The 2024 ITLOS COSIS Advisory Opinion: Delivering Climate Justice for Small Island States

Abstract for Scopus Indexing: In May 2024, the International Tribunal on the Law of the Seas ( ITLOS ) issued a historic advisory opinion on the obligations of States regarding climate change under the United Nations Convention on the Law of the Seas. This advisory opinion was issued in response to a request submitted by the Commission on Small Island States on Climate Change and International Law. Significantly, the Tribunal stated that: a) States must interpret their obligations under the Convention in light of the best available science; b) greenhouse gas ( GHG ) emissions constitute pollution of the marine environment; and c) they must take all necessary measures to reduce, prevent and control GHG emissions. ITLOS also noted that developed States have an obligation under the Convention to assist developing States in mitigating the effects of climate change. This advisory opinion marks an important first step in the fight for climate justice for small island States. Forthcoming are advisory opinions concerning climate change from the International Court of Justice ( ICJ ) and the Inter-American Court of Human Rights ( IACHR ). In this article, we explore the jurisdictional arguments some participants raised, the significance of the Tribunal’s opinion, and we contextualize the opinion in light of broader efforts towards climate justice.