Netherlands Polar Data Center

Summary

The Antarctic ice sheet (AIS) is losing mass at an accelerating rate, currently about 0.2-0.3 mm global mean sea level equivalents per year. This mass loss is entirely due to the ongoing acceleration of fast-flowing outlet glaciers, which is triggered by a warmer ocean eroding the buttressing ice shelves from below. The atmospheric wind field drives these warm ocean currents. Recent research has shown that the projected atmospheric warming and changes in the circumpolar circulation can lead to strong enhancement of ice shelf melting, initiating AIS mass losses that are a magnitude larger than those currently observed. Moreover, the inland sloping bedrock topography of West Antarctica raises concerns on the stability of the ice sheet once retreat has started. Reliable high-end estimates of future Antarctic mass losses are, therefore, urgently needed to allow adaption and mitigation measures. Here we propose to model the response of the Antarctic atmosphere-ocean-ice shelf system for a high-end warming scenario, using a regional atmospheric climate model forcing a finite element ocean-sea-ice model including ocean-ice shelf interaction. A hindcast, driven by reanalysis data, will generate a climatology (1980-2013) that can be evaluated using observations, and a scenario run until 2300, using the extended high-end scenario RCP8.5, will yield the maximum plausible sea level rise contribution from the AIS in 2300. Sensitivity tests will focus on the main drivers of enhanced ice shelf melt. We envisage that the results will significantly increase our understanding of this complex system and reduce the uncertainty in sea level rise projections.

People involved

Datasets

Publications

Jan T. M. Lenaerts, Stefan R. M. Ligtenberg, et al., 2018. Climate and surface mass balance of coastal West Antarctica resolved by regional climate modelling. Annals of Glaciology 59 (76pt1), 29-41

Willem Jan van de Berg & Brooke Medley, 2016. Brief Communication: Upper-air relaxation in RACMO2 significantly improves modelled interannual surface mass balance variability in Antarctica. The Cryosphere 10 (1), 459-463