Published on: 19.1.2021

Information produced by Finnish Environment Institute

Climate change and seasonal water resources

While climate change is known to increase precipitation, rain will not fall evenly round the year. How will this affect our water resources in summer and winter?

Climate change is expected to increase precipitation especially in winter, and as winters will also become milder, a larger share of the precipitation will come as rain. Because little or no evaporation occurs in the cold season, there will be no shortage of water in winter.

Some of the winter rain will be infiltrated into the unfrozen soil and become ground water. The groundwater level is consequently expected to be higher than today in wintertime, especially in Central, Eastern and Northern Finland, where it has usually gone down over the winter.

Not all precipitation will be infiltrated into the soil and turn into groundwater, however, as some of it will flow into lakes, potentially raising their water levels higher than today in winter.

The situation will be different in summertime. As the climate becomes warmer, there will be more evaporation, and summers will be extended and bring longer periods of hot weather with little rain. This will reduce ground moisture, and the groundwater level may drop.

Southwest Finland, which already suffers from water shortages in places, will be the most severely affected by drought. Farmland in the Southwest may increasingly need to be watered in the future, especially in early summer. Drought may also interfere with water supply, hydropower production and other similar pursuits.

Image: © Frauke Riether, Pixabay