US supreme court hears big oil’s bid to block climate damage lawsuits

Suncor Refinery in Commerce City, Colorado, on 26 July 2023. Photograph: Hyoung Chang/Denver Post/Getty ImagesView image in fullscreenSuncor Refinery in Commerce City, Colorado, on 26 July 2023. Photograph: Hyoung Chang/Denver Post/Getty ImagesDemocracy, climate and justiceUS supreme courtUS supreme court hears big oil’s bid to block climate damage lawsuitsHow the court will lean is unclear amid Suncor Energy and ExxonMobil’s attempt to stop lawsuits at state level

About this contentHilary BeaumontMon 5 Oct 2026 15.57 EDTFirst published on Mon 5 Oct 2026 09.34 EDTSharePrefer the Guardian on GoogleThe US supreme court began its new nine-month term hearing arguments on Monday in a major case in which big oil companies attempted to strike a fatal blow against lawsuits that seek to hold them accountable for the climate crisis.

After the almost two-hour hearing, while it was not yet clear which way the justices were leaning, experts said the court may find it challenging to write a majority decision siding with industry.

In Suncor Energy Inc v County Commissioners of Boulder County, local officials in Boulder are suing Suncor Energy and ExxonMobil in state court to force the companies to share a portion of the costs that the climate crisis has imposed on local taxpayers. However, Exxon and Canada-based Suncor are arguing that federal law prevents state courts from hearing Boulder’s climate change lawsuit.

If the supreme court justices side with Boulder or decide that the case is not in their jurisdiction, then it would continue in state court. But if the fossil fuel industry convinces the justices, the decision could apply not only to the Boulder case, but also to dozens of other climate cases brought by state and local governments around the US.

As a result of Justice Samuel Alito’s recusal from the case, there are only five conservative justices weighing in, so Boulder county must only convince one conservative justice to win, assuming the three liberal justices back Boulder. Some noted that the justices focused their questions primarily on the merits of the case rather than asking if the court had jurisdiction to hear it, suggesting they will make a decision on the question of whether federal law pre-empts Boulder’s state climate case.

Kannon Shanmugam, a lawyer for the fossil fuel companies, told the justices that climate change was a pressing issue, but state cases such as the one filed by Boulder were the wrong way to resolve it, and the issue should be left to lawmakers. He argued that if the cases were heard in state courts, it would allow a high number of lawsuits to be filed. “The breadth of Boulder’s argument is astonishing,” he said.

Shanmugam argued that climate change is different from other interstate pollution cases “because the claim runs through global climate change” and involves anyone who uses fossil fuels worldwide.

Kirti Datla, the director of Earthjustice’s strategic legal advocacy program, said the industry lawyer needed five justices to agree with him. “Some of the justices seemed to be persuaded by the idea that climate change is different, or the sheer number of these suits creates a problem of a different kind,” Datla said. But she added that the justices were struggling to come up with reasons based in law that would support the industry arguments. “It’s always been Suncor’s task to provide them with clear answers to those questions, and I didn’t hear clear answers to those questions in argument.”

Dennis Fan, the founder and director of the Appellate Litigation Clinic at Columbia Law School who wrote an amicus brief in the case, said it was too close to call, but he was concerned for the future of the climate cases. “They focused more on the merits,” he said. “That had me much more worried for Boulder.”

Fan said the industry hopes this case is going to be the “death blow” to this type of lawsuit. “The industry is going for the home run … They’re thinking, ‘If we win this argument, there will never, ever be climate change litigation again.’”

Boulder officials filed a lawsuit in Colorado court in 2018 arguing that Exxon and Suncor concealed and misrepresented to the public what they knew about the damage that burning fossil fuels would do to the climate, and that they should pay for the resulting costs of disasters. Initially, the firms sought to have the case moved to federal court. Then when the Colorado supreme court allowed Boulder’s case to make its way toward trial in state court, Exxon and Suncor appealed that ruling up to the supreme court, arguing it should be dismissed on grounds of federal pre-emption.