Global warming could trigger melting of 'unstable ice plugs' that would raise sea levels by up to 13 FEET, claims study
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An enormous region of East Antarctica is far more vulnerable to thaw that previously thought, according to a new study.
Researchers claim that global warming could trigger an unstoppable slide of ice into the ocean and raise world sea levels for thousands of years.
The Wilkes Basin in East Antarctica, stretching more than 600 miles (1,000 km) inland, has enough ice to raise world sea levels by 10 to 13 feet (three to four metres).
A study has said 'unstable ice plugs' are all that is holding back a giant sheet of ice known as the Wilkes Basin in East Antarctica. If they were to melt, the ice sheet could raise sea levels by up to four metres (13 feet) over the next few thousand years. Pictured is a large pack of floating ice known as an ice floe near East Antarctica
The Wilkes is vulnerable because it is held in place by a small rim of ice, resting on bedrock below sea level by the coast of the frozen continent.
That 'ice plug' might melt away in coming centuries if ocean waters warm up.
'East Antarctica's Wilkes Basin is like a bottle on a slant. Once uncorked, it empties out,' Matthias Mengel of the Potsdam Institute for Climate Impact Research, lead author of the study in the journal Nature Climate Change, said in a statement.
Co-author Anders Levermann, also at Potsdam in Germany, said the main finding was that the ice flow would be irreversible, if set in motion.
But he said there was still time to limit warming to levels to keep the ice plug in place.
Almost 200 governments have promised to work out a UN deal by the end of 2015 to curb increasing emissions of man-made greenhouse gases to prevent more droughts, heatwaves, downpours and rising sea levels.
Worries about rising seas that could swamp low-lying areas from Shanghai to Florida focus most on ice in Greenland and West Antarctica, as well as far smaller amounts of ice in mountain ranges from the Himalayas to the Andes.
IPCC REPORT: EFFECTS OF RISING SEA LEVELS AND GLOBAL WARMING
Europe: The Intergovernmental Panel on Climate Change (IPCC) expects 'multiple stresses and systemic failures due to climate change' in the Mediterranean. This will increase energy costs and damage tourism from 2050.
North America: Flooding will be a major threat in this area with rain and storms moving north of New York. Southern areas are expected to experience a shortage of water.
Asia: The majority of the people directly affected by sea level rise will be in southern and eastern Asia. However, water is also expected to affect most of Asia.
Australasia: There remains uncertainty about impact in Australasia, but extreme weather is predicted. The Great Barrier Reef will continue to degrade, with warmer water bleaching more coral.
Africa: Food security will be a major issue for Africa. Crops and livestock will be affected by both flooding and drought. There will also be more soil erosion from storms.
Central and South America: Scientists expect Northern Brazil may lose 22 per cent of its annual rainfall by 2100, while the area around Chile could get a 25 per cent increase.
This image, taken by Nasa's Galileo space probe as it flew by Earth on its way to Jupiter in 1996, shows the Wilkes Basin (bottom right) as part of the Ross Ice Shelf. The basin stretches back more than 600 miles (1,000 km) inland and could dramatically raise sea levels if 'ice plugs' holding it back were to melt, says a study
This study is among the first to gauge risks in East Antarctica, the biggest wedge of the continent and usually considered stable.
'I would not be surprised if this (basin) is more vulnerable than West Antarctica,' Levermann said.
Antarctica, the size of the United States and Mexico combined, holds enough ice to raise sea levels by some 188 feet (57 metres) if it ever all melted.
The study indicated that it could take 200 years or more to melt the ice plugs if ocean temperatures rise.
Once removed, it could take between 5,000 and 10,000 years for ice in the Wilkes Basin to empty as gravity pulled the ice seawards.
'It sounds plausible,' Tony Payne, a professor of glaciology at Bristol University who was not involved in the study, said of the findings.
The region is not an immediate threat, he said, but 'could contribute metres to sea level rise over thousands of years.'
The United Nations panel on climate change says it is at least 95 percent probable that human activities such as burning fossil fuels, rather than natural swings in the climate, are the dominant cause of warming since the 1950s.
Sea levels are likely to rise by between 0.85 to 2.7 feet (26 and 82 centimetres) by the late 21st century, after a rise of (0.62 feet) 19 cm since 1900, it says.
Antarctica, however, remains the biggest uncertainty in the calculations as to how much sea levels will rise.
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