Model insights into bed control on retreat of Thwaites Glacier, West Antarctica

Abstract Thwaites Glacier (TG) plays an important role in future sea-level rise (SLR) contribution from the West Antarctic Ice Sheet. Recent observations show that TG is losing mass, and its grounding zone retreating. Previous modeling has produced a wide range of results concerning whether, when, how rapidly further retreat will occur under continued warming. These differences arise at least part ill-constrained processes, including friction bed, atmosphere ocean forcing affecting ice-shelf grounding-zone buttressing. Here, we apply Sheet Sea-level System Model (ISSM) with specifications basal sliding behavior response to varying forcing. We find basin-wide bed character strongly affects TG's sub-shelf melt by modulating changes driving stress are balanced as glacier responds external Resulting dynamic thinning patterns alter modeled grounding-line across Thwaites' catchment, both rates magnitudes SLR this critical sector ice sheet. Bed introduces large uncertainties projections equal forcing, pointing crucial constraint needed predictive models Antarctica.