What Does the International Court of Justice Advisory Opinion on Climate Change Mean for Environmental Impact Assessment?

This briefing by the International Institute for Sustainable Development (IISD) analyzes the implications of the July 2025 International Court of Justice (ICJ) Advisory Opinion on the Obligations of States in Respect of Climate Change for Environmental Impact Assessments (EIAs). The document focuses on the ICJ's ruling that EIAs for fossil fuel extraction projects must now account for end-use emissions from the combustion of the extracted fuels, moving beyond previous focuses on operational emissions.

• The International Court of Justice (ICJ) ruled in July 2025 that end-use emissions resulting from the burning of extracted fossil fuels must be included in Environmental Impact Assessments (EIAs) for fossil fuel projects. The court stated that "possible specific climate-related effects must be assessed as part of EIAs at the level of proposed individual activities, e.g., for the purpose of assessing their possible downstream effects".
• The ICJ's ruling addresses a gap in previous EIA practices, where assessments typically only considered emissions from operating a site, such as powering rigs. This is significant because approximately 75%–85% of greenhouse gas emissions associated with a barrel of oil occur during ultimate consumption in vehicles or aircraft.
• Judges Bhandari and Cleveland clarified that the obligation to account for the increased concentration of GHGs resulting from production, licensing, and subsidy activities is derived from due diligence obligations as well as Articles 2 and 4 of the Paris Agreement.
• Prior to the ICJ's opinion, national and regional courts in the UK and EFTA had already established precedents for including downstream emissions. The UK Supreme Court in Finch v Surrey County Council (2024) required planning authorities to assess "downstream" GHG emissions, and the EFTA Court (2025) required a "reasoned estimate" of emissions from the subsequent combustion of extracted petroleum and natural gas.
• The ICJ Advisory Opinion has already influenced subsequent litigation within six months of its release. The European Court of Human Rights (ECtHR) in Greenpeace Nordic and Others v Norway (2025) and the Borgarting Court of Appeal (2026) both held that EIAs for oil and gas projects must include a quantification of anticipated GHG emissions, including combustion emissions both domestic and abroad.
• To mitigate legal risks, the IISD recommends that states update laws and guidance to ensure that: 1) the 'substitution' argument (that production would happen elsewhere) does not exempt end-use emission assessments; 2) there is a rebuttable presumption that all produced fossil fuels will be combusted; and 3) emissions are assessed against global and national climate objectives, such as IPCC 1.5°C-aligned pathways.

APA

Jones, N. (2026). What Does the International Court of Justice Advisory Opinion on Climate Change Mean for Environmental Impact Assessment? International Institute for Sustainable Development. https://www.iisd.org/system/files/2026-03/icj-advisory-opinion-environmental-impact-assessment.pdf

Chicago

Jones, Natalie. What Does the International Court of Justice Advisory Opinion on Climate Change Mean for Environmental Impact Assessment? International Institute for Sustainable Development, 2026. https://www.iisd.org/system/files/2026-03/icj-advisory-opinion-environmental-impact-assessment.pdf.

Wikipedia

{{cite report |last1=Jones |first1=Natalie |title=What Does the International Court of Justice Advisory Opinion on Climate Change Mean for Environmental Impact Assessment? |publisher=International Institute for Sustainable Development |date=March 2026 |url=https://www.iisd.org/system/files/2026-03/icj-advisory-opinion-environmental-impact-assessment.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{jones2026what, author = {Jones, Natalie}, title = {{What Does the International Court of Justice Advisory Opinion on Climate Change Mean for Environmental Impact Assessment?}}, institution = {International Institute for Sustainable Development}, year = {2026}, month = mar, url = {https://www.iisd.org/system/files/2026-03/icj-advisory-opinion-environmental-impact-assessment.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }