“ITLOS Delivers Landmark Ruling on State Obligations Under UNCLOS for Climate Change Action”

The International Tribunal for the Law of the Sea (ITLOS) recently issued an advisory opinion in response to a request from the Commission of Small Island States on Climate Change and International Law (COSIS). The advisory opinion sought clarification on the specific obligations of States under the UN Convention on the Law of the Sea (UNCLOS) with regards to climate change.

On May 21, 2024, ITLOS delivered a unanimous 153-page ruling addressing the questions posed by COSIS. The Tribunal’s findings shed light on the responsibilities of UNCLOS State Parties in preventing, reducing, and controlling pollution of the marine environment caused by anthropogenic greenhouse gas (GHG) emissions.

According to the advisory opinion, countries have a duty to take all necessary measures to combat marine pollution from GHG emissions and align their policies with international agreements such as the UNFCCC and the Paris Agreement. The Tribunal emphasized the importance of basing these measures on the best available science and striving to meet the 1.5°C temperature goal set out in the Paris Agreement.

ITLOS highlighted the obligation of due diligence in addressing marine pollution from GHG emissions, stressing the need for stringent standards given the potential for serious and irreversible harm to the marine environment. States are required to not only take action within their own jurisdictions but also cooperate internationally to tackle transboundary pollution.

The advisory opinion also outlined specific obligations for States, including the adoption of laws and regulations to address pollution from land-based sources, vessels, and the atmosphere. Additionally, countries are called upon to assist vulnerable developing States in their efforts to combat marine pollution from GHG emissions through various forms of support.

In response to the second question posed by COSIS, ITLOS emphasized the broad obligation of States to protect and preserve the marine environment from climate change impacts and ocean acidification. This duty includes restoring degraded marine habitats and ecosystems and conserving living marine resources threatened by climate change.

The advisory opinion underscores the importance of cooperation among States to address the challenges posed by climate change and ocean acidification. It also emphasizes the need for effective measures to prevent pollution from non-indigenous species introduced as a result of these environmental changes.

The ruling from ITLOS comes amidst ongoing efforts to clarify the responsibilities of States in relation to climate change, with the International Court of Justice (ICJ) expected to deliver its own advisory opinion on the matter later this year. The advisory opinions from both ITLOS and ICJ are crucial in shaping international efforts to combat climate change and protect the marine environment.

This news story is part of a project funded by the Foundation for International Law for the Environment (FILE) aimed at raising awareness and understanding of the implications of the advisory opinions on climate change obligations among sustainable development decision-makers.