The Synergistic Effect of China’s Dual Track Carbon Reduction Policies: A Joint Test Based on Carbon Trading and Green Certificate Trading

This study investigates the synergistic effects within China’s dual-track carbon reduction system integrating carbon trading (CT) and green certificate trading (GCT). It aims to empirically evaluate both the individual and combined impacts of these policies on regional carbon emission intensity. Using provincial panel data (2008–2021) and a multi-period difference-in-differences approach, we establish a quasi-experimental research framework. The results demonstrate that: both CT and GCT independently achieve significant emission reductions; their combination produces synergistic effects exceeding the sum of individual impacts (1 + 1 > 2); mechanism analysis reveals three transmission channels - energy structure optimization, green technology innovation, and industrial upgrading; heterogeneity analysis shows stronger synergistic effects in eastern regions with high environmental regulation intensity. These findings provide critical insights for designing integrated carbon-GCT markets and implementing region-specific policy combinations, ultimately supporting more efficient achievement of China’s dual carbon goals.