Scientists who made apocalyptic warnings that the sea level could rise more than two metres this century were probably wrong, according to a new assessment.
Researchers at King’s College London found that it would be closer to one metre by 2100 because Antarctica’s towering ice cliffs were less likely to collapse than had been claimed by US scientists.
The revised prediction challenges a study in 2016 by Penn State University claiming that Antarctic melting alone could contribute more than a metre to the rise in sea level.
The melting of glaciers and the Greenland ice sheet, plus thermal expansion of the oceans, are expected to add about another metre, meaning that the total rise would have been more than 2m had the US study been correct.
However, the King’s College London scientists studied sea level rises three million years ago, 125,000 years ago and over the past 25 years in more detail and found that they could be explained without assuming that the ice cliffs had collapsed.
Tamsin Edwards, lecturer in physical geography at King’s and lead author of the study published in Nature, said: “Unstable ice cliffs in Antarctica were proposed as a cause of unstoppable collapse of large parts of the ice sheet in the past. They were, therefore, also predicted to cause rapidly rising seas with global warming in our near future. But we’ve re-analysed the data and found this isn’t the case.”
Even if greenhouse gas emissions continued at a high rate, there was only a 5 per cent chance of Antarctica’s contribution to sea-level rise exceeding 39cm by 2100. It was most likely to be 15cm, meaning that the total increase would be about 120cm — still higher than the 98cm forecast in 2013 by the Intergovernmental Panel on Climate Change.