Abstract

The West Antarctic Ice Sheet (WAIS) is a marine ice sheet that rests on a bed below sea level. The stability of a marine ice sheet and its contribution to future sea level rise are controlled by the dynamics of the grounding line, where the grounded ice sheet transitions into a floating ice shelf. Recent observations suggest that Antarctic ice shelves experience widespread thinning due to contact with warming ocean waters, but quantifying the effect of these changes on marine ice sheet stability and extent remains a major challenge for both observational and modelling studies. In this talk, I provide an analytic expression for the ice flux at the grounding line of laterally confined marine ice sheets. This approach allows us to investigate how different calving laws change the stability of marine ice sheets. By combining these results with recent work that parametrizes sub-shelf melting with buoyant plume models, I obtain an algebraic expression for the ice flux at the grounding line as a function of ice shelf properties (for example ice shelf width and length) and leading order oceanic conditions (represented by the ambient ocean temperature and salinity). This allows us to directly link the extent and stability of a marine ice sheet to oceanic conditions. I will discuss the implications of these dependencies for projections of the future evolution of the West Antarctic Ice Sheet.