Declining groundwater levels in Germany until 2100 due to climate change

Climate change has a direct impact on groundwater resources. In Germany, too, there is a threat of declining groundwater levels in the coming decades. This is the result of a study by the Karlsruhe Institute of Technology (KIT) and the Federal Institute for Geosciences and Natural Resources (BGR), which has now been published in the scientific journal Nature Communications.

The experts from BGR and KIT had used artificial intelligence in various forecast models to investigate how climate change will affect groundwater resources in Germany in the 21st century. To do this, they used machine learning methods (deep learning) to evaluate the development of the groundwater level for various locations on the basis of existing groundwater data from all over Germany using different climate scenarios. The climate scenarios, which originate from the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), ranged from an assumed warming of the global mean temperature by the year 2100 of less than 2 degrees, as defined as a target by the Paris Climate Agreement, to a medium forecast model (+2.6 degrees) to the so-called "business-as-usual" scenario, which assumes a warming of up to 5 degrees compared to the pre-industrial situation without corresponding climate protection measures. "Only direct climatic influences and changes were included in the scientific study, while anthropogenic factors such as groundwater extraction were not included," emphasises Andreas Wunsch (KIT).

Mean changes in groundwater level Source: BGR

All three scenarios show more or less strong developments with drought effects, falling groundwater levels and a changed water availability. While the two more optimistic climate scenarios show less pronounced and statistically less clear trends, in the case of the strongest of the three warming scenarios, the experts from KIT and BGR found a trend towards significantly decreasing groundwater levels for most locations. "Especially for the near future, the results of this forecast are most relevant, as this scenario comes closest to the current situation," underlines Dr. Tanja Liesch (KIT).

"The future negative effects are particularly visible in northern and eastern Germany, where there are already such developments today. Here, there is a threat of longer periods of low groundwater levels, especially towards the end of the century," underlines Dr. Stefan Broda (BGR). A situation that does not occur to this extent in the two weaker warming scenarios. For the experts from KIT and BGR, this is an indicator that a reduction in greenhouse gas emissions can have a positive effect on future groundwater levels.

The published results were compiled as part of the BGR project MENTOR, which aims to develop a nationwide groundwater level forecast based on machine learning.

Contact: