WAIS Ice Shelves Show Early Signs of Irreversible Disintegration

PNAS, September 14

Extensive open fractures have developed in the ice shelves of the Pine Island and Thwaites glaciers in the West Antarctic Ice Sheet, potentially priming them for future collapse. No such crevasses existed at the beginning of satellite records in 1997, with rapidly growing crevasse-damaged areas by 2019, accelerating since 2016.  These damaged areas started to form from warmer ocean waters below, with surface warming occurring more recently, potentially similar to processes leading to the sudden disintegration of the Larsen B ice shelf in 2002.  This region already has the greatest contribution from Antarctica to global sea level rise.  Collapse of these ice shelves would in turn lead to accelerated mass loss of and retreat of the massive glaciers behind (Thwaites is 120 km wide), in a “domino effect” of mechanical weakening that could not be stopped by decreases in ocean or air temperatures, though it might possibly be slowed.

https://www.pnas.org/content/early/2020/09/08/1912890117

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