Positive feedbacks drive the Greenland ice sheet evolution in millennial-length MAR–GISM simulations under a high-end warming scenario
Year: 2026
Type: article
Abstract: . Understanding the complex interactions between the Greenland ice sheet (GrIS) and the atmosphere is crucial for predicting its future sea level contribution. However, studying these interactions remains challenging, as it requires high-resolution climate or atmospheric models to be run over extended timescales before their influence on the ice sheet–climate system becomes significant. Therefore, in this study, we coupled an ice sheet model (GISM) with a regional climate model (MAR) and conducted millennial-length simulations. The simulations consist of a zero-way, a one-way, and a two-way coupled configuration, which were forced by the IPSL-CM6A-LR global climate model output under the SSP5-8.5 scenario until 2300 and extended until the year 3000 by randomly sampling the last 51 years of forcing. They represent the first coupled simulations of an ice sheet model (ISM) and regional climate model (RCM) that extend beyond the centennial timescale and allow us to assess the evolving role of ice sheet–atmosphere feedbacks. Our results reveal that the ice sheet evolution is determined by positive as well as negative feedback mechanisms, that act over different timescales. The main observed negative feedback in our simulations is related to changing wind speeds at the ice sheet margin, due to which the integrated ice mass loss differs by only 2.36 % by 2300 between the two- and one-way coupled simulations, regardless of the differently evolving ice sheet geometries. Beyond this time however, positive feedback mechanisms related to decreasing surface elevation, namely the melt–elevation feedback and changes in cloudiness and orographic precipitation, dominate the ice sheet–climate system and strongly accelerate the integrated ice mass loss in the two-way coupled simulation. As a result, by the end of the simulations, the ice sheet has almost entirely disappeared in the two-way coupled simulation, with a sea level contribution of 7.135 m s.l.e., compared to the significantly smaller contributions of 5.635 m s.l.e. and 5.122 m s.l.e. for the one-way and zero-way coupled simulations, respectively. This highlights the importance of accurately representing the ice sheet–atmosphere interactions for long-term assessments of the Greenland ice sheet and climate.
Source: The cryosphere
Institutions: Vrije Universiteit Brussel, University of Liège
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: gold
Estimated APC paid: $1,574
OpenAlex ID: W7124423739