Tuesday, January 02, 2007

shrinkage

"A huge portion of ice broke off from Canada’s Ellesmere Island last year, but it was not until this year that scientists, using satellite photos, realized the full dimension of the catastrophe.

Ellesmere Island, lying in the Canadian territory of Nunavut, is the most northerly of the Canadian Arctic islands. It comprises an area of 196,235 km² (75,767 square miles), making it the world's tenth largest island and Canada's third largest island.

The Ellesmere ice shelf reduced by 90 percent in the twentieth century due to global warming, leaving the separate Alfred Ernest, Ayles, Milne, Ward Hunt, and Markham Ice Shelves.

Now, satellite images are showing that a massive rupture in the Ayles Ice shelf (which was one of six major ice shelves in Canada) led to the forming of a natural icy island, which actually floats in the Arctic Ocean.

The Ayles Ice Shelf was approximately 41 square miles in size, and was located approximately 500 miles south of the North Pole, off the northern coast of Ellesmere Island, Nunavut.

The scientists discovered that AIS broke clear 16 months ago from the coast of Ellesmere Island, and within an hour of breaking free, the shelf had formed as a new ice island, leaving a trail of icy boulders floating in its wake.

Warwick Vincent of Laval University, who studies Arctic conditions, traveled to the newly formed ice island and could not believe what he saw.

“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,” Vincent said. “We are crossing climate thresholds, and these may signal the onset of accelerated change ahead.”

“It is consistent with climate change,” Vincent said, adding that the remaining ice shelves are 90 percent smaller than when they were discovered in 1906. “We aren’t able to connect all of the dots … but unusually warm temperatures definitely played a major role.”

Luke Copland, assistant professor at the University of Ottawa's geography department, said: "The Arctic is all frozen up for the winter and [the floe] it's stuck in the sea ice about 50 km (30 miles) off the coast. The risk is that next summer, as that sea ice melts, this large ice island can then move itself around off the coast and one potential path for it is to make its way westward toward the Beaufort Sea, and the Beaufort Sea is where there is lots of oil and gas exploration, oil rigs and shipping."

The ice chunk is now 19 square miles in size. Initially, it was larger than Manhattan which only has about 24 sq. miles. It is basically a floating ice island. Only five Canadian ice shelves remain connected to land.

Copland said the break was likely due to a combination of low accumulations of sea ice around the mass's edges as high winds blew it away, as well as one of the Arctic's warmest temperatures on record. The region was 3 degrees Celsius (5.4 degrees F) above average in the summer of 2005, he said, according to Reuters.

"It's hard to tie one event to climate change, but when you look at the longer-term trend, the bigger picture, we've lost a lot of ice shelves on northern Ellesmere in the past century and this is that continuing," he said. "And this is the biggest one in the last 25 years."

Previous studies have shown that the Arctic water fails to freeze back in winter, a natural process that has been going on for millennia. According to scientists, 2006 is the second year in a row when the sea ice covering the Arctic Ocean didn't manage to reach its normal winter size, thus leading to an overall shrinking. Climate experts say that this is due to rapid global climate change and will cause a serious expansion of open water in the upcoming summer."

1 Comments:

At 1/02/2007 1:52 PM, Blogger dmc said...

strange to see these posts today, I've just posted on my blog my 2007 season goals which are more focused on bringing attention to global warming than racing. Glad to see someone else cares too.

 

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