Supreme Court to Review Climate Change Lawsuit Against Energy Companies

Why it matters locally: The Supreme Court's decision on this case could influence similar climate change lawsuits in Washington, potentially impacting local energy companies and industries reliant on fossil fuels.

WASHINGTON – The Supreme Court will hear arguments in *Suncor Energy Inc. v. County Commissioners of Boulder County* as justices consider a lawsuit seeking to hold energy companies responsible for climate change impacts. The case, originating in a Colorado state court, raises questions about whether federal law bars such claims. Boulder County seeks millions of dollars in compensation from Suncor and ExxonMobil. The outcome of this case could influence dozens of similar lawsuits filed across the country. Energy companies argue that these lawsuits aim to impose a "carbon tax" that could financially harm the industry. Conversely, Boulder County maintains its case should proceed, stating the energy companies are presenting arguments in the wrong forum. The dispute began in 2018 when Boulder County sued Suncor, which operates Colorado's only two oil refineries, and ExxonMobil. Boulder County claimed the companies deceived the public about climate change effects and contributed to climate change through fossil fuel production and marketing. After attempts to transfer the case to federal court failed, the energy companies sought dismissal from the state trial court, which denied their request. The companies then appealed to the Colorado Supreme Court, which affirmed the district court's decision, allowing Boulder's state-law claims to move forward. The Colorado court acknowledged the global significance of the issues but focused on the narrow question of whether the claims could proceed under Colorado law. Suncor and ExxonMobil petitioned the U.S. Supreme Court in August 2025, which granted review in February. Before addressing the merits, the U.S. Supreme Court must determine its jurisdiction. The Court typically reviews only final decisions from state courts. The energy companies argue the Colorado Supreme Court's ruling constitutes a final judgment because it acted under its original jurisdiction, not merely as an appeals court. They also cite the *Cox Broadcasting Corp. v. Cohn* exception, which permits review when a state court has decided federal-law issues that would terminate the litigation if reversed. Boulder County disputes the Supreme Court's authority, asserting the Colorado Supreme Court proceeding was not a "self-contained" action. Boulder County states the energy companies requested a review, not an order, and that calling it an "original proceeding" does not change its nature. Furthermore, Boulder County contends the *Cox Broadcasting* exception does not apply because the companies still have other federal-law defenses, such as constitutional arguments, to raise upon the case's return to state court. On the merits, the energy companies argue the Constitution limits states' ability to regulate "inherently transboundary issues such as global climate change." They assert that states ceded such regulatory power when joining the United States and that federal law governs air and water regulation in their interstate aspects. The companies also contend Boulder's claims are foreclosed by the federal government's control over foreign affairs, given that the alleged injuries stem from global greenhouse gas emissions. They argue such lawsuits interfere with federal diplomatic efforts balancing climate change with other interests. The companies further claim the Clean Air Act preempts Boulder's claims, as it establishes a comprehensive federal framework for air quality regulation through the Environmental Protection Agency (EPA). Boulder County counters that the Constitution's text does not prohibit its state-law claims. It notes that state courts have historically applied state law to address environmental harms crossing state lines. Boulder County also argues that the federal government's power over foreign affairs does not compel dismissal, asserting that the companies have not demonstrated a clear conflict with an express federal foreign policy. Regarding the Clean Air Act, Boulder County states the law regulates point-source emissions, and its lawsuit seeks monetary compensation, not sales blocks or emissions controls. Boulder County also points to recent EPA indications that it lacks direct regulatory power over some greenhouse gas emissions under the Clean Air Act, challenging the companies' preemption argument. Boulder County adds that if Congress believed climate change redress belonged at federal or international levels, it could legislate accordingly, noting current congressional consideration of such legislation. Supporting the energy companies, the Trump administration filed an amicus brief, arguing that state lawsuits attempting to address a global problem through "open-ended liability on fossil-fuel producers" would disrupt the federal system. Other amicus briefs echo these concerns, suggesting that numerous multi-billion-dollar judgments could destabilize the energy sector. In support of Boulder County, climate economists submitted a brief stating that requiring energy companies to compensate for their role in climate change would not destabilize the American economy. The Natural Resources Defense Council argued that scientific experts can quantify human contributions to climate change and attribute harms, providing a basis for Boulder's claims. The Brady Center to Prevent Gun Violence, joined by the Giffords Law Center to Prevent Gun Violence, stated that allowing Boulder's lawsuit would not lead to unlimited lawsuits, citing legal doctrines that protect out-of-state actors and require proof of causation. The complexity of the case increased when Justice Samuel Alito announced he would not participate due to stock ownership in oil and gas companies. This raises the possibility of a 4-4 tie, which would uphold the Colorado Supreme Court's decision allowing Boulder's claims to proceed.