NASA has used satellite records to study changing water supplies on land. The records cover more than twenty years, from 2002 to 2025. They show changes in Earth's gravity. Because water has weight, these changes help scientists follow water gains and losses. The study looks beyond rivers to water in soil and underground.
The team found forty regions where water changes were linked with human activity. Farming, building reservoirs and changing land use were among the activities studied. Climate also affects how much water an area holds. Therefore, the findings do not mean human activity explains every change. The new maps show long-term patterns in greater detail. They cover many parts of the world.