The role of agricultural water trade in alleviating water scarcity: A case study of Northwest China

Agricultural trade promotes the transfer of water resources, which has an impact on regional water scarcity, particularly in arid regions. Nevertheless, the understanding of how agricultural trade influences water scarcity and the populations under different water scarcity levels is still insufficient. This study examines the impact of domestic agricultural (food crop) trade on water scarcity in Northwest China by integrating a grid-based dynamic water balance model with a linear programming model. The results indicate that the agricultural blue water (surface and groundwater) footprint and green water (soil water) footprint in the Northwest region peaked in 2014, with the green water footprint being 17% higher than the blue water footprint. The increase in trade volume has effectively alleviated water scarcity in Northwest China, with green water playing a greater role than blue water, especially in Shaanxi and Ningxia. As trade volumes rise, the population facing mild water scarcity continues to grow after trade, with increases of 4.56%, 6.70%, and 5.36% in 2000, 2010 and 2014. Agricultural trade significantly alleviates the pressure of severe water scarcity and boosts the region's population carrying capacity. This study provides scientific evidence to support stronger coordination of water resources between regions, especially agricultural water trade between water-rich and water-scarce areas, and to inform the formulation of rational allocation policies for balancing regional water resource distribution and benefits.