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Sunday, August 10, 2008

Arctic meltdown is speeding up

Scientists warn that the North Pole could be free of ice in just five years' time instead of 60

by Robin McKie, science editor, The Observer, Sunday, August 10 2008

Ice at the North Pole melted at an unprecedented rate last week, with leading scientists warning that the Arctic could be ice-free in summer by 2013.

Satellite images show that ice caps started to disintegrate dramatically several days ago as storms over Alaska's Beaufort Sea began sucking streams of warm air into the Arctic.

As a result, scientists say that the disappearance of sea ice at the North Pole could exceed last year's record loss. More than a million square kilometres melted over the summer of 2007 as global warming tightened its grip on the Arctic. But such destruction could now be matched, or even topped, this year.

'It is a neck-and-neck race between 2007 and this year over the issue of ice loss,' said Mark Serreze, of the U.S. National Snow and Ice Data Center in Boulder, Colorado. 'We thought Arctic ice cover might recover after last year's unprecedented melting -- and indeed the picture didn't look too bad last month. Cover was significantly below normal, but at least it was up on last year.

'But the Beaufort Sea storms triggered steep ice losses, and it now looks as if it will be a very close call indeed whether 2007 or 2008 is the worst year on record for ice cover over the Arctic. We will only find out when the cover reaches its minimum in mid-September.'

This startling loss of Arctic sea ice has major meteorological, environmental and ecological implications. The region acts like a giant refrigerator that has a strong effect on the northern hemisphere's meteorology. Without its cooling influence, weather patterns will be badly disrupted, including storms set to sweep over Britain.

At the same time, creatures such as polar bears and seals -- which use sea ice for hunting and resting -- face major threats. Similarly, coastlines will no longer be insulated by ice from wave damage and will suffer erosion, as is already happening in Alaska.

Other environmental changes are likely to follow. Without sea ice to bolster them, land ice -- including glaciers -- could topple into the ocean and raise global sea levels, threatening many low-lying areas, including Bangladesh and scores of Pacific islands. In addition, the disappearance of reflective ice over the Arctic means that solar radiation would no longer be bounced back into space, thus heating the planet even further.

On top of these issues, there are fears that water released by the melting caps will disrupt the Gulf Stream, while an ice-free Arctic in summer offers new opportunities for oil and gas drilling there -- and for political disputes over territorial rights.

What really unsettles scientists, however, is their inability to forecast precisely what is happening in the Arctic, the part of the world most vulnerable to the effects of global warming. 'When we did the first climate change computer models, we thought the Arctic's summer ice cover would last until around 2070,' said Professor Peter Wadhams of Cambridge University. 'It is now clear we did not understand how thin the ice cap had already become -- for Arctic ice cover has since been disappearing at ever increasing rates. Every few years we have to revise our estimates downwards. Now the most detailed computer models suggest the Arctic's summer ice is going to last for only a few more years -- and given what we have seen happen last week, I think they are probably correct.'

The most important of these computer studies of ice cover was carried out a few months ago by Professor Wieslaw Maslowski of the Naval Postgraduate School in Monterey, California. Using U.S. Navy supercomputers, his team produced a forecast which indicated that by 2013 there will be no ice in the Arctic -- other than a few outcrops on islands near Greenland and Canada -- between mid-July and mid-September.

'It does not really matter whether 2007 or 2008 is the worst year on record for Arctic ice,' Maslowski said. 'The crucial point is that ice is clearly not building up enough over winter to restore cover and that when you combine current estimates of ice thickness with the extent of the ice cap, you get a very clear indication that the Arctic is going to be ice-free in summer in five years. And when that happens, there will be consequences.'

This point was backed by Serreze. 'The trouble is that sea ice is now disappearing from the Arctic faster than our ability to develop new computer models and to understand what is happening there. We always knew it would be the first region on Earth to feel the impact of climate change, but not at anything like this speed. What is happening now indicates that global warming is occurring far earlier than any of us expected.'

Link to article:


FredT said...

Hi Tenney,

More on this (sudden) (unexpected?) acceleration here :

The Canadian Ice Service is reporting an "unprecedented" opening of waters in the Beaufort Sea north of the Yukon-Alaska border, where expected increases in ship traffic have just prompted the U.S. Coast Guard to establish two new outposts on Alaska's north coast to strengthen its vessel-monitoring and search-and-rescue capabilities.

"We've never seen any kind of opening like this in history," senior ice forecaster Luc Desjardins said of the Beaufort's exceptional loss of ice this summer. "It is not only record-setting, it's unprecedented. It doesn't resemble anything that we've observed before."

Mr. Desjardins says there's also a "very good likelihood" that the best-known route of the Northwest Passage -- from north of Baffin Island to the Beaufort Sea south of Victoria Island -- will soon become fully navigable for the third consecutive summer, a year after the fabled shipping conduit drew global attention by opening more completely than ever.

"It takes less solar energy to dissipate and melt that ice," says Mr. Desjardins. "So we potentially could reach a new minimum. Time will tell if we are going to be approaching the 2007 sea-ice retreat -- there still five weeks (of melting) to go."

I'm trying to reach a complete source for this, without success so far.


Anonymous said...

Dear FredT,

Thank you for your comment. I do not think that the ice loss is unexpected. What was unexpected was the cooler weather that persisted over the Arctic in July. That cool spell is over, and if the warm air from northwestern Canada and Siberia continues to work its way into the Arctic Sea area, that thin ice is going to disappear very quickly -- well, it already is, the melt over the last two or three days has been incredible. See my updated post on the melt (August 9 post).



Anonymous said...

Sorry, the post of Sunday, August 10, has the updated graphics and satellite photos.

Owl said...

Not sure where this story is originating - Arctic sea-ice area has been running pretty consistently at 850k sqkm greater than last year. It may exceed 2005 to take second place. August 1/2 and August 6/7 had additional melt but they've both been followed by slower losses (cloudy weather). The forecast of ice-free within five years is reasonable - it's only going to take one hot summer to finish off the thin cover. But this summer won't equal last summer unless there is a freak weather event, imo.

Anonymous said...

Dear Owl,

Thanks for your comment.

I think the main thing these days is the volume of the ice -- extent no longer gives a very true picture.



Owl said...

Tenney, the average thickness this year to last year is about the same (1.3metres), so the surface float is most of what's left to measure. The article is about comparable losses. It's just not showing up that way: ...