Mega Freezer

One of Earth's largest icehouses, Greenland is melting much faster than expected, new satellite data indicates. The mega freezer locks up 10 percent of Earth's ice, the melting of which could raise global sea level by as much as 23 feet.

The recent measurements counter predictions made my climate scientists just a few years ago that estimated Greenland's ice would have minimal impact on sea level in the coming decades.

These new data come from the Gravity Recovery and Climate Experiment (GRACE). The twin satellites, launched in March 2002, circle the globe using gravity measurements to map changes in Earth's mass. Since mass and gravity are positively correlated, an increase in the gravitational force indicates a bump in mass. In that way, these measurements reveal the type and amount of material on Earth's surface. For instance, rock is denser than water, and water in its liquid phase is denser than solid ice.

Gravity measurements from 2002 to 2006 revealed Greenland lost between 36 and 60 cubic miles of ice per year, or enough to boost sea level by up to 0.019 inches a year. Global sea level rise has averaged 0.1 inches each year since 1993. The scientists, including Isabella Velicogna and John Wahr of the University of Colorado, Boulder, say Greenland's increasing contribution to sea level rise can't be overlooked.

--LiveScience Staff

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Credit: NASA/JPL