Climate policies are often evaluated using criteria that are heterogeneous and misaligned with the stated aims of these policies. By combining legal research methods with insights from economic theory, we systematically map and analyze the legal objectives of the European Union (EU) Emissions Trading System (ETS), a key climate policy instrument. We find that the EU ETS is shaped by a nuanced internal normative framework, the principal goal of which is emissions reduction, combined with three secondary goals of cost-effectiveness, economic efficiency and equity, and a meta-goal of coherence. Based on the contents and interrelations of these legal objectives, we formulate evaluation criteria that can be used to critically analyze and evaluate the EU ETS performance in a more comprehensive, transparent, and comparable manner. The resulting methodology is applicable to other environmental policies and jurisdictions.
