The first meeting of 2024 will be on 13-March from 9 - 10a. The first half of the meeting will be an invited speaker, Helene Serrousi (Dartmouth Engineering) and the second half will focus on the ISM selection progress.
Invited talk: Helene Serrousi (Dartmouth Engineering), title/abstract below.
Ice Sheet Model selection update
Excluded models
Ranking strategy
Timeline/process
Next meeting (confirm date & call for any agenda items)
Invited Speaker: Helene Serrousi (Dartmouth Engineering) Title:
Evolution of the Antarctic Ice Sheet over the next three centuries from an ISMIP6 model ensemble
Abstract:
The Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) is the primary effort of CMIP6 (Coupled Model Intercomparison Project-Phase 6) focusing on ice sheets, designed to provide an ensemble of process-based projections of the ice-sheet contribution to sea-level rise over the 21st century. However, the behavior of the Antarctic Ice Sheet (AIS) beyond 2100 remains largely unknown: several instability mechanisms can develop on longer time scales, potentially destabilizing large parts of AIS.
Projections of AIS evolution until 2300 are presented here, using an ensemble of 16 ice-flow models and forcing from global climate models. Under high-emission scenarios, the Antarctic sea-level contribution is limited to less than 30 cm sea-level equivalent (SLE) by 2100, but increases rapidly thereafter to reach up to 4.4 m SLE by 2300. Simulations including ice-shelf collapse lead to an additional 1.1 m SLE on average by 2300, and can reach 6.9 m SLE. Widespread retreat is observed on that timescale in most West Antarctic basins, leading to a collapse of large sectors of West Antarctica by 2300 in 30-40% of the ensemble. While the onset date of retreat varies among ice models, the rate of upstream propagation is highly consistent once retreat begins. Calculations of sea-level contribution including water density corrections lead to an additional ~10% SLE and up to 50% for contributions accounting for bedrock uplift in response to ice loading. Overall, these results highlight large sea-level contributions from the AIS and suggest that the choice of ice sheet model remains the leading source of uncertainty in multi-century projections.
Bio:
Helene Seroussi is an Associate Professor at Dartmouth College. Her research interests are focused on better understanding and explaining ongoing changes of the ice sheets, as well as reducing uncertainties in the ice sheet contribution to sea level rise by combining numerical models with remote-sensing and in-situ observations. She is one of the co-founders and main developers of the Ice-sheet and Sea-level System Model (ISSM) and a member of the scientific committee of ISMIP6.