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Author Topic: Potential Collapse Scenario for the WAIS  (Read 183740 times)

AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #450 on: April 04, 2016, 08:11:19 PM »
Here's one with DeConto, from Jan 13th this year:
https://www.youtube.com/watch?v=jK_8Pfo6wRk

Thanks, and I re-posted this link to the Sea Level Rise thread.
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #451 on: April 06, 2016, 11:41:57 PM »
The linked reference recommends erring on the side of precaution because the correlation of the observed record (per the WAIS Divide ice core) of temperature and snowfall for West Antarctica is more variable than indicated by current climate models (as normally it is assumed that as GMST increases so will the snowfall in West Antarctica, but the observed record indicates that that assumption may not be correct):

T. J. Fudge, Bradley R. Markle, Kurt Cuffey, Christo Buizert, Kendrick Taylor, Eric J. Steig, Edwin Waddington, Howard Conway & Michelle Koutnik (4 April 2016), "Variable relationship between accumulation and temperature in West Antarctica for the past 31,000 years", Geophysical Research Letters, DOI: 10.1002/2016GL068356


http://onlinelibrary.wiley.com/doi/10.1002/2016GL068356/abstract

Abstract: "The Antarctic contribution to sea level is a balance between ice loss along the margin and accumulation in the interior. Accumulation records for the past few decades are noisy, and show inconsistent relationships with temperature. We investigate the relationship between accumulation and temperature for the past 31 ka using high-resolution records from the WAIS Divide ice core in West Antarctica. Although the glacial-interglacial increases result in high correlation and moderate sensitivity for the full record, the relationship shows considerable variability through time with high correlation and high sensitivity for the 0-8 ka period but no correlation for the 8-15 ka period. This contrasts with a general circulation model simulation which shows homogeneous sensitivities between temperature and accumulation across the entire time period. These results suggest that variations in atmospheric circulation are an important driver of Antarctic accumulation but they are not adequately captured in model simulations. Model-based projections of future Antarctic accumulation, and its impact on sea level, should be treated with caution."
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #452 on: April 14, 2016, 01:37:14 AM »
With a hat-tip to Greenbelt's post in the "Sea Level Rise" thread, the linked article discusses how NOAA has new information indicating that sea level could rise by 3m in the 2050-2060 timeframe due to instabilities in the WAIS:

http://www.insurancejournal.com/news/national/2016/04/12/405089.htm

Extract: "Think sea level rise will be moderate and something we can all plan for? Think again.
Sea levels could rise by much more than originally anticipated, and much faster, according to new data being collected by scientists studying the melting West Antarctic ice sheet – a massive sheet the size of Mexico.
That revelation was made by an official with the National Oceanic and Atmospheric Administration on Tuesday at the annual RIMS conference for risk management and insurance professionals in San Diego, Calif.
The conference is being attended by more than 10,000 people, according to organizers. It was day No. 3 of the conference, which ends Wednesday.
Margaret Davidson, NOAA’s senior advisor for coastal inundation and resilience science and services, and Michael Angelina, executive director of the Academy of Risk Management and Insurance, offered their take on climate change data in a conference session titled “Environmental Intelligence: Quantifying the Risks of Climate Change.”
Davidson said recent data that has been collected but has yet to be made official indicates sea levels could rise by roughly 3 meters or 9 feet by 2050-2060, far higher and quicker than current projections. Until now most projections have warned of sea level rise of up to 4 feet by 2100.
These new findings will likely be released in the latest sets of reports on climate change due out in the next few years.
“The latest field data out of West Antarctic is kind of an OMG thing,” she said.
Davidson’s purpose was to talk about how NOAA is sharing information with the insurance community and the public, and to explain how data on climate change is being collected.
She explained that reports like those from the Intergovernmental Panel on Climate Change and the National Climate Assessment, which come out roughly every five years, are going on old data.
By the time the scientists compiling those reports get the data it’s roughly two years old, because it took those gathering the data that long to collect it. It takes authors of the reports a few years to compile them.
“By the time we get out the report, it’s actually synthesizing data from about a decade ago,” she said.
Angelina’s focus was also on the data. He spoke about the ongoing development of the Actuaries Climate Index and the Actuaries Climate Risk Index.
The goals of the projects are to create climate change indices that reflect an actuarial perspective, to create an index that measures changes in climate extremes, use indices to inform the insurance industry and the public, and promote the actuarial profession by contributing statistically to the climate change debate.
So far their findings show the climate is definitely changing – though neither Davidson nor Angelina addressed the cause of this change, which they said was not the purpose of their talk.
Angelina said a new way of looking at weather is required when dealing with climate change, and that just looking at averages isn’t enough to give an accurate picture of climate change and the risk it presents.
The projects he’s involved with have instead looked at weather extremes.
“By looking at extremes I can actually acknowledge that I have a problem,” he said."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #453 on: May 09, 2016, 09:30:01 PM »
Technische Universitaet Dresden provides the following very useful website that documents Antarctic Ice Sheet mass change per the GRACE satellite, as updated every month.  The first image shows the spatial distribution of ice mass loss (from 2002-2008 thru Jan 2016) across Antarctica.  The second image provides a key to the GRACE mass change basins, from which it can be seen that for the WAIS ice mass loss comes primarily from basins 20, 21, 22 and 23 (which will be detailed in my next post).

