The 66-square-kilometer (25.5-square-mile) ice island tore away from Ellesmere, a huge strip of land in the Canadian Arctic close to Greenland.

The break occurred in August 2005 and was so violent that it caused tremors that were detected by Canadian seismographs 250 kilometers (155 miles) away, but at the time no one was able to pinpoint what had happened.

The Canadian Ice Service contacted geographer Luke Copland of the University of Ottawa, who reconstructed the chain of events by piecing together data from the seismic readings and satellite images provided by Canada and the United States.

"This loss is the biggest in 25 years, but it continues the loss that occurred within the last century," Copland told AFP, saying 90 percent of the the ice cover had been lost since the area was discovered in 1906.

"What is important and interesting is that it is sudden, quite large even," he said.

"In the past, we looked to climate change (and) thought perhaps ice shelves ... would just melt apart by losing a little piece day by day, but it now seems that when you reach some kind of threshold, when you reach that level, the whole thing just breaks apart."

Following the discovery, biologist Warwick Vincent of Laval University in Quebec, visited the icy waters of the Arctic to view the "new island."

Vincent said he had seen nothing like it in the past decade. "It really is incredible," Vincent was quoted as saying by the newspaper National Post.

"People talk of endangered animals -- well, these are endangered landscape features, and we are losing them," he said.

Louis Fortier, scientific director of ArcticNet, a Canadian Artic research network, said the massive breakoff signaled a rise in Arctic warming.

"This Ellesmere ice shelf was sheltering unique ecosystems on the planet; there are freshwater lakes which were forming above and under the ice shelf," Fortier told AFP.

"The breakup of the ice cover on Ellesmere Island has been going on for 12,000 years, but it seems to have accelerated in recent years which is another indicator, among many others, of warming of the entire Arctic cryosphere," he said, referring to low-temperature elements of weather such as ice and snow.

Canada conducts land, sea and aerial observations of the Arctic ice surface, but often these studies target certain areas and ignore vast, uninhabited areas, the environment ministry says, making satellite images crucial.

The sudden formation of a "new island" in the Arctic "is a symptom among a cluster of symptoms of global warming, the most important evidently being the spectacular redcution in the extent and thickness of the Arctic ice field," Fortier said.

In an article published in December, Canadian and US researchers predicted that by 2040 Arctic Ocean ice will nearly disappear in the summer off the north coast of Greenland and Canada, opening a maritime corridor that would reduce shipping time between Europe and Asia.

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