Climate change

Since 1961, except for autumn, all seasons have warmed significantly. During the period 1961–2020, an increasing trend in absolute maximum temperature and absolute minimum temperature is observed.

The number and intensity of heat waves increased, and periods of cold weather became less frequent and pronounced. The number of hot days is increasing; a greater frequency of extremely hot days with the highest daily temperature above 35 °C is also observed.

Slovenia lies at the junction of the Alps, the Mediterranean and the Pannonian plain. It is characterized by landscape diversity, which affects the local climate diversity, as well as the changes that already and will continue to characterize individual areas in different seasons.

The course of climate change in the future depends in particular on the intensity of greenhouse gas (GHG) emissions. Due to the different possible courses of socio-economic development, different climate scenarios are important in the preparation of the risk assessment, which illustrate some typical possible courses of greenhouse gas emissions. Climate models are only an approximation of the true state of the climate system.

ARSO prepared an assessment of climate change in Slovenia until the end of the 21st century, based on three different scenarios of GHG emissions.

The results of these simulations predict for the future until the end of the 21st century:

• A significant increase in the annual average air temperature in the entire area of ​​Slovenia in all seasons.

Average air temperature will increase, with a median range of about 1 to about 4 °C, depending on the greenhouse gas emissions scenario.

A significant change in temperature will be felt in all seasons, in winter the warming will be more pronounced than the average annual warming.

• The rise in temperature will greatly increase the heat load in summer. The growing season of plants will be extended.

The number and length of heat waves will increase in the future. The strongest heat events in the near future will be comparable to today's, and in the period from 2040 onwards they will be stronger than the strongest heat waves from the comparative period (1981-2010).

The number of cold days will gradually decrease in the future. According to the pessimistic scenario, at the end of the century, approximately 40 fewer cold days are expected in most of Slovenia, and up to 60 fewer days in the highlands than in the comparison period.

Reciprocally, with the rise in air temperature, the surface layer of the soil will also heat up, which will affect the phenological development and the length of the growing season of plants. The spring phenological development of plants will be earlier, and the length of the growing season will increase with an earlier start in spring and a later end in autumn. The frequency of spring frosts will remain at a similar level as in the comparison period.

• A noticeable increase in precipitation is expected in winter. The intensity and frequency of extreme rainfall will also increase.

By the end of the 21st century, an increase in average annual precipitation of approximately 10% compared to the comparative period is expected in the entire area of ​​Slovenia, with the exception of the Julian Alps, with the change being more reliable in the eastern half of Slovenia.

The winter increase in precipitation does not mean an increase in snowfall, as with the rising air temperature, it will most likely become less and less frequent.

Both the intensity and frequency of extreme rainfall events will increase.

• Annual groundwater recharge and large flows will increase, most prominently in the east of the country.

The scenarios indicate an increase in groundwater supply, which is reliable mainly in the eastern half of Slovenia and in the southwest in the period after 2040. By the end of the century, according to a moderately optimistic scenario, an increase in supply in Slovenia is expected by approximately 20%, slightly more in NE Slovenia.

For a more detailed investigation of the results of the ARSO project "Assessment of climate change in Slovenia by the end of the 21st century", you can use the online tool Atlas of Climate Projections. Only this allows users to research the results of the project with the help of graphic displays for various aspects of climate change in Slovenia.