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Brief

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

End-use emissions from burning fossil fuels must now be factored into environmental impact assessments (EIAs). What do states need to clarify when changing the rules?

By Natalie Jones on March 17, 2026

Recommendations

  • The decision to assess end-use emissions in EIAs should not be affected by whether production to meet market demand for oil and gas would come from another project elsewhere if the proposal in question did not go ahead.

  • It should be assumed that all fossil fuels produced by a proposed project will be combusted to prevent fossil fuel companies from making unsubstantiated claims that the oil, gas, or coal will not be burned.

  • End-use emissions should be assessed in relation to national and global climate objectives and the state of global emissions reduction pathways. They should be considered cumulatively with other projects in a global context.

EIAs are a crucial policy tool used to inform development decision making by predicting the impacts of a proposed activity on the environment and identifying trade-offs between policy goals. A state’s duty to conduct an EIA before authorizing activities that may result in transboundary harm is well grounded in international environmental law. 

The International Court of Justice (ICJ) made several observations about the necessary content of EIAs in the context of climate change in its Advisory Opinion on the Obligations of States in Respect of Climate Change. Most notably, it ruled that end-use emissions from burning extracted fossil fuels must be considered in EIAs. This follows similar rulings by the United Kingdom Supreme Court and the European Free Trade Association Court. 

In the first 6 months following the ICJ’s verdict, its effects have been felt in at least two judgments of national and regional courts on the need to calculate anticipated end-use emissions resulting from the opening of new oil fields. To avoid increased legal risk, states should modify relevant laws, regulations, forms, and guidance to ensure all downstream and Scope 3 emissions are accounted for. 

This brief is part of a five-part series that seeks to help states understand their legal obligations under the ICJ Advisory Opinion and what actions they can take to ensure compliance. Other areas covered include climate adaptation, environmentally harmful subsidies, international investment law, and multilateral environmental agreements.