Urbanization Intensified the Trade-Off Between Food Security and Water Quality Security in the Yangtze River Delta

Rapid urbanization, while enhancing the living standards, posed significant challenges to food security (FS) and water quality security (WQS). Previous research mainly focused on assessing FS and WQS, remaining their trade-off and driving pathway unclear. Taking Yangtze River Delta as study area, this study quantified FS and WQS from 2000 to 2020, and explored their trade-off and driving pathways at both county and regional scales. The results indicated that FS and WQS showed opposite spatial patterns, while both of them experienced significant declining trends across county and regional scales. Although both synergy potential and trade-off intensity showed increasing trends, the mitigation of FS-WQS trade-off remained challenging due to the substantially greater rise in trade-off intensity compared to synergy potential. “Win-win” combinations were identified with high FS, high WQS and the lowest opportunity cost. Urbanization, especially urban expansion and population growth, significantly intensified the trade-off by reducing food production while increasing demands for both food and water quality. This study finally established a conceptual framework for characteristics and driving mechanisms of FS, WQS and their trade-off at different urbanization stages, offering scientific insights for sustainable development in rapidly urbanizing regions.