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solonavi 11 March 2008 Arctic, Climate, Global Warming, Technology 394 views No Comment Print This Post  Email This Post

BBC

Scientists in the US have presented one of the most dramatic forecasts yet for the disappearance of Arctic sea ice.

Their latest modelling studies indicate northern polar waters could be ice-free in summers within just 5-6 years.

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Summer melting this year reduced the ice cover to 4.13 million sq km, the smallest ever extent in modern times.

Remarkably, this stunning low point was not even incorporated into the model runs of Professor Maslowski and his team, which used data sets from 1979 to 2004 to constrain their future projections.

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Professor Maslowski’s group, which includes co-workers at Nasa and the Institute of Oceanology, Polish Academy of Sciences (PAS), is well known for producing modelled dates that are in advance of other teams.

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Professor Peter Wadhams from Cambridge University, UK, is an expert on Arctic ice. He has used sonar data collected by Royal Navy submarines to show that the volume loss is outstripping even area withdrawal, which is in agreement with the model result of Professor Maslowski.

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He cited the ice-albedo feedback effect in which open water receives more solar radiation, which in turn leads to additional warming and further melting.

Professor Wadhams said the Arctic was now being set up for further ice loss in the coming years.

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The US National Snow and Ice Data Center (NSIDC) collects the observational data on the extent of Arctic sea ice, delivering regular status bulletins. Its research scientist Dr Mark Serreze was asked to give one of the main lectures here at this year’s AGU Fall Meeting.

Discussing the possibility for an open Arctic ocean in summer months, he told the meeting: “A few years ago, even I was thinking 2050, 2070, out beyond the year 2100, because that’s what our models were telling us. But as we’ve seen, the models aren’t fast enough right now; we are losing ice at a much more rapid rate.

“My thinking on this is that 2030 is not an unreasonable date to be thinking of.”

And later, to the BBC, Dr Serreze added: “I think Wieslaw is probably a little aggressive in his projections, simply because the luck of the draw means natural variability can kick in to give you a few years in which the ice loss is a little less than you’ve had in previous years. But Wieslaw is a smart guy and it would not surprise me if his projections came out.”

: The US NSIDC monitors Arctic sea ice extent on a five-day mean. The 16 September 2007 record low falls below the previous minimum set on 20-21 September 2005, by an area roughly the size of Texas and California combined, or nearly five UKs.