Stanford Law School

A Seismic Shift in Climate Law

The episode examines the Environmental Protection Agency’s abrupt reversal of the 2009 greenhouse‑gas endangerment finding and the associated vehicle emissions standards, a move the administration touts as the largest deregulatory action in U.S. history. The discussion traces the Clean Air Act’s evolution from a 1970 focus on local pollutants to the 2009 finding that carbon dioxide, methane and other gases endanger public health, which spurred stricter fuel‑economy rules and accelerated electric‑vehicle adoption. The current administration argues that Congress never intended the Act to cover indirect climate harms, invoking the Major Questions Doctrine and the Supreme Court’s Loper Bright decision to challenge the EPA’s authority. Prof. Cus cites landmark cases—Massachusetts v. EPA, which affirmed EPA’s power to regulate greenhouse gases, and West Virginia v. EPA, where the Court applied the Major Questions Doctrine to limit agency reach—as the legal backdrop for the looming litigation. She also highlights attribution science linking intensified wildfires and other climate‑driven disasters directly to greenhouse‑gas emissions, underscoring the public‑health stakes. If courts side with the administration, decades of vehicle‑efficiency standards could be rolled back, slowing the transition to electric vehicles, raising emissions, and complicating U.S. commitments to climate mitigation. Conversely, a judicial rebuff would reaffirm the EPA’s regulatory footing, preserving market incentives for cleaner transportation and reinforcing the legal foundation for broader climate action.