Much has been written and studied on the topic of global warming since Svante Arrhenius—drawing on the earlier work of Joseph Fourier—first hypothesized in 1896 that the level of water vapor in the atmosphere increases as CO2 levels increase, that the presence of additional water vapor enhances the heat-trapping effects of CO2, and that fossil fuels are a major source of the CO2 that drives this pernicious process. The most current estimates project a 5.12ºC increase in surface air temperature by century’s end, although some of the scientists responsible for those estimates fear that the increase will be substantially higher given 2010’s record increase in greenhouse gas emissions. Indeed, some scientists hold that anthropogenic global warming threatens “the ability of the human race to survive.” As IPCC scientist Stephen Schneider put it: “Don’t be poor in a hot country, don’t live in hurricane alley, watch out about being on the coasts or in the Arctic, and it’s a bad idea to be on high mountains with glaciers melting.”
Regrettably, the United States has never passed a piece of legislation designed specifically to address the issue of global warming. As a result, the last decade has featured a burst of litigation by states and private entities grounded, among other things, in federal common law, and the Clean Air Act. At issue throughout was whether the provisions of the latter displaced the applicability of the former. The Supreme Court answered this question in the affirmative in the case of American Electric Power Company v. Connecticut in 2011. In that case, several states, the City of New York, and three private land trusts brought federal and state common law public nuisance claims against four power companies and the Tennessee Valley Authority, seeking a decree to cap their carbon dioxide emissions. However, left open was the question of whether this displacement extended to suits where non-equitable remedies are sought.
A few weeks ago, the Ninth Circuit grappled with this issue in the case of Native Village of Kivalina v. ExxonMobil Corp. In that case, a federally-recognized Tribe of Inupiat Eskimos residing on the northwest coast of Alaska brought suit against oil, energy, and utility companies, seeking money damages for the impending loss of their land to global warming-driven sea level rises. The court sided with the defendants, holding that the Clean Air Act displaced actions for money damages as well. Interestingly, sitting on the case by designation, Judge Phillip M. Pro of the U.S. District Court for Nevada offered a hint as to the avenues remaining open plaintiffs injured by the ravages of global warming seeking tort relief when he suggested in a concurring opinion that Kivalina may still pursue a remedy under state tort law. However, plaintiffs seeking to walk through this open door and pursue such claims may find the path before them poorly-illuminated as filing a state common law tort claim against greenhouse gas emitters raises several questions. The most daunting of these questions is which state or states’ law applies in the likely event that plaintiffs sue out-of-state greenhouse gas emitters and this is indeed the most challenging obstacle plaintiffs who choose this course will face.
Perhaps the Supreme Court’s jurisprudence regarding the Clean Water Act can provide some limited guidance, specifically the case of International Paper Company v. Ouellette. There, the Court held that, under the Clean Water Act, the law of the state from which water pollution emanates controls because applying affected states’ laws to out-of-state sources would frustrate the Act’s permitting framework. Similarly, the Clean Air Act imposes many obligations on states, including the primary responsibility for the design and implementation of schemes to achieve ambient air standards. Whether this delegation of responsibility renders applicable the Ouellette analysis or, alternatively, whether it sweeps state common law aside completely remains to be seen. If it doesn’t, a traditional choice-of-law analysis would become necessary.
Since the founding, American jurisdictions have employed a variety of approaches in choice-of-law determinations. For instance, some state courts have adopted a territorial approach, whereby the law of the state where the last event giving rise to the injury occurs controls the outcome of the case. A plurality of them employ a presumption that the law of the place of injury controls surmountable when it is shown that another state has the most significant relationship to the matter, in which case that state’s law controls. Some other states conduct pure interest analysis, whereby the state whose policy the case’s facts most implicate will have its law govern the outcome. Patently obvious is nightmare these rules would produce in multiparty greenhouse gas litigation containing plaintiffs hailing from several states with diverging approaches to choice-of-law issues. For instance, how do we determine where the last event giving rise to the injury occurred under the territorial approach? Would it be where the emission occurred? Where the plaintiff actually suffered the injury? And which state’s interests are paramount: emitter states or states where the plaintiffs have suffered harm? Such are questions that future litigants may have to face.
–Edward Smith, Associate
 Svante Arrhenius, On the Influence of Carbonic Acid in the Air Upon the Temperature on the Ground, 41 Philosophical Magazine and Journal of Science 237, 263-66 (1896).
 Id. at 270.
 A.P. Sokolov et. al., MIT Joint Program on the Science and Policy of Global Change, Probabilistic Forecast for 21st Century Climate Based on Uncertainties in Emissions (without Policy) and Climate Parameters 24 (2009), available at http://globalchange.mit.edu/files/ document/MITJPSPGC_Rpt169.pdf.
 See Greenhouse Gases Rise by Record Amount: Levels of Greenhouse Gas are Higher than the Worst-Case Scenario Outlined by Climate Experts Just Four Years Ago, The Guardian, Nov. 3, 2011, http://www.guardian.co.uk/ environment/2011/nov/04/greenhouse-gases-rise-record-levels.
