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AbruptSLR

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Consequences of ASLR from a WAIS Collapse
« on: March 06, 2013, 04:30:50 PM »
No hazard analysis would be complete without some evaluation of consequences as risk is equal to probability of occurrence time consequences.  I will start this evaluation of consequences by the most obvious impact of inundation.  As it is beyond my means to develop true inundation maps for future cases combining the effect of local tides/storm surge/storm tide/regional subsidence/regional variabilities together with the "finger print" effect for the Maximum Credible Event, MCE, for abrupt RSLR (see the graphs for California for this MCE RSLR values); therefore, I will just post a few images of inundation for a 6m increase in local sea level (see accompanying images); and I will make the following general comments:
-  The inundated areas worldwide contain over 100 trillion dollars of captial assests which merit some effort of resilient defense (which is currently not occurring).
-  The increase in water depth, due to ASLR, will locally amplify the amplitude of short term changes in sea level such as for: tides, storm surge and storm tides.
- Flooding (and coastal errosion) of the relatively flat coastal plains of Alaska and Siberia will introduce relatively warm ocean water on top of permafrost (and buried methane hydrates), which will accerate GHG emissions from these flooded areas.

There are a large number of other consequences and I will add to the list in the next few days, and then I hope to open a Summary Thread with Recommendations for further research.
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Lennart van der Linde

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #1 on: March 06, 2013, 07:48:28 PM »
ASLR,

As mentioned before, the Dutch Delta Committee has considered a little over 1m of SLR by 2100 and a little under 4m by 2200 as their worst-case scenario and concluded the Netherlands could adapt to that rise at some cost.

If about 6m of SLR around 2100 would be a more appropriate worst-case, ignoring exact gravitational effects for now, how would this change our (I'm Dutch myself) adaptation options and costs, in your view? Would defense still seem the best option, or retreat to higher land?

And in the somewhat longer term, what adaptation options, other than retreat, would our descendents have if SLR by 2300 would be about 10-12m, as some worst-cases seem to suggest is a real risk?

In other words, can we estimate some plausible 'limits to adaptation', even for a rich country like the Netherlands? And what would those imply for the (global) mitigation targets we should strive for?

AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #2 on: March 07, 2013, 01:02:46 AM »
Lennart,

 I have no clear idea/opinion on whether the EAIS will collapse, or not, therefore, I will limit my response to the 6 to 8m range of RSLR plus shor-term/dynamic water elevation rise:

