What makes climate change mitigation policies work?

This paper presents a meta-analysis of ex-post empirical evidence on the effects of mitigation policies on emissions. Drawing on 336 estimates from 121 studies, it covers a wide range of pricing and non-pricing mitigation policies across five broad sectors – agriculture, forestry and other land use, buildings, industry, power and transport. The analysis assesses how policy design attributes, studies’ methodological choices and contextual country-specific factors impact estimated policy effectiveness. The results highlight technology neutrality as a key determinant of policy effectiveness. Economic, regulatory, and information-based policies show comparable level of effectiveness in reducing emissions; for some policies, such as carbon taxes, estimated policy effectiveness rises over time. Estimated effectiveness of policies in the transport sector is lower than in other sectors. Observable macroeconomic and country specific characteristics – such as GDP per capita, oil prices, trade exposure, rule of law – explain little of the variation in the impact of policies on emissions. Instead, the findings point to unobserved factors - such as degree of policy enforcement and countries’ administrative capacity – as important drivers of policy effectiveness.