Supreme Court Hears Arguments on State Climate Lawsuits Against Oil Companies

The Supreme Court began its new term on Monday by hearing oral arguments in Suncor Energy Inc. v.

County Commissioners of Boulder County. The case involves a lawsuit filed by the city and county of Boulder, Colorado, against ExxonMobil and Suncor Energy, seeking damages for climate change harms. Boulder alleges deceptive marketing practices by the companies, modeling its suit after cases against the tobacco industry. The court's decision could determine the fate of over two dozen similar lawsuits seeking billions of dollars from fossil fuel companies.

Arguments lasted about two hours, with Justice Samuel Alito recusing himself due to fossil fuel stock holdings, leaving eight justices to hear the case. Boulder filed its initial lawsuit in Colorado state court in 2018. The Colorado Supreme Court held in May 2025 that federal law did not preempt state law, leading the companies to appeal to the U.S. Supreme Court.

Boulder seeks compensation for past and future damages, including costs for mitigating climate change effects, but does not ask to enjoin sales or operations or enforce emissions controls. Oil companies, represented by Kannon Shanmugam, argue that federal law, specifically the Clean Air Act, preempts state and local governments from bringing such claims, contending Boulder attempts to regulate global conduct.

Boulder, represented by Kevin Russell, asserts their claims are about deception and damages, not emissions regulation. The Trump administration supports the oil companies' view. Some conservative justices expressed concern that a ruling for Boulder could open the floodgates to similar lawsuits. The Supreme Court's decision is expected by early next year or June.