Air temperature changes until now

Mean air temperature

The average air temperature in Lithuania in the period of 1991-2006 has risen by 0.7-0.9°C, compared with the period of 1961-1990 (1).

Maximum and minimum temperature

Statistically significant increasing trends in maximum and minimum temperatures were detected for March, April, July, August and annual values over the period 1951–2010 in Lithuania, Latvia and Estonia. At the majority of stations in these countries, the increase was detected also in February and May in case of maximum temperature and in January and May in case of minimum temperature (11). Analysis of daily extreme temperatures in Lithuania in 1950–2003 shows that the average annual maximum and minimum air temperature has increased by 0.2 to 0.3°C/decade (12).

Changes in atmospheric circulation

Part of the major climate changes observed in the Baltic Sea region during the late 20th century has been related to changes in atmospheric circulation. It has been suggested that the increased frequency of anti-cyclonic circulation and westerly wind types have resulted in a slightly warmer climate with reduced seasonal amplitude and reduced ice cover (2). Recent research using tree-ring based chronologies indicates that the variability of recent decades may lie within the natural range (3).

Precipitation changes until now

Winter precipitation significantly increased by approximately 10 mm per decade at the large majority of precipitation stations in Lithuania, Latvia and Estonia during 1966 – 2015. In this period annual precipitation has generally increased, but the trend is mostly insignificant (14). There are no clear tendencies in changes of precipitation in time series from 1975-1984 to 2091-2100 (4). However, decreases in the duration of snow cover in Latvia and Lithuania have been found during the past five to seven decades (5). A slight positive trend in heavy precipitation events over the last half century has been reported; this increase is expected to continue and accelerate in the future by up to 22 % (13).

Air temperature changes in the 21st century

Air temperature will rise in 21st century by 2-5⁰C in Lithuania (6). The air temperature will probably rise in all seasons of the year. The increase will be the most intense in the winter season.

According to calculations based on a regional climate model and two different emission scenarios, wintertime average daily temperatures in the period 2071–2100 are simulated to increase with respect to the period 1961–1990 from 3° to more than 7ºC in east Europe and Russia depending on which emission scenario and which driving global model is used (7). The warming in the cold end of the temperature distribution is even larger. The strongest warming occurs on cold days.

The strong increase in wintertime temperature in east Europe and Russia is probably connected to the reduction of the snow cover in the scenario runs. The mechanisms involved are feedback processes involving temperature, snow cover and albedo. With decreasing snow cover the albedo becomes lower. The lower albedo implies that more shortwave radiation is absorbed in the ground which in turn leads to higher surface temperatures. The largest reduction of the length of the snow season is calculated to be in a zone reaching from central Scandinavia through southern Finland and the Baltic countries and further towards the southeast into Russia (8).

Precipitation changes in the 21st century

Projections of climate change show a future decrease in mean annual maximum snow depth everywhere over Northern Europe. This decrease is smaller in the northern parts of the Baltic Sea basin than in the southern areas. The simulations also show a decrease in the duration of the snow season. In areas such as Denmark, Germany, Poland, and most parts of the Baltic countries, where the present-climate snow depth is small, the scenario simulations show a complete lack of snow cover (5).

Wind climate changes in the 21st century

Mean and extreme geostrophic wind speeds in Northern Europe have been projected for the future periods 2046–2065 and 2081–2100, and compared with the baseline 1971–2000 (based on nine global climate models and the SRES A1B, A2 and B1 scenarios) (9). The geostrophic wind speed is a theoretical, calculated wind speed indicative of true surface wind speed. The results show:

• Mean wind geostrophic speeds: During the windiest time of the year, the monthly mean wind speeds will start to increase in the Baltic Sea already in 2046–2065. In Finland, increases are largest (5–7%) in November and January by 2081–2100. In November–February 2081–2100, a positive shift of 5–10% is projected to materialize in the Baltic Sea.
• Extreme geostrophic wind speeds: The extreme wind speeds (10-year return level estimates) will increase on average by 2–4% in the southern and eastern parts of Northern Europe, whereas a decrease of 2–6% dominates over the Norwegian Sea. These results agree with results on the future projections of 20-year return level estimates of gust winds that showed that the increase in winds is dominant in a zone stretching from northern parts of France over the Baltic Sea towards northeast (10).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Lithuania.

1. Republic of Lithuania (2010)
2. Omstedt et al. (2004)
3. Esper et al. (2002), in: Omstedt et al. (2004)
4. Kriaučiūniene et al. (2008)
5. HELCOM (2007)
6. Rimkus et al. (2007), in: Kriaučiūniene et al. (2008)
7. Räisänen et al. (2003), in: Kjellström (2004)
8. Kjellström (2004)
9. Gregow et al. (2011)
10. Nikulin et al. (2011), in: Gregow et al. (2011)
11. Jaagus et al. (2014)
12. Bukantis and Valiuškevičienė (2005), in: Jaagus et al. (2014)
13. Reckermann et al. (2011), in: Norwegian Meteorological Institute (2013)
14. Jaagus et al. (2018)