A new study by NASA and the European Space Agency (ESA) is showing that the melting rate for ice sheets in Greenland and Antarctica has increased over the past two decades. All together, the ice sheets are losing over three times as much ice as they were in the 90s.
The study, published today in the journal Science, combined data from satellites and aircraft, producing the most comprehensive assessment of ice sheet loss to date. The inclusion of satellite data makes the new study more than twice as accurate as the Intergovernmental panel on Climate Change's (IPCC) estimates of ice sheet loss, which were broad enough to actually encompass the possibility that antarctica was growing. Researchers estimate that the ice sheets have contributed 0.44 inces to global sea levels since 1992 - one-fifth of the total seal level rise over that period.
"What is unique about this effort is that it brought together the key scientists and all of the different methods to estimate ice loss," said Tom Wagner, NASA's cryosphere program manager. "It's a major challenge they undertook, involving cutting-edge, difficult research to produce the most rigorous and detailed estimates of ice loss from Greenland and Antarctica to date. The results of this study will be invaluable in informing the IPCC as it completes the writing of its Fifth Assessment Report over the next year."
The study found that ice sheet changes in Antarctica and Greenland were varied. Around two-thirds of the ice sheet loss came from Greenland.
"Both ice sheets appear to be losing more ice now than 20 years ago, but the pace of ice loss from Greenland is extraordinary, with nearly a five-fold increase since the mid-1990s," said Erik Ivins, a research scientist who co-coordinated the study from NASA's Jet Propulsion Laboratory. "In contrast, the overall loss of ice in Antarctica has remained fairly constant, with the data suggesting a 50-percent increase in Antarctic ice loss during the last decade."
(Image courtesy Ian Joughin, University of Washington)