Cross-posted from Warming Law.

In an earlier post, we explored the background, context, and historical significance of the Second Circuit decision handed down late Monday in Connecticut v. AEP, in which the court ruled that a group of states and environmental groups could sue several major electric utilities for contributing to a “public nuisance” in the form of global warming. In this post, we’ll explore the various next steps and implications of this decision, and explain why it brings even a greater sense of urgency to Congress’s ongoing deliberations of climate legislation.

There are two parallel arenas in which this ruling may have consequences: the courts and the federal government. The most immediate consequences of this ruling will be played out through the courts. Now that the Court of Appeals for the Second Circuit has determined that the plaintiffs have standing and can bring their claim, the electric utilities could simply return to the lower court as ordered, and proceed to defend themselves against the charge that they are contributing to a public nuisance in the form of global warming.

Alternatively (and more likely), the utilities may appeal this ruling to the U.S. Supreme Court. There are enough elements in the Second Circuit’s decision that vary with other federal appeals courts’ rulings (notably on issues of standing) that there is a decent chance the Court would actually hear the case, and if that happens, neither party would have reason to be overly confident. In its only other major global warming decision, Massachusetts v. EPA, the Court ruled in favor of states and environmental groups, recognizing that they had standing and agreeing with the argument that carbon dioxide satisfies the definition of “air pollutant” under the Clean Air Act. On the other hand, Massachusetts v. EPA was decided by a narrow one-vote margin, and there is no guarantee that Justice Anthony Kennedy, who is generally considered the Court’s “swing vote,” would rule again with environmentalists on this case. Also, in recent years, the Court has proven inhospitable to environmentalists who have brought claims against industry, ruling against them in all five of the environmental cases it heard last year, and in addition has been increasingly conservative in granting public interest litigants standing. Justice Kennedy swings on environmental cases, but more against than for.

(Note: One other possibility is that, before going to the Supreme Court, the utilities may ask the full Second Circuit to rehear the case en banc, which could also result in a delay of the case or reversal of Monday’s ruling.)

Without a doubt, the worst-case scenario for environmentalists here is that the Supreme Court takes and reverses this ruling — not only eliminating its valuable precedent for future cases, but also creating new nationwide precedent that could preclude the possibility of similar nuisance-based global warming litigation (or even other types of environmental litigation) for years, if not generations, to come.

The second arena in which this decision might have an impact is, obviously, the political branches, through regulatory and legislative action in Washington. Environmentalists and industry seem to agree that the courts are not the place to develop a solution to global warming, and as other commenters have noted, this week’s ruling is certainly a prod to both the EPA and Congress to get on with regulating greenhouse gas emissions. As we explained in Part I, in the absence of action by the political branches, courts have historically stepped in and used their common law authority to address environmental problems. However, once the political branches have taken action — such as by passing legislation addressing an issue, or promulgating regulations — the courts’ power to adjudicate the issue outside the scope of legislation is “displaced.”

Ironically, that is what all parties to this litigation would like to have happen here, and that would certainly be the best outcome for environmentalists. Nuisance claims and other tort claims, just like EPA regulations under the Clean Air Act, will never be a substitute for a comprehensive, flexible, economy-wide climate bill that attaches a price to carbon emissions. Moreover, even if the courts’ authority to deal with this case is eventually displaced, the Second Circuit’s decision, if not overruled, will still hold open an avenue by which other states and environmental groups may be able to bring future nuisance claims against polluters. We’re therefore hoping that action by the political branches comes before the Supreme Court has an opportunity to review the Second Circuit’s decision in this case, leaving environmentalists with the best of both worlds: an effective climate bill, and excellent precedent to aid us in future legal endeavors.