Research on the Carbon Emission Reduction Effect of the Dual Pilot Policy of Low-Carbon Cities and New Energy Demonstration Cities

Achieving the “double carbon” goal and optimizing the energy structure necessitates strategic deployments such as low-carbon cities (LCCs) and new energy demonstration cities (NEDCs). Prior research has primarily examined the effectiveness of these two policies when implemented independently. Despite overlapping scopes, there remains a need for a definitive conclusion regarding whether the concurrent implementation of these policies will yield a synergistic effect, thereby further reducing carbon emissions. Employing panel data spanning 2007–2021 from 280 Chinese cities, this study investigates the carbon emission reduction (CER) effect of the dual pilot policy (DPP), focusing specifically on LCCs and NEDCs through a multi-period difference-in-differences (DID) analysis. The findings reveal a significant synergistic effect between LCCs and NEDCs on CER, with the sequence of policy implementation playing a crucial role in determining the effectiveness of CER. Notably, cities first become NEDCs and subsequently transition into LCCs, demonstrating a more pronounced CER effect. Further analysis of the impact mechanism underscores that the DPP fosters urban CER by elevating inventive and improved green technology innovation. Among these, the contribution of inventive green technology innovation is particularly prominent, accounting for as much as 24%, far surpassing the 20% contribution of improved green technology innovation. A heterogeneity analysis indicates that the DPP’s impact is more significant in western and non-resource-based cities. Given China’s status as one of the world’s foremost carbon emitters, exploring China’s CER pathways holds profound practical significance and offers invaluable empirical insights for advancing global CER efforts.