tagged w/ Wilkins Ice Shelf
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The Wilkins Ice Shelf, a monster iceberg more than 100 kilometres across, is about to separate from the Antarctic continent and float free, possibly as a result of global warming, two German scientists said Friday. Rifts have developed in the narrow "ice bridge," which is the last link between the shelf and the Antarctic Peninsula, reported the European Space Agency (ESA), quoting scientists Angelika Humbert and Matthias Braun, who have been observing the ice using satellite photos.
Antarctica's ice sheet was formed by thousands of years of accumulated and compacted snow. Along the coast the ice gradually floats out onto the sea, forming massive ledges known as ice shelves.
Seven such ice shelves have retreated and disintegrated in the past 20 years. The Wilkins Shelf was stable for most of last century before it began retreating in the 1990s. Scientists are investigating whether unusual warming in the past 50 years is to blame.
The separation of the ice shelf from its land anchors, Charcot Island and Latady Island, would not raise world sea levels because the ice is already floating on the Antarctic Ocean.The Wilkins Ice Shelf, a monster iceberg more than 100 kilometres across, is about to... more
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So, when is this country going to get serious about capping GHG emissions? Now that we have a new president, just how far up on the priority list is it, and will it be enough?So, when is this country going to get serious about capping GHG emissions? Now that we... more
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New rifts have developed on the Wilkins Ice Shelf that could lead to the opening of the ice bridge that has been preventing the ice shelf from disintegrating and breaking away from the Antarctic Peninsula.
The ice bridge connects the Wilkins Ice Shelf to two islands, Charcot and Latady. As seen in the Envisat image above acquired on 26 November 2008, new rifts (denoted by colourful lines and dates of the events) have formed to the east of Latady Island and appear to be moving in a northerly direction.
Dr Angelika Humbert from the Institute of Geophysics, Münster University, and Dr Matthias Braun from the Center for Remote Sensing, University of Bonn, spotted the newly formed rifts during their daily monitoring activities of the ice sheet via Envisat Advanced Synthetic Aperture Radar (ASAR) acquisitions.
"These new rifts, which have joined previously existing rifts on the ice shelf (blue dotted line), threaten to break up the chunk of ice located beneath the 21 July date, which would cause the bridge to lose its stabilisation and collapse," Humbert explained. "These recent changes are happening slower and more continuously than the events we saw earlier this year."
In February 2008 an area of about 400 km² broke off from the ice shelf, narrowing the ice bridge down to a 6 km strip. At the end of May 2008 an area of about 160 km² broke off, reducing the ice bridge to just 2.7 km. Between 30 May and 9 July 2008, the ice shelf experienced further disintegration and lost about 1 350 km².
The Wilkins Ice Shelf, a broad plate of floating ice south of South America on the Antarctic Peninsula, had been stable for most of the last century before it began retreating in the 1990s. The peninsula has been experiencing extraordinary warming in the past 50 years of 2.5°C.
If the ice shelf breaks away from the peninsula, it will not cause a rise in sea level since it is already floating. However, ice shelves on the Antarctic Peninsula are sandwiched by extraordinarily raising surface air temperatures and a warming ocean, making them important indicators for on-going climate changeNew rifts have developed on the Wilkins Ice Shelf that could lead to the opening of... more
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Another large plate of ice has broken off the rapidly disintegrating Wilkins Ice Shelf in the Antarctic Peninsula, the above satellite images show.
While the ice shelf, located directly below South America, shrank significantly in previous months (see March images), this is the first documented occurrence of an ice shelf collapsing during the Southern Hemisphere's winter.
The European Space Agency's Envisat satellite revealed that approximately 62 square miles (160 square kilometers) of ice detached from the ice shelf between May 30 and May 31. This most recent loss narrowed the strip to a width of 1.7 miles (2.7 kilometers).
The Wilkins Ice Shelf connects the islands of Charcot and Latady and protects many miles of Antarctica's ice shelves from additional collapse.
A trend of "extraordinary warming" over the past 50 years in Antarctica has caused the loss of several ice shelves, Matthias Braun of Bonn University, and Angelika Humbert of Münster University, said in a statement.
The researchers also warned that the last strip of ice on Wilkins would disappear soon.
"The remaining plate has an arched fracture at its narrowest position," they said, "making it very likely that the connection will break completely in the coming days."
Another large plate of ice has broken off the rapidly disintegrating Wilkins Ice Shelf... more
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A large chunk of ice has started to break away from Antarctica's Wilkins Ice Shelf.
Wilkins is the largest ice shelf on the Antarctic Peninsula to be threatened so far.
Satellite images show the collapse began on February 28 as a massive iceberg fell away from the ice shelf's southwestern front.
This lead to a runaway disintegration of the shelf interior.
Wilkins Ice Shelf spans about 13,000 square km (5,000 square miles) and is located on the southwest Antarctic Peninsula about 1,600 km (1,000 miles) south of South America.
Michelle Carlile-Alkhouri reports.A large chunk of ice has started to break away from Antarctica's Wilkins Ice... more
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A very sizeable chunk of ice has begun to break away from Antarctica.
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