The U.S. Supreme Court heard arguments in October 2026 on a case that could reshape climate litigation across the country, according to an analysis published by the American Legislative Exchange Council. In *Suncor Energy (U.S.A.) Inc. v. County Commissioners of Boulder County*, the justices will decide whether federal law blocks state courts from forcing energy companies to pay for local damages supposedly linked to worldwide greenhouse-gas emissions. The ruling could establish nationwide boundaries for state-law climate liability and affect dozens of similar lawsuits already filed.
The case started in 2018 when Boulder County and the City of Boulder sued ExxonMobil and Suncor Energy under Colorado law, claiming the companies contributed to climate change, deceived the public about their products' dangers, and should cover costs tied to wildfires, flooding, damaged infrastructure, and other local effects. The remaining claims include public nuisance, private nuisance, trespass, unjust enrichment, and civil conspiracy. Energy companies contend that questions involving emissions crossing state and national borders fall under federal authority rather than individual state control. In September 2026, Reuters reported that ExxonMobil and Suncor had identified nearly 60 state and local governments that filed comparable lawsuits seeking billions of dollars.
The litigation hasn't advanced uniformly across jurisdictions. Honolulu secured a win at the Hawaii Supreme Court on the federal preemption issue, and Chicago won a major federal appellate victory when the Seventh Circuit rejected defendants' attempt at federal removal. However, in March 2026, Maryland's top court upheld dismissal of climate claims filed by Baltimore, Annapolis, and Anne Arundel County. In April, a California court paused coordinated climate cases while waiting for the Supreme Court's *Suncor* decision. The U.S. Department of Justice has filed legal action against several states and municipalities—including Hawaii, Michigan, New York, and Vermont—trying to block these climate suits.
The analysis warns that a patchwork of potentially billions of dollars in state and local liability could generate greater uncertainty for domestic energy production and investment, with consequences for infrastructure development, energy supply, and ultimately the prices families and businesses pay. The concern centers on federalism: while states keep significant power over energy and environmental policy within their borders, permitting a single state court to impose liability based on global emissions could produce regulatory and economic effects reaching far beyond that state's borders. A single multibillion-dollar verdict could shape energy markets and business decisions nationally and globally—all started by one city. The report argues these suits seek to pull billions from energy producers for alleged harms too distant to support traditional tort claims, and that major policy decisions carrying consequences for energy affordability and reliability are better handled transparently by elected lawmakers through clearly defined statutes and regulations rather than developed piecemeal through litigation.
Whatever the Court decides, state legislatures will have stronger reason to examine where environmental enforcement ends and open-ended climate liability begins. The report notes that ALEC has developed model legislation—the Energy Security and Independence Act and the Energy Producers and Consumers Protection Act—designed to bar climate-related claims against businesses lawfully engaged in fossil fuel production and to keep major energy-policy decisions with elected lawmakers. As lawsuits and legislative proposals continue to develop, states can be expected to debate and define clearer rules for lawful energy activity, civil liability, and the proper role of courts in energy production.