Antarctic ice sheet lost size in past 3 years, NASA says

The Antarctic ice sheet has shrunk significantly during a recent three-year period, 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 kilometres annually from April 2002 to August 2005.

The estimated loss was enough to raise global sea level about 1.2 millimetres during the study period or about 13 per cent of the overall observed sea level rise for the same period, according to the study conducted by researchers at the University of Colorado in Boulder.

That is about how much water the United States consumes in three months and represents a change of about 0.4 millimetre per year to the rise of the global sea level, 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.

"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.

Source: China Daily



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