Effectiveness of carbon pricing – A systematic review and meta-analysis of the ex-post literature

Abstract Today, about 70 carbon pricing schemes have been implemented around the globe, but their contributions to emissions reductions remains a subject of heated debate in science and policy. We use a rigorous, machine-learning-assisted systematic review and meta-analysis to quantify the effectiveness of carbon pricing in reducing emissions. Based on 483 effect sizes extracted from 80 causal ex-post evaluations across 21 carbon pricing schemes, we find that introducing a carbon price has yielded immediate and substantial emission reductions of about 10.4% on average (6.8% after correcting for publication bias), despite the low level of prices in most instances. Our study highlights critical evidence gaps with regard to dozens of unevaluated carbon pricing schemes and the price elasticity of emissions reductions. More rigorous synthesis of carbon pricing and other climate policies is required across a range of outcomes to advance our understanding of "what works" and accelerate learning on climate solutions in science and policy.