World at global warming ‘tipping point’

THE world may be on the brink of a global warming “tipping point” that could lead to sea levels rising 23ft and doom future generations to catastrophic flooding, an expert has warned.

A temperature rise of just 1C would trigger the unstoppable collapse of the Greenland ice sheet, a vast layer of ice stretching for 1,900km and covering 80% of Greenland, said Professor Tim Lenton, from the University of East Anglia, in Norwich.

Of this warming, 0.7C, already due to take place, has only been held up by natural time lags in the climate system.

The Intergovernmental Panel on Climate Change has reported that the ice sheet will take at least 1,000 years to melt.

But Prof Lenton’s group believes it could break up within 300 years. If this happened, sea levels would rise by 7m (23ft), flooding coastal areas and displacing millions of people.

Prof Lenton told New Scientist magazine: “We are close to being committed to a collapse of the Greenland ice sheet, but we don’t think we have passed the tipping point yet.”

A study by Prof Lenton’s team identified eight dangerous tipping points that could be crossed this century. Experts predict that a “business as usual” approach that makes no attempt to curb global warming would raise temperatures by up to 6C by 2100. This would probably be enough to cross all the tipping points, according to the professor.