Outcomes and policy focus of environmental litigation in the United States

Environmental policy in the United States is heavily influenced by civil litigation, which is used by government, environmental groups and industry to shape environmental protections. These disputes impact national and global environmental policy, but there is limited knowledge about outcomes for pro- and anti-regulatory plaintiffs or which areas of environmental policy are focused on by different plaintiffs. Drawing on 25,775 environmental civil suits and 4,142 judicial decisions filed in federal district courts between 1988 and 2022, we show that pro-regulatory plaintiffs tend to have a higher win rate than anti-regulatory ones, that federal enforcement litigation focuses overwhelmingly on pollution and waste-related conflicts, that environmental advocacy groups focus heavily on conservation-related conflicts and that climate and environmental justice-related themes are rarely discussed in environmental legal decisions. The inequality in legal advocacy that we document may help to explain areas of strength and weakness in US environmental policy, with implications for environmental justice and global sustainability. Environmental law is shaped by litigation outcomes as much as by legislation. This study examines nearly 30,000 civil suits and court decisions over 34 years to help reveal their influence on the legal and environmental landscapes of the United States.