Climate lawsuits are increasingly common these days. Republicans have made national efforts to combat climate change effectively impossible in both the legislative and executive branches. Now a growing number of private and public litigants are taking the fossil-fuel industry to court for the harms they have caused.
One such case will be the first one heard by the Supreme Court in its upcoming term. It pits a Colorado town that has faced wildfires and droughts against two oil and gas companies that it claims are responsible for these harms. If the lawsuit succeeds, it will be a momentous step in holding the industry accountable for climate-related problems. All they have to do is persuade a Supreme Court that has reliably sided with the fossil-fuel industry to abide by longstanding rules and practices.
The case, Suncor Energy v. County Commissioners of Boulder, began in 2018. The city of Boulder, Colorado, and its county sued two oil companies in state court for traditional claims of nuisance, civil conspiracy, unjust enrichment, and so on. They alleged that Suncor Energy and Exxon Mobil had harmed the city and its residents in two ways.
One was by “knowingly” altering the climate through “producing, promoting, refining, marketing and selling fossil fuels” at high enough levels to contribute to climate change. The other was by “intentionally” misleading the public about climate change’s impact and their role in causing it.
The overwhelming scientific consensus is that burning fossil fuels has contributed to climate change by releasing large amounts of greenhouse gases into Earth’s atmosphere. Oil companies have spent decades disputing that science and promoting climate denialism to undermine political support for regulation and reform. Recent research has shown, however, that companies like Exxon were not only aware that their products would contribute to climate change, but even accurately modeled how much damage their businesses would inflict.
In some ways, this case resembles the lawsuits filed against tobacco companies and asbestos manufacturers for the long-tail harms caused by their products. But the Boulder lawsuit is more humble than the multi-state litigation campaigns against those industries. The city only seeks damages for the harms caused to residents, not a broader restructuring of the oil industry or any sort of regulatory caps on emissions.
“In an interconnected society, conduct in one or more states can cause injury throughout the nation,” they told the justices in their brief for the court. “The Constitution generally permits states to use their traditional authority to address harms arising within their own borders. Whether those harms are better addressed at the federal level is a decision the Constitution almost always assigns to Congress, which is uniquely structured to weigh state and national interests.”
As you might imagine, Suncor and Exxon have no desire to pay damages to a single person or municipality that claims to have been harmed by climate change. They vigorously contested the lawsuit in Colorado’s courts, arguing—among other things not relevant in this particular appeal—that Boulder’s claims were preempted by federal law. A state district court rejected that argument, as did the Colorado Supreme Court in a ruling last year.
Why would federal law block such a lawsuit? The Constitution’s Supremacy Clause holds that the Constitution, as well all laws and treaties made under it, are the “supreme law of the land.” In other words, federal law supersedes state law if there is any conflict or overlap between them. Exxon argued that the Clean Air Act, or CAA, of all things, should prevent Boulder from holding it accountable for climate-related harms in state courts.
The Colorado Supreme Court rejected that argument for three reasons. First, Congress did not explicitly declare that it was preempting the kinds of claims being brought against Exxon in this case. Nor has Congress implicitly preempted the states by “completely occup[ying] the field of emissions regulations” since the CAA allows states to maintain their own emissions-regulation regimes. Finally, the court found no conflict between the state-level claims and federal law. Suncor and Exxon, the judges concluded, could comply with the former without breaking the latter.
The companies asked the Supreme Court to intervene, and it agreed to hear the case last term. The justices will decide two questions: First, does the Supreme Court have jurisdiction to review the lower court’s ruling at this stage? Second, does federal law prevent plaintiffs from suing energy companies for the harms caused by greenhouse-gas climate change?
Resolving the first question may decide whether the court reaches the second one at all. Boulder took issue with how the companies brought this case before the Supreme Court. They argued that it was inappropriate for the justices to weigh in at the current stage of the case. Technically, the Colorado Supreme Court only ruled on the companies’ motion to dismiss. Suncor and Exxon may yet prevail at a later stage in the case, the city acknowledged, and they have not exhausted their defenses in court.
