Coupling synergy level and interaction effect between the ecological environment and low-carbon development in the Yangtze River Delta urban agglomeration: Characteristics of spatial and temporal heterogeneity

Low-carbon development and the ecological environment are often assessed separately, but understanding their interaction effect and the coupled coordination development from a spatially heterogeneous perspective remains limited, particularly in the context of rapidly urbanizing urban agglomeration regions. To address this research gap, this study assessed the levels and variations in coupled coordinated development between low-carbon development and the ecological environment at the urban agglomeration level using a coupled coordination degree model. Key factors of the interaction effect for each system were initially identified by ordinary least squares, then a geographically and temporally weighted regression model was used to reveal the spatial and temporal heterogeneity of these factors. Our study showed that the comprehensive development level of lowcarbon development system in all cities exceeded that of the ecological environment system from 2006 to 2021. However, the level of synergy between the two systems showed slight improvement, with most cities exhibiting a moderate balance from 2010 to 2020. Regional heterogeneity was apparent in the coordinated development types, with highly balanced cities located primarily in the west and north of the urban agglomeration. Furthermore, our findings illustrated the positive effect of the air and climate environment on lowcarbon development, contrasted with the negative influence of the land environment. These results not only enrich our understanding of low-carbon development and ecological environment interrelations in the Yangtze River Delta urban agglomeration but also provide insights applicable to similar regions worldwide, thereby contributing to the global discourse on synergistic sustainable development of low-carbon and ecological environment.