In my opinion "Necessity is the Mother of Invention", and until we as a society at least admit what the risk is then we will never need a solution, and thus a solution will never be developed.  For example, the first figure shows a structural solution for a 2-mile long barrier in New Orleans, Louisiana, that was designed to resist over a 7.3 meter head; and was proof tested last year by Hurricane Isaac; and I believe that a structural solution to The Netherland's risks are economically possible depending on the motiviation of the people.  The next two figures show conceptual alternate approaches for using adaptive engineering for flood protection; including incremental upgrading, temporary evacuation (for the dynamic portion of the flood risk); pumping, and retreat.   However, regarding flood defense you can only talk so far in generalisms, and what is actually needs is for a MCE guidance for SLR to be mandated by law for resiliency checking so that engineers can provide real options rather than general ideas.
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #3 on: March 07, 2013, 07:43:27 PM »
The second consequence of the abupt WAIS collapse (this century), is associated with the carbon dioxide absorbed by the AABW and the consequence of the rapid decline in AABW associate with iceshelf and icesheet ice melting primarily from the WAIS (see the "Collapse Main Period" thread).  Roughly, the AABW circulates slow and it takes about 1,000 year for it to resurface in the Pacific after sinking in the Antarctic, thus issue such as steric expansion of the ocean, or a disruption of the ocean's great conveyor belt of currents will be very slow to develop.  However, this slow response following a sharp down in AABW production is not true with regard to carbon dioxide absorption from the Southern Ocean.  As illustrated in the accompanying figure as recently as ten years ago the ocean absorbed about 30% of all antropogenic carbon dioxide emissions.  As the Southern Ocean accounts for about half of this number, a complete collapse of the AABW production associated with a collapse of the WAIS flooding the Southern Ocean with fresh glacial melt water, would likely result in postive feedback on anthropogenic carbon dioxide emissions of about 15%.  Such an increase could ensure that radiative forcing for the world well above the forcing expected under RCP 8.5 (which is assumed in my hazard analysis)
« Last Edit: May 05, 2013, 07:35:46 PM by AbruptSLR »
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #4 on: March 07, 2013, 11:56:22 PM »
My third consequence if the local seasonal albedo flip due to both the reduction in Antarctic sea ice and WAIS area extent reduction.  This local seasonal Antarctic albedo flip, together with that for the seasonal Arctic sea ice loss and the early seasonal melting on land based snow in the Northern Hemisphere may move the world, by 2080, to the top of the climate sensitivity bump as shown in the attached figure from Hansen and Sato (previously posted in the "Forcing" thread).
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #5 on: March 08, 2013, 06:14:04 PM »
In addition to the increased local sesimic and volcanic activity that can be expected to become more frequent in the Antarctic as of a result of the abrupt collapse of the WAIS; it is also true that in some cases such as the San Andreas Slip-Strike Fault in Southern California (see first image), the rise in offshore sea level will likely trigger increased seismic activity due to the action shown in the second figure where the increase weight of the offshore water induces the onshore slip-strike fault to open and locally unzip (resulting in an earthquake).
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #6 on: March 08, 2013, 06:26:51 PM »
As discussed in several threads the collapse of the WAIS will temporarily drop the sea surface temperature, SST, for the entire Southern Ocean; which would lead to increase storm intensity and frequency, and as indicated on the attached figure the increases in the still water level associated with such storms (storm surge, storm tide, and increases in water level at the center of a low pressure system) need to be combined with the risks of SLR (see the "Philosophy" thread for a graph for ASLR in California suitable for combination in this manner).
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #7 on: March 08, 2013, 06:34:31 PM »
An abrupt increase in SLR will facilitate landslide, and submarine landslides, that may decrease the recurrence intervals between design tsunami events.  McMurtry et al. 2004 indicate that the Hawaiian island are particularly susceptible to the generation of giant submarine landslides, GSL, and associated mega-tsunamis, which occur at higher frequency during periods of rapidly changing sea level (see accompanying two figures and figure caption)
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #8 on: March 08, 2013, 07:02:14 PM »
When considering the consequences of ASLR one must also combine the RSLR together with stormwater run-off, and perhaps the most extreme example of this is the case of combine ASLR for California together with an Arkstorm event (an atmospheric river with a 300 to 400 year return period raining in California for about 40-days you can google this to learn more) in 2100.

The first figure shows the impact of combining 6.7 m of RSLR with an El Nino Event and a King Tide resulting in a 9m raise in the still water level in the California Delta. 

The second image show what would happen to the still water level in California in 2100 with a RCL 8.5 50% CL ASLR together with an Arkstorm event resulting in a stillwater elevation increase in the California Delta of +13m by 2100. 

The third image shows a RCP 8.5 95% RSLR, a ARkStorm event, and a King Tide) indicating saline water elevation at +30m in the California Delta (increased above sea-level by ARkStorm river flooding) by 2100, which would contaminate the California Central Valley's surface and ground water with salt (see the forth figure showning the draw-down of ground water in the California Central Valley). 

It is very important to note that ASLR from a collaspe of the WAIS by 2100 would affect the salinity of groundwater in affected coastal areas around the world leading to distruption to utilities and infrastructures upto miles from the coastline (particularly in areas where the groundwater levels have been drawn-down)
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #9 on: March 11, 2013, 02:19:09 AM »
The following are key points from a 2009 economic damage assessment for SRES A2 (which we are exceeding):

"Scientists led by a former co-chair of the Intergovernmental Panel on Climate Change [warn] that the UN negotiations aimed at tackling climate change are based on substantial underestimates of what it will cost to adapt to its impacts.