The companies also argued against the lawsuit on what can be charitably described as partly constitutional grounds and partly policy grounds. The companies claimed that the lawsuit violated the “equal sovereignty” of the states by punishing them for out-of-state conduct. Boulder countered that states have heard claims for in-state injuries by out-of-state harms since the Founding, and that to rule otherwise would unsettle a significant area of the court’s precedents.
“Asbestos, defective medical products, defamatory articles, and internet fraud may originate in one or several states, or even from abroad, and cause injury across the nation,” the city noted. “Such cases may prompt calls for a uniform federal rule,” they acknowledged, but it is Congress’s responsibility to fashion one, not the Supreme Court’s.
One sign that the companies face an uphill battle is the sheer terror emanating from their briefs, where they urge the justices to save them on what amount to policy-driven grounds, not legal ones. “Giving even a single jury the power to impose ruinous liability on selected members of the energy industry is a recipe for chaos,” they claimed in their brief for the justices. “Unleashing juries nationwide is a recipe for disaster. This misuse of the legal system cannot stand. State tort law is not the solution to global climate change.”
The oil companies’ overarching argument is fairly audacious. Climate change, they argued, “results from the accumulation of greenhouse gases emitted from every state in the nation and every nation in the world—emissions that cannot be unmixed and traced to their individual sources.” They effectively argue that because they and their products have caused damage everywhere, they cannot be held liable for it anywhere. The companies repeatedly emphasized that the problem is “inherently interstate and international.”
As a result, the lawsuit is a near-existential threat to the industry. “If claims such as Boulder’s are allowed to proceed, every political jurisdiction in the nation could bring a similar suit against any subset of the world’s fossil-fuel producers,” the companies told the justices in their brief. They warned that potential damages “in any one case could reach into the billions” and urged the justices to reject the risk of “potentially crushing monetary liability” if they lose in state court. (The companies avoided the word “existential” itself, perhaps because it would evoke the harms that climate change will cause without societal intervention.)
Suncor and Exxon also expressed concern that Boulder’s lawsuit would upset the United States’ ability to confront climate change on the international stage. “Allowing state and local governments to seek liability for greenhouse-gas emissions released abroad would directly undermine the federal government’s efforts to handle this quintessentially global challenge,” they told the justices.
After reading that sentence, I had to backtrack to make sure I hadn’t downloaded a brief from before 2025. The second Trump administration is not “carefully balancing mitigating the risks of climate change with satisfying domestic and global energy needs,” contrary to the companies’ claims to the justices. It is destroying any hope of curbing carbon emissions, either regulating polluters directly or by shifting consumers away from fossil fuels through investment.
To that end, the Trump administration has withdrawn the U.S. from the Paris Climate Agreement, opened up public lands to new oil and gas exploration, illegally slashed funding for solar and wind projects, paid off wind-power companies to not pursue existing ones, and intervened in climate-related litigation by state and local governments. Trump’s EPA has even worked to repeal the EPA’s endangerment finding, which allowed the agency to regulate carbon emissions under the Clean Air Act. As one legal scholar noted earlier this week, that repeal may have seriously undermined the companies’ claims that the CAA preempts these lawsuits.
In another age, this may be an insurmountable battle for the companies at the high court. But the court’s conservative majority tends to view climate regulations with skepticism. Four years ago, the justices went out of their way to strike down a moribund Obama-era EPA policy so that they could rule the agency had no power to set carbon caps on fossil-fuel power plants.
Indeed, the Supreme Court’s shadow docket traces its origins to the court’s extraordinary decision to block that EPA policy from going into effect in the first place. If Suncor Energy and Exxon Mobil hope to prevail, they will need a similarly adventurous and unprecedented approach from the justices on their behalf. Oral arguments on October 5 will give Americans their first chance to see if the high court is feeling bold enough to try it.
