Evolutionary characteristics and influencing factors of carbon emissions in China: An examination of a 43-year urban scale.

Since 1978, China's rapid urbanization and industrialization have significantly increased carbon emissions. This study employs spatial autocorrelation, kernel density estimation, and spatiotemporal geographically weighted regression (GTWR) methods to analyze the spatiotemporal evolution characteristics of carbon emissions across 336 Chinese cities from 1978 to 2020. It also explores the dominant influencing factors for different cities at various stages of development. The findings reveal that carbon emissions in Chinese cities exhibit a stepwise growth pattern: "slow growth (1978-1995) - low-level stability (1996-2000) - rapid growth (2001-2012) - high-level stability (2013-2020)." The gap between cities has widened rapidly, and spatially, the distribution follows a "core-periphery" pattern. The increase in carbon emissions in core cities has transformed the urban hierarchy from a "generally low-carbon" structure to a "pyramid" structure. Compared to 1995, the influence of population size on carbon emissions decreased in 2020 (0.54-0.38), while the impact of infrastructure development and technological advances increased (0.02-0.25, 0.09 to 0.19). Due to the varying stages of urban development across regions, the influencing factors of carbon emissions exhibit spatial heterogeneity. Specifically, population size has a stronger positive impact on carbon emissions in the Southeast, technological advances in East and North China, and industrial structure in the Yangtze River Basin region. Infrastructure construction and investment levels show a dampening effect on carbon emissions in the Yangtze River Basin. Finally, the study proposes policy recommendations focusing on implementing regional "gradient" carbon reduction and promoting regional collaborative carbon reduction driven by core cities.