A year ago US scientists caused alarm when they predicted the Arctic Ocean could be free of summer ice by 2030, but now researchers say those estimates were too conservative.
A US-based team has told a conference in California that the northern polar waters could be ice-free in summer by 2013.
This year's northern summer melt in the Arctic reduced the ice cover to just over 4 million square kilometres, the smallest ever amount recorded in modern times.
It is this kind of data that has led researchers to say previous estimates of when the Arctic waters will be completely free of ice in summer are far too conservative.
Professor Wieslaw Maslowski from the Naval Postgraduate School in Monterey in California says scientists are now moving the date closer.
He has been presenting his work to a meeting of the American Geophysical Union (AGU).
"We're just moving this date closer and closer to us simply because I believe what is happening, the system in the Arctic Ocean is very complex and from a mathematical point of view, it's non-linear," Professor Maslowski said.
"So there is a feedback loop that may accelerate this harder in a linear sense ... which is simply where you remove ice, you heat, you warm the ocean, which can melt more ice even further, and those kind of feedbacks are actually in place in Arctic right now, which is possibly causing this accelerated melt."
Two major impacts
Professor Maslowski says there are two major impacts from the climate point of view.
"One impact is that if we remove the sea ice, which is a very reflective ice cover in the high northern latitudes, we'll be observing much more solar radiation into the ocean and the feedback from the warmer ocean," he said.
"The ocean will expand so we may see some associated increase of sea level due to the warmer ocean in the Arctic.
"The second important thing to keep in mind is that if we melt all this ice that is currently out there in the Arctic, every summer we will be exporting a lot of fresh water, much more than currently, into the North Atlantic.
"And this fresh water export from the Arctic may affect the ocean circulation, which in turn can effect regional or global climate."
When he accepted his Nobel Peace Prize earlier this week, former US vice-president and environmental campaigner Al Gore referred to Professor Maslowski's work.
"Last September 21, as the Northern Hemisphere tilted away from the sun, scientists reported with unprecedented alarm that the north polar ice cap is in their words, 'falling off a cliff'," Mr Gore said.
"One study estimated that it could be completely gone during summer in less than 22 years.
"Another new study to be presented by US Navy researchers later this week warns it could happen in as little as seven years - seven years from now."
As the world meets in Bali, Mr Gore went on to repeat his calls for tough action on climate change.
But the trouble is, it looks increasingly like it may already be too late.
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