Century-scale simulations of the response of the West Antarctic Ice Sheet to a warming climate

• Published in: The Cryosphere
• Main Authors: Cornford, S.L, Martin, D.F, Payne, A.J, Ng, E.G, Le Brocq, A.M, M. Gladstone, R., Edwards, Thomas L, Shannon, S.R., Agosta, C, R. van den Broeke, M., Hellmer, Hh, Krinner, G, Ligtenberg, S. R. M., Timmermann, R, Vaughan, D.G.
• Other Authors: University of Bristol Bristol, Lawrence Berkeley National Laboratory Berkeley (LBNL), University of Exeter, Université de Liège, Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht University Utrecht, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), British Antarctic Survey (BAS), Natural Environment Research Council (NERC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDE]Environmental Sciences; Antarctic; Amundsen Sea; West Antarctic Ice Sheet; Thwaites Glacier; Antarc*; Ice Sheet; Ice Shelf; Ice Shelves; The Cryosphere
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-01284498; https://hal-insu.archives-ouvertes.fr/insu-01284498/document; https://hal-insu.archives-ouvertes.fr/insu-01284498/file/THE%20CRYOSPHERE-Century-scale%20simulations%20of%20the%20response%20of%20the%20West%20Antarctic%20Ice%20Sheet%20to%20a%20warming%20climate.pdf; https://doi.org/10.5194/tc-9-1579-2015

International audience We use the BISICLES adaptive mesh ice sheet model to carry out one, two, and three century simulations of the fast-flowing ice streams of the West Antarctic Ice Sheet, deploying sub-kilometer resolution around the grounding line since coarser resolution results in substantial underestimation of the response. Each of the simulations begins with a geometry and velocity close to present-day observations, and evolves according to variation in meteoric ice accumulation rates and oceanic ice shelf melt rates. Future changes in accumulation and melt rates range from no change, through anomalies computed by atmosphere and ocean models driven by the E1 and A1B emissions scenarios, to spatially uniform melt rate anomalies that remove most of the ice shelves over a few centuries. We find that variation in the resulting ice dynamics is dominated by the choice of initial conditions and ice shelf melt rate and mesh resolution, although ice accumulation affects the net change in volume above flotation to a similar degree. Given sufficient melt rates, we compute grounding line retreat over hundreds of kilometers in every major ice stream, but the ocean models do not predict such melt rates outside of the Amundsen Sea Embayment until after 2100. Within the Amundsen Sea Embayment the largest single source of variability is the onset of sustained retreat in Thwaites Glacier, which can triple the rate of eustatic sea level rise.