Climate change affects groundwater

Rising temperatures and more precipitation up to the turn of next century mean that parts of Sweden will have higher groundwater levels, while levels in the south-east of the country may decrease sharply. These are the findings of research carried out by SMHI, the Geological Survey of Sweden (SGU) and Uppsala University.

Climate change is therefore of great significance when it comes to access to groundwater. Current research indicates that by the turn of next century, south-east Sweden in particular could have up to just over 20% less groundwater formation. The decrease is most apparent in late summer.

“According to scenarios, climate change will bolster the current situation with little groundwater formation in south-east Sweden and low groundwater access in late summer,” says Joel Dahné, hydrology scientist at SMHI.

In addition to less access to drinking water, lower groundwater levels could create problems with saltwater intrusion into the groundwater, particularly by the coast.

In other parts of Sweden conditions vary, and some parts have more abundant access to groundwater. Levels could rise by one or more decimetres. Obviously this means greater access to drinking water, but it also increases the risk of landslides and also reduces the land’s ability to clean the water.

More rain and greater evaporation

The map shows a scenario for altered annual averages for groundwater formation, up to the turn of next century compared with today, for the land class till. (The projections do not include the mountain area coloured grey on the map.) Enlarge Image

The future scenarios show that precipitation during the winter half of the year will be in the form of rain, and less will be stored as snow. As a result, the spring floods will be smaller and groundwater levels will not be as high in spring and early summer. Rising temperatures result in greater evaporation longer into the autumn and, consequently, less groundwater formation at that time of year.

A computing model has been developed for the conclusions relating to groundwater. The model is partly based on daily values for temperature and precipitation.

The results are based on research carried out by SMHI, the Geological Survey of Sweden (SGU) and the Department of Earth Sciences at Uppsala University.