In A.E.P. v. Connecticut, the Court provided a thorough recitation of the EPA’s findings with respect to climate change:
Responding to our decision in Massachusetts, EPA un-dertook greenhouse gas regulation. In December 2009, the agency concluded that greenhouse gas emissions frommotor vehicles “cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare,” the Act’s regulatory trigger. §7521(a)(1); 74 Fed. Reg. 66496. The agency observed that “atmospheric greenhouse gas concentrations are now at elevated and essentially unprecedented levels,” almost entirely “due toanthropogenic emissions,” id., at 66517; mean globaltemperatures, the agency continued, demonstrate an“unambiguous warming trend over the last 100 years,”and particularly “over the past 30 years,” ibid. Acknowl-edging that not all scientists agreed on the causes andconsequences of the rise in global temperatures, id., at 66506, 66518, 66523–66524, EPA concluded that “compel-ling” evidence supported the “attribution of observed climate change to anthropogenic” emissions of greenhouse gases, id., at 66518. Consequent dangers of greenhousegas emissions, EPA determined, included increases inheat-related deaths; coastal inundation and erosion caused by melting icecaps and rising sea levels; more frequent and intense hurricanes, floods, and other “ex-treme weather events” that cause death and destroy infra-structure; drought due to reductions in mountain snow-pack and shifting precipitation patterns; destruction ofecosystems supporting animals and plants; and potentially “significant disruptions” of food production. Id., at 66524– 66535
In a footnote, no doubt inserted at the insistence of a Mass. v. EPA dissenter, Ginsburg noted:
2For views opposing EPA’s, see, e.g., Dawidoff, The Civil Heretic,N. Y. Times Magazine 32 (March 29, 2009). The Court, we caution, endorses no particular view of the complicated issues related to carbon-dioxide emissions and climate change.
The Court, however, did not decide on the issue of whether such a nuisance suit could be brought under federal common law, as the federal legislation displaces the federal common law claim.
We need not address the parties’ dispute in this regard.For it is an academic question whether, in the absence of the Clean Air Act and the EPA actions the Act authorizes, the plaintiffs could state a federal common law claim for curtailment of greenhouse gas emissions because of their contribution to global warming. Any such claim would be displaced by the federal legislation authorizing EPA toregulate carbon-dioxide emissions.
Going forward, these suits are not likely to continue, as the Court finds that federal legislation clearly displaces these nuisance suits:
We hold that the Clean Air Act and the EPA actions it authorizes displace any federal common law right to seek abatement of carbon-dioxide emissions from fossil-fuel fired power plants. Massachusetts made plain that emis-sions of carbon dioxide qualify as air pollution subject toregulation under the Act. 549 U. S., at 528–529. And we think it equally plain that the Act “speaks directly” to emissions of carbon dioxide from the defendants’ plants.
Justice Ginsburg, in noting that federal common law can be displaced before the EPA exercises its regulatory authority–the EPA hasn’t enforced the legislation yet–remarks that “Congress could hardly preemptively prohibitevery discharge of carbon dioxide unless covered by a permit. After all, we each emit carbon dioxide merely bybreathing.”
The Court even took great pains to distance itself from “setting emissions standards by judicial decree under federal tort law.”
If the plaintiffs in this case are dissatisfied with the outcome of EPA’s forthcoming rulemaking, their recourse under federal law is to seek Court of Appeals review, and, ulti-mately, to petition for certiorari in this Court.Indeed, this prescribed order of decisionmaking—thefirst decider under the Act is the expert administrativeagency, the second, federal judges—is yet another reason to resist setting emissions standards by judicial decree under federal tort law. The appropriate amount of regula-tion in any particular greenhouse gas-producing sector cannot be prescribed in a vacuum: as with other questionsof national or international policy, informed assessment ofcompeting interests is required. Along with the environ-mental benefit potentially achievable, our Nation’s energy needs and the possibility of economic disruption must weigh in the balance.