ISMIP6 Antarctica: a multi-model ensemble of the Antarctic ice sheet evolution over the 21st century

• Main Authors: Seroussi, Helene, Nowicki, Sophie, Payne, Antony J., Goelzer, Heiko, Lipscomb, William H., Abe-Ouchi, Ayako, Agosta, Cecile, Albrecht, Torsten, Asay-Davis, Xylar, Barthel, Alice, Calov, Reinhard, Cullather, Richard, Dumas, Christophe, Galton-Fenzi, Benjamin K., Gladstone, Rupert R.M., Golledge, Nicholas R., Gregory, Jonathan M., Greve, Ralf, Hattermann, Tore, Hoffman, Matthew J., Humbert, Angelika, Huybrechts, Philippe, Jourdain, Nicolas C., Kleiner, Thomas, Larour, Eric, Leguy, Gunter R., Lowry, Daniel P., Little, Chistopher M., Morlighem, Mathieu, Pattyn, Frank, Pelle, Tyler, Price, Stephen F., Quiquet, Aurelien, Reese, Ronja, Schlegel, Nicole-Jeanne, Shepherd, Andrew, Simon, Erika, Smith, Robin R.S., Straneo, Fiammetta, Sun, Sainan, Trusel, Luke D., Van Breedam, Jonas, van de Wal, Roderik S W, Winkelmann, Ricarda, Zhao, Cheng, Zhang, Tong, Zwinger, Thomas
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Glaciologie; Sciences exactes et naturelles; Antarc*; Antarctic; Antarctica; East Antarctica; Ice Sheet; The Cryosphere
• Online Access: http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/313217; https://dipot.ulb.ac.be/dspace/bitstream/2013/313217/3/tc-14-3033-2020.pdf

Abstract. Ice flow models of the Antarctic ice sheet are commonly used to simulate its future evolution inresponse to different climate scenarios and assess the mass loss that would contribute tofuture sea level rise. However, there is currently no consensus on estimates of the future massbalance of the ice sheet, primarily because of differences in the representation of physicalprocesses, forcings employed and initial states of ice sheet models. This study presentsresults from ice flow model simulations from 13 international groups focusing on the evolutionof the Antarctic ice sheet during the period 2015–2100 as part of the Ice Sheet ModelIntercomparison for CMIP6 (ISMIP6). They are forced with outputs from a subset of models from theCoupled Model Intercomparison Project Phase 5 (CMIP5), representative of the spread in climatemodel results. Simulations of the Antarctic ice sheet contribution to sea level rise in responseto increased warming during this period varies between −7.8 and 30.0 cm of sea level equivalent(SLE) under Representative ConcentrationPathway (RCP) 8.5 scenario forcing. These numbers are relative to a control experiment withconstant climate conditions and should therefore be added to the mass loss contribution underclimate conditions similar to present-day conditions over the same period. The simulated evolution of theWest Antarctic ice sheet varies widely among models, with an overall mass loss, up to 18.0 cm SLE, in response to changes in oceanic conditions. East Antarctica mass change varies between −6.1 and8.3 cm SLE in the simulations, with a significant increase in surface mass balance outweighingthe increased ice discharge under most RCP 8.5 scenario forcings. The inclusion of ice shelfcollapse, here assumed to be caused by large amounts of liquid water ponding at the surface ofice shelves, yields an additional simulated mass loss of 28 mm compared to simulations without iceshelf collapse. The largest sources of uncertainty come from the climate forcing, the ocean-induced melt rates, ...