Rising agricultural water scarcity in China is driven by expansion of irrigated cropland in water scarce regions

Increasing agricultural water scarcity is threatening food security and ecosystem sustainability in China. Previous studies showed a deceleration in the growth of irrigation water use in China due to reducing water use intensities of irrigation. However, a finer-scale analysis at the prefecture level is urgently needed to account for the impacts of land management policies and the impact of international food trade in water stress mitigation. Here, we address these gaps and demonstrate that the scarce irrigation water use trend reversed to rising after 2011 through shifting to irrigated cropland, even if grain import reduced water stress at the national scale, and we highlight the specificity of relationships between scarce water use and irrigated cropland change at both the river-basin and prefecture scales. These results call for an urgent re-evaluation of the implementation guidelines of China's Land Requisition-Compensation Balance policy on scarce irrigation water use.