Does urban agglomeration reduce carbon emissions in Chinese cities? New perspective on factor mobility

Urbanization in developing countries is often associated with high carbon emissions, mainly due to substantial fossil energy consumption in cities. However, only few studies have addressed how population concentration and factor mobility within urban agglomeration can reduce carbon emissions. Using a novel perspective on factor mobility, we delve into the impact of urban agglomeration on carbon emissions using a panel dataset of 284 Chinese cities spanning from 2004 to 2022. The results obtained using the two-stage least squares method indicate that urban agglomeration has a significant impact on reducing carbon emission intensity. Specifically, for every standard deviation increase in the clustering indicators of population, freight transport, and passenger transport, the carbon emission intensity decreased by 0.257 %, 0.317 %, and 0.147 %, respectively. The carbon emission reduction effect of urban agglomeration varies considerably across resource- and nonresource-based cities as well as population-inflowing and -outflowing cities. We also discovered that urban agglomeration reduces carbon emission intensity by enhancing energy efficiency and fostering technological innovation. This study provides a fresh perspective on urban agglomeration and proposes a new pathway to achieve sustainable development goals, emphasizing the importance of accelerating factor mobility to form high-quality urban agglomeration.