Supreme Court hears oil companies' bid to kill Boulder climate lawsuit

The US Supreme Court heard arguments on Monday in a case that could determine the fate of dozens of climate lawsuits seeking damages from oil companies, as the justices opened their new nine-month term.

Known as Suncor v Boulder, the dispute began in 2018 when the city and county of Boulder, Colorado, sued ExxonMobil and Suncor Energy, claiming they “knowingly caused and contributed to the alteration of the climate” while “concealing and/or misrepresenting the dangers” of their products. The plaintiffs say they have suffered hundreds of millions of dollars in losses from wildfires, flooding and other weather extremes linked to fossil-fuel emissions.

The companies are appealing after the Colorado Supreme Court let the lawsuit proceed under state law. Kannon Shanmugam, representing the oil giants, told the justices the case “involves an unprecedented effort to use state law to regulate global conduct” and argued the Constitution bars state law from being applied in this way.

President Donald Trump’s administration backed the companies, arguing the federal government’s authority to regulate air pollution precludes Boulder’s claims. The court will consider whether the Clean Air Act pre-empts the claims, whether the Constitution itself bars such suits, and whether it can review the case before trial.

It is one of around 40 similar suits brought by cities, states and tribes. A ruling for the companies “could extinguish them entirely”, environmental law professor Katrina Kuh told AFP. Ahead of the hearing, Justice Samuel Alito recused himself over oil and gas stock holdings, leaving conservatives with a 5–3 majority but opening the possibility of a 4–4 split.

Sources: AFP via The Straits Times (5 Oct 2026) — https://www.straitstimes.com/world/united-states/us-supreme-court-hears-bid-to-shut-the-door-on-climate-suits ; Reuters via Superhits 97.9 (5 Oct 2026, by John Kruzel and Andrew Chung) — https://superhits979.com/2026/10/05/us-supreme-court-weighs-bid-by-oil-companies-to-avoid-climate-lawsuit/ ; Reuters (28 Sep 2026, Alito recusal) — https://www.reuters.com/business/energy/us-supreme-courts-alito-wont-participate-climate-case-involving-oil-companies-2026-09-28/ ; Bloomberg Law — https://news.bloomberglaw.com/us-law-week/supreme-court-sets-climate-suit-for-first-case-of-october-term