[cnn-photo-caption image=http://i2.cdn.turner.com/cnn/2009/images/01/23/art.iceshelf.jpg caption="A New Zealand frigate patrols past the Ross Ice Shelf in the Southern Ocean in Antarctica."]
CNN Executive Editor
Professor David Vaughan has an infectious enthusiasm, even when he’s issuing dire warnings about the future of Antarctica. That’s where he is right now, at the Rothera Research Station. He’s just returned from a flight to the Wilkins Ice Shelf – which juts out of the western tip of the Continent. It will probably be his last.
An Englishman whose home is among the dreaming spires of Cambridge, where the British Antarctic Survey has its headquarters, Professor Vaughan has been visiting the world’s coldest places for twenty years. He was surprised to find that the Wilkins Ice Shelf, which began disintegrating a decade ago, hasn’t yet disappeared. But he says it’s in its death throes.
Last year, AC360° reported the Survey’s finding that a slice the size of Manhattan had broken off the ice shelf. Vaughan says the whole shelf is now connected to the rest of Antarctica by a strip of ice just a few hundred meters wide. It’s like looking at an hour glass. This huge slab of ice –11,000 square kilometres (the size of Jamaica) – is about to collapse into the sea. Maybe within weeks, maybe later in the year, says Vaughan.
In the last year, a sequence of images taken by NASA and the European Space Agency has shown fissures opening up – like fault-lines across the ice. I asked Vaughan what they looked like – close-up. “Huge, absolutely huge,” he says. “The cracks in the Wilkins ice shelf and the chunks of ice that are splitting away from the ice-shelf….they’re kind of shopping mall chunks of ice and some are floating off into the ocean.”
Scientists have a clearer view than even a few years ago about the rate of climate change in the Antarctic Peninsula, which stretches north like a thin finger into the south Atlantic. In the last fifty years, average temperatures there have risen more than 5 degrees Fahrenheit – faster than anywhere else in the southern hemisphere. Vaughan says the evidence is now “quite strong” that emissions of greenhouse gases have influenced the Antarctic climate, just as CFCs (Chlorofluorocarbons) have damaged the ozone layer. The process may have been further accelerated by the warming of the sea – gently cooking the underside of the ice-shelf.
Wilkins is not the first to collapse. “It s about the ninth in the series that s been lost,” says Vaughan...”and at least one of those ice shelves that's been lost had been there continuously for 10,000 years.”
The collapse of the ice shelves does not in itself much influence sea-levels, but many of them play an important role in holding back the huge Antarctic glaciers. Were they to accelerate toward the ocean, melting on contact, there would be an impact on sea levels. Vaughan has a scientist’s caution in peering into the future. “ The big ice sheets – Greenland and Antarctica – are now the major sources of uncertainty in predicting sea level rise in the future. What's happening on Wilkins and deeper in the Antarctic continent are major concerns for us."
A new study published in ‘Nature’ magazine suggests that other parts of Antarctic – far from the Wilkins Ice Shelf – have also been warming, though less fast. U.S. scientists reviewed a half century of satellite and weather records for Antarctica, which showed that temperatures had risen by nearly 1 degree Fahrenheit. The study concluded the process was “difficult to explain” without linking it to greenhouse gases.
Vaughan is a member of the United Nations Panel on Climate Change which predicted that sea levels could rise anywhere between 18 and 59 centimetres (7 to 23 inches) over the next century. Now, as he contemplates the gradually warming Antarctic summer, he wonders whether that assessment was too conservative.
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