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Tandem · 09-22-2003, 05:22 PM

Scientists in the United States and Canada say the largest ice shelf in the Arctic, a solid feature for 3,000 years, has broken up.

They said the Ward Hunt Ice Shelf, on the north coast of Ellesmere Island in Canada's Nunavut territory, broke into two main parts themselves cut through with fissures.

The researchers report a freshwater lake drains into the sea.

Large ice islands also calved off from the shelf and some are large enough to be dangerous to shipping and to drilling platforms in the Beaufort Sea.

They say local warming of the climate is to blame, adding that they did not have the evidence needed to link the melting ice to the steady, planet-wide climate change known as global warming.

Warwick Vincent and Derek Mueller of Laval University in Quebec City, Canada, and Martin Jeffries of the University of Alaska Fairbanks lived at the site, flew over it and used radar satellite imaging for their study.

Only 100 years ago the whole northern coast of Ellesmere Island, which is the northernmost land mass of North America, was edged by a continuous ice shelf.

The researchers say about 90 per cent of it is now gone.

A similar trend in the Antarctic has caused the break-up of huge ice shelves there.

"There's a regional trend in warming that cycles back 150 years," Dr Mueller said.

"I am not comfortable linking it to global warming ... it is difficult to tease out what is due to global warming and what is due to regional warming."

Climate change has affected ocean temperature, salinity and flow patterns, which also influence the break-up of ice shelves in the Antarctic.

Warmer temperatures weaken the ice, leaving it vulnerable to changed currents and other forces.

"It's not just as simple as it gets x degrees warmer and the ice melts this much," Mueller said.

--Reuters

09-22-2003, 05:22 PM	#1 (permalink)
Tandem Insane Location: Brisbane, Australia	Largest Arctic ice shelf breaks up: report Scientists in the United States and Canada say the largest ice shelf in the Arctic, a solid feature for 3,000 years, has broken up. They said the Ward Hunt Ice Shelf, on the north coast of Ellesmere Island in Canada's Nunavut territory, broke into two main parts themselves cut through with fissures. The researchers report a freshwater lake drains into the sea. Large ice islands also calved off from the shelf and some are large enough to be dangerous to shipping and to drilling platforms in the Beaufort Sea. They say local warming of the climate is to blame, adding that they did not have the evidence needed to link the melting ice to the steady, planet-wide climate change known as global warming. Warwick Vincent and Derek Mueller of Laval University in Quebec City, Canada, and Martin Jeffries of the University of Alaska Fairbanks lived at the site, flew over it and used radar satellite imaging for their study. Only 100 years ago the whole northern coast of Ellesmere Island, which is the northernmost land mass of North America, was edged by a continuous ice shelf. The researchers say about 90 per cent of it is now gone. A similar trend in the Antarctic has caused the break-up of huge ice shelves there. "There's a regional trend in warming that cycles back 150 years," Dr Mueller said. "I am not comfortable linking it to global warming ... it is difficult to tease out what is due to global warming and what is due to regional warming." Climate change has affected ocean temperature, salinity and flow patterns, which also influence the break-up of ice shelves in the Antarctic. Warmer temperatures weaken the ice, leaving it vulnerable to changed currents and other forces. "It's not just as simple as it gets x degrees warmer and the ice melts this much," Mueller said. --Reuters