On 23 July 2025, the International Court of Justice (ICJ) rendered its long-awaited Advisory Opinion on the Obligations of States in Respect of Climate Change. In the proceeding leading up to the Opinion, Yas Banifatemi, Yael Ribco Borman and María del Pilar Álvarez advised and represented the Oriental Republic of Uruguay in the submission of two written statements and an oral submission addressing the legal issues before the ICJ.

After hearing more than 100 delegations from States and International Organizations, in its Advisory Opinion the ICJ confirmed various key points:

First, in addition to several binding obligations upon State parties to climate change treaties and other treaties, customary international law sets forth obligations for States to ensure the protection of the climate system and other parts of the environment from anthropogenic greenhouse emissions, including the duty to prevent significant harm to the environment by acting with due diligence and the duty to cooperate with each other in good faith to prevent significant harm to the climate system and other parts of the environment.

Second, States have obligations under international human rights law to respect and ensure the effective enjoyment of human rights by taking necessary measures to protect the climate system and other parts of the environment.

Third, States’ obligations pertaining to the protection of the climate system and other parts of the environment from anthropogenic greenhouse emissions, in particular the obligation to prevent significant transboundary harm under customary international law, are obligations erga omnes. Accordingly, responsibility for breaches of such obligations may be invoked by any State when such obligations arise under customary international law.

Fourth, depending on the relevant primary obligation breached, individuals may be entitled to invoke the legal responsibility of States for the breach of their obligations in respect of climate change.

Fifth, the breach by a State of any treaty or customary obligation with respect to climate change entails the international responsibility of that State. The legal consequences resulting from the commission of an internationally wrongful act may include the obligations of cessation of the wrongful conduct, providing assurances and guarantees of non-repetition of the wrongful conduct and full reparation.

Sixth, while the questions of attribution and causation do not exclude the responsibility of a State for a breach of its obligations in relation to climate change, the factual questions regarding attribution and apportionment of responsibility and the establishment of a causal link must be assessed on a case-by-case basis.

Gaillard Banifatemi Shelbaya Disputes is proud to have assisted the Oriental Republic of Uruguay in these historical proceedings and we share in the hope that the Advisory Opinion will bring much-needed clarity in the face of the urgent challenges posed by climate change and the need for urgent coordinated action.