Skip to main content
Nossaman LLP


Council on Environmental Quality Proposes Important New NEPA Guidance Regarding Analysis of Greenhouse Gas Emissions and Mitigation of Environmental Impacts


The Council on Environmental Quality ("CEQ") has issued two draft guidance memos that address important National Environmental Policy Act ("NEPA") compliance issues:  (1) whether and how NEPA documents should evaluate and address impacts of greenhouse gas ("GHG") emissions; and (2) mitigation and monitoring of environmental impacts.  The guidance documents announce new policies that are likely to have an important legal and regulatory effect on many projects including infrastructure, energy, and development activities.  There is a 90-day comment period on these two draft guidances. 

GHG Guidance.  The draft GHG guidelines provide that federal agencies should quantify and describe expected direct and indirect GHG emissions where the emissions "may be meaningful."  While CEQ has not proposed a specific GHG significance "threshold," it proposes that annual direct GHG emissions of 25,000 metric tons or more of CO2 equivalent are "meaningful."  But the guidance also indicates that GHG emissions of less than 25,000 tons of CO2 emissions may warrant evaluation in NEPA documents.  How much below that amount will be "meaningful" will surely be subject to extensive litigation.  The draft guidelines note there is no single dominant source of GHG and then state "the global climate change problem is much more the result of numerous and varied sources, each of which might seem to make a relatively small addition to global atmospheric GHG concentrations."  This language suggests that individually small emissions may require analysis because they are part of a cumulatively "significant" whole. 

The guidance states that an environmental assessment or environmental impact statement analyzing the direct effects of emissions should quantify the cumulative emissions over the life of the project, discuss measures to reduce GHG emissions (including reasonable alternatives), and qualitatively discuss the link between the proposed action's GHG emissions and climate change.  Regarding indirect effects, the analysis "must be bounded by limits of feasibility." 
CEQ states its GHG guidance is not applicable to federal land and resource management actions, although there is no description of what falls within that excluded category. 

NEPA Mitigation and Monitoring Requirements.  CEQ also released draft guidance addressing federal agency obligations to (1) identify and evaluate measures to mitigate environmental impacts, and (2) implement mitigation measures identified in NEPA documents.  The guidance reflects the long-standing legal and regulatory effort to utilize NEPA's procedural mechanisms to require substantive changes in federal agency decisions.  The draft guidance focuses on public participation and accountability through the disclosure of the agency's mitigation efforts.  CEQ indicates that the goals of the guidance are to require federal agencies to adopt (1) binding commitments to implement mitigation measures, (2) monitoring programs to "ensure" the mitigation is implemented, and (3) reporting systems so that the public knows if and how the mitigation measures are implemented.  The guidance suggests that if funding for mitigation implementation is not available, and if the mitigation is necessary for the project, then the project should not go forward until the mitigation funding is available. 

CEQ also released a third guidance document describing the types of activities that may qualify for a categorical exclusion from NEPA review.  CEQ has set a 45-day public comment period on this draft guidance.

Click here to read the Draft Guidance on the Consideration of Greenhouse Gases.

Click here to read the Draft Guidance Clarifying Appropriateness of "Findings of No Significant Impact" and Specifying When There is a Need to Monitor Environmental Mitigation Commitments.

Click here to read the Draft Guidance Clarifying Use of Categorical Exclusions.

A partner with Nossaman, George Mannina has more than three decades of experience with environmental litigation and government relations.  He can be reached at 202.887.1491 or

  • Professionals
  • Practices
  • Success Stories
  • News
  • Events
  • Resources
  • Firm Pages