The ICJ Says Failing to Act on Climate Can Be a Wrongful Act, and Names Fossil Fuel Licensing and Subsidies

On 23 July 2025 the International Court of Justice delivered its advisory opinion on the obligations of states in respect of climate change. The opinion responds to two questions put by the UN General Assembly in a resolution adopted in March 2023, after a campaign led by Vanuatu and supported by a large group of states. The judges reached their conclusions unanimously. The first question asked what obligations states have under international law to protect the climate system for present and future generations.

The Court found that states have obligations under the UN climate treaties, including the Paris Agreement, and under customary international law, including a duty to prevent significant harm to the environment and a duty to cooperate. On the Paris Agreement, the Court found that the 1.5°C goal has become the primary temperature goal agreed by the parties, and that nationally determined contributions must reflect each party's highest possible ambition. On consequences, the Court's summary states that a failure by a state to take appropriate action to protect the climate system from greenhouse gas emissions, including through fossil fuel production, fossil fuel consumption, the granting of fossil fuel exploration licences or the provision of fossil fuel subsidies, may constitute an internationally wrongful act attributable to that state.

The Court was careful about the scope of that finding, and the wording matters for how it may be used. Advisory opinions of the ICJ are not binding in the way that judgments in contentious cases between states are. The Court also found that obligations under customary international law apply to all states, including those that are not party to the climate treaties. The practical effect of the opinion will depend on how it is used. The reference to fossil fuel subsidies is significant because subsidies remain widespread. The opinion also does not address the obligations of private companies directly.