Asia water tower loses 24 billion tonnes groundwater yearly

A new satellite-based study has found that groundwater reserves beneath High Mountain Asia, known as the 'Asian water tower', are depleting by about 24.2 billion tonnes annually. The research, led by Prof. Shudong Wang of the Chinese Academy of Science and published in Environmental Research Letters, used an AI-powered model combining satellite observations, earth system modelling, and explainable AI to reconstruct 20 years of groundwater storage changes across the region.

The study found that roughly two-thirds of High Mountain Asia experienced declining groundwater storage between 2003 and 2020. The largest losses were in heavily populated downstream basins like the Ganges-Brahmaputra, Indus, and Amu Darya, where irrigation demand is high. Climate factors explain nearly half the variation in groundwater storage, with human water withdrawals becoming an increasingly significant source of depletion, especially after 2010.

Researchers project that if current water use patterns continue, groundwater losses will accelerate. While increased glacier melt could temporarily slow the decline around the 2060s, this buffer effect is expected to be followed by faster losses, threatening agricultural areas downstream that depend on these reserves.