Insights into spatial sensitivities of ice mass response to environmental change from the SeaRISE ice sheet modeling project I: Antarctica

Abstract Atmospheric, oceanic, and subglacial forcing scenarios from the Sea‐level Response to Ice Sheet Evolution (SeaRISE) project are applied to six three‐dimensional thermomechanical ice‐sheet models to assess Antarctic ice sheet sensitivity over a 500 year timescale and to inform future modeling and field studies. Results indicate (i) growth with warming, except within low‐latitude basins (where inland thickening is outpaced by marginal thinning); (ii) mass loss with enhanced sliding (with basins dominated by high driving stresses affected more than basins with low‐surface‐slope streaming ice); and (iii) mass loss with enhanced ice shelf melting (with changes in West Antarctica dominating the signal due to its marine setting and extensive ice shelves; cf. minimal impact in the Terre Adelie, George V, Oates, and Victoria Land region of East Antarctica). Ice loss due to dynamic changes associated with enhanced sliding and/or sub‐shelf melting exceeds the gain due to increased precipitation. Furthermore, differences in results between and within basins as well as the controlling impact of sub‐shelf melting on ice dynamics highlight the need for improved understanding of basal conditions, grounding‐zone processes, ocean‐ice interactions, and the numerical representation of all three.