Some research has posited that while initially damaging to the environment, continued economic growth eventually leads to superior environmental quality. This relationship is often described as an ‘Environmental Kuznets Curve’ (EKC), after a similar hypothesis regarding income inequality made by economist Simon Kuznets. Following such findings, the EKC is sometimes offered as a rationale for encouraging economic growth as the best environmental policy option. This paper reconsiders the policy-relevance of the EKC idea, drawing on a wide range of international data collected in the Environmental Sustainability Index (ESI) project. Specifically, it tests the theoretical arguments advanced by Arrow and others (1995) that EKC relationships are unlikely to hold for environmental problems that are intergenerational in time or spread across national boundaries. The results of this research substantially confirm those arguments, providing more evidence that the EKC idea is an inadequate guide for environmental policy makers around the globe.