Driving Mechanism of Carbon Emissions by High-Density Urban Spatial Morphology at the Micro-Grid Scale—Taking Beijing as an example

Abstract. With the continuous advancement of urbanization, the impact of urban spatial form on carbon emissions has increasingly become a core topic in research on sustainable urban development.Taking the 2001 micro grids of Beijing, a typical representative of high-density cities, as an example, this paper estimates grid-scale carbon emissions using nighttime light data. It applies landscape pattern indices to explore six urban form attributes representing urban size, fragmentation, shape index, and compactness. Combining the geographical detector with the bivariate spatial autocorrelation model, the study reveals the mechanism and spatial heterogeneity of the impact of urban form on carbon emissions.The results indicate that: (1) From 2000 to 2023, Beijing's carbon emissions exhibited a "first increase and then decrease" trend, with a spatial distribution pattern of "concentration in high-carbon areas - expansion in medium-carbon areas - scattered low-carbon areas", and high-value areas continuously concentrated in the city's core regions. (2) The total amount of construction land increased by 58.7%, with the expansion direction radiating outwards from the core area, particularly towards the east and south. In terms of morphology, this manifested as increased fragmentation and localized clustering, exacerbating ecological and environmental pressures. (3) The high concentration of construction land is the main factor driving up carbon emissions (q=0.797), while patch density has a significant negative impact. The other morphological indices have a positive effect. Scattered land use, disordered urban sprawl, and uneven distribution of construction land can lead to increased transportation demand and resource consumption, resulting in a significant rise in carbon emissions.The article proposes carbon emission reduction suggestions for high-density cities from the perspective of urban morphological development, and the research results can provide scientific references for the spatial layout and low-carbon development of high-density urban areas.