CO2 is a tough pollutant to manage. It is long-lived and most of its emissions are intrinsic to burning fossil fuels, which industrialized economies depend on. Any serious plan for taming CO2 will require intense international cooperation, but no country acting alone has much incentive to control its pollution. Worse, no country will adopt costly emission controls without confidence that its economic competitors are doing the same. These simple factors make the problem of global climate change a really hard one to solve.

This book has advanced six arguments. First, gridlock on global warming exists, in large part, because governments have adopted the wrong models to guide their diplomatic efforts. They have relied too much on the history of international environmental accords. But those models mostly don't work well for problems such as regulating CO2 that require complicated coordination of policies that are costly and thus affect national economic competitiveness. The hallmark of the CO2 problem is the need for interdependent commitments. What one country is willing to adopt depends on what its economic competitors are implementing. None of the history of international environmental cooperation offers robust models for that kind of cooperation. And in the few instances where international environmental diplomacy offers relevant precedents the community of global warming diplomats have largely drawn the wrong lessons. Following the wrong models has made a hard problem even harder to solve.