WASHINGTON — The U.S. Supreme Court announced on Monday that it will hear arguments in a high-stakes case brought by major energy companies seeking to dismiss a lawsuit in Colorado that accuses them of contributing to the costs of climate change. Exxon Mobil Corp. and Suncor Energy Inc., two of the world's largest oil producers, are appealing a decision by the Colorado Supreme Court that allowed the suit, filed by the City of Boulder and Boulder County, to proceed in state court.
The lawsuit, first filed in 2023, alleges that the energy giants, through their production, marketing, and sale of fossil fuels, have violated Colorado state laws, including consumer protection statutes, by misleading the public about the environmental impacts of their products. Plaintiffs claim the companies bear responsibility for climate-related damages such as extreme heat waves, intensified wildfires, and other weather events that have burdened local governments with adaptation costs running into millions of dollars. According to court documents, Boulder County alone has spent over $10 million in recent years on wildfire mitigation and flood defenses linked to climate effects.
The Colorado Supreme Court's ruling in May 2025 rejected the companies' bid to move the case to federal court, determining that state courts have jurisdiction over these claims. This decision built on a trend of state-level actions against fossil fuel producers, as municipalities across the U.S. have filed more than a dozen similar suits since 2017, seeking damages estimated in the tens of billions.
Exxon Mobil and Suncor argue that the case intrudes on federal authority over interstate environmental issues. In their petition to the Supreme Court, the companies contend that climate change regulation is a matter for national policy, not fragmented state lawsuits, because greenhouse gas emissions cross state lines and require uniform federal oversight. They point to the Clean Air Act, the primary federal law governing air pollution, as evidence that Congress intended to centralize such regulation. "Allowing these claims to proceed in state courts would create a patchwork of conflicting rules that undermine national energy policy," a spokesperson for Exxon Mobil said in a statement following the Supreme Court's decision to take up the case.
The energy industry's position has garnered support from past and present federal administrations with differing views on climate policy. During Donald Trump's presidency, the administration actively backed the oil companies, filing a rare amicus brief in 2019 urging the Supreme Court to intervene in the Boulder litigation, even though the federal government was not a party to the suit. The brief argued that state courts lacked authority to address what it described as a global environmental challenge best handled at the federal level. Trump's administration was notably skeptical of aggressive climate measures, rolling back numerous Obama-era environmental regulations and withdrawing from the Paris climate accord.
In contrast, the Biden administration opposed the companies' appeal, submitting a brief that defended the right of states and localities to pursue such claims under their own laws. Officials in the Biden Justice Department argued that the Clean Air Act does not preempt all state actions related to climate harms, particularly those focused on consumer deception rather than direct emissions regulation. This shift highlighted the partisan divide on climate accountability, with Biden's team emphasizing local governments' roles in addressing unmitigated damages from fossil fuels.
The Boulder case is part of a broader wave of litigation targeting the oil industry. Similar suits have been filed by cities including New York, Honolulu, and San Francisco, as well as counties in California and Washington state, against companies like BP PLC, Chevron Corp., and Shell PLC. These cases often allege that the firms knew about the risks of climate change for decades but engaged in disinformation campaigns to protect profits. For instance, a 2023 investigation by the U.S. House Oversight Committee revealed internal documents from Exxon showing awareness of global warming's dangers as early as the 1970s.
The Supreme Court has a mixed history on these matters. In 2023, the justices declined to hear an earlier appeal by energy companies aiming to halt climate lawsuits in Hawaii and other states, allowing those cases to advance. However, in a 2021 decision involving Baltimore's suit against oil majors, the court sided with the companies on a procedural point, ruling 7-1 that the city could not amend its complaint to include certain federal claims after an initial dismissal. Justice Brett Kavanaugh, writing for the majority, emphasized the need for clear jurisdictional boundaries between state and federal courts.
Legal experts anticipate that the upcoming arguments, likely scheduled for the court's 2025-2026 term, could reshape the landscape of climate litigation. "This case goes to the heart of whether states can hold corporations accountable for environmental harms without federal interference," said Michael Gerrard, director of the Sabin Center for Climate Change Law at Columbia University, in an interview with The Appleton Times. Gerrard noted that a ruling in favor of the companies could effectively shield the industry from a significant portion of the more than 20 pending lawsuits nationwide.
On the other side, representatives for Boulder officials stress the urgency of local action amid federal inaction. Boulder County Commissioner Claire Levy stated, "We've seen the devastating impacts of climate change firsthand — from the Marshall Fire in 2021 that destroyed over 1,000 homes to ongoing drought stresses on our water supply. We can't wait for Washington to act; our communities need justice now." The fire, which scorched more than 6,000 acres and caused $2 billion in damages, was cited in the lawsuit as an example of exacerbated wildfire risks due to warmer, drier conditions linked to fossil fuel emissions.
The case also intersects with ongoing debates over federal climate policy. Comprehensive national efforts, such as a carbon pricing mechanism or aggressive emissions reductions, have repeatedly stalled in Congress, leaving states to fill the void. The Inflation Reduction Act of 2022 under Biden marked the largest climate investment in U.S. history at $369 billion, but it focused on incentives rather than liability for past harms. Critics from the energy sector argue that lawsuits like Boulder's could deter investment in cleaner technologies, while environmental advocates say they are essential for deterrence.
As the Supreme Court prepares to delve into the legal intricacies, the stakes extend beyond Colorado. A decision expected by mid-2026 could determine the viability of claims seeking to recover costs for sea-level rise defenses in coastal cities or infrastructure repairs after extreme storms. In Honolulu, for example, a parallel suit estimates damages at up to $4 billion for beach erosion and coral reef loss. Legal observers, including those from the American Petroleum Institute, warn that adverse rulings could lead to a flood of litigation, potentially costing the industry hundreds of billions in settlements or defenses.
Despite the companies' arguments, lower courts have increasingly sided with plaintiffs. In 2024, a California judge allowed Oakland's case against five major oil firms to proceed, rejecting claims of federal preemption. Similarly, the Vermont Supreme Court in 2023 upheld a suit by that state's attorney general, focusing on the industry's role in public nuisance. These victories have emboldened local governments, with the Union of Concerned Scientists estimating that unresolved climate damages could exceed $500 billion annually by 2050 if emissions continue unchecked.
The Supreme Court's composition, with a 6-3 conservative majority, adds another layer of uncertainty. Justices like Samuel Alito and Clarence Thomas have historically favored business interests in environmental disputes, while Sonia Sotomayor and Elena Kagan have advocated for broader state powers. The 2022 decision in West Virginia v. EPA, which limited federal regulatory authority over emissions, signaled a cautious approach to expansive climate rules, potentially influencing the Boulder outcome.
Looking ahead, the ruling could prompt legislative responses. If the court blocks state suits, advocates may push for federal reforms, such as amendments to the Clean Air Act to enable nationwide liability claims. Conversely, a win for Boulder could accelerate settlements, as seen in tobacco litigation decades ago, where companies paid out over $200 billion. For now, all eyes are on the high court as it weighs the balance between corporate accountability and federal uniformity in tackling one of the planet's most pressing crises.