The GRISLI-LSCE contribution to ISMIP6, Part 2: projections of the Antarctic ice sheet evolution by the end of the 21st century

• Main Authors: Quiquet, Aurélien, Dumas, Christophe
• Format: Text
• Language: English
• Published: 2020
• Subjects: Antarctic; Greenland; The Antarctic; Antarc*; Antarctica; Ice Sheet; Ice Shelves
• Online Access: https://doi.org/10.5194/tc-2020-140; https://tc.copernicus.org/preprints/tc-2020-140/

Of primary societal importance, the ice sheet contribution to global sea level rise over the 21 st century remains largely uncertain. In particular, the contribution of the Antarctic ice sheet by 2100 ranges from a few millimetres to more than one metre in the recent literature. The Ice Sheet Model Intercomparison Project for CMIP6 aimed at reducing the uncertainties on the fate of the ice sheets in the future by gathering various ice sheet models in a common framework. While in a companion paper we present the GRISLI-LSCE contribution to ISMIP6-Greenland, we present here the GRISLI-LSCE contribution to ISMIP6-Antarctica. We show that our model is strongly sensitive to the climate forcing used, with a contribution of the Antarctic ice sheet to global sea level rise by 2100 that ranges from −50 mm to +150 mm of sea level equivalent. Future oceanic warming leads to a decrease in thickness of the ice shelves and implies grounding line retreats while increased precipitation partially mitigates the ice sheet contribution to global sea level rise. Most of ice sheet changes over the next century are dampened under low greenhouse gas emission scenarios. Uncertainties related to sub-shelf basal melt induce large differences in simulated grounding line retreats, confirming the importance of this process and its representation in ice sheet models for the projections of the Antarctic ice sheet.