The real costs of adaptation are likely to be 2-3 times greater than estimates made by the UN Framework Convention on Climate Change (UNFCCC), say Professor Martin Parry and colleagues in a new report published by the International Institute for Environment and Development [IIED].

And as the IIED reported, the study Assessing the costs of adaptation to climate change: a review of the UNFCCC and other recent estimates concludes costs will be even more when the full range of climate impacts on human activities is considered.

The study finds that the mean “Net present value of climate change impacts” in the A2 scenario is $1240 TRILLION with no adaptation, but “only” $890 trillion with adaptation.

The mean [annual] impacts in 2060 are about $1.5 trillion….  As usual, there is a long right tail, with a small probability of impacts as large as $20 trillion
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #10 on: May 01, 2013, 06:03:31 AM »
The referenced article by the Yale economist Nordhaus indicates that fat-tailed probability density functions if verified for climate change would be a serious economic problem for the world; however, he notes that currently there is insufficient evidence that a fat-tailed probability density function exists associated with the world's sensitivity to thermal increases.  Therefore, if I am right that the WAIS has a fat-tailed risk of collapse this century, then Nordhaus's analysis verifies that the consequences will be significant (and should not have been ignored by policy makers).


ECONOMIC POLICY IN THE FACE OF SEVERE TAIL EVENTS
Yale University William D. Nordhaus, Sterling Professor of Economics, Yale University, 28 Hillhouse
Avenue, New Haven, CT 06510, United States (william.nordhaus@yale.edu).
The author is grateful for comments on these issues from William Brainard, Gary Yohe,
Richard Tol, MartinWeitzman, three anonymous referees, and the editors. The author has
no conflict of interest.
Received October 1, 2010; Accepted July 14, 2011.
C 2012 Wiley Periodicals, Inc.
Journal of Public Economic Theory, 14 (2), 2012, pp. 197–219.
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #11 on: May 05, 2013, 07:52:24 PM »
I thought that I would note that:

The top cities with the highest populations currently at risk from SLR, in order are: Calcutta, Mumbai, Dhaka, Guangzhou, Ho Chi Minh City, Shanghai, Bangkok, Rangoon, Miami and Hai Phong.

The ten cities with the most exposed infrastructure assests currently at risk from SLR, in order are: Miami, Guangzhou, New York/Newark, Calcutta, Shanghai, Mumbai, Tianjin, Tokyo, Hong Kong, and Bangkok.

However, in 2010 about 50% of the world's population lived with 15 miles of the coast; while by 2040 it is estimated that about 75% of the world's population will live along coasts.  As I am projecting that SLR could become highly non-linear beginning around 2040; it would be wise to at least use regulations to restrict future developments in areas at risk from the combination of SLR and short-term inundation events such as: storm surge, astronomical tides and El Nino events.  I also note that many of these coastal developments were, and will be, built on sandy foundations that could be subject to liquefaction once saturated by an increase in ground water elevations associated with SLR.
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #12 on: May 13, 2013, 05:33:16 PM »
In order to help appreciate the possible consequences of ignoring the possibility of abrupt SLR (from the collapse of the WAIS this century); I would like to note that in the design of infrastructure at risk of inundation, there is no stand-alone sea level rise load case.  At best there is a "future" design case for the service life of the structure that should combine at least the 95% confidence level (CL) of local relative sea level (at the end of the service life) together with the expected design values for at least: local storm surge, short-term rise in sea level due to local run-off, tides, storm-tides, wind, waves, current, subsidence and settlement, thermal loading and other live and dead loads.  It is further noted here that as the future water depth increases (due to SLR), storm-surge, storm-tide and gravitational tides all increase in amplitude.  Thus even a small increase in the design future local RSLR can result in unacceptable inundation due to wave overtopping, and/or due to a few inches of storm-surge overtopping , for even short periods of time.

