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Friday, September 28, 2012

Arctic Ice “Rotten” to the North Pole, scientist says

Arctic Ice “Rotten” to the North Pole, scientist says 

by Margaret Munro, The Vancouver Sun, September 21, 2012

When David Barber first headed to the Arctic in the 1980s, the ice would typically retreat just a few a kilometres offshore by summer’s end.

Now he and his colleagues have to travel more than 1,000 kilometres north into the Beaufort Sea to even find the ice.

And it’s nothing like the thick, impenetrable ice of Arctic lore.

This year the ice is “rotten” practically all the way to the North Pole, says Barber, a veteran Arctic researcher and director of the Centre for Earth Observation Science at the University of Manitoba.

“The multi-year ice, what’s left of it, is so heavily decayed that it’s really no longer a barrier to transportation,” he says, explaining how melt ponds have left much of the ice looking like Swiss cheese.

“You could have taken a ship right across the North Pole this year,” says Barber, whose research team was involved in a 36-day research cruise in the Beaufort on a Canadian Coast Guard ship.

The Arctic ice loss this summer shattered the record set in 2007. It hit the low point last weekend, covering 3.41 million square kilometers, or 24 per cent, of the Arctic Ocean, according to the U.S. National Snow and Ice Data Center, which has been tracking the ice with satellites since the late 1970s.

This year’s minimum is nearly 50-per -cent lower than the 1979 to 2000 average.

While the ice loss documented by the NSIDC is record-setting, Barber says the reality in the Arctic is ever worse.

The U.S. numbers are about “a 15% over-estimation of how much ice is actually there,” says Barber. That’s because satellites have trouble discerning ice conditions, he says, and will count heavily decayed ice as solid.

Regardless of who is doing the counting, he and other scientists consider the ice loss remarkable. And they say the impact will be felt far beyond the Arctic.

“It’s a globally significant change on our planet,” Barber said in an interview.

Many expect the Arctic could be “seasonally ice free” in the summer within a decade.

“I’d say 2020, plus or minus five years,” says Barber.

At that point the planet will be without its icy dome for the first time in eons.

A recent study that looked back 1,450 years indicates the current Arctic ice melt has already eclipsed the medieval warm period of about 1,000 years ago.

“The level that we are at now is unprecedented over the last 1,450 years,” says Barber. “And as far as we know we have to go back over a million years to find a period when the Arctic was seasonally ice-free in the summer.”

The Arctic melt is also happening faster than at any time in the planet’s past, says Barber, noting that the geological and historical records indicate it took tens of thousands of years to move to a seasonally-ice-free Arctic in the past.

“Now we are getting there in tens of years, not tens of thousands of years,” he says. “And we don’t know how the Earth is going to respond because we have never seen such a rapid change before.”

Environmentalists and scientists were quick this week to call for cuts in greenhouse gas emissions to slow the global warming that is melting the ice.

James Hansen, a prominent and outspoken NASA climate scientist, said the Arctic melting shows the risks society is running by failing to limit emissions produced by burning oil, coal and gas.

“The scientific community realizes that we have a planetary emergency,” said Hansen. “It’s hard for the public to recognize this because they stick their head out the window and don’t see that much going on.”

“We can see very viscerally in the ice how warming temperatures are changing the Earth’s environment,” Walt Meier, of U.S. NSIDC told a media briefing this week.

He and other researchers say the Arctic melt is just the tip of the iceberg.

Rising global temperaturess are also transforming northern ecosystems, melting permafrost and shattering ancient ice shelves. Giant icebergs from the disintegrating shelves are now sailing through Canada’s Beaufort Sea, creating a new hazard for oil rigs, says Barber, whose team is involved in national and international efforts to get a read on the new Arctic reality and it implications.

Global warming is also altering the oceans. More warm, salty water from the North Atlantic is flowing in the Arctic, and may be helping speed up ice melt.

Another concern is rising sea level. Arctic ice is already in the ocean so does not raise sea level when it melts. But the extra heat being absorbed by the Arctic Ocean due to the ice loss appears to be accelerating melting of the Greenland ice sheet, which does raise sea levels.

The growing expanse of open Arctic water, which traps a lot more of the sun’s heat than reflective ice, is also altering polar storms and winds, says Barber. And this in turn may be linked to the increasingly strange and extreme weather seen from New Orleans to Newfoundland.

Statistical evidence suggests the changes in the Arctic are slowing the jet stream and pushing it further south, leading to more “persistent” climate patterns – be it rain, drought or sunshine, he says. The challenge now is to understand the physical mechanism.

”Our society, our civilization and how we live our lives – it’s all predicated on a stable climate system,” says Barber, who notes that the planet has undergone abrupt climate change in the past and could do so again.

“The take-home message for people is we are running an experiment with Earth’s climate system,” says Barber, and greenhouse gases are contributing to enormous change – like melting Arctic ice – that is happening much faster than anticipated.

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