September 4, 2008 Warmer temps changing polar frontier? Play video

(NECN) - A chunk of ice shelf nearly the size of Manhattan has broken away from Ellesmere Island in Canada's northern Arctic, another dramatic indication of how warmer temperatures are changing the polar frontier, scientists said on Wednesday.

An Arctic ice shelf specialist at Trent University in Ontario said that the 4,500-year-old Markham Ice Shelf separated in early August and the 19-square-mile shelf is now adrift in the Arctic Ocean.

Warwick Vincent, director of Laval University's Center for Northern Studies and a researcher in the program ArcticNet said that this region was experiencing "extremely rapid climate change consistent with what all the predictions say about global climate change."

"It was a terrible thing to see, actually, this keeping in mind that these

are features that have been around for what we think is more then three

thousand years," he added.

Scientists said that two large sections of ice detached from the Serson Ice

Shelf, shrinking that ice feature by 47 square miles, or 60 percent, and

that the Ward Hunt Ice Shelf has also continued to break up, losing an

additional eight square miles.

Scientists reported last month that seven square miles of the 170-square-

mile and 130-feet-thick Ward Hunt shelf had broken off.

This comes on the heels of unusual cracks in a northern Greenland glacier,

rapid melting of a southern Greenland glacier, and a near record loss

Arctic sea ice this summer.

Earlier this year a 160-square mile chunk of an Antarctic ice shelf

disintegrated.

"When we've lost these ice shelves, we've lost those really kind of unique,

extreme, microbial environments that can't be replaced and once they've gone

they're basically gone forever," said Luke Copland, director of the

Laboratory for Cryospheric Research at the University of Ottawa.

Formed by accumulating snow and freezing melt-water, ice shelves are large

platforms of thick, ancient sea ice that float on the ocean's surface but

are connected to land.

Ellesmere Island was once entirely ringed by a single enormous ice shelf

that broke up in the early 1900s.

All that is left today are the four much smaller shelves that together cover

little more than 299 square miles.

Martin Jeffries of the US National Science Foundation and University of

Alaska Fairbanks said in a statement on Tuesday that the summer's ice shelf

loss is equivalent to over three times the area of Manhattan.

It totals 82 square miles, losses that have reduced Arctic Ocean ice cover

to its second-biggest retreat since satellite measurements began 30 years

ago.

During the last century, when ice shelves would break off, thick sea ice

would eventually form in their place.

The loss of these ice shelves means that rare ecosystems that depend on them

are on the brink of extinction, said Vincent.

Along with decimating ecosystems, drifting ice shelves and warmer

temperatures that will cause further melting ice pose a hazard to populated

shipping routes in the Arctic region, a phenomenon that Canada's Prime

Minister Stephen Harper seems to welcome.

Harper announced last week that he plans to expand exploration of the region's known oil and mineral deposits, a possibility that has become more

evident as a result of melting sea ice. It is the burning of oil and other

fossil fuels that scientists say is the chief cause of manmade warming and

melting ice.

Harper also said Canada would toughen reporting requirements for ships

entering its waters in the Far North, where some of those territorial claims

are disputed by the United States and other countries.