Retreat of Pine Island Glacier controlled by marine ice-sheet instability

• Published in: Nature Climate Change
• Main Authors: Favier, L, Durand, G, Cornford, Stephen, Gudmundsson, GH, Gagliardini, O, Gillet-Chaulet, F, Zwinger, T, Payne, AJ, Le Brocq, A.M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2014
• Subjects: Pine Island Glacier; West Antarctica; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Pine Island
• Online Access: http://hdl.handle.net/10871/15286; https://doi.org/10.1038/NCLIMATE2094

This a post-print, author-produced version of an article accepted for publication in Nature Communications. Copyright © 2014 Macmillan Publishers Limited. All rights reserved. The definitive version is available at http://www.nature.com/nclimate/journal/v4/n2/pdf/nclimate2094.pdf Over the past 40 years Pine Island Glacier in West Antarctica has thinned at an accelerating rate, so that at present it is the largest single contributor to sea-level rise in Antarctica. In recent years, the grounding line, which separates the grounded ice sheet from the floating ice shelf, has retreated by tens of kilometres. At present, the grounding line is crossing a retrograde bedrock slope that lies well below sea level, raising the possibility that the glacier is susceptible to the marine ice-sheet instability mechanism. Here, using three state-ofthe- art ice-flow models, we show that Pine Island Glacier’s grounding line is probably engaged in an unstable 40 km retreat. The associated mass loss increases substantially over the course of our simulations from the average value of 20 Gt yr????1 observed for the 1992–2011 period, up to and above 100 Gt yr????1, equivalent to 3.5–10mm eustatic sea-level rise over the following 20 years. Mass loss remains elevated from then on, ranging from 60 to 120 Gt yr????1. GENCI-CINES Service Commun de Calcul Intensif de l'Observatoire de Grenoble (SCCI) US Department of Energy NERC