Spatiotemporal evolution and influencing factors of urban carbon emission efficiency in China: Based on heterogeneous spatial stochastic frontier model

With the introduction of the “carbon peaking and carbon neutrality goals”, improving city carbon emission efficiency has become a necessary path to achieving economic, social, and environmental coordinated development. This article employs a heterogeneous spatial stochastic frontier model to estimate city carbon emission efficiency and conducts an empirical analysis of the spatiotemporal evolution, convergence, and influencing factors of city carbon emission efficiency. The research findings are as follows: (1) The heterogeneous spatial stochastic frontier model has better applicability in measuring carbon emission efficiency than the traditional stochastic frontier model. (2) Industrial structure, population density, degree of openness to foreign trade, carbon market pilot policies, and green technology innovation all contribute to improving carbon emission efficiency, while resource-based cities tend to reduce carbon emission efficiency. (3) Eastern and central regions of China generally show an upward trend in carbon emission efficiency. First-tier cities, represented by Shenzhen, consistently rank at the forefront of national carbon emission efficiency. In contrast, the northeastern and western regions exhibit a reversed “U”-shaped trend in carbon emission efficiency, and there is no evidence of random convergence at both the national and regional levels. (4) The spatial distribution of carbon emission efficiency exhibits a “north-south divide” and an “east-high, west-low” pattern. City clusters represented by the Yangtze River Economic Belt and the Guangdong-Hong Kong-Macao Greater Bay Area are gradually becoming core regions for improving carbon emission efficiency, forming a preliminary “multi-polar agglomeration” low-carbon development pattern. (5) Cities in the western and northeastern regions have higher per capita carbon emissions but lack matching carbon emission efficiency, resulting in an “efficiency mismatch” phenomenon between per capita carbon emissions and carbon emission efficiency.