Water storage in Germany continues to decline - heat increases evaporation

Potsdam. The water deficit in Germany and Europe has continued to worsen in recent months. This emerges from joint studies by the Potsdam Helmholtz Center for Georesearch (GFZ) with NASA and the German Aerospace Center. It is feared that “the water reservoir will not recover by the end of the year, even if there is more rain than usual in autumn,” wrote a GFZ spokesman.

The researchers monitor the total water content on and below the earth's surface. According to the GFZ, this can be used to calculate how much water storage changes.

“Since 2015, we have seen increasingly drier conditions in Germany than in the previous 15 years,” said Annette Eicker, head of the Global Geomonitoring and Gravity Field Section at the GFZ. The rainy year 2024 led to a recovery in water storage, but this was followed by another sharp decline. In principle, the decrease in groundwater storage is “responsible for most of the long-term decline in water storage in Germany”.

The researchers are concerned because the current data up to June “could not yet reflect the hot summer in Germany,” said the GFZ. The consequences of the heat waves would only become apparent in the data for the next few months. This data should not be available until autumn.

According to the researchers, heat in particular reduces water storage. The comparison with the precipitation data shows no long-term negative trend in the amount of precipitation. However, we see an increasing potential evaporation due to increased air temperatures - “i.e. the amount of water that can be transported from the ground into the atmosphere,” said the GFZ spokesman.