Global sea levels could rise twice as fast as previously thought, according to a study published yesterday (May 20) in PNAS. Experts surveyed by the study authors estimate that, if emissions continue on their current trajectory, accelerated ice melt in Greenland and Antarctica could contribute to rises of 2 meters and lead to the displacement of nearly 200 million of people.
“To put this into perspective, the Syrian refugee crisis resulted in about a million refugees coming into Europe,” study coauthor Jonathan Bamber of the University of Bristol tells BBC News. “That is about 200 times smaller than the number of people who would be displaced in a 2m sea-level rise.”
Previous estimates for sea-level rises come from a 2013 report by the Intergovernmental Panel on Climate Change (IPCC). Using computer models of future warming, that assessment predicted that if emissions are not reduced, the planet could warm by around 5 °C and sea levels will rise between 52 and 98 cm before the end of the century.
For the new analysis, researchers collected the opinions of 22 experts on ice sheet melt. Based on these assessments, the researchers concluded that sea levels could in fact rise between 62 and 238 cm by the end of the century. In the most extreme case, about 1.79 million square kilometers—an area the size of Libya—of land could be lost to the sea.
“This kind of survey of experts is important, because computer models are not perfect at predicting the future,” Tamsin Edwards, a climate scientist at King’s College London who was not involved in the research, tells BBC News. She emphasizes that the worst-case scenario is unlikely, “especially as we are starting to put policies in place to avoid such a high level of warming.”
Bamber tells CNN that although the chance that sea levels really will rise more than 2 meters this century is small—around 5 percent, according to the study—people can’t afford to be complacent. “Our study suggests that there is a real risk, a plausible risk of very substantial sea level rise coming from both ice sheets,” he says. “What we decide to do collectively as a species politically, globally, over the next decade is going to determine the future of the next generations in terms of the habitability of the planet and what sort of environment they live in.”