Damage Sensitivity and Stability in International Environmental Agreements

This paper examines the formation of International Environmental Agreements (IEAs). The economic literature focuses on scenarios where countries are weakly sensitive to environmental damages (constant or linear marginal damages) and finds that stable coalitions are small when countries choose their emission strategies simultaneously and the marginal benefit function is linear. Motivated by empirical evidence, our analysis addresses cases where countries are highly sensitive to environmental damages. In this context, we find equilibrium behaviors that reverse conventional wisdom. For instance, large coalitions including the grand coalition can be supported as an equilibrium outcome when the sensitivity of countries to environmental conditions is high. Our findings provide an additional explanation for large scale IEAs such as the Montreal Protocol