The World Court's ongoing contribution to international water law: The Pulp Mills Case between Argentina and Uruguay
ABSTRACT: The judgment of the International Court of Justice in the Pulp Mills (Argentina v. Uruguay) case makes a very important contribution to international law relating to shared international water resources and to international environmental law more generally. It does much to clarify the relationship between procedural and substantive rules of international environmental law. The Court linked interstate notification of new projects to the satisfaction of the customary due diligence obligation to prevent significant transboundary harm. It found that environmental impact assessment (EIA) is an essential requirement of customary international law in respect of activities having potential transboundary effects. The real significance of the judgment is that it held that the duty to notify, and the related duty to conduct an EIA taking account of transboundary impacts, exist in customary international law and thus apply to all states, not just those that have concluded international agreements containing such obligations. The Court confirmed that for shared international water resources, the principle of equitable and reasonable utilisation, universally accepted as the cardinal rule of international water law, is virtually synonymous with the concept of sustainable development, and suggests that considerations of environmental protection are absolutely integral to the equitable balancing of interests involved. The judgment makes it clear that the principle of equitable utilisation ought to be understood as a process, rather than a normatively determinative rule. This ought to help to address widespread confusion about the nature of the key rules and principles of international water resources law and its role in the resolution of water resources disputes and in environmental diplomacy more generally.