Friday, December 29, 2006

Ice shelf collapses in Canada

Guardian Unlimited reports that a Giant ice island breaks off Arctic shelf. You'll note those magic words that I've been pointing out as a common phrase in all climate change news: "What surprised us was how quickly it happened."
An ice island the size of a small city is adrift in the Arctic after breaking free from one of Canada's largest ice shelves, scientists said today.

The ice island is 37 metres (120ft) thick and measures 9 miles by 3 miles, according to the CanWest News Service. It broke clear from Ellesmere island, about 500 miles south of the North Pole, 16 months ago, triggering tremors so powerful they were picked up by earthquake monitors 155 miles away.

Scientists have only just released details about the island after piecing together the break-up from seismic monitors and satellite images.

Within days of breaking free from its fjord on Ellesmere, the floating ice island had drifted a few miles offshore. It travelled west for 31 miles until it froze into the sea ice in early winter.

The island was part of the Ayles ice shelf, one of six major ice shelves in Canada's Arctic. Scientists believe the shelf's break-up - the largest of its kind in the Canadian Artic in 30 years - is the result of global warming.

The Artic expert Warwick Vincent, of Laval University in Quebec, said he had never seen such a dramatic loss of sea ice and suggested the break-up indicated that climate change was accelerating.

Dr Vincent, who has travelled to the ice island, said yesterday: "This is a dramatic and disturbing event. It shows that we are losing remarkable features of the Canadian North that have been in place for many thousands of years. We are crossing climate thresholds, and these may signal the onset of accelerated change ahead.

"We think this incident is consistent with global climate change. We aren't able to connect all of the dots ... but unusually warm temperatures definitely played a major role."

He said Canada's remaining ice shelves were 90% smaller than when they were first discovered 100 years ago.

...
Using US and Canadian satellite images, as well as data from seismic monitors, Professor Copland discovered that the ice shelf collapsed on the afternoon of August 13 2005.

"What surprised us was how quickly it happened," he said. "It's pretty alarming. Even 10 years ago scientists assumed that when global warming changes occur that it would happen gradually so that perhaps we expected these ice shelves just to melt away quite slowly, but the big surprise is that, for one they are going, but secondly, that when they do go, they just go suddenly, it's all at once, in a span of an hour."
More from CNN: Ancient ice shelf breaks free from Canadian Arctic:
A giant ice shelf the size of 11,000 football fields has snapped free from Canada's Arctic, scientists said.

The mass of ice broke clear 16 months ago from the coast of Ellesmere Island, about 800 kilometers (497 miles) south of the North Pole, but no one was present to see it in Canada's remote north.
...
The Ayles Ice Shelf, roughly 66 square kilometers (41 square miles) in area, was one of six major ice shelves remaining in Canada's Arctic.

Scientists say it is the largest event of its kind in Canada in 30 years and point their fingers at climate change as a major contributing factor.

And this from the Montreal Gazette Ice shelf collapse sends chill:
Canada's North changing. Global warming suspected cause of huge breakup on Ellesmere Island
An ancient ice shelf has cracked off northern Ellesmere Island, creating an enormous 66-square-kilometre ice island and leaving a trail of icy blocks in its wake.

"It really is incredible," said Warwick Vincent of Universite Laval, one of the few people to have laid eyes on the scene. "It's like a cruise missile has come down and hit the ice shelf."
...
"We are seeing incredible changes," said Vincent, whose group is studying the island's disappearing ice shelves and their unique ecosystems. "People talk of endangered animals - well, these are endangered landscape features and we're losing them."

The Ayles ice shelf was one of six ice shelves left in Canada, remnants of a vast icy fringe that used to cover the top end of Ellesmere.

Scientists consider the Canadian shelves, located about 800 kilometres south of the North Pole, sentinels that reflect the accelerating change in the Arctic.

In 2002, one of Vincent's graduate students, Derek Mueller, discovered that Ellesmere's Ward Hunt ice shelf had cracked in half. The researchers have also seen the sudden collapse of ice dams and the draining of 30-kilometre-long lakes into the sea.

Technorati Tags: , , , ,

No comments:

Post a Comment