Technische Universitaet Dresden,
Gravimetric mass balance: Antarctic Ice Sheet project ESA Climate Change Initiative

https://data1.geo.tu-dresden.de/ais_gmb/

See also:
https://www.sciencedaily.com/releases/2016/05/160509085744.htm

Extract: "The Antarctic ice sheet, with a thickness of up to 4800 meter, has lost mass in the recent years. This was confirmed by a variety of scientific studies. Scientists now visualize the ice-mass loss: The interested public and scientific community can follow the Antarctic ice-mass changes month by month and divided by regions."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #454 on: May 09, 2016, 09:31:49 PM »
The four attached plots from Dresden detail the cumulative (from August 16 2002 to Jan 16 2016) ice mass loss from the AIS basins 20, 21, 22 and 23.  These are all basins to watch to see whether ice mass loss from these areas increase non-linearly as/when GMST departures exceed 2C above pre-industrial:
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #455 on: June 02, 2016, 06:00:11 PM »
The linked reference provides new field observations about changes in ocean circulation patterns from the continental shelf break to the coast in the Bellingshausen Sea, and they emphasize the importance of better understanding such recent changes in ocean circulation patterns in order to better understand the stability of the WAIS:

Xiyue Zhang, Andrew F. Thompson, Mar M. Flexas, Fabien Roquet & Horst Bornemann (1 June 2016), "Circulation and meltwater distribution in the Bellingshausen Sea: from shelf break to coast", Geophysical Research Letters, DOI: 10.1002/2016GL068998


http://onlinelibrary.wiley.com/doi/10.1002/2016GL068998/abstract

Abstract: "West Antarctic ice shelves have thinned dramatically over recent decades. Oceanographic measurements that explore connections between offshore warming and transport across a continental shelf with variable bathymetry towards ice shelves are needed to constrain future changes in melt rates. Six years of seal-acquired observations provide extensive hydrographic coverage in the Bellingshausen Sea, where ship-based measurements are scarce. Warm but modified Circumpolar Deep Water floods the shelf and establishes a cyclonic circulation within the Belgica Trough with flow extending towards the coast along the eastern boundaries and returning to the shelf break along western boundaries. These boundary currents are the primary water mass pathways that carry heat towards the coast and advect ice shelf meltwater offshore. The modified Circumpolar Deep Water and meltwater mixtures shoal and thin as they approach the continental slope before flowing westward at the shelf break, suggesting the presence of the Antarctic Slope Current. Constraining meltwater pathways is a key step in monitoring the stability of the West Antarctic Ice Sheet."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #456 on: June 03, 2016, 05:20:31 PM »
The linked (open access) reference cites research on four decades of marine glacier grounding line retreat in the Bellingshausen margin (see attached image).  This region contributes significantly to the instability of the WAIS:

Frazer D.W. Christie, Robert G. Bingham, Noel Gourmelen, Simon F.B. Tett & Atsuhiro Muto (22 May 2016), "Four-decade record of pervasive grounding line retreat along the Bellingshausen margin of West Antarctica", Geophysical Research Letters, DOI: 10.1002/2016GL068972


http://onlinelibrary.wiley.com/doi/10.1002/2016GL068972/abstract

Abstract: "Changes to the grounding line, where grounded ice starts to float, can be used as a remotely-sensed measure of ice-sheet susceptibility to ocean-forced dynamic thinning. Constraining this susceptibility is vital for predicting Antarctica's contribution to rising sea levels. We use Landsat imagery to monitor grounding line movement over four decades along the Bellingshausen margin of West Antarctica, an area little monitored despite potential for future ice losses. We show that ~65% of the grounding line retreated from 1990-2015, with pervasive and accelerating retreat in regions of fast ice flow and/or thinning ice shelves. Venable Ice Shelf confounds expectations in that despite extensive thinning, its grounding line has undergone negligible retreat. We present evidence that the ice shelf is currently pinned to a sub-ice topographic high which, if breached, could facilitate ice retreat into a significant inland basin, analogous to nearby Pine Island Glacier."

