In July 2021, the European Commission published a proposal for a Carbon Border Adjustment Mechanism (CBAM), part of a wider package of laws aimed at implementing the European Union (EU) Green Deal. The exact design of the CBAM is in flux, and priorities will have to be set. The chief concern is the compatibility of a CBAM with the law of the World Trade Organization (WTO). This Article explores whether and how the various CBAM design options under consideration can be reconciled with WTO requirements, focusing on a possible import border adjustment scheme.

In 2009, when carbon dioxide (CO2) levels were at 387.43 parts per million, the Center for Biological Diversity and 350.org submitted a citizen petition calling on the U.S. Environmental Protection Agency to take steps necessary to institute a national ambient air quality standard (NAAQS) for greenhouse gas (GHG) emissions under §§108-110 of the Clean Air Act (CAA). For 12 years, the petition was simply ignored. Then, the day President Donald Trump left office, outgoing EPA Administrator Andrew Wheeler issued a letter denying the petition.