As a result of climate change, Germany is threatened by falling groundwater levels
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.(DOI: 10.1038/s41467-022-28770-2)
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. For this purpose, they used machine learning methods (deep learning) to evaluate the development of groundwater levels for various locations on the basis of existing groundwater data from all over Germany using different climate scenarios taken from the IPCC's Fifth Assessment Report. These ranged from an assumed warming of the global mean temperature by the year 2100 of less than two degrees Celsius, as defined as a target by the Paris Climate Agreement, to a medium forecast model (plus 2.6 degrees) to the so-called business as usual scenario, which assumes a warming of up to five degrees compared to the pre-industrial state without appropriate climate protection measures. "Only direct climatic influences and changes were included in the scientific study, while we did not include anthropogenic factors such as groundwater withdrawals," emphasizes Andreas Wunsch from KIT's Institute for Applied Geosciences (AGW) and lead author of the study.Graphic: KIT/BGR
Left: Plot of mean groundwater level changes (in percent) in 2100 compared to 2014 for all studied sites and.
Climate projections in the business-as-usual scenario.
Right: "Heatmaps" of modeled groundwater levels at an example site. (Graphic: KIT/BGR)
Projections show: Falling groundwater levels independent of scenario.
According to the experts, all three climate scenarios examined lead to more or less strong developments with drought effects, declining groundwater levels, and a change in water availability. While the two more optimistic scenarios show less pronounced and numerical trends, the experts from KIT and BGR noted a trend toward significantly decreasing groundwater levels for most sites in the case of the strongest of the three warming scenarios. "Especially for the near future, the results of this forecast are very relevant, as this scenario comes closest to the current situation," emphasizes Dr. Tanja Liesch from AGW.
"The future negative effects are particularly visible in northern and eastern Germany, where there are already corresponding developments today. Here, longer periods of low groundwater levels are imminent, especially toward the end of the century," emphasizes Dr. Stefan Broda of the BGR. This situation 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 elaborated in the BGR project MENTOR, which aims at developing a nationwide groundwater level prediction based on machine learning.
Andreas Wunsch, Tanja Liesch & Stefan Broda: Deep learning shows declining groundwater levels in Germany until 2100 due to climate change. Nature Communications, 2022. DOI: 10.1038/s41467-022-28770-2. https://www.nature.com/articles/s41467-022-28770-2
Details on the KIT Climate and Environment Center: https://www.klima-umwelt.kit.edu/
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