When the U.S. Supreme Court held in AEP v. Connecticut (AEP) that the Clean Air Act displaced federal common law public nuisance claims against power companies responsible for emitting carbon dioxide, it left open the issue of whether a state public nuisance claim was available. Nearly a decade later, state and local governments (as well as a fishing industry trade group) are bringing a second wave of climate change public nuisance cases—this time based on state law.
Defined as an unreasonable interference with a public right, public nuisance is at the core of these complaints, although some also assert other causes of action. Yet the cases in this second wave differ from the earlier cases in potentially significant ways. Whether these factual differences will make a difference in legal outcomes remains to be seen.
Based on state law
First, the current cases, which have been filed mostly in state court, rely almost exclusively on state law. Defendants have removed several of these cases to federal court, and district courts have issued conflicting rulings on whether to remand the cases to state court. Those courts that have granted plaintiffs’ motions to remand—the district court in County of San Mateo v. Chevron and the district court in Mayor and City Council of Baltimore v. BP—have largely accepted plaintiffs’ characterization of their claims as state law claims. Those ruling for the defendants—the district court in City of New York v. BP and the district court in City of Oakland v. BP—have essentially held that federal common law governs the claims—and then concluded that such claims are displaced under AEP.
Each of these rulings is on appeal, but even if plaintiffs are allowed to proceed with their state law claims, they likely will have to demonstrate that Congress has not preempted those claims. Notably, preemption is more difficult to establish than displacement. Whereas displacement simply asks whether a statute “speaks directly to the question at issue,” preemption requires “clear and manifest” evidence that Congress intended to preempt state law. Moreover, federalism principles support a general presumption against preemption, particularly with respect to a state’s traditional police powers. No analogous presumption exists for displacement.
Fossil fuel company defendants
Second, defendants in the current cases are fossil fuel companies, not power companies. Although producing and distributing fuels does generate greenhouse gases (GHGs), the fossil fuel companies do not directly emit most of the GHGs associated with their products; their customers do. This fact might cut in different directions. Unlike the defendants in AEP, the fossil fuel companies lack permits governing fossil fuel combustion, undermining potential arguments that federal regulation displaces or preempts the public nuisance claims. On the other hand, defendants are already disclaiming liability on the ground that the bulk of GHG emissions occur when the fuels are no longer within their control. Notably, some jurisdictions (including California) do not require control of the instrumentality as an element of public nuisance.
Evidence of harm and causation
Third, if courts reach the merits of the state public nuisance claims, they will be presented with stronger evidence of harm and causation than existed when the earlier cases were filed. Scientific consensus on the phenomenon of climate change is now bolstered by lived experiences of sea level rise, extreme heat, unprecedented flooding, and other climate catastrophes. Detailed estimates of the cumulative GHG emissions from individual companies are also available. Indeed, at the climate change tutorial held by the judge presiding over the Oakland and San Francisco public nuisance cases, the defendants disputed neither the existence of climate change nor the contribution of fossil fuel emissions to the problem. Rather, the defendants questioned their responsibility for those emissions under public nuisance law. Challenging defendants’ assertions of innocence, the plaintiffs note that the defendant companies have long promoted fossil fuel consumption despite their knowledge of the resulting climate harms. In other words, proximate causation, rather than causation in fact, is likely to be a central issue.
Fourth, the current plaintiffs are primarily seeking the creation of an abatement fund to pay for climate adaptation projects. In contrast, the AEP plaintiffs sought specific emissions caps, subject to annual reductions—a form of relief that would have required courts to function as environmental regulators on an ongoing basis. Whether a less intrusive request for relief would ease courts’ reluctance to adjudicate climate change public nuisance cases is uncertain. In the wake of AEP, the U.S. Court of Appeals for the Ninth Circuit concluded in Kivalina that the Clean Air Act displaced plaintiffs’ federal public nuisance action for damages, notwithstanding the statute’s lack of a damages remedy. But the matter might come out differently under a preemption analysis, especially as Congress generally left damages to state law when it enacted the federal environmental statutes.
The second wave of public nuisance climate change litigation raises novel questions that may take years to resolve. These suits could result in sizeable judgments against the defendants, but are significant for other reasons as well. These cases highlight the fossil fuel industry’s role not only in causing climate change but also in blocking efforts to address the issue. Furthermore, the litigation could influence public and political understandings of climate change and put pressure on fossil fuel companies to support a legislative response, such as a carbon tax combined with immunity from public nuisance liability.