Supreme Court Should Take Chance to Resolve Climate Change Split

The US Supreme Court repeatedly has declined to resolve a central question underlying the wave of the climate change litigation advancing through state and federal courts: Does the Clean Air Act preempts state common law claims of public nuisance?

The time has come for the court to step off the sidelines and clarify this sprawling and inconsistent body of cases. It can do so this term in Suncor Energy USA Inc. v. County Commissioners of Boulder County. Several recent developments make Supreme Court review more necessary and likely.

The petition for certiorari, filed on Aug. 8, asks the justices to review a Colorado Supreme Court decision that rejected arguments of preemption and other defenses raised in the defendant energy companies’ motion to dismiss last year. The decision cleared the way for plaintiffs to proceed to trial on state tort and consumer deception claims from alleged climate change effects.

We may have the Supreme Court’s decision on the petition soon. Notably, Boulder County “waived” its right to respond to the petition in late August—a tactic sometimes intended to signal that a case is unworthy of the court’s attention. But the court requested a response, now due by Nov. 10. This order indicates that at least some of the justices think the petition deserves serious consideration.

This petition arises against the backdrop of a long and complex history of climate change litigation in US courts. For more than 15 years, dozens of lawsuits have alleged public nuisance, consumer deception, and related claims against energy companies and others for purported contributions to climate change.

The Supreme Court has substantively addressed these claims only once—in American Electric Power Co. Inc. v. Connecticut in 2011. It’s time to do so again.

In AEP, the court held that plaintiffs couldn’t pursue federal common law public nuisance claims related to climate change because the Clean Air Act displaced the field. However, the court didn’t address whether the Clean Air Act similarly preempts state common law claims.

That omission has fueled a wave of state court litigation testing the boundaries of federal preemption. Granting certiorari in Suncor would allow the Supreme Court to close that gap and provide the clarity that both courts and litigants have lacked for over a decade.

Following AEP, plaintiffs shifted strategy, rebranding their claims under state law. What has followed is a patchwork of inconsistent rulings as courts have rejected divergent conclusions about the interplay between federal preemption and state common law.

Only a few outliers—such as courts in Hawaii and, most recently, this Colorado case—have allowed such claims to proceed past motions to dismiss. By contrast, a rising number of courts have recently concluded that the Clean Air Act preempts these state law claims.

As one Pennsylvania court noted in the May 16 opinion in Bucks County v. BP P.L.C., there is a “growing chorus singing from the same hymnal” in finding preemption appropriate. State or federal courts in New York, California, Pennsylvania, Delaware, Maryland, New Jersey, and most recently South Carolina have joined this consensus, with a South Carolina judge emphasizing in the Aug. 6 opinion in City of Charleston v. Brabham Oil Co. that, “the ranks of this chorus are welling for sound public policy reasons.”

Many of the decisions were issued after the Supreme Court declined to grant certiorari earlier this year in a climate change case coming out of the Hawaii Supreme Court. But the litigation landscape has evolved sharply in the months since.

There is now a clear, well-developed split of authority, and there has been substantial percolation in the lower courts since the last time the justices considered a climate change lawsuit petition. Both are key metrics the Supreme Court uses to decide whether to take a case.

The national significance of Suncor is undeniable. On Sept. 11, the Solicitor General filed an amicus brief urging the Supreme Court to grant review. The filing represents a more direct and forceful articulation of federal interest than the court received in previous climate litigation, and one more consistent with the Obama administration’s statements in AEP.

Beyond this brief, in the past year, the US has filed its own lawsuits seeking to enjoin states from pursuing climate change lawsuits or passing retroactive climate change fee assessment laws—further underscoring the national dimension of the issue.

Several amici have echoed this call for review, including a brief of considerable heft filed on Sept. 5 by former US Air Force General Richard Myers and former US Navy Admiral Michael Mullen, highlighting the national security implications of not resolving the current uncertainty.

These developments underscore that the question presented in Suncor isn’t a parochial dispute, but one of exceptional and recurring federal significance. Whatever hesitation the Supreme Court may have shown in the past, the rapidly evolving litigation environment and deepening doctrinal division make this term the right time to address these critical federal questions.

The court should grant review in Suncor to restore coherence and constitutional order to climate change litigation nationwide.

The case is Suncor Energy USA Inc. v. Cty. Commissioners of Boulder Cty., U.S., No. 25-170, amici briefs filed 9/26/25.

This article does not necessarily reflect the opinion of Bloomberg Industry Group, Inc., the publisher of Bloomberg Law, Bloomberg Tax, and Bloomberg Government, or its owners.

Author Information

Donald Kochan is professor of law and executive director of the Law and Economics Center at George Mason University Antonin Scalia Law School.

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