An Integrated Hydrological‐Socioeconomic Assessment Framework for Water Security in the Asian Water Tower

ABSTRACT Water security in the Asian Water Tower is increasingly threatened by uneven water resource distribution, intensified climate change, and enhanced human activities. However, existing studies often neglect dynamic upstream‐downstream interactions and water towers' regulatory functions. Here, this study developed a comprehensive assessment framework integrating the dynamic water supply–demand index, water tower index (WTI), and socioeconomic exposure, which systematically identified water security risks and impacts in the 10 major basins of the Asian Water Tower. Results indicated that southeastern humid basins such as the Yangtze, Mekong, and Salween maintained water security. In contrast, northwestern arid basins such as the Indus, Tarim, and Amu Darya River Basins experienced significant water scarcity and were highly dependent on upstream water supply (high WTI). Future scenario simulations revealed that the Yellow River Basin will achieve water security due to increased upstream supply capacity (67%–161%). The Amu Darya River Basin is projected to deteriorate most severely, with water scarcity areas expanding from 27% to 100%. Water scarcity in the Indus River Basin is projected to worsen significantly due to glacier retreat, increased water demand (60%–68%), and decreased water supply (8%–51%). Socioeconomic exposure analysis showed that over 200 million people in the Ganges and Indus River Basins faced water security risks, and that GDP exposure in certain basins increased by more than tenfold. This study emphasizes that adaptive trans‐regional water governance strategies centered on basin characteristics should be formulated to enhance water tower security. The results are derived from multi‐model ensemble simulations and scenario‐based projections, and they reflect potential water security risks rather than actual observed water security status.