A group of leading scientists is warning global warming is happening at a faster rate than previously thought. In a new report, twenty-six experts say global sea levels could rise up to six-and-a-half feet by the year 2100. The group writes, “Climate change is accelerating beyond expectations.” Many of its members were part of the UN’s Nobel-winning Intergovernmental Panel on Climate Change, which has urged nations to cap emissions. The warning comes less than two weeks before world leaders gather in Copenhagen to negotiate a climate treaty.