The Greenland ice sheet is losing mass at an accelerating rate since 2000, according to a study. These results are described in a paper in Science by scientists of Utrecht University.
The Greenland ice sheet contains enough water to cause a global sea level rise of 7 metres. Since 2000, the ice sheet has lost about 1500 Gt in total (1 Gt is the mass of 1 cubic kilometre of water), representing about 0.5 mm of global sea level rise per year. This mass loss is equally distributed between increased iceberg production, driven by acceleration of Greenland’s fast-flowing outlet glaciers, and increased meltwater production at the ice sheet surface. Recent warm summers further accelerated the mass loss to 273 Gt per year in the period 2006-2008, which represents 0.75 mm of global sea level rise per year.
Snowfall
At the same time that surface melting started to increase around 1996, snowfall on the ice sheet also increased at approximately the same rate, masking surface mass losses for nearly a decade. Moreover, a significant part of the additional meltwater refroze in the cold snowpack that covers the ice sheet. Without these moderating effects, post-1996 Greenland mass loss would have been double the amount of mass loss observed now.
Method
Researchers used the Regional Atmospheric Climate Model (RACMO2/GR) at high (about 11 km) horizontal resolution to calculate surface processes over Greenland, satellite radar measurements to determine iceberg production and ice sheet mass loss from the Gravity Recovery and Climate Mission (GRACE) satellites.
This research is funded by the Netherlands Organisation for Scientific Research (NWO).
More information
Roy Keeris, Utrecht University Press Office, +31 (0)30 253 2411, r.b.keeris@uu.nl.