The urban-rural dietary water footprint and its inequality in China's urban agglomerations

Food system is the main consumer of water resources, and the differences in urban and rural diets pose new challenges to the water sustainability and increase the uncertainty of food security in China. In this study, we quantified the dietary water footprint (DWF) of urban and rural residents at the city scale in four major urban agglomerations in China from 2015 to 2021, identified the key economic and educational factors of urban and rural DWF, and measured the inequality of urban and rural DWF driven by the main influencing factors. We found that there was a 27.17 % increase in urban DWF and a 23.18 % increase in rural DWF between 2015 and 2021. Cereals had the largest water footprint among the 12 food types, accounting for 20.27 % and 31.57 % of urban and rural DWF, respectively. Meanwhile, milk and dairy products contributed the most to the difference between urban and rural DWF, up to 57.89 m³ each year. The main economic factor of DWF was consumption expenditure. The number of primary school students and the number of primary schools are the most important educational factors of urban and rural DWF, respectively. The results show there is an inequality between DWF and major educational factors, with a decreasing trend in DWF inequality over time. This study revealed for the first time the difference between urban and rural DWF at the city scale, and clarified the impact of regional educational inequality on DWF. A greater focus should be placed on the primary education-related factors that influence DWF inequality, in order to better target sustainable DWF strategies for urban and rural residents.