The “Asian water tower” is losing 24 billion tonnes of groundwater every year

by | Aug 20, 2026 | Science

The “Asian water tower” is losing 24 billion tonnes of groundwater every year

A new research initiative has quantified the rate of groundwater depletion across High Mountain Asia, a mountainous region that functions as a critical freshwater source for downstream nations. The study, led by researchers from the Chinese Academy of Sciences, employed satellite technology combined with artificial intelligence to track underground water storage changes over a period spanning two decades. The findings indicate that roughly two-thirds of the region experienced declining groundwater reserves during this timeframe, with annual losses estimated at 24.2 billion tonnes.

The research identified two primary drivers of groundwater depletion. Climate-related processes, particularly changes in glacial and snow coverage, account for approximately half of the observed variation in groundwater storage. Meanwhile, human extraction of groundwater for agricultural irrigation has emerged as an increasingly significant factor, especially in densely populated downstream basins such as the Ganges-Brahmaputra, Indus, and Amu Darya watersheds. The influence of irrigation-driven water withdrawal intensified notably after 2010.

Scientists anticipate that groundwater losses will persist if current consumption patterns continue unchanged. Projections suggest that temporary relief may occur around the 2060s due to increased glacier melt providing supplementary water, but this phenomenon would be temporary and ultimately give way to accelerated depletion. Should existing water use practices remain unaltered, downstream agricultural regions that depend heavily on groundwater reserves face escalating threats to their water security.

The research team overcame traditional obstacles to studying groundwater in mountainous terrain by integrating multiple data sources and computational approaches. The framework combined satellite observations, hydrological modeling, and machine learning algorithms to reconstruct historical groundwater variations and identify contributing factors. Validation against thousands of ground-based well measurements and independent datasets supported the study’s conclusions, establishing a methodology applicable to other complex mountain regions with limited direct measurement capabilities.

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