Suncor Energy case tests climate liability limits

The Supreme Court is weighing whether Boulder County can force Suncor Energy and one other energy company to pay for global climate change effects under Colorado public nuisance law. The case, Suncor Energy v. County Commissioners of Boulder County, marks the culmination of a legal strategy that emerged after the Supreme Court unanimously rejected federal climate-nuisance suits in American Electric Power v. Connecticut in 2011.

Documents released by the House Judiciary Committee on September 30 reveal the internal logic of this approach. Paul Hanle, who founded the Environmental Law Institute’s Climate Judiciary Project, wrote in a May 2022 email that without legislative or executive action, "real government action might still be derived from court decisions." Hanle stated the project’s goal was to target "key judges" with seminars to influence case outcomes. The CJP has put at least 140 federal judges through its climate "education" seminars.

Behind-the-scenes influence also extended to the federal judiciary’s Reference Manual on Scientific Evidence. In December 2022, the National Academies of Sciences, Engineering, and Medicine invited Michael Burger of Columbia’s Sabin Center for Climate Change Law to write the climate chapter. The Federal Judicial Center objected to Burger’s involvement because he is of counsel at Sher Edling, a firm representing cities and counties suing oil companies. Burger subsequently offered to contribute "behind the scenes," and his edits were incorporated into drafts circulated by the chapter's named authors. The Federal Judicial Center later withdrew the climate chapter, and the National Academies followed suit in August.

Legal experts argue that plaintiffs face a fundamental causation problem. Greenhouse gases mix globally, with approximately 90 percent of emissions occurring outside the United States, making it difficult to link specific local impacts like droughts in Boulder to particular companies’ production. To overcome this hurdle, Boulder’s trial court declared that in a multiple contributor tort case, there is no need to tie specific injuries to the actions of defendants. This legal standard effectively lowers the burden of proof required for climate-related tort claims.

During oral arguments, Justice Elena Kagan acknowledged the strength of Suncor’s causation argument but questioned why causation should matter for preemption. Justice Clarence Thomas pressed Boulder’s lawyer on the scope of liability, who conceded that "nothing in our theory" prevents suing retailers. The CJP curriculum for judges includes modules on "source attribution" studies that trace nearly two-thirds of carbon dioxide emissions since the 1750s to 90 fossil-fuel and cement producers. The curriculum also notes that industrial animal agriculture has been subjected to similar analysis, suggesting a potential expansion of liability beyond energy companies.

Chief Justice John Roberts asked if the suit was an attempt to evade federal decisions treating interstate air pollution as a matter of federal law. Justice Brett Kavanaugh cited Justice Ruth Bader Ginsburg’s opinion in AEP, which stated that federal judges lack the scientific, economic, and technological resources to set emissions policy. Kavanaugh asked whether this limitation also applies to a six-person state jury in Boulder.