The West Antarctic ice sheet has a portion that is grounded on the Antarctic continent below sea level but cantilevered out into the ocean. If this sheet should break off and separate from the continent and plunge into the sea, global sea levels would rise by 5 to 6 m. The sheet has shown rapid change in recent decades, and satellite observations are being used to monitor its mass balance through measurements of ice flow velocity. Joughin and Tulaczyuk (2002) find strong evidence, in contrast to previous estimates of ice mass thinning, that the sheet seems to be thickening, which, if true, would signal an end to the Holocene retreat of the associated ice streams. The limited length of the observational record and natural variability together call for continued and improved measurements following the procedures of Joughin and Tulaclzyk (2002).
Reference
Joughin, I., and S. Tulaczyk, 2002: Positive mass balance of the Ross ice streams, West Antarctica. Science, 295, 476-480.