While urbanization is driving economic development, it has caused more than 70% of global carbon emissions. Reducing urban carbon emissions is an inevitable requirement for low-carbon city construction. At the same time, in order to alleviate the urban diseases caused by urbanization, polycentric agglomeration has become a new form of urban spatial expansion. Does the polycentric spatial structure help reduce regional carbon emissions? This paper uses nighttime light data to measure the polycentricity of provincial and municipal spatial structure in China and empirically analyzes the impact of polycentric spatial structure on carbon dioxide emissions at different geographic scales. The results show that the eastern region of China presents a significant stronger trend of polycentric spatial development, while its polycentricity has significantly increases emission due to excessing optimal level. As for western areas, polycentricity on provincial distribution strengthens specialization and increases productivity to reduce carbon emissions. At the city level, polycentric spatial structure is suitable emission reduction, especially for western area. Therefore, current common polycentric spatial structure is not beneficial to emission reduction. Urban planning needs to comprehensively consider internal and external conditions. Inter-provincial cities should strengthen collaboration and specialization and avoid vicious competition. The internal development of cities can properly develop multi center and form vertical division and efficiency improvement.
Keywords polycentric development, carbon dioxide emissions, nighttime light data, urbanization