For example, as New York City, NYC, is now initiating a resiliency approach to inundation following the effects of Superstorm Sandy; I would like to make the following observations regarding this approach:

-  Both the USACE (US Army Corps of Engineers) and FEMA (Federal Emergency Management Agency) use the historical record in order to define the probabilities of storm surge recurrence levels for the 100-year (strength level) and the 500-year (resiliency level) storm surge events; and using such an approach Tropical Storm Irene was about a 100-year event and Superstorm Sandy was about a 1,000-year inundation event.  Thus by this line of logic NYC should real only need to spend a few billion dollars on resiliency measures to add a few extra feet of protection above the 100-yr strength design level to guard against the less frequent 500-yr event.

- The 2009 NYC Panel on Climate Change (NPCC) released a report for the NYC area with SLR of 2-5 inches by the mid-2020's, and 7-12 inches by the mid 2050's, and a so call "Rapid Ice Melt" scenario with increased ice mass loss from the GIS and the WAIS giving SLR projection in NYC of: 5 - 10 inches by the mid-2020's and 19 - 29 inches by the mid 2050's.  Note that for my RCP 8.5 95% CL value for SLR is approximately 39 inches by 2055 (which includes the risk of a WAIS collapse this century, assuming that we stay on an RCP 8.5 forcing pathway until about 2050).

- Unfortunately, the USACE/FEMA 500-yr return period historically based storm-surge value is likely too low because: (a) the frequency of large hurricanes are projected to increase non-linearly with global warming; (b) the frequency of the east to west path that Superstorm Sandy took is more likely to occur in the future (while the historical hurricane paths have all be from south to north-northeast); and (c) the diameter of future hurricanes are projected to be larger than the historical norm.  All of these three factors result in both higher 100-yr return period and higher 500-yr return period, design "storm surge" (including storm-tides and normal tides) levels.

- If the resiliency case considers either too low of SLR, or design "storm surge" levels there will be a problem with currently planned resiliency measures; however, if both are too low then NYC could have wished that it started investing sooner in a proper storm surge barrier (such as London has).
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #13 on: June 22, 2013, 08:42:16 PM »
It is difficult to express the true consequences of 5m of SLR this century, so here I will just provide a link to the University of Hamburg which maintains one of the best compilations of economic estimate of damage from SLR, which can be found at:

http://www.uni-hamburg.de/suche.html?q=sea+level+rise

As only one small example of this damage the attached first two images of possible damage to the Thames Estuary area for SLR this century up to 5m are shown and you can down load the paper at the following link:

http://epub.sub.uni-hamburg.de/epub/volltexte/2012/16791/pdf/waislondonwp_FNU77.pdf

This paper is entitled:

Plausible responses to the threat of rapid sea-level rise for the Thames Estuary
By: Lonsdale, K.G., Downing, T.E., Nicholls, R.J., Parker, D., Vafeidis, A. T., Dawson, R. and Hall, J.
« Last Edit: June 22, 2013, 08:47:37 PM by AbruptSLR »
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #14 on: June 26, 2013, 03:44:26 PM »
Bruce,

Per your comment in the "Tectonic" thread that:

I will be testifying before a Calif. House select committee on sea level rise next month. They want to hear from a fisherman. I was asked to supply support documents so any suggestions would be helpful. I think they want me to keep it relevant to the fishing industry which makes my job kinda tough. Biological ramifications are difficult to predict but I expect cliff erosion will sand in some nearshore reef structure and natural shorelines will be reduced as SLR comes up against existing infrastructure like roads and rail lines. Additional ideas would be helpful.

Regarding additional ideas of impact of ASLR on fish, I direct your attention to my Reply #8 in this "Consequence" thread; where I present a figure showing the area of the California Delta inundated by combined ASLR by 2100, plus an El Nino Event, plus high tides; this is followed by a figure showing the portions of the California Delta inundated by combined ASLR by 2100 plus a possible Atmospheric River event.  The amount of saltwater intrusion into the California Delta in such cases would have a major impact on the fish in this area, and as indicated in that post would also introduce saltwater into the local groundwater supply.  Furthermore, the intrusion of saltwater into groundwater would not be limited to the California Delta area, but would affect the entire California coastal areas (note that particularly in Southern California the groundwater levels have been drawn down by wells for water supply); and as these groundwater supply sources are contaminated, more freshwater supplies will need to be diverted from fish as a replacement to avoid economic loss and human suffering.

