CLIMATE CHANGE ON THE TERRITORY OF THE REPUBLIC OF TATARSTAN

Abstract

The paper looks at the dynamics of air temperature changes in Kazan in the 19th-21st centuries against the background of climatic processes occurring in the Northern hemisphere. The study used proven statistical methods of time series processing, correlation and trend analysis, and a Potter filter to isolate the low-frequency component. The fastest rate of warming in the region was established to occur in the winter-spring period. At the same time, the three decades between 1991 and 2021 turned out to be warmer in each month than the 5 previous three-decade periods. The contribution of the entire Northern Hemisphere to the fluctuations in the air temperature in Kazan was estimated (42% in winter and 27% in summer). It has been established that the average annual temperatures in Kazan and the entire Northern Hemisphere changed in the opposite phase until 1970. Since 1870, the winter temperature in Kazan has increased by 4.7°C. During the summer period, a ‘hump’ (warming) was detected on the low–frequency temperature curve in Kazan in the period 1920–1960, which can be explained by the fact that during this period the atmosphere in the Northern Hemisphere was more transparent (by 2%) than in the other periods. The consequences of climate change in the region in recent decades have had an effect on the dynamics of agro-climatic resources of Tatarstan. Several agrometeorological indicators were calculated, including the M.I. Budyko dryness index, the Selyaninov hydrothermal coefficient (HTC), and the Sapozhnikova moisture coefficient. According to the estimates made, there has been an increase in the duration of the growing season and the sum of effective temperatures, and also a weak trend toward increasing aridity in the summer period has emerged. Using ensemble calculations based on 40 climate models from the CMIP6 project, the paper provides an assessment of future climate changes in the region: the annual temperature in Kazan is expected to increase by 2.4°C by the end of the 21st century according to the ssp245 scenario. Under the ‘toughest’ ssp585 scenario, this increase will be 5.5°C.