The Supreme Court will hear oral arguments Monday in a case that could block one of the last remaining legal paths for holding fossil fuel companies responsible for damage from climate change.
The case, Suncor Energy vs. Boulder County, centers on a procedural question of whether the companies must face lawsuits in state courts, or if federal law precludes those.
The answer could shape the future of claims from dozens of states, counties and cities seeking to use state laws to recoup billions of dollars for the costs associated with climate disasters such as fires and floods.
Other legal avenues for holding fossil fuel companies accountable have already been foreclosed, including by a 2011 Supreme Court decision that effectively left no future for similar cases in federal court.
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“So if this one is closed, too, then seeking court remedies is going to be largely off the table,” said Jonathan Adler, a professor at William & Mary Law School who filed a brief in the case.
The city and county of Boulder, Colorado, filed a state lawsuit that aims to hold Suncor Energy and Exxon Mobil responsible for costs associated with climate disasters, arguing under a state law that the companies deceived the public about the danger of their products.
The Colorado Supreme Court ruled that federal law doesn’t stand in the way of the claims moving forward in state court. Similar claims have been filed across the country, including Vermont, Minnesota and Hawaii, and courts have been split on the question of whether federal law preempts the lawsuits.
Suncor Energy and Exxon Mobil told the Supreme Court in a filing in the case that the justices have a chance to address whether the climate change litigation can proceed before “the energy industry is threatened with potentially enormous judgments.”
“There are few, if any, more consequential questions pending in the lower courts concerning the relationship between state and federal law,” the companies wrote in their petition for the court to hear the case.
In an unusual move, the Supreme Court agreed to review the issue before the case has gone to trial and before a state court has made a final judgement. So the justices also will decide whether they have jurisdiction over the case at this early stage, a question that could give them a way to avoid a major decision at this time.
The Trump administration has unsuccessfully attempted to block several state law cases, suing states that are suing fossil fuel companies. Congress is also trying to weigh in: Sen. Ted Cruz (R-Texas) introduced a bill that would expressly foreclose state claims against fossil fuel companies.
The Supreme Court has declined to look at the same question previously, last year on a lawsuit from the city and county of Honolulu, and in 2023 on the same Suncor v. Boulder case. At least four justices must agree to grant a petition.
In both of those instances, Justice Samuel Alito recused himself early in the process, leaving the other eight justices to decide whether the court should take up the case. Alito owns stock ConocoPhillips and Phillips 66, companies implicated in related cases.
This time around, Alito did not recuse himself early on, and the court decided to take up the case. But this week, the conservative justice reversed course, recusing himself with a one-sentence announcement from the Supreme Court clerk.
Across the country, climate-related cases against fossil fuel companies vary in terms of their legal claims and the remedies they’re asking the court to provide. But the basic facts are the same, said Corey Riday-White, the legal director of the Center for Climate Integrity.
“They knew, they lied, they should be held accountable,” he said.
Riday-White likened Boulder’s case to those involving tobacco companies, opioid manufacturers and Meta. “You have companies that promote and sell a harmful product without warning the public about those harms, and the courts are the proper venue to go to to get compensated for those harms,” he said.
Suncor Energy and Exxon Mobil argue Boulder’s lawsuit amounts to an attempt to regulate its emissions across the country and the globe — a role only federal law can take.
The companies, in their brief, called the variety of claims against fossil fuel firms “complete chaos,” and said using state law to address climate change “represents a serious threat to one of our Nation’s most critical sectors.”
Saikrishna Prakash, a professor at the University of Virginia School of Law, argues in a brief filed in the case that Boulder is attempting to regulate fossil fuel production across the United States. Prakash contends that allowing the lawsuit to move forward would create a slippery slope to local governments being allowed to regulate consumers of fossil fuels, such as regular Americans who use gas stoves.
“[Boulder’s] lawsuit reflects a desire to change the world and rests on a long-arm theory of regulatory power, where Colorado may regulate worldwide to stem the effects of greenhouse gas emissions,” Prakash wrote.
Boulder argues in court filings that the federal government is not charged with regulating the “deceptive marketing” of fossil fuels. And it asserts that if the Supreme Court ruled that the Clean Air Act preempted any state laws that indirectly affect emissions, that would negatively affect everything from state gasoline taxes to local energy-efficiency regulations.
Historically, greenhouse gas emissions have been regulated under the Clean Air Act. But this year, the Environmental Protection Agency rescinded the endangerment finding, which provided the basis for the federal government’s ability to regulate emissions under that law.
EPA officials from Republican and Democratic administrations filed a brief arguing that consumer protection and deceptive advertising lawsuits like Boulder’s are not preempted by the Clean Air Act.
Dozens of other amici briefs have been filed, including from members of Congress, climate economists, city and county governments, manufacturing and transportation trade groups and the Justice Department.
In one, a group of Colorado ranchers explains how climate change has affected their livelihoods. One rancher said she had to sell all the cattle on her third-generation ranch after a wildfire ripped through in 2025. Another said his cattle didn’t have enough drinking water and were unable to graze their usual pastures.
“They fear that if municipal government keeps absorbing the increasing costs imposed by heat, drought, fires, and flooding, it will not be able to provide the services on which they depend to continue ranching,” their brief said.
Deirdre Macnab, a cattle rancher who learned about the case from her local newspaper, said she’s watched climate change take a toll on her neighbors and her own ranch, recalling fires that killed 60 of her neighbor’s cattle and took out miles of fences and transmission lines.
“Changing climate is happening, really, before our eyes,” she said. “A very significant part of climate change is tied to the fossil fuel companies, and I believe it’s critically important, and government’s role, to hold them accountable if they’re not holding themselves accountable.”
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