Diffusion of “dual carbon” policies among Chinese cities: A network evolution analysis

Numerous regions across China have introduced “dual carbon” policies, yet the response of cities to these policies remains unclear. In this study, we used emission data from 271 Chinese cities for the years 2010, 2015, and 2020 to construct a complex network of urban carbon emissions with a modified gravity model. To further investigate the drivers of the “dual carbon” policy diffusion, we conducted a simulation of network evolution under the two policy diffusion mechanisms of coercion and learning. Our findings indicate that the “dual carbon” policy exhibits a network diffusion effect, with cost-effectiveness serve as a critical factor influencing its spread. And the China's low carbon price lacks incentives for reduction, carbon pricing needs to be increased and differentiated emission reduction incentives, penalties for over-emission, and carbon quotas based on the type of decoupling of the city need to be introduced to facilitate the diffusion of policies. Additionally, through counterfactual scenario analysis and an exploration of network structural characteristics, we highlighted the vital role of cities with high betweenness centrality within urban agglomerations in facilitating efficient policy diffusion. This study also offers a process for selecting pilot cities, providing a valuable reference for future policy initiatives.