BBC: Pledges made at December’s UN summit in Copenhagen are unlikely to keep global warming below 2C, a study concludes. Writing in the journal Nature, analysts at the Potsdam Institute for Climate Impacts Research in Germany say a rise of at least 3C by 2100 is likely. The team also says many countries, including EU members and China, have pledged slower carbon curbs than they have been achieving anyway. They say a new global deal is needed if deeper cuts are to …