The National Environmental Policy Act (“NEPA”) was an important environmental law for several decades before climate change became an issue of concern. In the 1990s, efforts began to include in NEPA’s environmental assessments and environmental impact statements both the impact of federal government actions on climate change and the impact of climate change on proposed federal actions. These efforts were encouraged by the Council on Environmental Quality (“CEQ”). However, implementation at the agency level has since been uneven. Some federal agencies have resisted making serious efforts to incorporate climate change impacts into their decision-making process. Moreover, the courts have not been consistent in their reviews of agency compliance with NEPA, and the judiciary often gives substantial deference to an agency’s minimal NEPA compliance. Since 2017, determining NEPA’s requirements for climate change analysis has become more challenging because the Trump administration is changing federal environmental policies and regulations in order to encourage fossil fuel energy development and use, which will increase the emissions of greenhouse gases (“GHG”).