Massive ice shelf breaking away

Foto: British Antarctic Survey
Location map showing Wilkins Ice Shelf on the Antarctic PeninsulaSatellite images now show that icebergs have begun to calve from the northern front of the Wilkins Ice Shelf - indicating that the huge shelf has become unstable. This follows the collapse three weeks ago of the ice bridge that had previously linked the Antarctic mainland to Charcot Island.

The Wilkins Ice Shelf had been stable for most of the last century, but began retreating in the 1990s. Researchers believe it was held in place by an ice bridge linking Charcot Island to the Antarctic mainland. But the 127-square-mile bridge lost two large chunks last year and then shattered completely on April 5.

Monitored
The ice bridge, effectively formed a barrier pinning back the northern ice front of the central Wilkins Ice Shelf. As a consequence of the collapse, the rifts, which had already featured along the northern ice front, widened and new cracks formed as the ice adjusted in the days that followed, ESA writes on their web pages.

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The ice shelf has been monitored by using a combination of radar images from ESA's Envisat satellite and the German Aerospace Centre's TerraSAR-X satellite. On 24 April, the satellite data showed that the first icebergs had started to break away from the fragile ice shelf. An estimate suggests that, so far, about 700 sq km of ice has been lostfrom the Wilkins Ice Shelf.

Latest and largest
In contrast to the ice bridge, which shattered very quickly, it is expected that the discharge of ice will continue for some weeks. The icebergs are calving as a result of fracture zones that have formed over the last 15 years and which turned Wilkins into a fragile and vulnerable ice shelf.
The retreat of Wilkins Ice Shelf is the latest and the largest of its kind.



"The changes to Wilkins Ice Shelf provide a fabulous natural laboratory that will allow us to understand how ice shelves respond to climate change and what the future will hold for the rest of Antarctica," David Vaughan from the British Antarctic Survey said.

The quality and frequency of images acquired by ESA satellites mean that the break-up of Wilkins Ice Shelf can be analysed far more effectively than any previous event. ESA's Webcam from Space is available to the public. View the images, documenting the break-up of Antarctica's Wilkins Ice Shelf