The US has been an obstacle for the last 8 years, maybe.  On the other hand, Kyoto was brokered and almost entirely written by the US (Al Gore), the only country in the world to not eventually ratify itth -- go figure. (Which supports the thesis the German sociologist of imperialism, Karl Schmitt -- who has now been rediscovered by the left in that discipline.  His thesis was that you can tell who the true sovereign state is within an international system by looking at the one never seems to have to be held to its own rules for that system.)