Dynamics of carbon balance and its influencing factors in the Yangtze River Delta: a spatial network perspective.

Understanding carbon balance is crucial for assessing regional carbon budgets and formulating effective emission reduction policies. However, existing studies have primarily focused on carbon balance dynamics in a specific region, overlooking intercity linkages, making it difficult to guide carbon reduction strategies for inter-regional cooperation. Based on the carbon balance dynamics calculated from the carbon emissions and sinks of 16 core cities in the Yangtze River Delta (YRD) from 2000 to 2020, this study introduced a regional network-based framework to analyze the functional roles of cities in carbon balance, and employed Geodetector to quantify the spatial heterogeneity and interaction effects of key socio-ecological drivers. The results showed that the total carbon emissions in the YRD increased by 3.06 times, while carbon sinks only grew by 1.11 times, leading to a decline in the carbon balance index from -0.67 in 2000 to -0.87 in 2020. The carbon balance network in the YRD exhibited a "hub-driven, multi-level collaborative structure", with Shanghai, Suzhou, Wuxi, and Ningbo as core nodes, maintaining strong interconnections with other cities. During 2000-2020, the network density and correlation numbers initially increased before decreasing, indicating a relatively loose structure and significant potential for enhanced intercity cooperation. Socioeconomic factors, such as industrial activity and freight, were the dominant drivers of carbon emissions, whereas ecological factors, particularly vegetation coverage, most influenced carbon sinks. The carbon balance pattern was finally revealed in the YRD and policy suggestions were proposed for different cities according to their characteristics and their role in the network, which provides an insight for policymakers to develop coordinated low-carbon strategies in the YRD.