Mighty melt

2019-03-07 08:06:07

By Jeff Hecht THE West Antarctic Ice Sheet may vanish within 7000 years with or without global warming, scientists warned last week. “Whatever we do isn’t going to have an effect,” says Brenda Hall of the University of Maine in Orono. West Antarctica contains enough ice to raise global sea level by between 5 and 6 metres. The ice sheet is now gradually retreating. It rests on land below sea level, and scientists warned a decade ago that if global warming allowed water to work its way underneath it, the sheet could collapse catastrophically within a century, flooding the world’s low coastlines. Now Hall’s team has dated the retreat of the ice using sophisticated techniques. They report that the ice has been steadily retreating over thousands of years (Science, vol 286, p 280). Hall believes the retreat could carry on at the same average rate for another 7000 years until all the ice has melted. She doubts that human activity has had any effect, since global warming has yet to penetrate the thick ice. The only thing that can save the ice sheet is the onset of another ice age, Hall believes, and this may not occur for well over 7000 years. “The disappearance of the ice sheet may be inevitable,