1 + 1 > 2? The synergistic effect of carbon emissions reduction policies: empirical evidence from China

The low-carbon city pilot policy (LCCPP) and the carbon emissions trading pilot policy (CETPP) are important measures for China to reduce its carbon emissions. However, the existing literature typically focuses narrowly on the effect of a single policy tool, leaving it unclear whether the LCCPP and CETPP are in conflict or complementary. Therefore, we investigated the synergistic effect of the LCCPP and CETPP in China using the difference-in-differences (DID) method. Compared with the 5.4% reduction of the LCCPP and the 5.1% reduction of the CETPP, the dual pilot policy (DPP) can improve the carbon emissions reduction effect to 11.9%. However, the effect of the DPP takes time to become apparent owing to a policy lag. The DPP primarily achieves its effect by promoting technological progress and optimizing energy allocation. In addition, the carbon emissions reduction effect of the DPP is more evident in large, high-ranking, and resource-based cities. Our work can help policymakers fully consider the coordination between future climate policies and design reasonable mixed policy tools.