The “Common Concern of Humankind”: Establishing Erga Omnes Obligations for Climate Change Responsibility in the ICJ’s Forthcoming Advisory Opinion

Adam Perri

In March 2023, the United Nations General Assembly (“UNGA”) requested the International Court of Justice (“ICJ”) to render an advisory opinion on the following questions:

(a) What are the obligations of States under international law to ensure the protection of the climate system and other parts of the environment from anthropogenic emissions of greenhouse gasses [(“GHGs”)] for States and for present and future generations[?]

(b) What are the legal consequences under these obligations for States where they, by their acts and omissions, have caused significant harm to the climate system and other parts of the environment, with respect to:

(i) States, including, in particular, small island developing States, which due to their geographical circumstances and level of development, are injured or specially affected by or are particularly vulnerable to the adverse effects of climate change?

(ii) Peoples and individuals of the present and future generations affected by the adverse effects of climate change?

This advisory opinion request comes at both a time of urgent global need for climate change action and an ongoing paradigm shift, at domestic and international levels, recognizing the importance of such cooperative, collective action to sustain a habitable environment for present and future generations. This Comment explores the current landscape of the climate change crisis that the ICJ will consider through the background of environmental agreements and climate change litigation, as well as human rights agreements and established principles of transboundary harm. Ultimately, this Comment will argue that the ICJ’s advisory opinion should unequivocally recognize that States’ responsibilities regarding climate change have the character of erga omnes obligations,  by which each State is responsible to the entire global community.

Within international law, erga omnes obligations are significant because, by “their nature,” they concern the international community as a whole and implicate a schema of natural law at the foundation of all international law that supersedes state sovereignty. Erga omnes obligations are derived from two primary sources of international law: treaties and custom. In many cases, the erga omnes obligations of international law are codified in the form of treaties, such as the prohibition against genocide in the Genocide Convention. In other cases, erga omnes obligations, even if partially or fully codified in treaties, draw broadly from customary international law and its overlapping concept of jus cogens—the peremptory norms of international law from which no derogation is permitted. Unlike in most disputes between States, which result from one nation directly breaching its obligations toward another nation, the breach of erga omnesobligations may result in any State seeking to hold the breaching party accountable. This Comment considers the strength of a potential erga omnes obligation for climate change action in light of the strong foundation provided by both treaty and customary sources of international law.