Spatial disequilibrium and influencing factors of carbon emission intensity of construction land in China

Revealing the spatial disequilibrium and influencing factors of carbon emission intensity of construction land (CEICL) is of great significance for improving the sustainable utilization of urban land, and helping to achieve global green and low-carbon development. This study estimates the CEICL of 285 cities in China from 2008 to 2019. Then, this paper analyzes the spatial disequilibrium of CEICL, and discusses the spatial heterogeneity of the influencing factors at different levels of CEICL. The results show that the CEICL has an inverted "U-shape", increasing first and decreasing later, with most cities concentrating on 0.3 million tons/km2 and some cities breaking through 3 million tons/km2. Also, the results imply a relatively large gap in CEICL among cities, despite a gradually narrowing trend of this gap. Among regions, the average annual difference of CEICL is about 0.1-0.4 million tons/km2 for cities of the same scale. Within regions, CEICL decreases with increasing city scale, and the agglomeration characteristics of high-high and low-low values within regions are significant and stable, and the spatial lock-in effect is strong. Moreover, the results infer a negative spatial spillover effect in CEICL in China, and the significant spatial heterogeneity effect of the seven factors (i.e., population agglomeration intensity, industrial structure upgrading, land development intensity, land investment intensity, economic output level, technological R&D and innovation, and ecological resource endowment) on CEICL in cities of different regions and scales. This study provides a scientific basis and empirical support for developing differentiated and feasible carbon reduction policies based on cities' own characteristics.