Supreme Court opens term with Boulder climate case against Exxon and Suncor

The Supreme Court opened its 2026-27 term on Monday with arguments in a climate lawsuit brought by the city and county of Boulder, Colorado, against Exxon Mobil and Suncor Energy, CBS News reported. Arguments were scheduled to begin at 10 a.m. Eastern, according to the city of Boulder, and the case was the first on the term’s calendar.

The suit is one of dozens filed in state courts by states and local governments seeking money damages for past and future harms they attribute to the buildup of greenhouse gases, CBS reported. Boulder filed in 2018, alleging that the companies’ production and marketing of fossil fuels contributed to extreme heat, larger and more frequent wildfires and damage to the ecosystem. Its complaint raises five claims under state law.

The question before the justices

The issue is whether the suit can proceed or is barred by federal law, CBS reported. The Colorado Supreme Court ruled in May 2025 that federal law did not preempt Boulder’s claims, the city said. Exxon and Suncor appealed. The justices also asked lawyers on both sides to address whether the Supreme Court has jurisdiction to review the Colorado ruling, according to CBS.

Lawyers for the companies argued in filings that the Constitution and the Clean Air Act preclude claims that seek to address harms from interstate greenhouse gas emissions. If the Colorado decision stands, they wrote, “it would authorize all fifty States, the tens of thousands of municipalities, and even the hundreds of millions of individuals in our country to ask local courts to establish countless, conflicting climate policies for the Nation.” The Trump administration supports the companies, and so do West Virginia and 25 other states, CBS reported.

Michael Williams, West Virginia’s solicitor general, told reporters last week that the dispute “is a national problem, so it requires a national solution.” He said states can regulate emission sources within their own borders. “What they’re not free to do is say, hey you emitters, anywhere in the world … we’re going to make you pay money for any of those emissions anywhere in the world,” he said.

Boulder’s response

Boulder’s lawyers urged the court to dismiss the appeal for lack of jurisdiction. If the justices decline, they argued, the Colorado ruling should be upheld. “That climate change is a global problem does not disempower states from redressing its local harms either,” they wrote, adding that the litigation “merely asks that petitioners bear their fair share of local costs incurred in part because of their tortious conduct.” They also argued that the Clean Air Act governs emissions rather than the conduct of upstream fossil fuel producers, according to CBS.

The city says the lawsuit is not about regulating emissions or stopping fossil fuel production. Kevin Russell of the firm Russell & Woofter argued for Boulder, according to the city. Earthjustice, which filed a friend-of-the-court brief supporting Boulder, said climate mitigation in Boulder alone could cost taxpayers $157 million by 2050.

Alito recuses

Only eight justices are taking part. The court said last week that Justice Samuel Alito had recused himself and gave no reason, CBS reported. His 2025 financial disclosure shows individual holdings in two energy companies, ConocoPhillips and Phillips 66, and does not list individual stock in Exxon or Suncor, according to CBS. With eight justices, a 4-4 split is possible. In that event, the Colorado Supreme Court’s decision would stand, CBS reported.

Jonathan Adler, a William & Mary law professor who has written about federalism and environmental law and filed a brief supporting Boulder, said the case is not a judgment on whether such suits will succeed. “It’s a judgment about whether folks get to make their case,” he told CBS. He added that even if Boulder proceeds, the scope of what it can pursue could be narrowed significantly. CBS noted that a win for Boulder at the Supreme Court would not mean it ultimately prevails against the companies.

The justices’ October argument session runs from Oct. 5 to Oct. 14, SCOTUSblog reported.