A study suggests possible causes for changes in the rate of ice mass loss from Greenland. The Gravity Recovery and Climate Experiment (GRACE) satellite mission recorded accelerating mass loss from Greenland from 2003 to mid-2013, when ice loss abruptly paused for 12-18 months. Michael Bevis and colleagues analyzed ice mass measurements from GRACE and the Greenland GPS Network during 2003-2016. The largest acceleration in mass loss prior to 2013 and the largest deviation from the trend during the 2013-2014 pause both occurred in southwest Greenland, an area largely devoid of marine-terminating glaciers, suggesting that the ice mass changes were driven largely by changes in surface mass balance (SMB) rather than changing rates of glacial discharge into the ocean. The accelerating ice loss and pause were associated with an increasingly negative and abrupt reversal of the summertime North Atlantic Oscillation (NAO) index. Regional climate model simulations of the period 2004-2012 are consistent with a negative NAO index reducing SMB through increased insolation and air temperatures and decreased snowfall. According to the authors, the results suggest that the Greenland Ice Sheet is highly sensitive to atmospheric forcing and that southwest Greenland could become a major contributor to sea level rise under continued climate warming.
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Article #18-06562: "Accelerating changes in ice mass within Greenland, and the ice sheet's sensitivity to atmospheric forcing," by Michael Bevis et al.
MEDIA CONTACT: Michael Bevis, Ohio State University, Columbus, OH; tel: 614-499-5966, 614-247-5071; e-mail: mbevis@osu.edu
Proceedings of the National Academy of Sciences