Quantifying Past and Future Terrestrial Water Storage Scarcity Across China Through Midcentury

Abstract

Terrestrial water storage (TWS) in China, with the world's largest irrigated expanse and extensive mid-low latitude glaciers, is essential for effective water resource management and socioeconomic risk adaptation. However, the responses of TWS to human intervention and climate change, both during historical periods and under future scenarios, remain inadequately quantified. We reconstruct and project long-term TWS using a data-driven framework that integrates remote sensing, Earth system model (ESM) and machine learning. Our reconstructed record reveals an amplified TWS decline in China's drylands and a moderate yet persistent TWS reduction in glacier regions during 1985–2015, accentuated since the 21st century with a 13% increase in affected areas. TWS changes in drylands are primarily attributed to human irrigation ((Formula presented.) 39%) and precipitation ((Formula presented.) 24%), with the impacts of irrigation magnified by 9%–12% during drought. Humid basins show a moderate TWS response to irrigation and precipitation, modulated by intricate but unexplored interactions between atmospheric drivers, glacier-snow dynamics and underlying hydrological processes. Such discrepant response highlights the necessity for region-specific water resource management strategies: northern drylands should prioritize optimized irrigation practices while southern humid basins would benefit from enhanced adaptation to climate variability. Projections from nine ESMs indicate a likely amplification of TWS decline (13%–43%) in drylands and glacial zones by mid-century if maintaining current human intervention levels. Our findings emphasize the need to reassess climate change-induced water scarcity and refine human management regulations, particularly as existing strategies may be overlooking broader sustainability challenges in a warming climate.