Telegraph: In a dramatic warning timed to coincide with the climate change summit in Copenhagen, 2,500 leading environmental experts have argued that the rising temperature of the earth is pushing us towards social and economic catastrophe. The nature and scale of the coming devastation is still a matter for debate; experts often exaggerate. But it is time to acknowledge that, for whatever combination of reasons, temperatures are rising. We do not know by how much they will rise in the next few …