Air temperature changes in the 21st century
The increase in annual mean temperature is expected to be much larger in Russia than the global warming. By 2020, its growth will exceed the multi-model spread (standard deviation) which will be 1.1 ± 0.5°C with respect to the period 1980–1999. By the middle of the century, the temperature rise will be even larger (2.6 ± 0.7°C), particularly in winter (3.4 ± 0.8°C). In the southern and northwestern regions of European Russia, the rise of the lowest daily temperature minima is expected to be 4–6°C. The rise of daily temperature maxima will not exceed 3°C. Thus, the annual difference between the highest and lowest daily temperatures will decrease for all Russia and particularly in the European part of Russia. In Siberia and the Far East the number of frosty days will decrease by 10–15 days and in the EPR by 15–30 days.
Projected changes in average annual temperature by 2100 compared with1960-1990, according to an ensemble of results of different models and the A1B emission scenario, are higher over northern parts of the country, with increases of above 5.5°C in the Arctic regions. In central parts of the country, increases range between around 4.5-5.5°C, and in southern and western regions, increases lie in the range of 3.5-4°C. There is moderate agreement between the models over most of Russia (10).
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 (8). 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 (9).
The Arctic is extremely vulnerable to climate change. The region is warming much more rapidly than the global average. The IPCC report states that the winter warming of northern high latitude regions by the end of the century will be at least 40 percent greater than the global mean, based on a number of models and emissions scenarios. Temperature increases for the central Arctic are projected to be about 3-4°C during the next 50 years. Even an optimistic scenario for projecting future greenhouse gas emissions yields a result of a 4°C increase in autumn and winter average temperatures in the Arctic by the end of this century (7).