More data: Needed for antarctic, Greenland ice loss estimates

Satellite observation of global ice sheet loss is currently too short to separate long-term trends from short-term natural variability, researchers say. In a study published in the journal Nature Geoscience, Bert Wouters of the University of Colorado, Boulder, and colleagues compared nine years of satellite data from the Gravity Recovery and Climate Experiment with reconstructions of about 50 years of mass changes to the ice sheets of Antarctica and Greenland. The ability to accurately predict any accelerating trend in mass loss depends on the length of the record, they said, and while there may be almost enough satellite data to detect an acceleration in mass loss of the antarctic ice sheet, a truly dependable prediction could require 10 more years of observation, while doing the same for Greenland may require another 20 years. Based on their findings, the researchers said, caution should be exercised in making any assertions that accelerations in melt will be sustained into the future. Care should be taken in extrapolating current measurements to predict future sea-level rise, they said.