Plate Nº 56 · recorded October 10, 2026
Earth & ClimateReported finding
Asian Water Tower Loses 24 Billion Tonnes of Groundwater a Year
A satellite-based study finds that High Mountain Asia — the 'Asian Water Tower' — is losing 24.2 billion tonnes of groundwater annually, with two-thirds of the region in decline since 2003.
By Marcus Bennett3 min read509 words
In brief
- Groundwater beneath High Mountain Asia is declining by about 24.2 billion tonnes per year.
- Roughly two-thirds of the region saw groundwater losses between 2003 and 2020.
- The steepest declines hit the Indus, Ganges-Brahmaputra, and Amu Darya basins.
- Climate-related forces account for nearly half of the variation; human pumping became more pronounced after 2010.
- Accelerated glacier melt may briefly slow losses around the 2060s, but depletion is expected to accelerate afterward.
The groundwater beneath High Mountain Asia — a region long nicknamed the "Asian Water Tower" — is shrinking by roughly 24.2 billion tonnes every year, a new satellite-based study reports.
The estimate spans 2003 to 2020 and comes from a team led by Prof. Shudong Wang at the Aerospace Information Research Institute of the Chinese Academy of Sciences. The findings appeared in Environmental Research Letters on August 20, 2026 (DOI: 10.1088/1748-9326/ae2e1b).
High Mountain Asia feeds some of Asia's largest rivers. Its basins — including the Indus, Ganges, Brahmaputra, and Amu Darya — supply water to more than a dozen countries and to hundreds of millions of people who farm, drink, and trade along their banks.
How can satellites track water hidden underground?
Researchers struggle to monitor groundwater in steep, remote terrain. Wells are sparse, and the GRACE satellites — twin probes that detect changes in Earth's gravity field — can struggle to separate groundwater signals from other forces in mountainous regions.
Wang's team trained a "lightweight Transformer" — a type of AI architecture designed to handle sequential data — to combine GRACE readings with other satellite sensors, Earth-system modeling outputs, and explainable AI methods. Explainable AI tools flag which inputs most influenced each prediction, letting researchers check the model's logic against physical knowledge.
The framework reconstructed about 20 years of groundwater storage change. To validate the result, the team compared its output with thousands of well readings and independent datasets.
Where are the biggest losses?
Roughly two-thirds of High Mountain Asia saw groundwater storage decline between 2003 and 2020. The steepest drops occurred in heavily populated downstream basins where irrigation demand is high. The Indus, Ganges-Brahmaputra, and Amu Darya basins topped the list.
A few higher-elevation inland pockets showed localized gains, which the researchers link to geology and shifting precipitation patterns rather than to broad recovery.
What is driving the depletion?
Climate-related processes account for nearly half of the variation the team observed. Changes in the cryosphere — the frozen parts of the Earth system, including glaciers, snow, and permafrost — play a particularly important role.
Human withdrawals of groundwater now contribute a growing share. The influence of irrigation pumping became especially pronounced after 2010, as farms expanded across the downstream basins.
What happens after the glaciers thin?
The researchers ran the framework forward under current water-use patterns. Their projections suggest groundwater losses will continue for decades.
Around the 2060s, accelerated glacier melt may briefly slow the rate of decline, as meltwater recharges underground reservoirs. The team calls this a temporary "buffer effect." Once the long-term phase sets in, depletion is expected to accelerate again, with the steepest consequences for farms and cities downstream.
Wang and colleagues describe their framework as a new way to study groundwater in data-poor mountain regions. The same approach could inform water management in other parts of the world where on-the-ground monitoring remains thin.
The work received funding from China's National Key R&D Program and the National Natural Science Foundation of China.
via english.cas.cn (Original)
More from Marcus Bennett
Nearby plates
- NASA Backs Mission to Probe Mysterious Moon Pit for Hidden Cave
- Antarctica Gained 695 Billion Tons of Ice. The Trigger Was Thousands of Miles Away
- Some rivers lost flow between 1951 and 2020 even as rainfall rose
- Chile's Atacama Desert Blanketed in Rare August Snow
- NASA Picks PSI-Led Team to Probe Possible Cave Beneath Lunar Pit