Is a warming of the Antarctic continental shelf reversible

Antarctic ice sheet mass loss and thus part of global sea-level rise is related to enhanced ice \nstream discharge to the fringing ice shelves. The transfer of ice into the ocean occurs via \niceberg calving and ice shelf basal melting. For decades the balance of both terms was \nassumed to be in favor of the calving, but recent results, based on remote sensing, revealed \nthat basal melting seems to be at least of similar importance. A recent model study indicates \nthat future atmospheric conditions in the southern Weddell Sea may switch the continental \nshelf, formerly dominated by the formation of cold saline waters, to one influenced by warm \nopen ocean waters with consequences for the basal mass flux and ice shelf/ice sheet \ndynamics. Here, we continue the simulations showing a warming of the Filchner-Ronne Ice \nShelf cavity, applying 20th-century atmospheric and basal mass flux forcing at different future \npoints in time. Our numerical study indicates that once the system reaches the 'warm phase', \na positive meltwater feedback stabilizes the shelf circulation such that only a reduction to \n20th century basal mass flux can stop warm water from penetrating onto the continental shelf \nand into the sub-ice cavity. This has implications for the future of the Antarctic Ice Sheet, \nsince a major decrease of basal melting only can be achieved by a significant disintegration \nof the floating portion of the ice sheet.