In a landmark advisory opinion delivered on 23 July 2025, the International Court of Justice (ICJ) clarified that under existing international law, all countries must act to reduce greenhouse gas emissions and protect the climate system, regardless of whether they’re signatories to the Paris Agreement. The Court affirmed that a “clean, healthy and sustainable environment” is a fundamental human right, and determined that failure to regulate emissions – including private-sector fossil fuel activities, subsidies, or licensing – can amount to an internationally wrongful act, triggering state responsibility. Consequences could include the duty to cease harmful conduct, issue guarantees against repetition, and provide full reparation – whether through restitution, compensation, or satisfaction – if a clear causal link to damage is established

Though ICJ advisory opinions are not legally binding, they carry substantial weight and are expected to supercharge future litigation and climate diplomacy. This ruling provides vulnerable nations – such as Pacific Island states – with a stronger legal foundation to hold high-emitting nations accountable. Leading scholars argue it opens avenues for lawsuits at both domestic and international levels, and may influence major legal frameworks governing climate responsibility and reparations for those most impacted by climate disasters