International Environmental Agreements

The regulation of environmental externalities at the global level requires international agreements between sovereign states. Game theory provides an appropriate theoretical tool for analysis. However, game theory can result in a wide range of outcomes, and therefore it is important to discuss the assumptions and mechanisms of the different approaches and to relate these with what is observed in practice. The basic picture is not optimistic: If there are large gains of cooperation, the stable coalition is small. This grim picture challenges the perspective and design of international agreements. This article discusses and compares the different approaches: noncooperative, cooperative, dynamic, and evolutionary. Asymmetries and the options for side payments are considered. At the end, some more optimistic ways forward are presented.