While the linked research, indicating more rapid bedrock uplift in Amundsen Sea Embayment, seems like good news, if one refers to projections from ice sheet models that do not include Pollard's & DeConto's ice cliff and hydrofacturing mechanism and which assume radiative forcing scenarios of RCP 4.5 or less. However, if one assumes radiative forcing scenarios close to BAU for the next two decades and projections from Pollard & DeConto's recent work, then Barletta et al (2018)'s finding are actually bad news regarding the potential collapse of the WAIS this century.
V.R. Barletta el al. (22 Jun 2018), "Observed rapid bedrock uplift in Amundsen Sea Embayment promotes ice-sheet stability," Science,:
Vol. 360, Issue 6395, pp. 1335-1339, DOI: 10.1126/science.aao1447.
http://science.sciencemag.org/content/360/6395/1335Abstract
The marine portion of the West Antarctic Ice Sheet (WAIS) in the Amundsen Sea Embayment (ASE) accounts for one-fourth of the cryospheric contribution to global sea-level rise and is vulnerable to catastrophic collapse. The bedrock response to ice mass loss, glacial isostatic adjustment (GIA), was thought to occur on a time scale of 10,000 years. We used new GPS measurements, which show a rapid (41 millimeters per year) uplift of the ASE, to estimate the viscosity of the mantle underneath. We found a much lower viscosity (4 × 1018 pascal-second) than global average, and this shortens the GIA response time scale from tens to hundreds of years. Our finding requires an upward revision of ice mass loss from gravity data of 10% and increases the potential stability of the WAIS against catastrophic collapse.
Title: "Bedrock in West Antarctica rising at surprisingly rapid rate"
https://phys.org/news/2018-06-bedrock-west-antarctica-surprisingly-rapid.htmlExtract: "The findings, reported in the journal Science, have surprising and positive implications for the survival of the West Antarctic Ice Sheet (WAIS), which scientists had previously thought could be doomed because of the effects of climate change.
The unexpectedly fast rate of the rising earth may markedly increase the stability of the ice sheet against catastrophic collapse due to ice loss, scientists say.
Moreover, the rapid rise of the earth in this area also affects gravity measurements, which implies that up to 10 percent more ice has disappeared in this part of Antarctica than previously assumed.
Researchers led by scientists at The Ohio State University used a series of six GPS stations (part of the POLENET-ANET array) attached to bedrock around the Amundsen Sea Embayment to measure its rise in response to thinning ice.
The "uplift rate" was measured at up to 41 millimeters (1.6 inches) a year, said Terry Wilson, one of the leaders of the study and a professor emeritus of earth sciences at Ohio State.
In contrast, places like Iceland and Alaska, which have what are considered rapid uplift rates, generally are measured rising 20 to 30 millimeters a year.
"The rate of uplift we found is unusual and very surprising. It's a game changer," Wilson said.
And it is only going to get faster. The researchers estimate that in 100 years, uplift rates at the GPS sites will be 2.5 to 3.5 times more rapid than currently observed.
…
While modeling studies have shown that bedrock uplift could theoretically protect WAIS from collapse, it was believed that the process would take too long to have practical effects.
"We previously thought uplift would occur over thousands of years at a very slow rate, not enough to have a stabilizing effect on the ice sheet. Our results suggest the stabilizing effect may only take decades," Wilson said.
Wilson said the rapid rise of the bedrock in this part of Antarctica suggests that the geology underneath Antarctica is different from what scientists had previously believed.
…
Some scientists suggest that WAIS may have passed a tipping point in which ice loss can no longer be stopped, which could be catastrophic, Wilson said. The glaciers there contain enough water to raise global sea levels up to four feet.
The problem is that much of this area of Antarctica is below sea level. Relatively warm ocean water has flowed in underneath the bottom of the ice sheet, causing thinning and moving the grounding line—where the water, ice and solid earth meet—further inland.
The process seemed unstoppable, Wilson said. "But we found feedbacks that could slow or even stop the process."
One important feedback involves "pinning points—elevated features of the earth rising from the surface below the grounding line that pin the ice sheet to solid earth. These pinning points are going up in response to the uplift of the earth and could prevent further retreat of the ice sheet.
Another feedback is lowering sea levels. Massive ice sheets along the ocean have their own gravitational pull and raise the sea level near them. But as the ice thins and retreats, the gravitational pull lessens and the sea level near the coast goes down.
"The lowering of the sea level, the rising of pinning points and the decrease of the inland slope due to the uplift of the bedrock are all feedbacks that can stabilize the ice sheet," Wilson said.
Other researchers had estimated how much the earth would have to rise to protect WAIS given a range of future climate warming scenarios.
Results of this study estimate that the bedrock at the Pine Island Glacier grounding line (which is part of WAIS) will have risen about 8 meters in 100 years. That is about three times higher than values shown by others to reduce run-away retreat in this area.
"Under many realistic climate models, this should be enough to stabilize the ice sheet," Wilson said.
She said while this study delivers some potentially good news for the Amundsen Sea Embayment, that doesn't mean all is well in Antarctica.
"The physical geography of Antarctica is very complex. We found some potentially positive feedbacks in this area, but other areas could be different and have negative feedbacks instead," she said. Regardless of feedbacks, models suggest that the WAIS will collapse if future global warming is large."
