ICJ to Deliver Advisory Opinion on Climate Change

The UN’s highest court has announced the date when it will deliver its advisory opinion on the obligations of States with respect to climate change. A little over two years has passed since the UN General Assembly (UNGA) requested the International Court of Justice (ICJ) to determine what States’ climate change-related obligations are – and what happens in case of their breach. The ICJ will deliver its advisory opinion in open court on 23 July 2025.

Judge Iwasawa Yuji, President of the Court, will read out the advisory opinion during an afternoon public sitting at the seat of the Court – the Peace Palace in The Hague, the Netherlands.

The process that led up to the advisory opinion has been long in the making. Frustrated with the slow pace of international climate negotiations, vulnerable countries have long seen the value of, and made several attempts at, having the World Court weigh in on countries’ legal obligations with respect to climate change.

In 2002, Tuvalu – a small island developing State (SIDS) in the Pacific – considered bringing a claim against the US and Australia – two developed countries that are also major greenhouse gas (GHG) emitters. At the time, neither Australia nor the US had ratified the Kyoto Protocol that would provide for quantified emissions limitation or reduction commitments for each country.

In 2011, having garnered the support of more than 30 like-minded countries, another Pacific SIDS, Palau, led an attempt to have the UNGA request an ICJ advisory opinion to clarify the legal responsibility of the largest emitters. This was met with pushback from the US, and fears of losing billions in foreign aid for education, healthcare, and other sustainable development objectives led to the initiative being postponed.

It wasn’t until March 2023, when, following a youth-led campaign, the UNGA adopted a resolution (A/RES/77/276), proposed by a group of more than 100 countries, deciding to request the ICJ to issue an advisory opinion clarifying States’ climate change-related obligations. Citing the UN Charter, key human rights treaties, the UNFCCC and the Paris Agreement on climate change, and the UN Convention of the Law of the Sea (UNCLOS), along with the fundamental principles of international environmental law, the Assembly asked the Court two questions:

What are the obligations of States under international law to ensure the protection of the climate system and other parts of the environment from anthropogenic GHG emissions for States and for present and future generations?
What are the legal consequences under these obligations for States where they, by their acts and omissions, have caused significant harm to the climate system and other parts of the environment, with respect to: a) States, including SIDS, which, due to their geographical circumstances and level of development, are injured or specially affected by, or are particularly vulnerable to, the adverse effects of climate change? b) Peoples and individuals of the present and future generations affected by the adverse effects of climate change?

Over the course of two years, a record number of countries and admitted organizations engaged in the proceedings, making written statements and oral arguments and responding to questions from the judges. This level of engagement shows the significance States and stakeholders attach to the forthcoming advisory opinion.

The much-anticipated advisory opinion follows several rulings by regional courts, most notably:

The 2024 advisory opinion by the International Tribunal for the Law of the Sea (ITLOS), clarifying the specific obligations of States under the UN Convention on the Law of the Sea (UNCLOS) with respect to climate change;
Three 2024 rulings by the European Court of Human Rights (ECtHR) on climate change and human rights; and
The May 2025 advisory opinion by the Inter-American Court on Human Rights (IACtHR) on the climate emergency and human rights.

Other initiatives are underway, including a 2025 request for an advisory opinion on the human rights obligations of African States in addressing the climate crisis.

While the ICJ’s advisory opinions are not legally binding, they carry significant legal weight and authority. The Court is expected to clarify rights and obligations of States under existing international law, providing a clear legal benchmark to remove any ambiguities surrounding countries’ obligations going forward.

An Earth Negotiations Bulletin (ENB) team will cover the delivery of the ICJ advisory opinion by providing a briefing note on the history of the process, a summary of the announcement and the advisory opinion, and a brief analysis.

The SDG Knowledge Hub coverage of the ICJ advisory opinion process is here.

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This news story is part of a project that seeks to raise awareness and build momentum and knowledge around the ICJ advisory opinion on obligations of States in respect of climate change and to promote a better understanding of the implications of the advisory opinion among sustainable development decision makers.