This systematic review and meta-analysis evaluates the effectiveness of carbon pricing schemes in reducing emissions. Based on 483 effect sizes from 80 causal ex-post evaluations across 21 carbon pricing schemes, the study finds that introducing a carbon price has led to immediate and substantial emission reductions for at least 17 of these policies, with statistically significant reductions ranging from -5% to -21% (correcting for publication bias, -4% to -15%). The analysis highlights critical evidence gaps, particularly regarding the price elasticity of emissions reductions and the effectiveness of unevaluated carbon pricing schemes. The study emphasizes the need for more rigorous synthesis of carbon pricing and other climate policies to advance understanding and accelerate learning on climate solutions. The findings suggest that carbon pricing policies are effective in reducing greenhouse gas emissions, with the effectiveness varying based on policy design and context. The meta-analysis also addresses heterogeneity in effect sizes, finding that differences in estimates are driven by policy design and context rather than carbon price levels, sectoral coverage, or policy type. The study concludes by identifying areas for further research, including the evaluation of higher carbon prices and the need for high-quality primary research to improve the evidence base.This systematic review and meta-analysis evaluates the effectiveness of carbon pricing schemes in reducing emissions. Based on 483 effect sizes from 80 causal ex-post evaluations across 21 carbon pricing schemes, the study finds that introducing a carbon price has led to immediate and substantial emission reductions for at least 17 of these policies, with statistically significant reductions ranging from -5% to -21% (correcting for publication bias, -4% to -15%). The analysis highlights critical evidence gaps, particularly regarding the price elasticity of emissions reductions and the effectiveness of unevaluated carbon pricing schemes. The study emphasizes the need for more rigorous synthesis of carbon pricing and other climate policies to advance understanding and accelerate learning on climate solutions. The findings suggest that carbon pricing policies are effective in reducing greenhouse gas emissions, with the effectiveness varying based on policy design and context. The meta-analysis also addresses heterogeneity in effect sizes, finding that differences in estimates are driven by policy design and context rather than carbon price levels, sectoral coverage, or policy type. The study concludes by identifying areas for further research, including the evaluation of higher carbon prices and the need for high-quality primary research to improve the evidence base.