 Ando Arike, Owning the Weather: The Ugly Politics of the Pathetic Fallacy, Harper’s Magazine, Jan. 2006, at 72 (quoting IPCC Chairman Dr. Rajendra Pachauri).
 Arthur Max, Climate Report: Poor Will Suffer Most, Global Pol’y Forum (Apr. 6, 2007), http://www.globalpolicy.org/socecon/envronmt/climate/2007/0406climatereport.htm.
 See Am. Clean Energy and Security Act of 2009, H.R. 2454 (2009) (died in the Senate); Climate Stewardship and Innovation Act of 2007, S. 280, 110th Cong. (2007) (died in committee); Global Warming Pollution Reduction Act of 2007, S. 309, 110th Cong. (2007) (died in committee); Climate Stewardship an Innovation Act of 2005, S. 1151, 109th Cong. (2005) (defeated by Senate vote); Climate Stewardship Act of 2003, S. 139, H.R. 4067, 108th Cong. (2003) (same); S. Res 98, 105th Cong. (1997) (enacted 95-0) (declaration opposing ratification of the Kyoto Protocol).
 E.g., Connecticut v. Am. Elec. Power Co., 406 F. Supp. 2d 265 (S.D.N.Y. 2005) (plaintiffs sought CO2 caps on defendant’s emissions under a public nuisance theory), vacated 582 F.3d 309 (2d Cir. 2009), rev’d 131 S. Ct. 2527 (2011); Comer v. Murphy Oil USA, Inc., Cause No. 1:11CV220-LG-RHW 2012 U.S. Dist. LEXIS 39580 at*62 (S.D. Miss. Mar. 20, 2012) (plaintiffs state and federal common law nuisance claims dismissed because the Clean Air Act displaced both causes of action); Native Village of Kivalina v. Exxon Mobil Corp., 663 F. Supp. 2d 863 (N.D. Cal. 2009) aff’d No. 09-17490, slip op. 11641 (9th Cir. Sept. 21, 2012) (plaintiffs seeking compensatory and punitive damages for harm to their village caused by global warming under public nuisance theory) ; California v. General Motors Corp., No. C06-05755 MJJ, 2007 U.S. Dist. LEXIS 68547 (N.D. Cal. Sept. 17, 2007) (plaintiffs sought caps on greenhouse gas emissions from defendant’s automobiles under public nuisance and civil conspiracy theories).
 E.g., Massachusetts v. EPA, 415 F.3d 50 (D.C. Cir. 2005) (plaintiffs appealed EPA’s denial of petition to regulate greenhouse gases from mobile sources under the Clean Air Act, 42 U.S.C. § 7401 (2006)); rev’d 549 U.S. 497 (2007); Northwest Environmental Defense Center v. Owens Corning Corp., 434 F. Supp. 2d 957 (D. Or. 2006).
 The Supreme Court held in Massachusetts v. EPA, that greenhouse gases are “air pollutants” under the Clean Air Act, 42 U.S.C. § 7602(g) (2012), 597 U.S. 497 (2007).
 131 S. Ct. 2527 (2011), rev’g 582 F.3d 309 (2d Cir. 2009), vacating 406 F. Supp. 2d 265 (S.D.N.Y. 2005).
 131 S. Ct. 2527, 2532 (2011).
 See Michael B. Gerrard, American Electric Power Leaves Open Many Questions for Climate Litigation, 246 N.Y.L.J. 1 (2011).
 No. 09-17490, slip op. 11641 (9th Cir. Sept. 21, 2012).
 Id. at 11648-50.
 Id. at 11657.
 Id. at 11671. In American Electric Power Co. v. Connecticut, the Supreme Court noted that their holding touched only upon federal—as opposed to state—common law and that the latter of these remained an open avenue unless it was later found that the Clean Air Act displaced state common law as well. 131 S. Ct. at 2540.
 See generally Michael B. Gerrard, What Litigation of a Climate Nuisance Suit Might Look Like, 121 Yale L.J. Online 135 (2011).
 See id. at 138.
 479 U.S. 481 (1987).
 Id. at 494-95.
 See 42 U.S.C. § 7407(a) (2012).
 See generally Joseph Story, Commentaries on the Conflict of Laws (1834).
 See Symeon C. Symeonides, Choice of Law in the American Courts in 2010: Twenty-Fourth Annual Survey, 59 Am. J. Comp. L 303, 330 (2011) (noting that 10 states employ a territorial approach in torts cases and 12 states apply it in contracts cases); Restatement of the Law of Conflict of Laws §§ 377, 384 (1934).
 See Symeonides, supra note 24, at 330 (noting that 24 states apply a balancing approach in torts cases and 23 apply it in contracts cases); Restatement (Second) of the law of Conflict of laws §§ 6, 145, 146 (1971).
 See Symeonides, supra note 24, at 330 (7 states apply interest analysis in some form or another); Brainerd Currie, Notes on Methods and Objectives in the Conflict of Laws, Duke L.J. 171, 173-74 (1959) (discussing the contours of interest analysis).