Choices that the world makes this century could determine the fate of the massive Antarctic ice sheet. A study published online this week in Nature1 finds that continued growth in greenhouse-gas emissions over the next several decades could trigger an unstoppable collapse of Antarctica’s ice — raising sea levels by more than a metre by 2100 and more than 15 metres by 2500.
“That is literally remapping how the planet looks from space,” says study co-author Rob DeConto, a geoscientist at the University of Massachusetts Amherst. The good news, he says, is that it projects little or no sea-level rise from Antarctic melt if greenhouse-gas emissions are reduced quickly enough to limit the average global temperature rise to about 2 °C. >>