When James Hansen, NASA’s former lead climate scientist, has something to say about the effects of climate change, people tend to listen up. According to a report from Slate, Hansen, along with 16 other coauthors, has concluded in a new study that glaciers in Greenland and Antarctica will likely melt 10 times faster than previous models estimated.

The study suggests that the average global sea level could rise as much as 10 feet over the course of the next 50 years. The study is still yet to be peer-reviewed, but it highlights a new feedback loop in the Southern Ocean that results in cooler freshwater from melting glaciers shoving warm, salty water beneath the ice sheets. This has an overall effect of speeding up melting.

Hansen is famous for his unapologetically realistic yet usually correct predictions, and he acknowledges that the new study isn’t quite in line with previous models. The team used a mixture of paleoclimate records, complex computer models, and observable measurements of sea level rise, but believe that the real world is moving faster than the models predict.

The model doesn’t predict exactly when the sea will rise by a certain amount, only that it is likely to get out of control long before the end of the century. Melting glaciers have long been a concern to both climate scientists and people who live near the ocean, and the new findings suggest that it will be a much larger problem moving forward.

At a time when action is a necessary step to protect coastal assets, Hansen and his colleagues are hoping that world leaders will listen.