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Arctic on thin ice this fall

By Bill Scanlon, Rocky Mountain News (Contact)

Published April 30, 2008 at 12:42 p.m.
Updated April 30, 2008 at 12:42 p.m.

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CU-Boulder researchers are forecasting a three-in-five chance that the 2007 record low for Arctic sea ice extent will be broken again in 2008 because of warming temperatures and thinning ice.

Photo by Jim Maslanik/ University of Colorado

CU-Boulder researchers are forecasting a three-in-five chance that the 2007 record low for Arctic sea ice extent will be broken again in 2008 because of warming temperatures and thinning ice.

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The Arctic ice this September likely will be thinner than at any time since observations have been kept, a consequence of continued warming and thinner, younger ice, scientists predict.

That's bad news for polar bears, walruses and seals, as well as for global warming in general, but possibly good news for ships seeking an ice-free way across the Northwest Passage.

Just last year, the extent of Arctic sea ice was the smallest on record, decreasing by some 460,000 square miles, an area the size of Texas and California combined, say the scientists from the University of Colorado's Center for Astrodynamics Research.

There is a three in five chance that this September's minimum will be smaller than the record set last year, said Sheldon Drobot, who leads CCAR's Arctic Regional Ice Forecasting System group

When ice melts all the way through, it is replaced the next winter by younger ice, that starts thin and more easily melts.

Right now, 63 percent of the ice in the Arctic Sea is younger than normal, while only 2 percent of it is older than normal, Drobot said.

"The current Arctic ice cover is thinner and younger than at any previous time in our recorded history. And this sets the stage for rapid melt and a new record low."

Arctic sea ice, defined by the area of the ocean covered by at least 15 percent ice, has declined by roughly 10 percent in the past decade, the CU scientists say.

Change in Arctic sea ice is "one of the more compelling and obvious signs of climate change," Drobot said.

The declining ice "may well open up the Northwest Passage," which runs through the Bering Strait, the Chukchi, Sea, the Beaufort Sea and through the Canadian Archipelago to the Atlantic Ocean, said CU aerospace engineering professor Jim Maslanik.

"It also is quite possible that extensive ice-free conditions could develop at or near the North Pole."

Maslanik and Drobot, joined by CU colleagues and others from NASA, used passive microwave, visible infrared radar and laser satellite data to make their forecasts.

They develop "signatures" of individual ice sections roughly 15 miles square. They measured their thickness, roughness, snow depth and ridge characteristics, also using ocean buoys to measure and track the sea ice.

By tracking them over the seasons the past six years as they moved around the Arctic they develop a profile of what is happening.

The ice typically reaches its minimum in September at the end of the summer's warming.

Last summer, CU's ice forecasting group correctly forecast the 2007 record minimum. They'll provide updated forecasts throughout the spring and summer.

For more information visit the Web at http://ccar.colorado.edu/arifs.

Comments

  • April 30, 2008

    2:09 p.m.

    Suggest removal

    P_Denver writes:

    Yes -- global warming is real; it's documented

    No -- mankind is not materially affecting it one way or the other.

    Enviro-nuts -- if you disbelieve the above, answer the question: What caused all the global warming / cooling cycles that occurred before mankind was on the planet? Dinosaurs?

  • April 30, 2008

    3:30 p.m.

    Suggest removal

    ai3d writes:

    I agree with you P.
    I think it was volcanic activity and the shifting of the plates that caused the cooling of the earth, I think the global warming of the planet is the planet going back to its original state of being a tropical planet.
    The reason I think this is the pollutants that we put into the atmosphere are very similar to volcanic eruptions, so if anything I feel that the more pollutants we put into the atmosphere, the more likely we would have a colling effect. I am most likely wrong, but seeing as the "data" on global warming is not that old (compared to the billions of years the planet has been around)I don't really trust that info. If I study something for 10 minutes, does my info that I collect make it a staple of science? Well in terms of the planet, we have studied the "global warming" only about a millisecond of time.
    Another fun fact to go along with global warming. We have studied the sun. We know that suns explode. We don't know if/when it will happen. Let's get everyone in a frantic state of mind about it. Save our Sun!
    Chances are the Earth will be around long, long, long after humans destroy themselves.