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A Historical Primer on WAIS Collapse, Pt. 2: Recent History August 4, 2014

Posted by Will Thomas in Commentary Track.
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This post continues my post from May, which was written to lend some historical background to the recently released news that the large marine glaciers emptying into the Amundsen Sea seem to have passed a point of no return, and will continue to collapse until they are gone, whereupon the rest of the West Antarctic Ice Sheeet (WAIS) may well follow. Total sea level rises should be 2–3m within a few centuries, though the exact timescales could be faster or slower.  The above video from the NASA Jet Propulsion Laboratory features Eric Rignot, one of the leaders of the two teams who have reached this conclusion.  (The other team is led by the University of Washington’s Ian Joughin, on whom more below.)

The history in Pt. 1 concluded circa 1980, when geologist John Mercer (1922-1987) connected the prospect of WAIS collapsing to global warming.  Shortly thereafter the University of Maine’s Terry Hughes—who had previously linked future WAIS collapse to an ongoing global retreat from the Last Glacial Maximum (18,000 years ago)—identified (pdf) the Amundsen Sea glaciers as WAIS’s “weak underbelly,” which would be the “mechanism for disintegration of [WAIS] during a proposed Super Interglaciation triggered by CO2-induced climatic warming.” This post addresses what occurred in the intervening decades to convince the glaciological community of the assertion.

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A Historical Primer on WAIS Collapse, Part 1: Early History May 22, 2014

Posted by Will Thomas in Commentary Track.
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Two new papers, in Science, and in Geophysical Research Letters, demonstrate that Thwaites Glacier in Antarctica has reached a point of instability, which, at some point in the future, will lead to the collapse of that part of the West Antarctic Ice Sheet (WAIS), and, eventually, the rest of it as well.  Over a period of some centuries, sea level rises will be catastrophic.  The video above is by NASA, discussing some of the key points.

Various reports on this subject have traced work on this question back to geologist John Mercer (1922-1987), either to a well-known paper he published in Nature in 1978 linking WAIS collapse to anthropogenic global warming, or to a more obscure paper he published in 1968, in which he posited that WAIS was the source of higher sea levels during the Sangamon interglacial 120,000 years ago.  That earlier paper also mentioned possible future danger from “industrial pollution,” but only tangentially within a larger focus on Antarctica’s glacial history.

Having published on the history of this subject, I’d like to develop the available narrative somewhat, both to expand on its roots, but also to discuss some of the twists and turns that have led us from an initial suspicion that WAIS could rapidly collapse to the disquieting conclusion at which glaciologists have now arrived. (more…)