Significant benefits from international cooperation over marine plastic pollution

Abstract Plastic pollution in the world’s oceans threatens marine ecosystems and biodiversity, leading to a loss of well-being for people 1,2 . The connected nature of the marine environment suggests that coordinated actions by countries sharing a common ocean border may provide more effective pollution control than unilateral actions by any one country. However, economic theory and empirical evidence suggest that countries often fail to cooperate, even when joint welfare would be higher under cooperation 3 . Here we provide the first analysis of the potential economic benefits of cooperative marine plastic pollution (MPP) management in the North Atlantic. An estimated transfer matrix showing how plastics move across the North Atlantic is combined with game theory and estimates of benefits and costs to derive the potential net benefits of international cooperation. A fully cooperative outcome across 16 countries leads to a substantial reduction in MPP, resulting in significant aggregate annual net benefits. However, MPP reduction burdens are unevenly spread across countries. Constraining the agreement to avoid such consequences results in both less MPP reduction and lower aggregate benefits. As the United Nations works on a future global plastic pollution treaty, these results demonstrate that close cooperation will be a critical determinant of its success.