Supreme Court Hears Climate Liability Case Suncor v. Boulder

The Supreme Court of the United States opened its new term on October 5, 2026, with oral arguments in Suncor Energy v. County Commissioners of Boulder County. The case determines whether state and local governments can use state tort laws to hold fossil fuel companies liable for climate-related damages, such as wildfires, pest infestations, and infrastructure repair costs.

Boulder County and the city of Boulder sued Suncor Energy and ExxonMobil in 2018, alleging the companies committed fraud by hiding the risks of fossil fuels while funding climate-denial narratives. While the Colorado State Supreme Court ruled in 2025 that these claims regarding production and marketing were not preempted by federal law, the oil companies appealed to the high court. They argue that the Clean Air Act and the U.S. Constitution preclude state-level claims, asserting that local governments cannot dictate national energy or foreign policy.

The Trump administration and the Department of Justice have supported the oil companies' position. However, the current Environmental Protection Agency stance—that the Clean Air Act does not authorize federal regulation of greenhouse gases—may complicate the companies' preemption arguments. Justice Samuel Alito recused himself from the case due to financial holdings in oil and gas companies, leaving eight justices to decide the matter and creating the possibility of a 4-4 tie.

A ruling in favor of the energy companies could lead to the dismissal of nearly 60 similar lawsuits nationwide, including a major suit by California. The court is expected to issue a decision by the end of June.