Authors: Shaina Rogstad*, UMass Amherst, Alan Condron, Woods Hole Oceanographic Institution, Robert DeConto, University of Massachusetts Amherst, David Pollard, Pennsylvania State University
Topics: Climatology and Meteorology, Cryosphere, Anthropocene
Keywords: climate, cryosphere, modeling, polar, Antarctica
Session Type: Paper
Start / End Time: 9:35 AM / 10:50 AM
Room: Virtual Track 2
Presentation File: No File Uploaded
Observational evidence indicates that the Antarctic Ice Sheet is losing mass at an accelerated rate, and ice sheet models highlight the potential for a significant ice collapse in the next century. The impacts of this large fresh water forcing on sea-ice formation, ocean circulation, and climate could be significant, but the current generation of GCMs don’t adequately capture ice sheet meltwater discharge. Here we present results for 2005-2250 from several climate model simulations performed under IPCC future climate scenarios RCP 4.5 and 8.5 with a high-resolution, fully coupled, ocean-atmosphere-sea ice model (CESM 1.2). In each experiment, temporally and spatially variable runoff from Antarctica is prescribed from a regional dynamic/thermodynamic ice sheet/shelf model. Our results highlight a significant rise in subsurface ocean temperatures (>1C) at the ice sheet grounding line that may accelerate rates of ice melt beyond those currently projected. In contrast, the increased runoff creates a cold surface layer that allows Antarctic sea ice to continue to expand through the end of the current century causing delayed atmospheric warming. These competing feedbacks have significant implications for ice sheet evolution that can help inform the next iteration of ice sheet models and constrain future climate states.