See also:
http://www.climatecentral.org/news/overlooked-area-antarctica-major-ice-loss-20408
Extract: "During a 2009-2010 field mission, Bingham looked to shed more light on the region by scanning the ground below one of the fastest-moving Bellingshausen glaciers, the Ferrigno Ice Stream. He found a huge canyon underneath that is likely funneling warm ocean water under the ice.
“This only served to highlight to me that there is so much about the Bellingshausen Sea sector of West Antarctica that has gone unmonitored while most of the world's eyes (glaciologically speaking) were looking beyond to Pine Island Glacier,” Bingham said.
To get a better picture of the overall ice loss in the area, Bingham and his Ph.D. student Frazer Christie, analyzed hundreds of satellite images of the area going back to 1975 and tracked the position of the grounding line along 1,240 miles of coast.
They found that 65 percent of the coastline had seen grounding line retreat since 1990, while only 7 percent had seen an advance. The total amount of ice lost over the last 40 years is about 390 square miles, an area about the size of Dallas.
The results “show that this whole coastline has been in a state of retreat since records began in the early 1970s,” Bingham said. That contrasts with previous thinking that only certain glaciers, like the Ferrigno Ice Stream, were seeing significant ice loss while the rest were fairly stable.
“The study illustrates that Antarctica is not immune to changes and that some of what we are seeing today started decades ago,” Eric Rignot, a NASA glaciologist who was not involved with the work, said in an email.
One notable oddity was the Venable Ice Shelf, which has thinned, but hasn’t retreated much. The researchers think it is pinned to a ridge on the seafloor that is keeping it stable for now. Scientists think the same was true of Pine Island Glacier — for a while.
Exactly what the pervasive ice loss in the Bellingshausen Sea area means for future global sea level rise isn’t entirely clear, in part because of the paucity of data from the area. Bingham says that researchers need a better idea of the topography underlying the ice so they can better model how it will change in the future."
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― Leon C. Megginson

AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #457 on: June 29, 2016, 12:30:39 AM »
The linked document describes a plan for the next decade of research in the WAIS to try to better quantify the rate and volume of change of ice mass loss now & in the future.  While the document has many stellar authors, to me it is conspicuous that Eric Rignot is missing:

Ted Scambos and Robin Bell, Richard Alley, Sridhar Anandakrishnan, David Bromwich, Kelly Brunt, Knut Christianson, Timothy Creyts, Sarah Das, Robert DeConto, Pierre Dutrieux, Helen Amanda Fricker, David Holland, Joseph MacGregor, Brooke Medley, David Pollard, Matthew Siegfried, Andrew Smith, Eric Steig, David Vaughan, Patricia Yaeger (April 2016), "How Much, How Fast? A Decadal Science Plan Quantifying the Rate of Change of the West Antarctic Ice Sheet Now and in the Future"

http://nsidc.org/sites/nsidc.org/files/files/WAIS_SciPlanHMHF_final.pdf

Extract: "This document is the outcome of a community science meeting held September 16-19, 2015 in Loveland Colorado, and a dedicated workshop on January 13-15, 2016 at the University of Colorado in Boulder.


The primary geographic focus of the How Much, How Fast? effort will be the Thwaites Glacier and the adjacent areas of the Amundsen Sea."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #458 on: June 29, 2016, 06:47:32 PM »
I was unable to find a link to the following reference (in press), but as the title sounds interesting, I provide the following partial information:

Little, Christopher M., and Urban Nathan M. , (2016) "CMIP5 Temperature biases and 21st Century Warming around the Antarctic Coast"
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Lennart van der Linde

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Re: Potential Collapse Scenario for the WAIS
« Reply #459 on: September 02, 2016, 10:18:12 AM »

Lennart van der Linde

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Re: Potential Collapse Scenario for the WAIS
« Reply #460 on: September 02, 2016, 01:25:01 PM »
DeConto on Russia Today, at beginning of April:
https://www.youtube.com/watch?v=i9DRolVl1DA

AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #461 on: January 09, 2017, 01:49:41 AM »
The linked article is entitled: "Collapse of West Antarctic Ice Sheet Reveals Inadequacy of Current Climate Strategies", and provides a nice summary of key issues about a possible WAIS collapse this century.

http://www.truth-out.org/news/item/38794-collapse-of-west-antarctic-ice-sheet-reveals-inadequacy-of-current-climate-strategies

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kiwichick16

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Re: Potential Collapse Scenario for the WAIS
« Reply #462 on: January 09, 2017, 11:17:53 AM »
thanks for that  aslr.........30 mm sea level rise per year would certainly get my attention

but have I missed it, or has the increase in sea level rise from 3mm / year to 5 mm/year not been verified yet????

AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #463 on: January 09, 2017, 05:15:26 PM »
thanks for that  aslr.........30 mm sea level rise per year would certainly get my attention

but have I missed it, or has the increase in sea level rise from 3mm / year to 5 mm/year not been verified yet????

It has been verified, but may partially be due to the recent major El Nino event.

Edit: See the attached Jason-2 record thru Sept 17 2016
« Last Edit: January 09, 2017, 05:21:13 PM by AbruptSLR »
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #464 on: January 09, 2017, 05:16:34 PM »
The linked article is entitled: "Antarctica Past Points to Sea Level Threat", & the reference research clearly increases the recognized probability that the WAIS might collapse this century (with continued warming).

http://climatenewsnetwork.net/antarctic-past-sea-level-threat/?utm_source=Climate+News+Network&utm_campaign=d3139ab809-EMAIL_CAMPAIGN_2017_01_09&utm_medium=email&utm_term=0_1198ea8936-d3139ab809-38798465

Extract: "Evidence of Antarctic ice sheet melting and sea level rise almost 15,000 years ago raises alarm over current climate change dangers."

See the associated linked (open access) reference at:
Fogwill et. al. (2017) , "Antarctic Ice Sheet Discharge Driven by Atmospheric-Ocean Feedbacks at the Last Glacial Termination", Scientific Reports, 7, Article No. 39979, doi: 10.1038/srep39979.

http://www.nature.com/articles/srep39979
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Lennart van der Linde

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Re: Potential Collapse Scenario for the WAIS
« Reply #465 on: March 26, 2017, 10:30:05 PM »
Documentary on Andrill with Rob DeConto and David Pollard on potential future sea level rise (from 45m34s onwards):
https://www.youtube.com/watch?v=i-_EECtAoRQ

Hyperion

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Re: Potential Collapse Scenario for the WAIS
« Reply #466 on: April 12, 2017, 11:34:50 AM »
Documentary on Andrill with Rob DeConto and David Pollard on potential future sea level rise (from 45m34s onwards):
https://www.youtube.com/watch?v=i-_EECtAoRQ

Interesting. You can see how this process drives tectonics. The ice mass loss at the periphery causes depressurisation of the puddle of fluid water and carbonate rich magma that the continental fringes float on due to seafloor sediment subductions. This causes trench blockwise subsidence for example as per the 700km / 800km long stretches some 50 km wide that dropped ~30 metres in the Valdivia May 22, 1960 9.5 and Offshore Maule/Biobío February 27, 2010 8.8 events off Chile.
Simultaneously the increase in central Ice mass balance presurisses the ~500+ km deep superheated fluid basalt conduits that connect the continental keels to the midocean spreading zones. When you look at the repeat blockwise pattern of repeated ~50km wide food basalt sheets that spread out from the mid ocean trenches, and take note that the chemical composition of basalt formed is the same for thousands of km along the rifting zone, its clear that this is how it works. The seafloor is extruded in flood basalt pulses caused by the hydraulic pump of the ice sheet pistons, and blocks are simultaneously stacked under the continental fringes. Which is why the layers get younger as you go down. The heat, and tectonic mayhem released by these periodic isostatic overdrive episodes of course can cause large effect on sea levels and ice sheet stability ::)
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #467 on: May 05, 2017, 09:35:18 AM »
The linked reference has recent data on ice mass loss from Antarctica & it indicates significant losses from the WAIS:

Gardner, A. S., Moholdt, G., Scambos, T., Fahnstock, M., Ligtenberg, S., van den Broeke, M., and Nilsson, J.: Increased West Antarctic ice discharge and East Antarctic stability over the last seven years, The Cryosphere Discuss., doi:10.5194/tc-2017-75, in review, 2017.

