Scale effects and driving factors of spatiotemporal evolution of carbon emission efficiency: A case study of Henan province

Analyzing the evolution patterns of carbon emission efficiency at different spatiotemporal scales and revealing the driving mechanisms of multi-dimensional factors on carbon emission efficiency are of great significance for scientifically formulating energy-saving and emission-reduction policies and measures. The study first measured the carbon emission efficiency of 17 prefecture-level cities in Henan province from 2006 to 2022 using the super-efficiency SBM model. Then, the spatiotemporal evolution patterns of carbon emission efficiency at the municipal and regional scales were revealed through spatial analysis and the Gini coefficient method. Finally, the spatial Durbin model was employed to examine the degree of influence and constraint relationship of various factors affecting carbon emission efficiency in Henan. The results suggest that: (1) At the municipal administrative level, there is a significant difference in the carbon emission efficiency among the 17 prefecture-level cities in the province, with most not reaching the optimal level, and the unevenness phenomenon is prominent. Carbon emission efficiency presents a clear central and peripheral difference feature in geographical space. (2) There are significant differences in the carbon emission efficiency among different parts of the study area, and the carbon emission efficiency in Central Henan has remained in a relatively stable state for a long time, while the regions with low carbon emission efficiency are mainly concentrated in Southern, Northern, and Western Henan. (3) The factors influencing carbon emission efficiency in Henan have significant differences at the municipal and regional scales. In the future, Henan should formulate and implement differentiated carbon reduction policies based on the scale differences of carbon emission efficiency, focusing on optimizing the industrial structure, strengthening technological innovation, and reasonably guiding energy consumption to promote the overall improvement of carbon emission efficiency in the province.