The risk, which will play out over centuries, may also be greater than expected for a significant portion of the world's population in coastal regions. Using so-called active ice sheet models, scientists from South Korea and the US projected how much ice sheets would raise global oceans by 2150 under three emissions scenarios: swift and deep cuts as called for by the UN's IPCC advisory panel, current climate policies, and a steep increase in carbon pollution. The new analysis shows that a given amount of sea level rise -- whether 30 or 300 centimetres -- will devastate twice the area projected in most models to date