http://www.the-cryosphere-discuss.net/tc-2017-75/

Abstract. Ice discharge from large ice sheets plays a direct role in determining rates of sea level rise. We map present-day Antarctic-wide surface velocities using Landsat 7 & 8 imagery spanning 2013–2015 and compare to earlier estimates derived from synthetic aperture radar, revealing heterogeneous changes in ice flow since ~ 2008. The new mapping provides complete coastal and inland coverage of ice velocity with a mean error of < 10 m yr-1, resulting from multiple overlapping image pairs acquired during the daylit period. Using an optimized flux gate, ice discharge from Antarctica is 1932 ± 38 Gigatons per year (Gt yr-1) in 2015, an increase of 35 ± 15 Gt yr-1 from the time of the radar mapping. Flow accelerations across the grounding lines of West Antarctica's Amundsen Sea Embayment, Getz Ice Shelf and Marguerite Bay on the western Antarctic Peninsula, account for 89 % of this increase. In contrast, glaciers draining the East Antarctic Ice Sheet have been remarkably stable over the period of observation. Including modeled rates of snow accumulation and basal melt, the Antarctic ice sheet lost ice at an average rate of 186 ± 93 Gt yr-1 between 2008 and 2015. The modest increase in ice discharge over the past 7 years is contrasted by high rates of ice sheet mass loss and distinct spatial patters of elevation lowering. This suggests that the recent pattern of mass loss in Antarctica, dominated by the Amundsen Sea sector, is likely part of a longer-term phase of enhanced glacier flow initiated in the decades leading up to the first continent wide radar mapping of ice flow.
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #468 on: May 20, 2017, 05:38:38 AM »
The linked article is entitled: “Decoding Antarctica's response to a warming world”.  Hold your breath.

http://www.bbc.com/news/science-environment-39975709

Extract: “In the iceberg-infested waters of the Amundsen Sea Embayment (ASE), it obtained the very first cores to be drilled from just in front of some of the mightiest glaciers on Earth. 

Chief among these are Pine Island Glacier and Thwaites Glacier, colossal streams of ice that drain the White Continent and which are now spilling mass into the ocean at an alarming rate. 

There's concern that deep, warm water is undercutting the glaciers, possibly tipping them into an unstoppable retreat. And that has global implications for significant sea-level rise. 
...
The goal was to retrieve seafloor sediments that would reveal the behaviour of the West Antarctic Ice Sheet (WAIS) in previous warm phases. To read the future in the past. 

"If you find ice-rafted debris (stones dropped by icebergs), for example, you can be sure there was ice on land and that the ice had advanced to the coast," explained Claus-Dieter Hillenbrand from the British Antarctic Survey (BAS). 

"But also new developments - especially what's known as geochemical provenance - have emerged in the last 10 years that mean it's even possible now to compare this material with rocks on land to pin down the actual sources in the hinterland." 
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #469 on: June 02, 2017, 12:47:49 AM »
The linked article indicates that the collapse of the WAIS is almost inevitable:
"Guest post: Is the collapse of the West Antarctic Ice Sheet inevitable?"

https://www.carbonbrief.org/guest-post-collapse-west-antarctic-ice-sheet-inevitable

Extract: "So, is the eventual collapse of the West Antarctic Ice Sheet already inevitable? Model projections under low emissions scenarios suggest that ice sheet retreat could stabilise, but under medium and high scenarios, collapse is unstoppable.

The motto for early 21st Century cryospheric science should be “that happened faster than I thought it would.” Wherever we look, either in the past or in the present, we are challenged to keep up – in the ways we measure, theorise, project, and prepare for the future."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #470 on: June 15, 2017, 07:07:16 PM »
Get ready for a lot of future hydrofracture events in the WAIS:

"Scientists stunned by Antarctic rainfall and a melt area bigger than Texas"

https://www.washingtonpost.com/news/energy-environment/wp/2017/06/15/scientists-just-documented-a-massive-melt-event-on-the-surface-of-antarctica/?utm_term=.526054dc4fdf

Extract: "Scientists have documented a recent, massive melt event on the surface of highly vulnerable West Antarctica that, they fear, could be a harbinger of future events as the planet continues to warm.

