Jonathan Bamber, University of Bristol, Bristol, United Kingdom, Michiel Van den Broeke, University of Utrecht, Utrecht, Netherlands, Curt Davis, University of Missouri, Columbia, and Eric Rignot, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109.
Large uncertainties remain in estimating and predicting Antarctica’s contribution to global sea level. Climate warming may enhance snowfall in the interior but increase glacier discharge at the coast as warmer air and ocean temperatures erode buttressing ice shelves and reduce backforce resistance to grounded ice flow. Recent work suggests that changes in integrated snowfall over continental Antarctica are insignificant. We use satellite interferometric synthetic-aperture radar observations from 1992 to 2006 to calculate total ice sheet discharge into the ocean, and compare it with interior snow accumulation from a regional atmospheric climate model. We deduce a net ice sheet loss of 141+/-59 Gt/yr, equivalent to 0.4+/-0.2 mm/yr sea level rise. The loss is concentrated in the Bellingshausen and Amundsen seas sector of West Antarctica and the northern tip of the Antarctic Peninsula. Adding satellite radar altimeter data, we attribute almost all loss to glacier acceleration conditioned by thinning of ice shelves.
