Insights into the vulnerability of Antarctic glaciers from the ISMIP6 ice sheet model ensemble and associated uncertainty
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Published:2023-12-07
Issue:12
Volume:17
Page:5197-5217
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ISSN:1994-0424
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Container-title:The Cryosphere
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language:en
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Short-container-title:The Cryosphere
Author:
Seroussi HélèneORCID, Verjans Vincent, Nowicki SophieORCID, Payne Antony J.ORCID, Goelzer HeikoORCID, Lipscomb William H.ORCID, Abe-Ouchi AyakoORCID, Agosta CécileORCID, Albrecht TorstenORCID, Asay-Davis XylarORCID, Barthel AliceORCID, Calov Reinhard, Cullather Richard, Dumas Christophe, Galton-Fenzi Benjamin K.ORCID, Gladstone RupertORCID, Golledge Nicholas R.ORCID, Gregory Jonathan M.ORCID, Greve RalfORCID, Hattermann ToreORCID, Hoffman Matthew J.ORCID, Humbert AngelikaORCID, Huybrechts PhilippeORCID, Jourdain Nicolas C.ORCID, Kleiner ThomasORCID, Larour Eric, Leguy Gunter R.ORCID, Lowry Daniel P.ORCID, Little Chistopher M., Morlighem MathieuORCID, Pattyn Frank, Pelle TylerORCID, Price Stephen F.ORCID, Quiquet AurélienORCID, Reese RonjaORCID, Schlegel Nicole-JeanneORCID, Shepherd Andrew, Simon Erika, Smith Robin S.ORCID, Straneo FiammettaORCID, Sun SainanORCID, Trusel Luke D.ORCID, Van Breedam JonasORCID, Van Katwyk Peter, van de Wal Roderik S. W., Winkelmann RicardaORCID, Zhao ChenORCID, Zhang Tong, Zwinger ThomasORCID
Abstract
Abstract. The Antarctic Ice Sheet represents the largest source of uncertainty in future sea level rise projections, with a contribution to sea level by 2100 ranging from −5 to 43 cm of sea level equivalent under high carbon emission scenarios estimated by the recent Ice Sheet Model Intercomparison for CMIP6 (ISMIP6). ISMIP6 highlighted the different behaviors of the East and West Antarctic ice sheets, as well as the possible role of increased surface mass balance in offsetting the dynamic ice loss in response to changing oceanic conditions in ice shelf cavities. However, the detailed contribution of individual glaciers, as well as the partitioning of uncertainty associated with this ensemble, have not yet been investigated. Here, we analyze the ISMIP6 results for high carbon emission scenarios, focusing on key glaciers around the Antarctic Ice Sheet, and we quantify their projected dynamic mass loss, defined here as mass loss through increased ice discharge into the ocean in response to changing oceanic conditions. We highlight glaciers contributing the most to sea level rise, as well as their vulnerability to changes in oceanic conditions. We then investigate the different sources of uncertainty and their relative role in projections, for the entire continent and for key individual glaciers. We show that, in addition to Thwaites and Pine Island glaciers in West Antarctica, Totten and Moscow University glaciers in East Antarctica present comparable future dynamic mass loss and high sensitivity to ice shelf basal melt. The overall uncertainty in additional dynamic mass loss in response to changing oceanic conditions, compared to a scenario with constant oceanic conditions, is dominated by the choice of ice sheet model, accounting for 52 % of the total uncertainty of the Antarctic dynamic mass loss in 2100. Its relative role for the most dynamic glaciers varies between 14 % for MacAyeal and Whillans ice streams and 56 % for Pine Island Glacier at the end of the century. The uncertainty associated with the choice of climate model increases over time and reaches 13 % of the uncertainty by 2100 for the Antarctic Ice Sheet but varies between 4 % for Thwaites Glacier and 53 % for Whillans Ice Stream. The uncertainty associated with the ice–climate interaction, which captures different treatments of oceanic forcings such as the choice of melt parameterization, its calibration, and simulated ice shelf geometries, accounts for 22 % of the uncertainty at the ice sheet scale but reaches 36 % and 39 % for Institute Ice Stream and Thwaites Glacier, respectively, by 2100. Overall, this study helps inform future research by highlighting the sectors of the ice sheet most vulnerable to oceanic warming over the 21st century and by quantifying the main sources of uncertainty.
Funder
National Aeronautics and Space Administration Office of Science Academy of Finland Australian Government Japan Society for the Promotion of Science National Center for Atmospheric Research Bundesministerium für Bildung und Forschung Deutsche Forschungsgemeinschaft Horizon 2020 National Science Foundation Fonds Wetenschappelijk Onderzoek Norges Forskningsråd Agence Nationale de la Recherche
Publisher
Copernicus GmbH
Subject
Earth-Surface Processes,Water Science and Technology
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