It used to be that climate scientists worried about how to make the public care about changes that might not happen for a century. Today they have a bigger problem: some of the changes aren’t waiting around that long.

Stefan Rahmstorf, a climatologist at Potsdam University, points out that models tend to underestimate sea level rise, too. “As climatologists, we’re often under fire because of our pessimistic message, and we’re accused of overestimating the problem,” he says. “But I think the evidence points to the opposite—we may have been underestimating it.”