For Climate-and-Trade Policies, the Principle of “Common but Differentiated Responsibilities” Cuts Both Ways

Because countries decarbonize at different rates, leakage—the displacement of emissions as emitters respond to the costs of climate policy—has become a concern (Elkerbout 2024). Leakage is a potential problem in the European Union (EU) and United Kingdom (UK), where manufacturers face carbon costs through domestic carbon pricing programs but importers of similar goods do not. Even in countries with no domestic carbon price, differences in average carbon intensity between domestic and foreign producers can motivate the introduction of new fees on imports—as with the Republican proposal for a Foreign Pollution Fee Act in the United States.To mitigate the risk of leakage and protect the competitiveness of domestic industries, carbon border adjustment mechanisms (CBAMs) seek to level costs between domestic and foreign producers. Such policies to address leakage and level the playing field in international trade in turn raise equity concerns. Some imports that might be affected by CBAMs originate in developing countries, including least-developed ones, which are responsible for small shares of global greenhouse gas emissions and negligible shares of historical emissions. This makes CBAMs relevant to fundamental international climate policy governance issues: how to distribute the efforts of cutting global emissions, given widely divergent stages of economic development and historical responsibility across roughly 200 nations.