpable people from Bangladesh into those nations (often better placed) - sure - that would seem pretty morally sound to me. Good luck getting votes for that one though...

ccgwebmaster

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Re: Sea Level Rise Projections and Maps
« Reply #93 on: February 06, 2014, 07:40:22 PM »
This is in relation to flooding - not specifically that related to sea level rise, but suggesting that it isn't as big a driver of migration as heat stress (and hinting that the reason heat stress is bigger as a factor is because of related economic factors).

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2103.html

JimD

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Re: Sea Level Rise Projections and Maps
« Reply #94 on: February 06, 2014, 08:16:57 PM »
ccg

Quote
If population is too high, is it ethical to officiously strive to preserve life though? Is it ethical to try to absorb large numbers of people at the risk of those in the region they are moving into? If by trying to preserve too many people you threaten or damage the prospects for people indefinitely into the future, is that any more moral?

My intention for the activist community to force the contemplation of mass migrations is more to bring home to those who are unaware of it how untenable the current population is.  Maybe it would trigger serious discussion of population reductions.  Probably not of course.

In a strictly selfish long term survival sense no country should be allowing immigration.  All have too many people already.  A surprising fact to many, and also a source of some of the angst about immigration in the US, is that we allow more legal immigration by far than any other country in the world.  In 2006 our legal immigration was more than the entire rest of the world put together.  We just have our political favorites and various rules about how it is to be done.  A downside in terms of AGW is that all of those new people want a lifestyle just like everyone else here.  It would be smart of the rest of the world not to let anyone come here to live.     
We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

JimD

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We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

tombond

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Re: Sea Level Rise Projections and Maps
« Reply #96 on: March 01, 2014, 10:12:16 AM »
With regard to SLR projections the most important period is the next 50 years or so and how we as communities plan adaptation measures.

Currently here in Western Australia the Government is planning to adapt to a SLR of about 1 metre by 2100.  However in reality coastal development is business as usual and risk analysis for SLR planning is confined to a few small sentences like those below.

"Response to changing climatic patterns will require vulnerability and risk assessment for infrastructure and communities.  For example, assessment of sea-level change may lead to responses that are precautionary and with a long-term view.  Over time this may lead to changes in policies and standards for buildings and urban structures at risk of inundation."

In other words it is too hard and too far away to worry about.

The reality is the IPCC AR5 SLR estimation of 1 metre by 2100 for the RCP 8.5 scenario is likely to be too conservative given the IPCC’s consensual process and a “snowballs chance in hell” of global governments/communities agreeing to any meaningful emission reductions before mid-century. 

By contrast Hansen’s 1 metre SLR by mid-century could be nearer a credible maximum estimation given the acceleration in land ice melt during this past decade.

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

See also the IPCC AR5 report Summary for Policymakers - Cryosphere page 9

https://www.ipcc.ch/report/ar5/wg1/

For the Cryosphere, it notes that the combined land ice melt rates for Greenland and Antarctica had increased from 60Gt/year for the 1990s decade to 360Gt/year for the 2000s decade, say a five year doubling period. 

Coastal planners would be wise to continually monitor land ice melt mass losses as a SLR prediction tool.  If this five year doubling period is maintained then Hansen’s estimation of SLR of one metre by mid century might be realised.  If the doubling period slows then coastal planners will have more time to plan adaptation measures.

Either way, all coastal planning decision making will be informed and based on real scientific observations and data with less chance of ‘surprises’.   

JimD

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Re: Sea Level Rise Projections and Maps
« Reply #97 on: March 01, 2014, 03:36:41 PM »
tombond

Something I always think is going on with the developers is what their calculations are on their Return On Investment and what the local rules are for depreciating their capital investments.  If they think that the entire lifecycle completes before they run into problems then they will go ahead and build even knowing that eventually the water destroys everything.  They will have their money and be long gone.  It will be someone else's problem.

I expect that for most building projects that means even by 2050 they have pocketed their money and are long gone.
We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

Lennart van der Linde

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Re: Sea Level Rise Projections and Maps
« Reply #98 on: March 06, 2014, 11:57:12 AM »
A new paper by Marzeion & Levermann estimates at most 8 meters of lowering around Greenland and Antarctica for 3 degrees C of warming and about 7 meters of mean global sea level rise, if I read figure 1 in their supplementary information correctly:
http://iopscience.iop.org/1748-9326/9/3/034001/media/erl491558suppdata.pdf

The full article is about the threat of SLR to world cultural heritage:
http://iopscience.iop.org/1748-9326/9/3/034001/article

It seems still a quite conservative estimate, compared to the risks that Rohling et al 2013 see:
http://www.nature.com/srep/2013/131212/srep03461/pdf/srep03461.pdf

They think at least 9 meters of global mean SLR in the long run is probably almost inevitable by now.

skanky

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Re: Sea Level Rise Projections and Maps
« Reply #99 on: March 06, 2014, 12:37:45 PM »
For those considering the impact on Western countries, here is an example of an attempt to move a small town - http://www.bbc.co.uk/news/magazine-26447507

Now imagine doing the same in say, Miami.