[Spatiotemporal Transition, Convergence Trend, and Driving Factors of Urban Carbon Emission Intensity in China]

Analyzing the spatiotemporal transition, convergence trend, and driving factors of carbon emission intensity in Chinese cities can provide a scientific theoretical basis and empirical support for cities to control carbon emission intensity. Based on the calculation of carbon emission intensity for 284 prefecture-level and above cities in China from 2006 to 2021, this study uses exploratory spatiotemporal data to investigate the spatiotemporal transition of carbon emission intensity in Chinese cities. A spatial convergence test model was also developed to identify carbon emission intensity convergence trends and an MGWR model was introduced to analyze the spatial heterogeneity of its driving factors. The results showed that: ① The carbon emission intensity of cities nationwide and in the three major regions showed a decreasing trend over time, with a strong spatial positive correlation in the spatiotemporal distributions of each city. ② In terms of the local spatial structure and dependency relationship of carbon emission intensity, cities in the central and western regions exhibited higher volatility, while cities in the eastern region were relatively more stable. Overall, a certain inertia and locking feature was observed in the spatial pattern, with most cities escaping significant spatiotemporal transitions. ③ Except in the eastern region, the σ convergence characteristics of urban carbon emission intensity in the whole country and the central and western regions were not obvious. However, they all exhibited significant absolute and conditional β convergence. The speed of conditional β convergence was significantly faster than that of absolute β convergence, with the spatial convergence speed decreasing in the order of the central, western, and eastern regions. ④ The main driving factors of carbon emission reduction effects varied at different spatiotemporal scales, with certain spatial heterogeneity effects. This study comprehensively examines the spatiaotemporal transition, convergence trend, and driving factors of urban carbon emission intensity in China, trying to provide reference for differentiated emission reduction strategies of cities, which is of great significance for the transformation from "dual control of energy consumption" to "dual control of carbon emission" and the green transformation of economic and social structure.