[Spatio-temporal Characteristics and Influencing Factors of Carbon Sources/Sinks in the Yangtze River Delta Under Carbon Neutrality Target].

Clarifying the dynamic relationship between carbon sources/sinks and urban development is crucial to achieving carbon neutrality and sustainable development in the region. This study used net ecosystem productivity （NEP） to evaluate the carbon sinks of the terrestrial ecosystem in the Yangtze River Delta （YRD） from 2005 to 2020. Geodetectors were used to explore the impact of urban expansion, socio-economic factors, and their interactions on carbon sources/sinks in the YRD and to evaluate the gap in achieving carbon neutrality in cities. The results showed that： ① In 2005-2020, the NEP contribution of the YRD was 69.13 Mt·a and the loss of carbon sinks due to urban expansion was 1.97 Mt. The carbon emissions offset by carbon sinks were approximately 3% to 6%. ② The high carbon source areas were mainly distributed in the central and eastern YRD and the high carbon sink areas were primarily distributed in Zhejiang Province and southern Anhui Province. The forest-rich cities of Huangshan and Lishui, with smaller gaps between carbon emissions and carbon sinks, had the greatest potential for achieving carbon neutrality. Industrial or resource-based cities such as Xuzhou and Maanshan faced greater pressure to achieve carbon neutrality. Developed cities such as Shanghai and Suzhou had the largest carbon neutrality gap. ③ Urban expansion, economic and industrial agglomeration, high-density distribution of the population, and compact urban form were the key variables leading to the widening gap between carbon emissions and carbon sinks in the YRD. The increase in ecological space could effectively reduce carbon emissions. Urban expansion and socioeconomic development could be coupled with each other and have significant synergistic effects on carbon emissions.