Two Years In: Reflecting on ICJ Advisory Proceedings on Climate Change

By Elena Kosolapova, SDG Knowledge Hub

This month marks two years since the UN Secretary-General transmitted to the UN’s highest court the UN General Assembly’s (UNGA) request for an advisory opinion to clarify States’ climate change-related obligations under international law, along with the legal consequences of their breach. This milestone presents an opportunity to revisit the landmark moments of a process that followed, reflect on the main issues at stake, and weigh the implications of the forthcoming ruling that could be a game changer.

Picking up on a youth-led campaign, on 29 March 2023, at its 64th plenary meeting, the UNGA adopted a resolution (A/RES/77/276), proposed by a group of over 100 countries, deciding on the questions to be put to the International Court of Justice (ICJ). 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 greenhouse gas (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 small island developing States (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?

On 12 April 2023, the ICJ received the General Assembly’s request for an advisory opinion on obligations of States in respect of climate change, accompanied by a dossier of documents “that are likely to throw light upon these questions,” and proceedings commenced.

From UNGA’s request to hearings at the Peace Palace

On 17 April 2023, the Deputy-Registrar of the ICJ gave notice of the request for an advisory opinion to all States entitled to appear before the Court. On 20 April, the President of the Court fixed the deadlines for written submissions (20 October 2023) and for comments on the written statements made by others (22 January 2024). Both were subsequently extended.

In a testament to the importance the international community attaches to the advisory opinion, the Court received a record number of written statements from states and admitted organizations ever to have been filed in advisory proceedings before the Court – a total of 91.

The States that submitted written statements are Albania, Antigua and Barbuda, Argentina, Australia, the Bahamas, Bangladesh, Barbados, Belize, Bolivia, Brazil, Burkina Faso, Cameroon, Canada, Chile, China, Colombia, Costa Rica, the Democratic Republic of the Congo, the Cook Islands, Denmark, the Dominican Republic, Ecuador, El Salvador, Egypt, Finland, France, The Gambia, Germany, Ghana, Grenada, Iceland, India, Indonesia, Iran, Japan, Kenya, Kiribati, the Republic of Korea, Kuwait, Latvia, Liechtenstein, Madagascar, the Marshall Islands, Mauritius, Mexico, the Federated States of Micronesia (FSM), Namibia, Nauru, Nepal, the Netherlands, New Zealand, Norway and Sweden (jointly), Pakistan, Palau, Peru, the Philippines, Portugal, Romania, the Russian Federation, Saint Lucia, Saint Vincent and the Grenadines, Samoa, Saudi Arabia, Seychelles, Sierra Leone, Singapore, Slovenia, Solomon Islands, South Africa, Spain, Sri Lanka, Switzerland, Thailand, Timor-Leste, Tonga, Tuvalu, the UK, the United Arab Emirates (UAE), Uruguay, the US, Vanuatu, and Viet Nam.

The organizations that filed written statements are the African Union (AU), the Alliance of Small Island States (AOSIS), the Commission of Small Island States on Climate Change and International Law (COSIS), the European Union (EU), the Pacific Islands Forum Fisheries Agency, the International Union for the Conservation of Nature (IUCN), the Melanesian Spearhead Group (MSG), the Organisation of African, Caribbean and Pacific States (OACPS), the Organization of the Petroleum Exporting Countries (OPEC), the Pacific Island Forum (PIF), the Parties to the Nauru Agreement Office, and the World Health Organization (WHO).

Subsequently, the Court received 62 written comments on those statements.

Oral hearings in the advisory proceedings on the obligations of States with respect to climate change were held at the seat of the Court in The Hague, the Netherlands, from 2-13 December 2024. The hearings served as a platform for those who submitted written statements – and for those who did not – to present their views on States’ obligations under international law – and legal consequences that apply following breach of these obligations, especially with regard to future generations and SIDS that are particularly vulnerable to the adverse effects of climate change. In total, the Court heard 96 oral statements from States and 11 from international organizations, many of which had also filed written statements.

Issues at stake

Presenting their oral arguments, States and accredited organizations outlined the role of the UNFCCC, the Paris Agreement on climate change, and other environmental treaties. In defining the scope of States’ obligations, they also discussed human rights law, customary international law, and general principles of international law. The point in time at which knowledge of the adverse impacts of GHG emissions gave rise to States’ duty of due diligence to prevent harm to the environment was hotly debated.

The hearings revealed diverging perspectives on the legal consequences of breaching climate change-related obligations. Some underscored the climate regime’s non-punitive approach to compliance, while others emphasized the customary law of State responsibility, including obligations to cease wrongful conduct and provide reparations.

At the conclusion of the hearings, the judges invited written responses to their questions regarding: fossil fuel production; the interpretation of mitigation obligations under the Paris Agreement; the right to a healthy environment; and declarations related to State responsibility and liability for loss and damage. States and admitted organizations provided a total of 65 written replies.

High expectations

While the ICJ’s advisory opinions are not legally binding, they can clarify rights and obligations of States under existing international law and, as such, carry significant legal weight and authority. The Court’s ruling is expected to provide a clear legal benchmark and remove any ambiguities surrounding countries’ obligations under international law with respect to climate change.

Ensuing legal clarity would help strengthen the international climate talks many countries are increasingly frustrated with in terms of the pace and effectiveness of delivery of the Paris Agreement’s mandate. Indeed, the current set of nationally determined contributions (NDCs) puts the world on track to 3°C of warming compared to pre-industrial levels – far above the 1.5°C goal. Negotiations last year in Baku also cast doubt on many countries’ commitment to transition away from fossil fuels – a trajectory many speakers during the oral hearings hoped the advisory opinion would help alter.

With the Loss and Damage Fund woefully underfunded, it is the hope of many that the advisory opinion would help accelerate redress of loss and damage. It could also help pin down a fast mitigation target, support climate justice and human rights, and course correct on SDG implementation.

The ICJ is expected to deliver its advisory opinion in open court in the coming months.

Read the SDG Knowledge Hub’s coverage of the ICJ advisory opinion process, including policy briefs and guest articles by government representatives, legal counsel, and prominent experts here.

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This Policy Brief 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.