Research Article: Assessing Cumulative Significance of Greenhouse Gas Emissions: Resolving The Paradox—The Sphinx Solution

Abstract

The United States courts are increasingly requiring federal decision-makers to assess greenhouse gas emissions of proposed actions in National Environmental Policy Act (NEPA) analyses. With respect to NEPA, the cumulative effect of a proposal must be assessed in reaching a determination regarding the significance of its environmental impact. Analysis of cumulative impacts is one of NEPA's most challenging requirements. The problem of assessing cumulative greenhouse gas emission (GHG) impacts under NEPA is one of the thorniest in American environmental law and poses perhaps the most significant challenge to NEPA's regulatory framework in decades. A strict regulatory interpretation of “significance” can also lead to a paradox (Eccleston's Cumulative Impact Paradox), when one considers how the environment appeared before the intervention of human activities. A Finding of No Significant Impact (FONSI), by its very definition, states that an action will not have a significant effect, including a cumulatively significant effect. Because the global GHG concentration is generally considered to have already breached a cumulatively significant level (i.e., cumulatively significant impact), the assessment of proposals that emit even innocuous levels of GHGs can become a paradoxical effort. Specifically, a logical paradox arises in which many, if not most, federal activities should require preparation of an environmental impact statement (EIS) because they are technically ineligible for a FONSI. A strict interpretation of “significance” leads to such a conclusion, even in cases where the direct and indirect impacts of a relatively ‘small’ proposed activity may be finite but essentially innocuous. As described in this article, NEPA practitioners and decision-makers are beginning to appreciate the implications of this Cumulative Impact Paradox. This paradox must be resolved, if the analysis of cumulative GHG emissions is to contribute in a meaningful way to federal decision making.