The impact of urban polycentricity on carbon emissions: A case study of the Yangtze River Delta Region in China

In the context of increasing global carbon emissions(CEs) and widespread restructuring of the urban spatial structure, it is worth exploring whether polycentricity can reduce urban CEs. Given the previous controversies and the lack of sufficient evidence regarding the relationship and underlying mechanisms between polycentricity and CEs, the aim of this study is to address these gaps. In this study, topographic scanning population data and non-parametric methods are used to identify urban centers and to calculate the multi-center index of the cities in the Yangtze River Delta (YRD) region. Using a geographical gauging approach, a correlation between urban polycentricity and urban CE based on the identification of their spatial impacts is subsequently investigated. The findings of this study indicate the following: initially, urban polycentricity is linked to an increase in CEs within the city. Furthermore, there may be spillover effects, leading to the potential for polycentricity to reduce CE in surrounding urban areas. Urban polycentricity can enhance industrial agglomeration, thereby reducing urban CEs. Additionally, the improvement of urban transportation infrastructure contributes to an increase in the CE augmentation effect of urban polycentricity. The direct and indirect effects of urban polycentricity on CEs are heterogeneous. Moreover, both the direct and indirect effects of polycentricity on CEs are anticipated to increase proportionally as the size and economic status of the city increase. The aforementioned results demonstrate that there is a correlation between the polycentric nature of urban spatial configuration and the severity of CEs in metropolitan areas. Urban planners should consider the need to propose appropriate strategies for optimizing the spatial structure of cities in different phases of development. In addition, they should propose strategies for synergistic spatial adjustments to urban agglomerations.