Small islands sound the climate crisis alarm before the highest court 

For the first time, more than 130 states have agreed to collectively seek the opinion of the International Court of Justice (ICJ) regarding the survival of mankind.Led by Vanuatu and a core group of countries, in April 2023 they agreed to consult the ICJ on the obligations of states to protect the climate system. The court, based in The Hague in the Netherlands, is the principal judicial organ of the UN.The ICJ is now set to deliver an opinion on this matter, and on the legal consequences under international law of causing significant harm to the climate system. This includes issues related to the prevention of significant harm to the environment, and the protection and preservation of the marine environment, among others.The Commission of Small Island States on Climate Change and International Law (COSIS), which requested the first climate-related advisory opinion from the International Tribunal for the Law of the Sea (ITLOS), participated in the ICJ proceedings. COSIS presented the small islands’ perspective, and has drawn on the conclusions of the ITLOS advisory opinion.The written phase of the ICJ proceedings concluded in 2024, followed by two weeks of hearings involving 107 states and international organisations, which ended on 13 December.Vanuatu’s special envoy for climate, Ralph Regenvanu, captured the significance of the case at the opening of the hearings: “This may well be the most consequential case in the history of humanity.” The court’s opinion is expected for 2025. It will mark the first time a climate case has been brought before the ICJ since governments acquired, over half a century ago, scientific proof that burning fossil fuel increases atmospheric CO2 concentration and temperatures, which will ultimately jeopardise the ability to sustain human life on the planet.Small island developing states (SIDS) are both victims of climate change and moral leaders in the fight for environmental justice. They offer the Global North valuable lessons through their ancestral and intimate knowledge of the ocean and natural world, showcasing ways to live in harmony with nature, particularly the ocean.Despite their minimal historical contribution to greenhouse gas emissions, SIDS have taken on moral leadership by bringing the ICJ into the effort to safeguard humanity. Vanuatu, supported by the SIDS, achieved a tremendous feat by building consensus among more than 130 states to secure the UN General Assembly’s request to refer these questions to the ICJ.International courts, rooted in Western justice systems, differ significantly from Indigenous systems of justice. Yet, we have witnessed lawyers from island nations – representing formerly colonised states – donning wigs to argue their case before the ICJ judges.SIDS propose a collective approach to the inaction of major polluters. They recall natural law and appeal to the shared sense of responsibility and wisdom of the international community, urging states to emerg