In the Antarctic summer of 2016, the surface of the Ross Ice Shelf, the largest floating ice platform on Earth, developed a sheet of meltwater that lasted for as long as 15 days in some places. The total area affected by melt was 300,000 square miles, or larger than the state of Texas, the scientists report."
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Re: Potential Collapse Scenario for the WAIS
« Reply #471 on: June 15, 2017, 11:56:09 PM »
rs is on this now, too:

https://robertscribbler.com/2017/06/15/the-rains-of-antarctica-are-coming-warm-summer-storms-melted-texas-sized-section-of-ross-ice-shelf-surface-during-2016/

The Rains of Antarctica are Coming — Warm Summer Storms Melted Texas-Sized Section of Ross Ice Shelf Surface During 2016
"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."

AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #472 on: June 16, 2017, 04:38:15 PM »
rs is on this now, too:

https://robertscribbler.com/2017/06/15/the-rains-of-antarctica-are-coming-warm-summer-storms-melted-texas-sized-section-of-ross-ice-shelf-surface-during-2016/

The Rains of Antarctica are Coming — Warm Summer Storms Melted Texas-Sized Section of Ross Ice Shelf Surface During 2016

What concerns me is that in a few decades time, austral summertime atmospheric river events may likely fall as rainfall instead of as snowfall.  Such an atmospheric river event could devastate a local Antarctic ice shelf within a single week.
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AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #473 on: August 13, 2017, 07:36:18 PM »
The linked article cites a study that finds that the West Antarctic Rift System is the largest volcanic region on Earth, and that some of these volcanic may very well become more active should the WAIS thin sufficiently, which would be a positive feedback mechanism for a more complete collapse of the WAIS:

Title: "Scientists find what they think is largest volcanic region on Earth hidden in Antarctica after student's idea"

http://www.independent.co.uk/environment/antarctica-west-antarctic-rift-system-volcanoes-university-of-edinburgh-max-van-wyk-de-vries-a7891206.html

Extract: "A remote survey discovered 91 volcanoes ranging in height from 100m to 3,850m in a massive region known as the West Antarctic Rift System.

Geologists and ice experts say the range has similarities to east Africa's volcanic ridge, currently acknowledged to be the densest concentration of volcanoes in the world.

Researchers from the University of Edinburgh remotely surveyed the underside of the ice sheet for hidden peaks of basalt rock, like those of other volcanoes in the region whose tips push above the ice.

Previous studies have suggested that volcanic activity may have occurred in the region during warmer periods and could increase if Antarctica's ice thins in a warming climate.

Dr Robert Bingham, of the University of Edinburgh's School of GeoSciences, said: "It is fascinating to uncover an extensive range of volcanoes in this relatively unexplored continent.

"Better understanding of volcanic activity could shed light on their impact on Antarctica's ice in the past, present and future, and on other rift systems around the world.""
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

sidd

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Re: Potential Collapse Scenario for the WAIS
« Reply #474 on: August 14, 2017, 07:14:44 AM »
That Nicolas paper(DOI: 10.1038/ncomms15799 )  has a figure in it that tells me Mercer's indicator to watch midsummer 0C isotherm is flashing, it's  in the deep interior of  Ross shelf in 2016.
I attach fig 1c

for the locations of the weather stations, see the (open access) article.

sidd



AbruptSLR

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Re: Potential Collapse Scenario for the WAIS
« Reply #475 on: August 14, 2017, 11:02:04 AM »
That Nicolas paper(DOI: 10.1038/ncomms15799 )


For those who would like a link to the Nicolas et. al. (2017) paper, I provide the following:

Julien P. Nicolas et. al. (2017), "January 2016 extensive summer melt in West Antarctica favoured by strong El Nino", Nature Communications, DOI: 10.1038/ncomms15799

http://www.ccpo.odu.edu/~klinck/Reprints/PDF/nicolasNatComm17.pdf

Abstract: "Over the past two decades the primary driver of mass loss from the West Antarctic Ice Sheet (WAIS) has been warm ocean water underneath coastal ice shelves, not a warmer atmosphere. Yet, surface melt occurs sporadically over low-lying areas of the WAIS and is not fully understood. Here we report on an episode of extensive and prolonged surface melting observed in the Ross Sea sector of the WAIS in January 2016. A comprehensive cloud and radiation experiment at the WAIS ice divide, downwind of the melt region, provided detailed insight into the physical processes at play during the event. The unusual extent and duration of the melting are linked to strong and sustained advection of warm marine air toward the area, likely favoured by the concurrent strong El Nino event. The increase in the number of extreme El Nino events projected for the twenty-first century could expose the WAIS to more frequent major melt events."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson