Germany’s water deficit has worsened in recent years, with higher temperatures increasing evaporation and reducing water storage, according to new satellite analysis by the GFZ Helmholtz Centre for Geosciences, NASA and the German Aerospace Centre (DLR).

“Since 2015, we have been seeing increasingly drier conditions in Germany than in the 15 years prior to that,” said Prof Annette Eicker, head of GFZ’s Global Geomonitoring and Gravity Field section.

The analysis of data from the GRACE Follow-On satellite mission shows that Germany’s total water storage in June 2026 was about 25 billion tonnes below the long-term average. The deficit includes water stored both near the surface and underground, including groundwater.

The researchers said water storage recovered temporarily in 2024 after an unusually wet year, but then fell sharply again. GFZ hydrologist Andreas Güntner said the decline in groundwater storage accounts for the majority of Germany’s long-term reduction in water storage.

The latest figures also show that the problem is not simply a result of declining rainfall. Researchers compared the satellite measurements with precipitation data and found no long-term downward trend in rainfall levels.

Instead, they identified a rise in potential evaporation as temperatures have increased. This refers to the amount of water that could move from the land surface into the atmosphere under prevailing atmospheric conditions. Higher temperatures increase direct evaporation from surface water and also increase water loss from plants.

The impact is particularly visible in southern, south-western and eastern Germany. The north-west, including areas near the North Sea, has recorded smaller deficits. GFZ said the number of Junes with below-average water storage has increased markedly since 2015.

The researchers are concerned that Germany’s water reserves may not recover by the end of 2026, even if autumn rainfall is above average. The available satellite data currently extend only through June, meaning they do not yet capture the effects of the hot summer that followed.

Those effects are expected to become visible in later measurements, which GFZ said will only become available in the autumn because of the complex processing required to analyse the satellite observations.

The GRACE and GRACE Follow-On missions measure small changes in Earth’s gravitational field. Researchers use those measurements to estimate changes in the distribution of water across and beneath the land surface. The data have been available since 2002, although their spatial resolution is about 250km by 250km and cannot be used to assess individual small areas.

Independent monitoring also shows persistent dryness in parts of Germany. The Helmholtz Centre for Environmental Research’s German Drought Monitor tracks soil moisture using hydrological modelling and data from about 2,500 weather stations. Its system distinguishes between conditions in the upper soil and deeper layers, where short periods of rain have a more limited effect.

The latest GFZ assessment therefore points to a continuing water-storage deficit, with the effects of the summer heat still to be reflected in the next round of satellite data.