The D.C. Circuit upheld FERC's approval of a natural gas pipeline that would run from northern Pennsylvania to Alabama. Plaintiffs argued that FERC violated NEPA by failing to factor downstream greenhouse gas emissions into its evaluation of the project's environmental impacts. The court found that FERC had addressed downstream emissions by estimating the amount of carbon dioxide emissions resulting from the gas that the project would transport and predicating that those emissions would be partially offset by reductions in higher carbon-emitting fuel that the project's natural gas would replace.