Similiarly, all estuaries (Upper Newport Harbor, Monterey Bay, etc) along the West Coast would also be subjected to such saltwater intusion that would have major impacts on fish in these areas.  Of course such impact would not be limited to the West Coast of the USA as I am discussing eustatic SLR; therefore, all migratory sealife (not just fish) would be impacted by the loss of coastline (see the losses in Alaska at the beginning of this thread) and estuaries all the way to Central America. 

Furthermore, the changes in salinity of the Southern Ocean associated with a collapse of the WAIS this century would have a major impact not only on the AABW driven currents but also on the merdinonal overturning circulation and upwelling of CO2 from the Southern Ocean seafloor; all of which would have major impacts on migratory fish and on global weather patterns and rainfall patterns that would then impact freshwater fish in California.
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #15 on: July 09, 2013, 01:45:52 AM »
The following abstract and selected images from assess economic impacts of up to 2m of SLR, this century:

 The Economic Impact of Substantial Sea-Level Rise
 by: David Anthoff;  Robert J. Nicholls; and Richard S.J. Tol;  Working Paper FNU-175

Abstract:
"Using the FUND model, an impact assessment is conducted over the 21st century for rises in sea level of up to 2-m/century and a range of socio-economic scenarios downscaled to the national level, including the four SRES storylines. This model balances the costs of retreat with the costs of protection, including the effects of coastal squeeze. While the costs of sea-level rise increase with greater rise due to greater damage and protection costs, the model suggests that an optimum response in a benefit-cost sense remains widespread protection of developed coastal areas, as identified in earlier analyses. The socio-economic scenarios are also important in terms of influencing these costs. In terms of the four components of costs considered in FUND, protection dominates, with substantial costs from wetland loss under some scenarios. The regional distribution of costs shows that a few regions experience most of the costs, especially East Asia, North America, Europe and South Asia. Importantly, this analysis suggests that protection is much more likely and rational than is widely assumed, even with a large rise in sea level. This is underpinned by the strong economic growth in all the SRES scenarios: without this growth, the benefits of protection are significantly reduced. It should also be noted that some important limitations to the analysis are discussed, which collectively suggest that protection may not be as widespread as suggested in the FUND results. Equity weighting allows the damages to be modified to reflect the wealth of those impacted by sea-level rise. Taking these distributional issues into account increases damage estimates by a factor of three, reflecting that the costs of sea-level rise fall disproportionately on poorer developing countries."

For all three attached figures, the cases refer to the SRES cases.  The third attached figure demonstrates the importance of planning appropriate protection measures.
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #16 on: July 09, 2013, 01:51:13 AM »
The pdf for the article referenced in the immediately preceeding post is attached for those who are interested in the details.
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sidd

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #17 on: July 10, 2013, 10:22:16 PM »
I have issues with Tol and the FUND model. I find Tol much less convincing than Stern, for example. The discount rate used in the paper quoted is 1% above the growth rade of per capita income, which I think is too high for matters pertaining to intergenerational equities.

AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #18 on: July 11, 2013, 01:38:19 AM »
Sidd,

From my personal point of view, I agree with you that the FUND model results are non-conservative from a safety point of view; however, I posted this information primarily for relative comparisons.  Feel free to add other consequence information that better emphasizes safety.

Best,
ASLR
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Re: Consequences of ASLR from a WAIS Collapse
« Reply #19 on: July 12, 2013, 05:10:06 PM »
The attached figure (From Hanson et al. 2011, see citation below) shows assets for the top 10 countries in the world that will be exposed to flood damage by 2070, and which indicates that the USA alone will have approximately $9 trillion dollars in assets at risk to flood damage, related to SLR; without considering ASLR.  This figure illustrates that substantial infrastructure growth until 2070 is expected in areas of high flood risk; which could be readily re-directed to safer areas by appropriate regulation without any expenditure of public money.

