The historian’s task is not so much to recount the past as to imagine the future. Great catastrophes happen because, until they do, people cannot imagine that they will. If people could imagine it they would take the necessary steps to avert it. So it was with the terror of the French Revolution, the tragedy of 1914, Auschwitz and the atom bomb, and so it will be with the greatest disaster of all, the great climate catastrophe of the second half of the twenty first century. The imaginative failure, not to say stupidity and ignorance, of the times is the more reprehensible because on this occasion, unlike most, the scientists have been warning us for so long in solemn, insistent and now virtually unanimous voice. If we don’t quit oil decisively and urgently a.s.a.p., we will face whole countries going under the sea, extremely severe droughts, floods and hurricanes, hundreds of millions homeless and without food and water, and, almost certainly, vicious resource wars that might well go nuclear. I wish the scientists weren’t saying all this. But they are. How can people be so stupid as not to pay attention to these dire warnings? A friend of mine writes in one of those round robins people send round at Christmas ‘2014 has been a lovely warm and sunny year. If this is global warming bring it on’. A nice man but clearly he has been reading the newspapers. I am in despair.