International Tribunal for the Law of the Sea Advisory Opinion on Climate Change and International Law Led by Small Island State Leaders

The cost of loss and damage for developing countries is projected to reach $400 billion per year by 2030 and the initial pledges made at COP28 are considered paltry in comparison to the scale of the challenge. Furthermore, the definition of “vulnerability” and the eligibility criteria for accessing the fund are still being negotiated.

In any case, the ITLOS unanimous Advisory Opinion is a game changer. It is a significant event in the legal landscape related to climate change precisely because it will shape actions around climate change at both the international legal level and within the corporate sector. It will immediately affect the 168 States that are Parties to UNCLOS, but even states that are not party to UNCLOS, such as the US, recognize many of its provisions as forming part of customary international law.

The Advisory Opinion delivered by ITLOS includes several critical points. It concluded that States Parties to the UNCLOS Convention have specific obligations under article 194 “to take all necessary measures to prevent, reduce, and control marine pollution from anthropogenic GHG emissions and to endeavour to harmonize their policies in this connection”; provides guidance as to states’ obligations in relation to climate change under UNCLOS; found that states have a due diligence obligation to protect and preserve the marine environment from the deleterious effects of climate change; the obligations of states to assist developing states; and affirms that where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.

Importantly, oil companies and others have been brought into the legal ambit. The opinion underscores the evolving regulatory landscape concerning climate responsibility, and points to heightened scrutiny and regulatory enforcement concerning greenhouse gas emissions and environmental preservation.

The further significance of the ITLOS Advisory Opinion is that it will be cited in national, regional and international courts on all matters related to climate change. Immediately, it will be taken into account by the Inter-American Court on Human rights, which is currently considering a case, brought in January 2023 by Chile and Colombia, for an Advisory Opinion to address the climate emergency within the framework of international human rights law. Similarly, the International Court of Justice (ICJ) is now considering a request from the UN General Assembly, prompted by Vanuatu, to provide an Opinion on the obligations of states regarding Climate Change. The ICJ will undoubtedly consider the ITLOS Opinion before rendering its own Opinion by January 2025.

So, the ITLOS opinion has put a juggernaut in motion. The matter of the impact of Climate Change is no longer a matter for negotiation between powerful nations and weak states at COP – the stage is enlarged from a gladiatorial arena to include the precincts of law. The playing field is less uneven, and small island states are now imbued with a sense of hope and optimism.

But both industrial nations and their companies, which profit worldwide, will fight back to preserve their advantages. Having seen that the law is on their side, all of the small states, including those that did not join the COSIS effort, should bind together to secure their own advantage, which the ITLOS Opinion has provided.