未来能源研究所-对于气候和贸易政策，“共同但有区别的责任”原则是双向的（英）

For Climate-and-Trade Policies, the Principle of “Common but Differentiated Responsibilities” Cuts Both Ways Issue Brief 25-08 by Milan Elkerbout, Katarina Nehrkorn, and David Kleimann — May 20251. IntroductionBecause 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. 1 Article 3(1) of the UNFCCC is the most explicit legal expression of CBDR, followed by the statement that developed country parties to the UNFCCC should take the lead in combating climate change. The United States is a party to the UNFCCC.2. Common but Differentiated Responsibilities (CBDR)The principle of CBDR is the foundational precept—included in the United Nations Framework Convention on Climate Change (UNFCCC 1992; Congressional Research Service 2025)1—that could provide guidance. Like most principles in international law, the CBDR does not have a precise, universally agreed interpretation that allows for uncontroversial translation into action. A developing country might hold that for mitigating climate change, richer, industrialized countries that contributed comparatively more to atmospheric carbon concentrations should reduce emissions faster than developing countries with lower historical emissions. In fact, the principle of CBDR has two extensions. The first is Respective Capabilities (RC): a country’s capacities (e.g., economic or technological) to address climate change. Whereas developing countries have asserted that CBDR should be based on historical responsibility, developed countries have argued that it should be based on capabilities, giving way to the longstanding RC view (Jolly and Trivedi 2021). Th