The Emergence of the Environmental Impact Assessment Duty as a Global Legal Norm and General Principle of Law

More than half a century ago, Rudolph Schlesinger announced a global survey of legal principles in the pages of the American Journal of International Law. The project's objective was the identification of a “common core” of legal norms among the family of nations and the ultimate goal the production of something akin to a global restatement of law. Such an endeavor was to yield global principles of law, ultimately giving substance to the General Principles of Law provision under Article 38 of the Statute of the International Court of Justice. In spite of the initial enthusiasm surrounding the project, its ultimate goal was never realized.Five decades later, the prospect of engaging in such a project, focused on the environmental law field, promises more fruitful outcomes. In this article I argue that globalization and other trends have made the EIA duty – the duty to perform environmental impact assessments for projects that are likely to have a significant impact on the environment – a globally accepted norm. A 197-jurisdiction survey finds that the duty has been nearly universally adopted. The article suggests that the EIA duty may now be seen as a “general principle of law recognized by civilized nations,” and in that sense has joined the body of public international law. Finally, the survey results also point to comparative law methodology as a promising opportunity for identifying new legal norms in the international environmental law field, independent of the cumbersome process of treaty negotiation or the time-consuming development of customary law