SSP3-7.0 projections of Antarctic sub-ice-shelf melting with the Energy Exascale Earth System Model

To date, few Earth System Models (ESMs) have the ability to simulate the flow in the ocean cavities below Antarctic ice shelves and its influence on basal melting. Yet capturing both this flow and the resulting melt patterns is critical for representing local, regional, and global feedbacks between the climate and sub-ice-shelf melting. Here, we present a small ensemble of historical simulations and SSP3-7.0 projections in an ESM that includes Antarctic ice-shelf cavities, the Energy Exascale Earth System Model (E3SM) v2.1. The simulations have active ocean, sea-ice, atmosphere, land and river components. The model domain has 12 km horizontal resolution around Antarctica, which is adequate for capturing dynamics in the larger ice-shelf cavities, melt fluxes aggregated across Antarctic regions, and water masses across most of the Antarctic continental shelf. The projections show significant warming and freshening of water masses on the Antarctic continental shelf, a deepening and poleward shift of the Amundsen Sea Low (ASL), and a significant increase in Antarctic melting through the 20th and 21st centuries. We also see a significantly more modest drift in water-mass properties and melt rates in our control simulation with constant 1950 conditions from which the historical runs were branched. In addition to providing an estimate of future melting and other changes in regional and global climate under SSP3-7.0, these simulations are also a steppingstone to coupled ice sheet-ocean simulations planned for the near future. We briefly discuss these plans and the coupling strategy that we are developing.