for National Geographic News
A Manhattan-size Arctic ice shelf that broke away from Canada's Ellesmere Island in August 2005 has broken in half, satellite pictures reveal.
Aided by record low Arctic sea ice levels this past summer, the Ayles Ice Island had drifted unusually far south.
Scientists had expected the originally 26-square-mile (66-square-kilometer) iceberg to remain in the Arctic Ocean, rotating with the currents, as other ice islands have done in the past.
"What's different this year is it has made its way down into Queen Elizabeth Islands, out of the Arctic Ocean," said Luke Copland, a geographer at the University of Ottawa in Ontario, Canada. (See Canada map.)
"What's helped it to do that was the very low sea ice," he added.
In the Queen Elizabeth Islands warmer temperatures likely contributed to the breakup, according to Copland.
Scientists with the National Snow and Ice Data Center in Boulder, Colorado, reported on Monday that Arctic sea ice extent this September reached a record low of 1.65 million square miles (4.28 million square kilometers).
That's 23 percent lower than the previous record set in September 2005.
Sea ice normally blocks passage from the Arctic Ocean to the Queen Elizabeth Islands, but this summer's melt cleared the way for the Ayles Ice Island.
"That process allows it to get further south where, of course, it's warmer," Copland said. "And that's going to be a factor allowing it to break apart."
In the relatively warmer southern climes, the Ayles Ice Island split in two on September 4, satellite images show.
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