Climate change tests the nation state in ways that it has not been tested, perhaps ever. It demands a response that can't be contained at any scale other than the planetary. When we have meetings in Paris and Copenhagen, we see people who understand themselves as progressive or left desperately hoping for the coordination of a binding agreement, of a planetary power - because this is the only way we can understand conventional political concepts to have any grasp in a future world in which climate has shifted things so much.