Sustainable Development in International Law : Nature and Operation of an Evolutive Legal Norm

Abstract

The wide dissemination of sustainable development in international law has generated considerable academic interest. However, because of the evasive and flexible content of what has been termed by the ICJ a concept in the Gabcíkovo-Nagymaros case, and more recently an objective in the Pulp Mills case, academic commentary has often struggled to ascertain sustainable development’s legal nature, which has proved a notion defying legal classification. One attractive thesis has been Lowe’s analysis of sustainable development as an interstitial or modifying norm which exerts its normative influence as an interpretative tool in the hands of judges. Its interpretative function is certainly very significant. Judicial bodies have used it to legitimize recourse to evolutive treaty interpretation, as a rule of conflict resolution, and even to redefine conventional obligations. However, beyond this convenient hermeneutical function, by laying down an objective to strive for in hundreds of treaties, sustainable development primarily purports to regulate state conduct. As an objective, it lays down not an absolute but a relative obligation to achieve sustainable development. Such obligations are known as obligations of means or of best efforts. Legal subjects are thus ultimately under an obligation to promote sustainable development