Guardian: The consensus reached at today’s meeting of climate change scientists is an important one for policymakers. At the conference being held in Copenhagen, in advance of a key meeting of climate change negotiators in December, scientists have said that even after (as yet unachieved) reductions in greenhouse gas emissions we only have a 50:50 chance of preventing a two-degree rise in global temperatures. This is depressing stuff. Given the evidence from Copenhagen, it makes many wonder why …