Arctic Ocean Free of Ice in Summer Perhaps in a Few Years

Sea ice in the Arctic is disappearing at a far greater rate than previously expected according to latest dedicated satellite data.

Preliminary results from the European Space Agency's CryoSat-2 probe indicate that 900 cubic kilometres of summer sea ice has disappeared from the Arctic ocean over the past year.

This rate of loss is 50% higher than most scenarios outlined by polar scientists and suggests that global warming, triggered by rising greenhouse gas emissions, is beginning to have a major impact on the region. In a few years the Arctic ocean could be free of ice in summer, triggering a rush to exploit its fish stocks, oil, minerals and sea routes.

Using instruments on earlier satellites, scientists could see that the area covered by summer sea ice in the Arctic has been dwindling rapidly. But the new measurements indicate that this ice has been thinning dramatically at the same time. For example, in regions north of Canada and Greenland, where ice thickness regularly stayed at around five to six metres in summer a decade ago, levels have dropped to one to three metres.

"Preliminary analysis of our data indicates that the rate of loss of sea ice volume in summer in the Arctic may be far larger than we had previously suspected," said Dr Seymour Laxon, of the Centre for Polar Observation and Modelling at University College London (UCL), where CryoSat-2 data is being analysed. "Very soon we may experience the iconic moment when, one day in the summer, we look at satellite images and see no sea ice coverage in the Arctic, just open water."

CryoSat-2 is the world's first satellite to be built specifically to study sea-ice thickness and was launched on a Dniepr rocket from Baikonur cosmodrome, Kazakhstan, on 8 April 2010. Previous Earth monitoring satellites had mapped the extent of sea-ice coverage in the Arctic. However, the thickness of that ice proved more difficult to measure.

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