A recent NASA study highlights the growing impact of human activities on terrestrial water storage, revealing significant changes across the globe. The research utilized over two decades of satellite measurements from the GRACE and GRACE-FO missions to assess how water movements in lakes, rivers, soil, and subsurface areas are influenced by human actions.
Human Impact on Water Storage
The findings illustrate trends in terrestrial water storage from April 2002 to November 2025, identifying 40 regions where changes correlate strongly with human activities such as irrigation, land-use changes, and reservoir constructions. These effects were observed on every continent except Australia, emphasizing the widespread influence of human conduct on water resources.
Mary Michael O’Neill, a hydrologist at NASA’s Goddard Space Flight Center and the study’s lead author, noted that in four continental regions, human activities exhibited a stronger correlation with water storage trends than climate variables. Notable regions affected include California’s Central Valley and northern India, where excessive groundwater use has significantly reduced water storage levels, often faster than previously estimated.
Advanced Satellite Measurements
The study’s data comes from GRACE and GRACE-FO missions, which consist of satellites that measure changes in gravity caused by variations in mass, including water and ice. This innovative method allows scientists to infer water gains and losses, providing detailed insights into long-term water trends across the globe.
By analyzing the data collected over more than 20 years, researchers were able to create detailed maps that reveal human impacts on water storage that may have gone undetected with earlier methods. Matthew Rodell, deputy director for Earth Sciences at Goddard and a co-author of the study, emphasized that this improved spatial resolution has revealed stronger trends in water storage changes than previously recognized.
Regional Variations in Water Storage
Across several regions, the reliance on groundwater for irrigation has led to significant declines in water storage. In North America, areas such as California’s Central Valley and the southern High Plains have experienced reductions linked to long-term drought conditions. In northern India, groundwater pumping has driven declines, with new analyses showing a more pronounced downward trend than earlier assessments indicated.
Conversely, certain agricultural practices have contributed to increases in water storage. For instance, in parts of sub-Saharan Africa, the expansion of rainfed cropland has resulted in rising water tables despite low precipitation levels. Similarly, in Maranhão state, Brazil, the transition from forests to soybean fields has led to positive water storage trends, attributed to efficient water use and traditional practices that facilitate aquifer recharge.
Future Research Directions
The study also shed light on water storage projects, such as large reservoirs and hydrologic engineering initiatives. The Boguchany Reservoir in Russia was identified as a significant contributor to water storage trends in nonpolar northern Asia. The enhanced resolution of the analysis allows for better monitoring of smaller reservoirs and hydrologic changes in remote areas.
Moving forward, O’Neill aims to further investigate how various human activities impact downstream water storage and to improve temporal analysis of these changes. She expressed interest in integrating high-resolution data with standard monthly products to enhance the understanding of how localized trends evolve in response to specific events like droughts or policy shifts.
Source: NASA
