Posted on behalf of Kate Larkin

A 260 square kilometre iceberg has broken free from the Petermann Glacier, one of the two largest remaining glaciers in Greenland.

Shedding in the early hours of August 5, 2010, the 600ft thick iceberg is drifting 1000 km south of the North Pole and is an ice island four times the size of Manhattan, as reported by the University of Delaware Udaily.

“It is the largest Arctic iceberg to calve since 1962”, Professor Andreas Muenchow, research leader at the University of Delaware told BBC News.

The event was captured from space by the NASA MODIS-Aqua satellite. First reported by Trudy Wohlleben of the Canadian Ice Service, a team at the University of Delaware team subsequently monitored the event in near real time as it unfolded.

The Greenland ice sheet is known to be a dynamic and unstable region with 1000’s of icebergs calving each year. Just two years ago, in July 2008, a 27 square kilometre iceberg broke free from the Petermann glacier with an approximate mass of one to two gigatonnes. This latest shedding is 10 times larger.

It is not clear if the latest Arctic ice instability can be linked to global warming, although scientists have said global temperatures in the first half of 2010 are the highest on record.

The enormous ice block may enter the Nares Strait, and may pose as a hazard to shipping in this deep waterway between northern Greenland and Canada. However the iceberg will be monitored by the University of Delaware team and collaborators using an ocean and ice observing array, positioned in the Nares Strait since 2003. And the iceberg may have one positive effect – as it moves on its passage along the Nares Strait researchers say it may act as a huge ice dam, creating a barrier between Canada and Greenland and preventing further ice to escape.

Credit: ESA