There is actually no shortage of rain in Central Europe – there is sufficient rainfall, especially in winter. But climate change means that agricultural droughts will still occur more frequently in the future, as researchers have determined. Warming increases evaporation so much, especially in spring, that the soil dries out faster than the rain can compensate. Central Europe is also one of the hotspots for such droughts.
To date, Germany is relatively water-rich; there is usually enough precipitation in this country to replenish water bodies and groundwater and thus compensate for water withdrawal for drinking water, industries and agriculture. But this is beginning to change due to climate change: summer heat waves and dry periods are increasing and at the same time evaporation from soils and vegetation is increasing. According to studies, Germany has lost around 15.2 billion tons of water from its natural water reservoirs over the last 20 years. In recent years, drought and drought-related crop failures have also occurred more frequently.
Soil moisture is crucial in spring
Emily Black from the University of Reading and her colleagues have now examined in more detail whether these droughts are just outliers or a trend. To do this, they used climate data and modeling to analyze whether and how climate change affects soil moisture during the growing seasons – i.e. the time of year when plants need the most water. Previous studies had already suggested that the weather in spring is crucial for whether or not a drought develops in the summer. “Our analysis of soil moisture at the beginning of the growing season and its fluctuations during the growing season show the link between climate change and the water balance of the land surface,” explains the team.
In fact, the results of the analyzes confirmed that rainfall per se is not sufficient to prevent agricultural droughts. What is more important is that the soil receives enough water in spring, but this becomes more difficult as warming increases. The reason: “Climate change is warming the air, causing more water to evaporate from the soil and plants,” explains Black. “This causes the fields to dry out even when there is more rain – especially in the spring.” Climate forecasts predict increasing precipitation for many regions, including parts of Germany. However, these often fall as short but heavy rains or in winter. In spring and summer, soil moisture can still fall below the critical threshold for plant growth.
Central Europe is one of the hotspots
Central Europe is also affected by such agricultural droughts despite rain. “We have identified several hotspots for worsening agricultural droughts. These include western North America, western Europe and the mid-latitudes of central and eastern Europe,” report Black and her team. In the southern hemisphere this applies to southwest Africa, parts of Amazonia and northern South America. “Consistent with this, agricultural drought events have already become more frequent in most of these regions,” the researchers write. “This trend is predicted to continue to grow throughout the 21st century.”
As a result, many growing areas important for grain production and other staple foods would be affected. “Farmers will need more drought-resistant crops and better water management practices,” Black says.
Source: University of Reading; Specialist article: Nature Geoscience, doi: 10.1038/s41561-025-01898-8)