· Losses contradict earlier climate forecast
· New calculations based on satellite readings
The Antarctic ice sheet, which contains 90% of the world’s ice, has lost significant mass in the past few years. The discovery comes as a surprise to scientists, who thought that the continent would gain ice this century because of increased snowfall in a warming climate.
A research team from the University of Colorado used satellite data to estimate that the ice sheet is losing up to 36 cubic miles of ice every year. By comparison, a city the size of Los Angeles uses one cubic mile of fresh water every year.
“This is the first study to indicate the total mass balance of the Antarctic ice sheet is in significant decline,” said Professor Isabella Velicogna of the Cooperative Institute for Research in Environmental Sciences (Cires).
Most of the ice loss measured by Professor Velicogna – around 35 cubic miles – came from the West Antarctic ice sheet.
According to the British Antarctic Survey, if the West Antarctic ice sheet – which is about eight times smaller in volume than the East Antarctic ice sheet -melted completely, global sea levels would rise by more than six metres (20 ft).
At twice the size of Australia, Antarctica is the Earth’s fifth largest continent and contains 70% of its total fresh water resources. An ice sheet covers about 98% of the continent with an average thickness of about 2,000 metres (6,500 ft).
Understanding how the mass of this ice sheet changes over time is important in working out how sea levels around the world change, with obvious impacts on society. In a paper published online today in Science Express, the researchers said that there have been significant improvements in monitoring the ice sheet in the last few years but that there is also confusion: many studies give contrasting estimates of the changes to Antarctica.
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