Hanson, S., Nicholls, R., Ranger, N., Hallegatte, S, Corfee-Morlot, J., Herweijer, C. and Chateau, J., "A global ranking of port cities with high exposure to climate extremes", Climatic Change, (2011) 104:89-111, doi: 10.1007/s10584-010-9977-4
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Re: Consequences of ASLR from a WAIS Collapse
« Reply #20 on: July 13, 2013, 10:04:47 PM »
Lennart,

[...] and I believe that a structural solution to The Netherland's risks are economically possible depending on the motiviation of the people.  The next two figures show conceptual alternate approaches for using adaptive engineering for flood protection; including incremental upgrading, temporary evacuation (for the dynamic portion of the flood risk); pumping, and retreat. [...] 

AbruptSLR,
from reading your posts I am not sure if you realised, that the poeple in Netherlands are the experts in coastal protection for centuries - they got their land from the sea and it is already 6m below sea level. So if they prepare for 4 m more, that results in 10 m below sea level - and additional storm flooding is taken into account, too. As far as I know for most serious coastal protection projects poeple all over the world ask dutch experts to design it. So if the dutch are not sure if protection is worth the effort, we all are in serious trouble. But if you are aware that facts, please feel free to ignore my post because it is to trivial.

AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #21 on: July 14, 2013, 12:04:03 AM »
SATire,

At the begining of my engineering career I learned a lot about flood protection from the Dutch, and I agree that they have strong expertise on this topic.  That said, I believe (and I have experienced) that one can see further when standing upon the shoulders of giants; and I believe that using modern technology it is possible (but challenging) to develop flood protection systems that are still more cost effective  than what the Dutch have built in the past; provided that decision makers understand the SLR threats that the world is facing sufficiently to make difficult decisions. 

For example, the mayor of New York City, NYC, as decided to spend $20 Billion on resilience measures for NYC on the assumption that Superstorm Sandy was no more than a one in a 700 year event; and that such a flooding event is thus not likely to happen again soon.  I have estimated that a storm surge barrier could practicably be built for NY Outer Harbor that could resist both future SLR and increased design storm surge levels, and provide a good benefit-cost ratio.

If by some miracle decision makers can halt anthropogenic global warming then that would be an even better idea; but as I do not see that happening any earlier than 2050; I think that it is defeatist to ignore at least the design of flood protection systems for at least high value areas like NYC, London, Shanghai, Tokyo, etc.; all of which are in flood hazard zones.

Best,
ASLR
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AbruptSLR

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #22 on: July 18, 2013, 01:36:07 AM »
The following paper (see abstract) provides an improved methodology for calculating flood damage associated with SLR:

How changing sea level extremes and protection measures alter coastal flood damages
by: M. Boettle, D. Rybski, and J. P. Kropp; Water Resources Research; Volume 49, Issue 3, pages 1199–1210, March 2013; DOI: 10.1002/wrcr.20108

Abstract
"While sea level rise is one of the most likely consequences of climate change, the provoked costs remain highly uncertain. Based on a block-maxima approach, we provide a stochastic framework to estimate the increase of expected damages with sea level rise as well as with meteorological changes and demonstrate the application to two case studies. In addition, the uncertainty of the damage estimations due to the stochastic nature of extreme events is studied. Starting with the probability distribution of extreme flood levels, we calculate the distribution of implied damages in a specific region employing stage-damage functions. Universal relations of the expected damages and their standard deviation, which demonstrate the importance of the shape of the damage function, are provided. We also calculate how flood protection reduces the damages leading to a more complex picture, where the extreme value behavior plays a fundamental role."
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Re: Consequences of ASLR from a WAIS Collapse
« Reply #23 on: July 22, 2013, 05:07:54 AM »
I got tired of ignoring the human face of climate change; and while the attached picture is actually an Australian family seeking refuge from a wildfire; it might as well be any family in the future hit by storm surge riding on the back of sea level rise.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Re: Consequences of ASLR from a WAIS Collapse
« Reply #24 on: August 21, 2013, 01:24:58 AM »
The following weblink leads to an article just published in "Nature Climate Change" stating that the world's 136 largest coastal cities could risk combined annual losses of $1 trillion (750 billion euros) from floods by 2050 unless they drastically raise their defenses against inundation due both to SLR, and storm action.

