Scientists find Antarctic ice shrank significantly

WASHINGTON (Reuters) - The Antarctic ice sheet shrank significantly during the past three years, according to the findings of a NASA study released on Thursday.

Using data from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (GRACE), scientists concluded that Antarctica's ice sheet decreased by about 152 cubic kilometers annually from April 2002 to August 2005.

The estimated loss was enough to raise global sea level about 1.2 millimeters (0.04724 inch) during the study period or about 13 percent of the overall observed sea level rise for the same period, according to the study conducted by researchers at the University of Colorado, Boulder.

That is about how much water the United States consumes in three months and represents a change of about 0.4 millimeter (0.01575 inch) per year to global sea level rise, the study concluded.

Most of the mass loss came from the West Antarctic ice sheet, the study said.

"Antarctica is Earth's largest reservoir of fresh water," researcher Isabella Velicogna said.

"The GRACE mission is unique in its ability to measure mass changes directly for entire ice sheets and can determine how Earth's mass distribution changes over time," she said.

"Because ice sheets are a large source of uncertainties in projections of sea level change, this represents a very important step toward more accurate prediction," Velicogna said.

Measuring variations in Antarctica's ice sheet mass is difficult because of its size and complexity.

Twin GRACE satellites, which can track tiny changes in Earth's gravity field, monitored the entire Antarctic ice sheet as a whole.

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