Reviewed by Lexie CornerFeb 7 2025
Using multi-source remote sensing data, a research team from the Chinese Academy of Sciences (CAS) Institute of Geographic Sciences and Natural Resources Research (IGSNRR) developed a monthly time series of water storage changes for 105,400 lakes and reservoirs in arid regions worldwide from 1985 to 2020. The study was published in Nature Water.
The attribution of surface water storage changes to precipitation, watershed hydrology, and human water management. Image Credit: ZHAO Gang
Drylands, characterized by an aridity index (AI) below 0.65, cover approximately 45 % of the Earth's surface and support over three billion people. Water scarcity in these regions poses significant challenges to human health and ecosystems. However, long-term trends in surface water storage and their underlying drivers remain poorly understood due to limited high-resolution, long-duration observational data.
The study found that surface water storage in global drylands increased by 2.20 cubic kilometers per year, primarily due to the construction of new reservoirs. While natural lakes and older reservoirs showed no significant overall change, they accounted for water storage variability in 91 % of river basins in arid regions.
Further analysis indicated that long-term water storage changes were driven mainly by human activities, including climate warming and water resource management, rather than variations in precipitation as previously assumed.
This study provides observational data on long-term surface water storage trends in drylands and establishes a connection between these changes and human activity.
The study highlights a decoupling between surface water storage and precipitation in arid regions, posing new challenges to the sustainability of societies and ecosystems.
Gang Zhao, Study First Author and Professor, Chinese Academy of Sciences
The findings highlight the role of global warming and human activity in driving long-term hydrological changes. Relying solely on precipitation-based water resource management may lead to inaccurate assessments of water availability. Instead, integrated water resource planning should consider climate trends, basin characteristics, and human activities for more accurate water availability projections.
Journal Reference:
Zhao, G. et. al. (2025) Decoupling of surface water storage from precipitation in global drylands due to anthropogenic activity. Nature Water. doi.org/10.1038/s44221-024-00367-7