Guardian: What a difference three months makes. Back in November, the world broadly agreed that emissions of carbon dioxide were heating up the planet and that we needed to do something about it, even if we couldn’t agree exactly what. And though we’d had the usual pre-summit rollercoaster ride of dire predictions and naive exhortations (yes, I plead guilty to some of those), even hardheaded types dared to hope that Copenhagen might produce the basis of a global climate treaty. As late as 7 …