[Impact of Urban Agglomeration Network Structure on the Coordinated Development of "Carbon Reduction" and "Growth"]

Exploring the impact of urban agglomeration network structures on the coordinated development of "carbon reduction" and "economic growth" serves as a critical pillar for achieving green-low carbon transformation and sustainable economic development within urban agglomerations. Based on panel data from 155 prefecture-level and above cities in China's 11 national-level urban agglomerations from 2006 to 2021， this study employs a modified gravity model and social network analysis to identify urban agglomeration network structures. Additionally， a revised Grubel-Lloyd index is used to measure the synergy level between carbon reduction and economic growth. Using a two-way fixed-effects model and a synergy effect model， this paper systematically examines the impact， underlying mechanisms， and heterogeneous effects of urban agglomeration network structures on the synergistic development of carbon reduction and economic growth. The findings reveal that： ① The average network structure index of Chinese urban agglomerations exhibited a fluctuating upward trend during the study period， increasing from 0.070 in 2006 to 0.218 in 2021. ② The optimization of the urban agglomeration network structure could significantly promote the coordinated development of "carbon reduction" and "growth." For each unit increase in the urban agglomeration network structure， per capita carbon emissions decreased by 1.219×10² kg， per capita real GDP increased by 3.659×10⁴ yuan， and the level of coordination between carbon reduction and growth improved by 0.837 units. ③ Mechanism analysis confirmed that the optimization of urban agglomeration network structures facilitated knowledge flows and industrial specialization， which in turn drove the coordinated development of carbon reduction and economic growth. ④ Heterogeneity analysis indicated that higher urban network status and larger urban agglomeration scales amplified the synergy effects of network structure optimization on carbon reduction and economic growth. Therefore， policymakers should rationally plan and advance urban agglomeration network construction， actively guide knowledge flow and industrial specialization， and tailor regional development policies to local conditions to empower urban agglomerations in synergistically advancing carbon reduction and economic growth.