Richard A. Lovett
for National Geographic News

December 29, 2006
A huge Canadian ice shelf 500 miles (800 kilometers) from the North
Pole has disintegrated, leaving a large floating island of ice stranded
30 miles (48 kilometers) offshore, scientists reported yesterday.

The entire 25.5-square-mile (66-square-kilometer) Ayles Ice Shelf broke
free from the northern coast of Ellesmere Island on August 13, 2005 The
event registered as a small earthquake on instruments stationed 150
miles (250 kilometers) away, Warwick Vincent of Quebec's Laval
University told the CanWest News Service.

"It's like a cruise missile came down and hit the ice shelf," Vincent
said. "It no longer exists."

The breakup was spotted on satellite photos shortly after it occurred,
but scientists have held back until now to make an announcement.

"We've spent the last year reconstructing exactly what happened," said
Luke Copland, a geographer with the University of Ottawa in Ontario,
Canada.

Sixteen months of study led Copland and colleagues to the conclusion
that several factors were at work, mostly related to global warming.

Long-Term Trend

Ice shelves are floating tongues of glaciers that fill bays in the
Arctic and Antarctic. The shelves are attached to land and are much
thicker than pack ice-freely floating masses of sea ice.

The Ayles ice shelf was believed to be 3,000 to 4,500 years old.

Before the breakup the Canadian Arctic had six ice shelves.

"Now there are five," Copland said. In the past hundred years, he
added, Canada's ice shelves have shrunk by 90 percent.