LONDON, Dec 28: There is a one in 20 chance of a dramatic rise in world sea levels over the next century due to global warming, according to a new risk assessment published on Friday.

The survey — by the British Antarctic Survey (BAS) and Norwegian environmental safety organization, Det Norske Veritas — said there was a five per cent chance of the giant West Antarctic Ice Sheet disintegrating due to climate change and raising sea levels by one metre (yard) in the next 100 years.

“You have to balance the likelihood against the severity of the impacts, and in this case even a five per cent chance of this happening is really damn serious,” said scientist David Vaughan of BAS, responsible for British scientific research in Antarctica.

Scientists have already predicted a rise in sea levels of 50cm over the next century due to a combination of climate change and increased extraction of ground water, even with no contribution from melting Antarctic ice.

“So we might be looking at something like one and a half metres in the next century,” Vaughan said.

Vaughan said the possible breakup of the West Antarctic Ice Sheet, which accounts for 13 per cent of ice on the frozen continent, had nothing to do with the impact of human industrial activity on the climate, but was part of a far older process.

But he said major world polluters could not walk away from the problem.

“The potential impacts of a major change in the West Antarctic Ice Sheet are severe — sea level rise will be fantastically expensive for developed nations with coastal cities and dire for poor populations in low-lying coastal areas,” Vaughan said.

Not only would there be flooding on a potentially vast scale, but changes in ocean currents could also have untold consequences on weather patterns, he added.

Previous calculations have said low-lying countries such as Bangladesh could lose 17 per cent of its land area and as much as half of its farmland if sea levels rose by one metre, and small island nations could be completely swamped.—Reuters