http://phys.org/news/2013-08-coastal-cities-losses.html
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Re: Consequences of ASLR from a WAIS Collapse
« Reply #25 on: August 21, 2013, 01:43:58 AM »
The following reference is a commentary in the current PNAS (see weblink) about the rapidly accumulation commitment to future SLR, the uncertainty of how fast this SLR will occur, and the consequences of this SLR:

Rapid accumulation of committed sea-level rise from global warming;
by: Benjamin H. Strauss; PNAS, Vol. 110 no 34, pp 13699 to 13700

http://www.pnas.org/content/current#PhysicalSciencesEarthAtmosphericandPlanetarySciences

Introduction
"As carbon emissions and scientific research have accumulated over recent years, climate scientists have come to see global climate change as an increasingly urgent threat. In PNAS, Levermann et al. provide a powerful new indicator of danger. When their findings on the long-term sensitivity of global sea level to global warming (∼2.3 m/°C) are put in the context of recent research on the sensitivity of global temperature to cumulative carbon dioxide emissions, simple analyses suggest (described below) that we have already committed to a long-term future sea level >1.3 or 1.9 m higher than today and are adding about 0.32 m/decade to the total: 10 times the rate of observed contemporary sea-level rise. By midcentury, the central estimate of commitment would rise to >3.1 m assuming today’s trends continue or to 2.1 m under an aggressive emissions cutting and atmospheric carbon dioxide removal scenario. Both scenarios threaten the future viability of many hundreds of coastal municipalities in the United States alone, but the low emissions path would likely spare hundreds more, including many major cities.

Many studies have projected sea levels throughout the 21st century. The great majority show strongly accelerated rates of rise by 2100, but only a few project past then. Among these, the work of Levermann et al. stands out for matching physical models with evidence of ancient sea-level responses to temperature and for focusing on the amount of sea-level rise rather than its more elusive rate. (In a loose analogy, it is trivial to predict a pile of ice in a warm room will all melt, but demanding to predict the exact rates over time.)"
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― Leon C. Megginson

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Re: Consequences of ASLR from a WAIS Collapse
« Reply #26 on: August 21, 2013, 07:15:06 PM »
The following linked reference indicates that downscaled CMIP5 climate model projections show a marked increase the frequency and intensity of hurricanes, typhoons and cyclones, this century for forcing comparable to RCP 8.5.  When such severe storm events are combined with projected SLR the consequences on low-lying coastal communities in the effect regions will likely be  devastating:

http://www.pnas.org/content/early/2013/07/05/1301293110.abstract


Downscaling CMIP5 climate models shows increased tropical cyclone activity over the 21st century;
by: Kerry A. Emanuel, 2013, PNAS July 8, 2013, doi: 10.1073/pnas.1301293110



"Abstract
A recently developed technique for simulating large [O(104)] numbers of tropical cyclones in climate states described by global gridded data is applied to simulations of historical and future climate states simulated by six Coupled Model Intercomparison Project 5 (CMIP5) global climate models. Tropical cyclones downscaled from the climate of the period 1950–2005 are compared with those of the 21st century in simulations that stipulate that the radiative forcing from greenhouse gases increases by  over preindustrial values. In contrast to storms that appear explicitly in most global models, the frequency of downscaled tropical cyclones increases during the 21st century in most locations. The intensity of such storms, as measured by their maximum wind speeds, also increases, in agreement with previous results. Increases in tropical cyclone activity are most prominent in the western North Pacific, but are evident in other regions except for the southwestern Pacific. The increased frequency of events is consistent with increases in a genesis potential index based on monthly mean global model output. These results are compared and contrasted with other inferences concerning the effect of global warming on tropical cyclones."
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Re: Consequences of ASLR from a WAIS Collapse
« Reply #27 on: August 27, 2013, 02:12:04 AM »

