Climate Coalitions in an Integrated Assessment Model

An analytically tractable approximation of a numerical model is used to investigate coalition formation between nine major world regions with regard to their policies for greenhouse gas emission reduction. Full cooperation is not individually rational. Assuming non-transferable utility, side payments do not ensure full cooperation either. Without side payments, the largest stable coalitions are small and consist of similar regions. With side payments, the largest stable coalitions exclude either the main culprits or the main victims of climate change. In all cases, optimal emission control is modest.