Massive ice island breaks off Greenland glacier

Yahoo News 7 Aug 10;

WASHINGTON (AFP) – A massive ice island four times the size of Manhattan has broken off an iceberg in north-western Greenland, a researcher at a US university said.

Andreas Muenchow at the University of Delaware said in a statement Friday that the last time the Arctic lost such a large chunk of ice was in 1962.

Muenchow's research focuses on the Nares Strait, a region between far north-eastern Canada and northwestern Greenland, about 1,000 kilometers (620 miles) south of the North Pole.

Early on August 5, "an ice island four times the size of Manhattan was born in northern Greenland," said Muenchow.

The freshwater stored in the ice island could "keep all US public tap water flowing for 120 days," Muenchow said.

Satellite images of the area show that the Petermann Glacier lost about one-quarter of its 70 kilometer (43-mile) long floating ice-shelf.

The Petermann glacier is one of Greenland's two largest glaciers that end in floating shelves, and connects Greenland's ice sheet directly with the ocean.

Muenchow credits Trudy Wohlleben of the Canadian Ice Service with detecting the ice island early Thursday, hours after raw data from a NASA satellite was downloaded, processed, and analyzed at the university.

The ice island will enter Nares Strait, between northern Greenland and Canada, where it will run into small islands.

"The newly born ice-island may become land-fast, block the channel, or it may break into smaller pieces as it is propelled south by the prevailing ocean currents," said Muenchow.

The ice island could then head along the Canadian coast and reach the Atlantic within the next two years, he said.

Huge ice sheet breaks from Greenland glacier
BBC News 7 Aug 10;

A giant sheet of ice measuring 260 sq km (100 sq miles) has broken off a glacier in Greenland, according to researchers at a US university.

The block of ice separated from the Petermann Glacier, on the north-west coast of Greenland.

It is the largest Arctic iceberg to calve since 1962, said Prof Andreas Muenchow of the University of Delaware.

The ice could become frozen in place over winter or escape into the waters between Greenland and Canada.

If the iceberg moves south, it could interfere with shipping, Prof Muenchow said.

Cracks in the Petermann Glacier had been observed last year and it was expected that an iceberg would calve from it soon.

The glacier is 1,000 km (620 miles) south of the North Pole.

A researcher at the Canadian Ice Service detected the calving from Nasa satellite images taken early on Thursday, the professor said.

The images showed that Petermann Glacier lost about one-quarter of its 70km-long (43-mile) floating ice shelf.

There was enough fresh water locked up in the ice island to "keep all US public tap water flowing for 120 days," said Prof Muenchow.

He said it was not clear if the event was due to global warming.

Patrick Lockerby, a UK engineer with a background in material science, told the BBC he had predicted the calve on 22 July, posting images on the science2.0 website.

"I was watching the floating ice tongue wedged between two walls of a fjord for three quarters if its length with the last part at the outlet end wedged by sea ice. I thought once the sea ice was gone, the pressure would be too great and the tongue would calve."

He said there could be a beneficial outcome if the calving drifts to block the Nares Strait and effectively prevents the loss of more ice from the Lincoln Sea.

The first six months of 2010 have been the hottest on record globally, scientists have said.