GLOBAL CLIMATE CHANGE: CAUSES OF OCCURRENCE AND CONSEQUENCES FOR AGRICULTURAL PRODUCTION IN THE SOUTHERN STEPPE

Relevance of the research. If greenhouse gases in the XXI century enter the atmosphere in the same volume as now, the increase in the average temperature on the planet will reach 2–4°C, and therefore the threat of extinction of up to 20–30% of species of animals and plants in existing biocenosis is not excluded. At the same time, the water level in the world ocean will rise, which during the XX century became higher by 17 cm, that is, more than for the previous 2000 years. Simultaneously with the increase in the average monthly air temperature in the conditions of natural moisturizing (without irrigation) of the southern Steppe subzone of Ukraine in recent years, insufficient precipitation has been recorded, especially in July, August and September that, according to various estimates, is typical for the semi-desert and desert. As a result, the aridity of the climate has increased and the frequency of droughts has risen as well. If for the period of 400 years, in the XI–XIV centuries droughts occurred only 8 times, in the XVII–XVIII – 17, in the XIX – 20, in the XX century the number of them increased to 30. The purpose of the article is to reveal the causes of global climate change on the planet and its impact on agricultural production of the southern Steppe subzone that resulted in increasing the coefficient of moisture, evaporation and moisture deficit. Research methods. The study was carried out using long-term meteorological observations of Kherson meteorological station. Scientific research was based on the complex application of statistical, monographic, abstract-logical methods and system analysis. Research results. The analysis of the main causes of global and regional climate change was conducted. Four models of the bases of climate change on the planet Earth were made. The influence of climate change on the formation of crops yield in the subzone of the southern Steppe was specified. The amount of precipitation fell during the growing period of 2011–2017 in medium dry and dry years shows that, compared to the long-term average precipitation, it was significantly lower and amounted to 47.2–63.6 mm. In average for the 65 years (1945–2010) evaporation was 722.0 mm, and the deficit of moisture, respectively 487.4 mm. In wet years, the volatility does not exceed 608.6 mm, and the deficit of moisture was made up of 243.6 mm. In average as to water supply years the evaporation increased up to 645.7–746.3 mm and the deficit of moisture increased up to 406.7–507.7 mm. In mid-dry and dry years, evaporation increased up to 769.8–934.5 mm, and the deficit of moisture – up to 580.9–791.0 mm. Conclusions. The decrease in precipitation, especially in dry years, compared to average annual indicators, was recorded in spring period as 24–27% and in autumn – as 62–65%, along with a simultaneous increase in air temperature in those periods as 2.7 and 2.8°C respectively. In general, during the vegetation period the increase in evaporation was 30–31% and the deficit of moisture was 53–55% that resulted in low yields of crops. The main way to overcome the negative impact of global climate change on the agricultural production of the southern Steppe subzone is the effective use and further extending the areas of actual irrigation, that will ensure stable high yields and food security of the state.