Spatiotemporal Disparities in and Convergence of Urban Green Transition Development in China

Against the backdrop of the global green development concept, scientifically assessing the level of urban green transformation (UGT) in China and revealing its spatiotemporal evolution are critical for promoting high-quality development in the country. We constructed an evaluation index system based on four dimensions: economic, social, resource, and environmental transformation. Using the entropy method, we determined the scores for a comprehensive green transformation development index for 285 prefecture-level-and-above cities in China from 2000 to 2023. We further employed kernel density estimation, standard deviation ellipses, the Dagum Gini coefficient, and convergence models to systematically examine the dynamic evolution, regional disparities, and convergence characteristics pertaining to UGT. The key findings are as follows: (1) There is a steady upward trend in the overall level of UGT in China, with intra-regional differences gradually converging. However, a “better–getting-better” differentiation pattern exists, while there is no observable multi-peak polarization. (2) Based on the UGT level, cities in China can be classified into four types: leading areas, potential areas, catching-up areas, and lagging areas. Spatially, a gradient pattern consisting of “high in coastal areas and low in inland areas” was identified. The overall centroid of green transformation has shifted southward, with a northeast–southwest distribution direction. The spatial agglomeration pattern exhibits a transition from dispersion to concentration. (3) There is a decreasing trend in overall disparity among the eight major economic regions, with inter-regional disparity being the primary source, while intra-regional disparity in coastal areas has increased. (4) Regarding convergence characteristics, σ-convergence can be observed in all economic regions except the Eastern Coastal, Southern Coastal, and Middle Yangtze River economic regions. Both absolute β-convergence and conditional β-convergence were found for China overall and its eight comprehensive economic regions, with the highest convergence speed in the Northeast region and the lowest in the Middle Yangtze River region. Furthermore, spatial absolute β-convergence and conditional β-convergence are also present, indicating strong spatial dependence among cities. This study provides empirical evidence and policy references for promoting UGT and optimizing regional development layouts in China.