Future food security risks driven by crop production and water scarcity in China's Yangtze River Delta under SSP–RCP scenarios

Against the backdrop of global climate change and socioeconomic transition, the coupled dynamics of crop production and water scarcity have posed severe challenges to regional food security. Focusing on the Yangtze River Delta (YRD), this study conducts a comprehensively assessment of future food security risks constrained by water resource limitations and shifting grain supply–demand dynamics, under two combined SSP-RCP scenarios (SSP1–2.6 and SSP3–7.0) across two future time horizons (the 2050s and 2070s), by projecting grain supply and demand that incorporate SSP-driven changes in population structure, dietary preferences, crop sown area, and unit-area yield. Based on the Pressure-Exposure-Resilience (P- E -R) framework, we constructed a Food Security Risk Index (FSRPS) comprising three components—Water Scarcity Index ( WSI , pressure), Proportion of Irrigated Grain Production ( P Ir , exposure), and Grain Self-sufficiency Rate ( RATE , resilience). This index was then applied to analyze the spatiotemporal evolution and driving mechanisms of food security risks in the YRD. The results indicate that in the 2017 baseline year, the spatial distribution of food security risks exhibited a distinct north-higher-than-south pattern. Across future scenarios, regional risk will increase significantly compared with the baseline, accompanied by growing spatial heterogeneity. Notably, driven by intensifying water scarcity and high irrigation dependence, the overall risk under the low-emission pathway (SSP1–2.6) — reaching 4.63 in 2050 and 4.12 in 2070 — is higher than that under SSP3–7.0 (4.04 and 3.87, respectively). Spatially, central and northern Jiangsu, Shanghai, and northern Anhui are the core sensitive regions (maximum risk index variation >0.3), whereas Zhejiang and the mountainous areas of southern Anhui remain relatively stable (variation generally below 0.01). Accordingly, two targeted regulation strategies are proposed: under SSP1–2.6, coordinate grain production with water resource carrying capacity; under SSP3–7.0, enhance agricultural climate resilience and implement differentiated zonal governance. This study provides a scientific reference for climate-adaptive food security and water resource management policies in the YRD.