The ICJ guidance will inform the growing number of national and international climate cases, writes Georgia Gratton
Last year saw historic outcomes in international legal cases centred on climate change, from the European Court of Human Rights (ECHR) to the world's highest court for marine protection, Itlos. And 2025 could see more, as the visible impacts of a heating planet increase.
The UN International Court of Justice (ICJ) is expected to reach an outcome in 2025 that is likely be a "watershed moment for international climate governance", think-tank IISD's Earth Negotiations Bulletin (ENB) says. Hearings for the ICJ proceedings wrapped up in mid-December. The court — which all 193 UN member states are party to — will issue an advisory opinion on states' responsibilities with regard to climate change. ICJ advisory opinions are not legally binding, but the outcome will "serve as definitive guidance from the world's highest court", environment organisation ClientEarth lawyer Lea Main-Klingst tells Argus.
The issue under consideration at the ICJ was originally spearheaded by the small island state of Vanuatu, and led to a UN General Assembly request for the ICJ's advisory opinion on states' obligation to "ensure the protection of the climate system and other parts of the environment from anthropogenic emissions of greenhouse gases for states and for present and future generations". It also seeks the ICJ's opinion on the legal consequences for states when they "by their acts and omissions, have caused significant harm to the climate system and other parts of the environment".
Countries gave verbal evidence outside the negotiating blocs typically seen at forums such as Cop climate summits, meaning countries "were free to articulate their own positions, often with surprising divergences from other speakers in the same negotiating group", according to ENB. Countries and some organisations will also be able to submit written evidence on topics including fossil fuel production and mitigation — actions to cut greenhouse gas (GHG) emissions.
Case study
The ICJ proceedings "will be very relevant to all climate-related cases both at the domestic and international level — and the number of these cases is only growing", Main-Klingst says. The ECHR ruled in April that signatories to the European Convention on Human Rights must protect their citizens from "serious adverse effects of climate change". And the Itlos outcome in May — another advisory opinion — was similar, finding that states have an obligation to reduce their GHG emissions to protect oceans.
The UK could prove to be a case study. The country's Supreme Court ruled in June — days before the current Labour government took power — that consent for an oil development in southern England was unlawful as it had not taken into account downstream emissions. The new government had already pledged to issue no new oil and gas permits, but it has since used the ruling to kick-start an overhaul of environmental guidance for oil and gas firms, which could have implications for previously approved developments.
The damage caused by climate change is growing, making it more crucial to settle legal parameters. Scientists are in agreement that 2024 will be the hottest on record, smashing the current record set in 2023. And insured losses from natural catastrophes — proven to be made more intense by climate change — easily broke the $100bn mark in 2024, for a fifth consecutive year, reinsurance firm Swiss Re says. This does not take into account the scale of uninsured assets, which are often in the most vulnerable countries. These factors put further pressure on international courts to clarify and set expectations on an issue that is not confined to national borders.
