Impact of climate change on water resources and agricultural production

The article highlights the research results on the assessment of natural moisture supply in Ukraine, the state of water resources and agricultural production in the face of modern climate change taking into account the forecast for the medium and long term prospects. It was established that the rate of air temperature growth for the period of 1975-2019 in Ukraine ranges from 0.61 to 0.82oC, while in neighboring post-Soviet countries (Russia, Moldova, Belarus) – this figure is 0.47 - 0.59oC, and in the northern hemisphere and Europe – it is 0.34 and 0.47oC respectively. These data show that the rate of air temperature rise in Ukraine is much higher compared to European countries and the whole world. The rapid rise in average annual temperature in Ukraine is not accompanied by a significant increase in precipitation. Its amount in Ukraine as well as in some other regions remains virtually unchanged. Due to the steady increase in temperature, the area of ​​Ukraine with a significant deficit of natural moisture supply for the period of 1990-2015 increased by 7%, and with excessive and sufficient natural moisture supply, on the contrary, decreased by 10%. If the current warming rates are kept until 2050 and 2100, the territory of the country with insufficient humidity will increase up to 56 and 71%, respectively. As a result of such changes, there is a high probability of medium and long-term prospects of increasing arable land with insufficient natural moisture supply up to 20.6 million hectares (67%) and up to 24.9 million hectares (80%) with a simultaneous decrease in arable land with sufficient natural moisture supply up to 5.5 - 1.8 million hectares. At present, the potential total evaporation is 40-45 km3/year higher than in 1990. As a result, despite the decrease in water consumption, the total amount of water consumption taken from the territory of Ukraine is 20-25 km3 higher. Further climate change will lead to an increase in the volume of additional water consumption till 2050 by 80 km3, and till 2100 - by almost 150 km3 compared to 1990. Modern climate change has significantly affected the cropping systems and their productivity at regional level. The average yield of grain and legumes in the Forest-Steppe and Polissya compared to 1990 increased by 46-61%, and in the Steppe it decreased by 10%. A similar trend is observed with regard to the changes in the productivity of other major cereals, except corn, the yield of which increased in all areas, but in the Forest-Steppe and Polissya by 71-82%, and in the Steppe - only by 9%. The general increase in the production of grain and legumes in the country for the last years was only due to more humid regions - Polissya and Forest-Steppe. Climate change, which has already taken place, proved to be favorable for the spread of the most economically profitable crops in the north of the country, while limiting their production in the south. Thus, in the face of climate change, the conditions of moisture supply in the territory of Ukraine are the main limiting factor that limits not only the level of crop productivity, but also the use of natural and anthropogenic potential of agriculture.