Summary
Calculations have been made for how the water level, water release, water temperature and ice extent are expected to change in Lake Vättern up to the year 2100 due to global warming.
The most noticeable effects of the future climate on Lake Vättern are expected to be:
- More frequent low water levels
- Less frequent high water levels
- No change in the highest water levels (the calculated maximum water level)
- An increase in water temperature
- A shorter ice cover period.
With a warmer climate the evaporation is expected to increase, both from vegetation in the lake’s catchment area as well as directly from the surface of the lake. This means that the water level in Lake Vättern is expected to be lower in the future. Calculations show that the average water level in Lake Vättern is expected to drop by one to two decimetres by the end of the century, with about the same reduction for all seasons.
The number of days per year where the water level is below 88.3 m is expected to increase from the present value of around 1.5 months to about 3 months by the middle of the century and 4-6 months by the end of the century. The highest levels, the calculated maximum water level, are expected to remain unchanged in the future.