Litigants have been using and will continue to utilise the US court system to try to set the course for how to govern greenhouse gas emissions (GHG) in the wake of federal and state environmental agencies opting not to do so.

As has been well documented, the US chose not to sign the Kyoto Protocol, the international treaty governing GHG emissions. Further, the Environmental Protection Agency (EPA), the leading federal environmental agency in the US, has historically resisted efforts to regulate GHG emissions, maintaining it did not have any authority to regulate GHG emissions under the federal Clean Air Act (CAA). Thus, it is not surprising that those interested in forcing regulation of GHG emissions in the US have resorted to litigation.