Justices Signal Skepticism of State Climate Liability Claims in Suncor Oral Argument
On October 5, the Supreme Court held oral argument in Suncor Energy (U.S.A.) Inc. v. County Commissioners of Boulder County. The case asks whether local governments may use state tort law to hold fossil-fuel producers liable for harms tied to global climate change.
The core issue in this case is whether federal law preempts Boulder's state-law claims against Suncor and Exxon Mobil. Boulder's theory is that the companies' worldwide conduct increased the use of fossil fuels, which raised greenhouse-gas emissions, which contributed to climate change, which in turn harmed Boulder.
While individual states’ ability to regulate point sources of emissions under the source state’s law has long been recognized, Boulder’s theory does not cleanly fall under that area of permissible state regulation because it targets producers rather than “emitters” of greenhouse gases and the county is trying to hold them liable for their role in causing harm in one state based on their indirect contributions to climate change.
Suncor and Exxon Mobil argued that this crossed the line into exclusive federal jurisdiction under the Clean Air Act, but the Colorado Supreme Court rejected the companies' federal preemption defenses. Petitioners offered three grounds for reversal:
- The constitutional structure makes interstate pollution an inherently federal area.
- The Constitution forbids a state from regulating out-of-state conduct based on attenuated in-state effects.
- The Clean Air Act independently preempts the claims.
Boulder answered that states have always been able to provide tort remedies for in-state injuries caused by out-of-state conduct. It also argued that some of its claims are not preempted because they target conduct the Clean Air Act does not regulate, such as Petitioners' alleged “deception” about how fossil-fuel products affect climate change.
At oral argument, several justices seemed open to reversal. Justice Kavanaugh pointed out that Supreme Court precedent already makes "crystal clear” that interstate air and water pollution are matters for federal law unless Congress specifically states otherwise. Chief Justice Roberts asked whether Boulder's focus on fuel production, rather than emissions, was an attempt to evade those precedents. Justice Barrett largely accepted that interstate pollution is "an enclave of federal common law." She described the Clean Air Act's saving clause as preserving a limited area of state authority rather than broadly authorizing state regulation in this area.
Other justices pushed back on Petitioners' theories. Justice Sotomayor stressed that the Clean Air Act does not address fuel marketing or production, which suggests that she sees room for state law to reach that conduct. Justice Kagan doubted that the Constitution bars states from regulating interstate pollution, although she suggested that the Clean Air Act itself might preempt Boulder’s claims. In her view, Boulder's claims depend on the premise that the companies caused excessive emissions, and the Act sets up the scheme for deciding which emissions are excessive. Boulder noted in response that the EPA has disclaimed authority to regulate greenhouse gases pursuant to the Clean Air Act. Justice Gorsuch focused on a related problem: if EPA lacks authority to regulate greenhouse gases, he asked, would the Clean Air Act leave a gap in which nobody can sue at all?
Several justices also raised concerns about the practical limits of Boulder's theory of state regulation. Chief Justice Roberts asked how things would work out if municipalities in every state copied Boulder's pleadings. Justice Thomas asked whether anything would stop plaintiffs from suing large retailers, and Boulder's counsel conceded that nothing in Boulder's theory would. Justice Kavanaugh noted that an expert agency is better equipped than judges to set emissions policy, and he suggested the same reasoning applies to "a six-person state jury in Boulder." Boulder pointed to other limits on liability, including choice-of-law constraints, the dormant Commerce Clause, personal jurisdiction, and proximate cause, which would be addressed later in the litigation.
Several justices also raised questions about jurisdiction, which could give the Court an off-ramp. The Court can hear this interlocutory appeal only if the Colorado Supreme Court's ruling was a "self-contained" original proceeding. Justice Jackson suggested the case was premature because other federal defenses remain pending in state court. Petitioners urged the Court to answer the question "sooner rather than later" given the dozens of similar lawsuits pending across the country.
Ultimately, the questioning suggested that a majority may be prepared to reverse, likely by relying on the Court's existing interstate-pollution precedents. The jurisdictional questions and the separate treatment of Boulder's deception claims remain wild cards. And a late-breaking recusal by Justice Alito could yield a 4-4 vote, resulting in an affirmance by an equally divided Court.
Regardless of how this case is decided, it is expected to have significant consequences for energy producers’ exposure to climate-related tort liability nationwide.