The Council on Environmental Quality (“CEQ”) released final guidance providing a framework for federal agencies to quantify greenhouse gas (“GHG”) emissions for projects subject to the National Environmental Policy Act (“NEPA”). When addressing climate change, agencies should consider both the potential effects of a proposed action on climate change as well as the effects of climate change on a proposed action and its environmental impacts.

CEQ recommends using projected GHG emissions as a proxy to quantify impacts—along with providing a qualitative discussion of the relationship between GHG emissions and climate change—to assist federal agencies in making “a reasoned choice among alternatives and mitigation actions.” Both direct and indirect effects should be analyzed in comparison to the no-action alternative—amounting to cumulative effects analysis. The guidance expressly provides that a separate cumulative effects analysis for GHG emissions is not necessary. The preference is for a quantitative analysis of GHG emissions based on available tools and information. Where agencies do not quantify projected GHG emissions, a qualitative analysis should be included along with an explanation of why quantification was not reasonably available. Simply stating that the proposed project represents only a small fraction of GHG emissions globally is insufficient. Finally, proposed mitigation of GHG emissions should be evaluated to ensure they are “verifiable, durable, enforceable, and will be implemented.”

In analyzing how climate change will affect a proposed project, CEQ does not expect agencies to undertake original research or analysis; rather the expectation is that agencies will rely on existing, relevant scientific literature, incorporating such research by reference into an environmental document. Accounting for climate change during the planning process allows agencies to consider a project’s vulnerability to climate change, in addition to particular impacts of climate change on vulnerable communities, allowing agencies to explore opportunities to increase a project’s resilience to climate change as part of the initial design.

Overall, CEQ would have agencies treat the analysis of GHG emissions and climate change like any other environmental impact under NEPA. The guidance acknowledges that the “rule of reason” and proportionality play a role in determining the extent of analysis, which should be commensurate with the quantity of projected GHG emissions “as it would not be consistent with the rule of reason to require the preparation of an EIS for every federal action that may cause GHG emissions regardless of the magnitude of those emissions.”

This guidance does not carry the force and effect of law. Nevertheless, it does provide a common approach to be used by federal agencies in analyzing climate change, and is bound to be persuasive in determining whether an EIS adequately addresses climate change impacts.