Establishing the erga omnes character of the obligation to prevent transboundary environmental harm

Abstract

This article argues that the obligation to prevent transboundary environmental harm is erga omnes. In a fractured landscape, this obligation is the closest that international environmental law comes to a general obligation to protect the environment and should its erga omnes character be established, all States will be able to act when it is breached. In the absence of a settled methodology for identifying erga omnes obligations and using methodologies put forward in the literature and the characteristics of the erga omnes concept, this article argues that four criteria need to be met for an obligation to be erga omnes, namely that the obligation (i) has an agreed upon customary content, that it protects a (ii) common and (iii) essential interest, and (iv) that the ‘international community as a whole’ is the ultimate beneficiary. Using these criteria, the article is able to establish the erga omnes character of the obligation to prevent transboundary environmental harm.