The linked reference discusses the intrusion of seawater into groundwater due to SLR, which has widespread consequences:

http://onlinelibrary.wiley.com/doi/10.1002/grl.50192/abstract


Climate-driven sea level anomalies modulate coastal groundwater dynamics and discharge; by: Meagan Eagle Gonneea, Ann E. Mulligan, and Matthew A. Charette; published online: 3 JUN 2013; DOI: 10.1002/grl.50192


Abstract:
"To better understand the physical drivers of submarine groundwater discharge (SGD) in the coastal ocean, we conducted a detailed field and modeling study within an unconfined coastal aquifer system. We monitored the hydraulic gradient across the coastal aquifer and movement of the mixing zone over multiple years. At our study site, sea level dominated over groundwater head as the largest contributor to variability in the hydraulic gradient and therefore SGD. Model results indicate the seawater recirculation component of SGD was enhanced during summer while the terrestrial component dominated during winter due to seasonal changes in sea level driven by a combination of long period solar tides, temperature and winds. In one year, sea level remained elevated year round due to a combination of ENSO and NAO climate modes. Hence, predicted changes in regional climate variability driven sea level may impact future rates of SGD and biogeochemical cycling within coastal aquifers."
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Re: Consequences of ASLR from a WAIS Collapse
« Reply #28 on: February 05, 2014, 04:37:17 PM »
According to the linked paper published in the Proceedings of the National Academy of Sciences (PNAS), global average storm surge damages could increase from about $10-$40 billion per year today to up to $100,000 billion per year by the end of century, if no adaptation action is taken.  However, the attached table of sources for SLR contributions show that their estimated contribution from Antarctica are likely too conservative from a scientific point of view, or too non-conservative from a safety point of view.  Thus these estimated losses can be viewed as lower bound estimates; which at $100,000 billion per year by 2100 without adaptive measures, would clearly destabilize society, even if we learn to mitigate the atmospheric damage:

Coastal flood damage and adaptation costs under 21st century sea-level rise by Jochen Hinkela,Daniel Linckea,Athanasios T. Vafeidisb,Mahé Perrettec,Robert James Nichollsd,Richard S. J. Tole,Ben Marzeiong, Xavier Fettweish,Cezar Ionescuc, and Anders Levermannc published in Proceedings of the National Academy of Sciences (PNAS). DOI: 10.1073/pnas.1222469111.

http://www.pnas.org/content/early/2014/01/29/1222469111

Abstract: "Coastal flood damage and adaptation costs under 21st century sea-level rise are assessed on a global scale taking into account a wide range of uncertainties in continental topography data, population data, protection strategies, socioeconomic development and sea-level rise. Uncertainty in global mean and regional sea level was derived from four different climate models from the Coupled Model Intercomparison Project Phase 5, each combined with three land-ice scenarios based on the published range of contributions from ice sheets and glaciers. Without adaptation, 0.2–4.6% of global population is expected to be flooded annually in 2100 under 25–123 cm of global mean sea-level rise, with expected annual losses of 0.3–9.3% of global gross domestic product. Damages of this magnitude are very unlikely to be tolerated by society and adaptation will be widespread. The global costs of protecting the coast with dikes are significant with annual investment and maintenance costs of US$ 12–71 billion in 2100, but much smaller than the global cost of avoided damages even without accounting for indirect costs of damage to regional production supply. Flood damages by the end of this century are much more sensitive to the applied protection strategy than to variations in climate and socioeconomic scenarios as well as in physical data sources (topography and climate model). Our results emphasize the central role of long-term coastal adaptation strategies. These should also take into account that protecting large parts of the developed coast increases the risk of catastrophic consequences in the case of defense failure."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson