Center-of-gravity shift and inequality of human water use in China over the last half century

Understanding the spatial dynamics and inequality of human water use is essential for achieving sustainable water management. Although previous studies have examined the spatial evolution of regional water use, comprehensive assessments that couple sectoral decomposition with long-term (> 50 years) national-scale dynamics remain limited. To address this gap, we compiled multi-sectoral water use data from 1970 to 2020 and analyzed spatial trends and inequalities in China's water use using the center-of-gravity approach and Gini coefficients. Our results reveal distinct directional shifts among sectors: irrigation and industrial water use moved northeastward and southwestward, respectively, while total water use exhibited minimal spatial displacement. Water-use inequality declined from high to moderate levels before 2000 and has since stabilized. Irrigation water use dominated both the spatial redistribution and inequality of total water use, driven primarily by changes in irrigated area and industrial scale. Inter-provincial disparities accounted for the largest share of overall water-use inequality. These findings offer new insights into the spatial evolution of China's water use and provide an empirical basis for promoting more equitable and sustainable water allocation policies.