Climate litigation

Climate litigation emerged in the 1980s and 1990s, initially focusing on environmental impact assessments for fossil fuel projects. A landmark early case was Massachusetts v. EPA (2007), in which the U.S. Supreme Court held that the Environmental Protection Agency had authority to regulate greenhouse gases under the Clean Air Act. Since then, the field has expanded dramatically, with cases filed in over 55 countries across six continents.¹ The growth has been driven by scientific consensus on climate change, the adoption of the Paris Agreement, and the increasing availability of climate attribution science that links specific emissions to specific harms.

Litigants employ several strategies, including human rights claims, constitutional challenges, and corporate liability suits. In Urgenda Foundation v. State of the Netherlands (2019), the Dutch Supreme Court ordered the government to cut emissions by at least 25% by 2020, citing the European Convention on Human Rights.² Similarly, Neubauer v. Germany (2021) struck down parts of Germany's climate law as insufficient to protect future generations. Corporate cases, such as Milieudefensie v. Royal Dutch Shell (2021), have sought to hold companies liable for their contribution to climate change, although some have been overturned on appeal.

International courts have begun to weigh in on climate obligations. In 2024, the International Tribunal for the Law of the Sea (ITLOS) issued an advisory opinion stating that greenhouse gas emissions constitute marine pollution and that states have a legal obligation to reduce them.³ The Inter-American Court of Human Rights and the International Court of Justice have also been asked for advisory opinions on climate change, reflecting a trend toward using international law to clarify state duties.

Beyond headline cases, climate litigation includes niche areas such as cases against financial institutions for financing fossil fuels, youth-led suits, and litigation over climate adaptation measures like flood defenses. In the U.S., state-level cases have targeted utility companies for deceptive practices regarding climate risks. Some cases have been filed by municipalities seeking damages for climate impacts, such as the City of Baltimore's suit against oil companies. Additionally, litigation has been used to challenge inadequate climate risk disclosures by corporations, and to force governments to consider climate impacts in permitting decisions for new projects.

Advisory opinion

A non-binding legal opinion issued by an international court or tribunal, often requested by a UN body or member state.

Attribution science

The study of how much human-induced climate change contributes to specific weather events or impacts.

Greenhouse gas (GHG)

Gases such as carbon dioxide and methane that trap heat in the atmosphere, contributing to global warming.