Addressing cross-border environmental displacement: when can international treaties help?

Environmental degradation is increasingly causing cross-border displacement of people, but countries have formed no treaties to facilitate collaboration on the issue. When is such collaboration feasible, and how should environmental displacement treaties be designed? We present a game-theoretic analysis. In our model, countries first decide on ratifying a treaty, and doing so commits them to helping other countries that face cases of environmental degradation in the future. The equilibrium analysis suggests that treaty formation is easier under conditions of mutual vulnerability than if some countries are at a greater risk of environmental degradation than others. Our most important finding is that contrary to the received wisdom, treaties imposing stringent demands on countries are easier to form than treaties that are easy to comply with. We also examine the benefits of using displacement treaties to build capacity for cooperation. We illustrate the utility of the analysis with a discussion of the Kampala Convention on environmental displacement and consider the potential for future treaty formation in Sub-Saharan Africa and Oceania.