Abstract

For external attendees, please email Yohei Takano (yokano at bas.ac.uk) or Birgit Rogalla (birgal at bas.ac.uk) to arrange for access to BAS .

The Antarctic Ice Sheet (AIS) is one of the major Earth components and is crucial to the future evolution of global sea level. The Antarctic ice shelves, the floating parts of AIS , have been observed thinning and losing buttressing to the grounded ice. Here we use a two-way coupled UKESM1 .0-ice model with an interactive ice sheet model to investigate the Antarctic ice shelf-ocean interactions. We extend an SSP5 -8.5 run described in Siahaan et al. (2022) to 2200; and focus on the evolution of Antarctic ice shelf melting. The basal melt rates of three large cold ice shelves (Ross, Filchner-Ronne and Amery) exhibit similar peak-and-decline behaviours, despite the warming in the ice shelf cavities. This is due to ice geometric feedback: 1. Strong stratification beneath the ice shelf after the fast melting prevents the warm seawater from approaching the ice; 2. The flattening and rising of the ice shelf base reduce the oceanic heat transferred into the ice. The melt rates in the experiment without interactive ice sheets are several times larger than those in the experiment with interactive ice sheets. Comparisons of the two experiments suggest the need to include geometric feedback in climate models to reduce the uncertainty in the projections of Antarctic mass evolution.