How high will sea levels rise? For reasons that are not clear, the rapidly increasing ice melts of Antarctica and Greenland were left out of the initial draft of the IPCC’s 2007 report – allegedly because computer models don’t have current data to accurately access the impact. So, the report might project only a 5 to 23-inch rise in sea level. But one prominent glaciologist thinks the worst case for sea level rise could be five times higher than the IPCC's estimate.