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 findings point to unobserved factors - such as degree of policy enforcement and countries’ administrative capacity – as important drivers of policy effectiveness.

Key findings

• 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 explain little of the variation in the impact of policies on emissions.