The effectiveness of international environmental agreements

Many argue that international environmental agreements (IEAs) can alter states’ cost-benefit analyses by providing crucial information about the costs of environmental degradation. Thereby, IEAs may help to effectively curb environmental pollution. However, previous attempts to empirically measure institutional effectiveness found it difficult to provide credible estimates because they have missed to produce convincing counterfactuals. This study empirically estimates the effectiveness of one prominent example of an international environmental institution, the Long Range Transboundary Air Pollution agreement (LRTAP). It sets forth a transparent identification strategy in light of latest advancements in the causal inference literature and presents evidence for the non-effectiveness of the LRTAP in changing member states’ behavior in terms of anthropogenic emissions of two substances (NO _x and SO₂). By deriving and illustrating the use of difference-in- differences (DID) design in the context of IEAs, this study provides a general methodological tool kit to drawing causal inferences about the effectiveness of international environmental institutions.