Greenland glacier calves island four times the size of Manhattan

Aug 06, 2010
This is Greenland's Petermann Glacier in 2009. Credit: Photo courtesy of Prof. Andreas Muenchow, University of Delaware

A University of Delaware researcher reports that an "ice island" four times the size of Manhattan has calved from Greenland's Petermann Glacier. The last time the Arctic lost such a large chunk of ice was in 1962.

"In the early morning hours of August 5, 2010, an ice island four times the size of Manhattan was born in northern ," said Andreas Muenchow, associate professor of physical ocean science and engineering at the University of Delaware's College of Earth, Ocean, and Environment. Muenchow's research in Nares Strait, between Greenland and Canada, is supported by the National Science Foundation (NSF).

of this remote area at 81 degrees N latitude and 61 degrees W longitude, about 620 miles [1,000 km] south of the North Pole, reveals that Petermann Glacier lost about one-quarter of its 43-mile long [70 km] floating ice-shelf.

Trudy Wohlleben of the Canadian Ice Service discovered the ice island within hours after NASA's MODIS-Aqua satellite took the data on Aug. 5, at 8:40 UTC (4:40 EDT), Muenchow said. These raw data were downloaded, processed, and analyzed at the University of Delaware in near real-time as part of Muenchow's NSF research.

Petermann Glacier, the parent of the new ice island, is one of the two largest remaining in Greenland that terminate in floating shelves. The glacier connects the great directly with the ocean.

The new ice island has an area of at least 100 square miles and a thickness up to half the height of the Empire State Building.

This satellite image from August 5, 2010, shows the huge ice island broken off from Greenland's Petermann Glacier. Credit: Prof. Andreas Muenchow, University of Delaware

"The freshwater stored in this ice island could keep the Delaware or Hudson rivers flowing for more than two years. It could also keep all U.S. public tap water flowing for 120 days," Muenchow said.

The island will enter Nares Strait, a deep waterway between northern Greenland and Canada where, since 2003, a University of Delaware ocean and ice observing array has been maintained by Muenchow with collaborators in Oregon (Prof. Kelly Falkner), British Columbia (Prof. Humfrey Melling), and England (Prof. Helen Johnson).

"In Nares Strait, the ice island will encounter real islands that are all much smaller in size," Muenchow said. "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. From there, it will likely follow along the coasts of Baffin Island and Labrador, to reach the Atlantic within the next two years."

The last time such a massive ice island formed was in 1962 when Ward Hunt Ice Shelf calved a 230 square-mile island, smaller pieces of which became lodged between real islands inside Nares Strait. Petermann Glacier spawned smaller ice islands in 2001 (34 square miles) and 2008 (10 square miles). In 2005, the Ayles Ice Shelf disintegrated and became an ice island (34 square miles) about 60 miles to the west of Petermann Fjord.

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User comments : 10

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omatumr
1.9 / 5 (9) Aug 06, 2010
Why has scaremongering replaced factual information?

"The new ice island has . . . a thickness up to half the height of the Empire State Building." As I recall, the thickness of the Greenland ice sheet is ~8,000 feet.

The height of the Empire State Building is 1,250 feet. Therefore, 630 feet is more than "half the height of the Empire State Building" and less than one-tenth (0.1) the thickness of the Greenland ice sheet.
knikiy
5 / 5 (4) Aug 07, 2010
Is the Greenland ice sheet uniform in thickness?
ramudu
1 / 5 (2) Aug 07, 2010
QUITE ALARMING, action plan drawn out needs to be implemented, to achieve improvement ! >
thermodynamics
5 / 5 (4) Aug 07, 2010
Knikiy: Good question. The answer is no. The ice sheet varies considerably in thickness dependent on the location within Greenland, the terrain below the sheet, the proximity to the ocean, and many other variables. So, there is no single thickness.
NotParker
5 / 5 (1) Aug 07, 2010
Was it as warm in 1962 as it is now?
TehDog
5 / 5 (2) Aug 07, 2010
/q Petermann Glacier, the parent of the new ice island, is one of the two largest remaining glaciers in Greenland that terminate in floating shelves. /q

Ice shelves are typically much thinner than their feeding glaciers. (Sea melt)
neiorah
5 / 5 (1) Aug 09, 2010
I cannot help it but I am worried for our world.
LordOfRuin
5 / 5 (2) Aug 09, 2010
It's not our world that we should be worried for, but ourselves. Long after we have made our environment unsuitable for comfortable living, the world will carry on.

Plant forests, and plant them near coasts, to wet the interiors and then plant more. We need to geoengineer our world into a more stable environ.
Skeptic_Heretic
5 / 5 (2) Aug 09, 2010
It's not our world that we should be worried for, but ourselves. Long after we have made our environment unsuitable for comfortable living, the world will carry on.

Plant forests, and plant them near coasts, to wet the interiors and then plant more. We need to geoengineer our world into a more stable environ.

And we can do that without the aid of governments and politicians.

it affects us all, so we must all affect our future.
Bog_Mire
not rated yet Aug 13, 2010
The rich will pay for coastal real estate, alway will always did. Sorry SH, but how can we stop that happening without legislative intervention?

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