In the light of this, it seems to me, we should recognize that the problem of climate change that occupies international negotiations today is not in fact a diplomatic problem. It is primarily a scientific problem: the problem of discovering a cheap and effective source of clean energy that will remove both the cost of signing up to a treaty and the motive to defect from it. The solution to this scientific problem is indeed more likely to be found through international cooperation - but cooperation among scientists, not among states.