A new assessment found runaway carbon emissions and melting ice sheets could result in such a worst case scenario, potentially double the upper limit outlined by the UN climate science panel’s last major report.
Such big sea level rises so soon would lead to nightmarish impacts, says Jonathan Bamber of the University of Bristol. “If we see something like that in the next 80 years we are looking at social breakdown on scales that are pretty unimaginable.” Around 1.79 million square kilometres of land could be lost and up to 187 million people displaced. “Many small island states, particularly those in the Pacific, will effectively be pretty much inhabitable. We are talking about an existential threat to nation states,” says Bamber.
One factor regarding this predicted rise is that relatively new satellite measurements are showing ice mass loss happening faster than models expected. Another key one is the idea that ice cliffs in Antarctica could collapse under their own weight after buttressing ice sheets supporting them are melted by climate change. The risk of a disastrous 2 metre sea level rise can still be avoided if emissions are cut quickly enough, says Bamber. “We can make some choices but we have to make them very soon.”