Contemporary climate change problems in Central Asia

. According to the moderate climate change scenario, the direct impact of climate change on irrigated crops, including cotton, wheat, apples, tomatoes, and potatoes, is pro-jected to decrease the yields by 1 – 13% by 2050. However, the demand for food is expected to increase overall due to the population growth and poverty reduction goals. The rate of climate change in the countries varies. The highest decadal rates of climate change were recorded in Uzbekistan at 0.29°C (1950-2005) and in Kazakhstan at 0.26°C (1936-2005). The climate change rate in Kyrgyzstan and Tajikistan were 0.08°C and 0.10°C, respectively. In these upstream countries, the area of forests and mountain ranges is relatively large, and the possible negative impact of climatic factors is relatively small. Thus, the contemporary problems in Central Asia in the context of climate change are related to a growing scarcity of water resources; uneven distribution of water resources across the countries in relation to the needs; relatively low water use efficiency (especially in agriculture); relatively high population growth rates and intensification of economic processes. If additional resource-saving measures are not taken, the negative consequences of climate change in the region may include an increased risk of water shortages, droughts, and other dangerous hydrome-teorological events that lead to instability of agricultural production and threaten food secu-rity; and particularly the shrinkage of glaciers and therewith one of the key sources of freshwater. Overall, a strategy of action plans on climate change nationally and region-wide is urgently needed, including both adaptation and mitigation measures.


Introduction
In recent decades, climate change has become one of the most threatening environ-mental problems globally. Between 1880 and 2017, the average surface temperature in the world increased by 1.1 °C [1]. However, the dynamic and interconnected na-ture of ecosystems and societal activities is complex, and determining and assessing climate change at the global, regional and local levels are both an urgent and im-portant task. In Central Asian countries, energy shortages, food problems, water scarcity, and environmental degradation can be directly linked to climate change. Since the mid-twentieth century, the average annual temperature across the region has risen from 0.5°C in the south to 1.6°C in the north [2]. The area of Central Asian glaciers has shrunk by a third since the beginning of the 20th century. In general, the weather in the region is expected to be warmer and drier with more frequent and robust heat waves and extreme events such as heavy rainfall, floods, and mudflows, as well as with significant shifts in drought and rainfall patterns [3].
Due to the negative impact of human activities on the climate system and all its components, the process of global warming continues today, and there is no way or means to stop. One of the main reasons for climate change is the steady increase in greenhouse gases in the atmosphere. Carbon dioxide (CO2) accounts for 80% of the anthropogenic greenhouse effect, methane gas -18-19%, and the number of other gases -1-2% [4]. By 2018, the amount of CO2 in the atmosphere had exceeded 400 ppm. Due to climate change, water scarcity, energy shortages, food problems, and environmental pollution are observed in the Aral Sea basin countries [5].
An increase in water shortages from year to year will lead to decreased food production, higher prices, and increased unemployment. Therefore, the determining and assessing climate change at the global, regional and local levels is one of today's most pressing problems.
Our research indicates that some of the critical adaptation measures to climate change needed today include: developing region-wide agreeable principles and sen-sible solutions that apply to all water users of transboundary rivers; strengthening the legal framework for water use and its implementation; introducing a system of efficient use and conservation of water resources; improving the monitoring of water resources; enhancing the irrigation and drainage system infrastructure; and, deploy-ing the advanced irrigation technologies.
Geographic information systems were used for processing, mapping, and fore-casting. Data was analyzed using IBM SPSS Statistics v.27 software. Aligning with the in-situ data, satellite imagery was utilized. The sensor of the satellite images is Landsat, downloaded from the open source 'Earth Explorer' database.

Results
The mountainous areas of the Aral Sea basin have ice reserves of about 1,000 cubic kilometers, equal to the ten-year water reserves of the two main rivers of the region -the Amudarya and the Syrdarya.
The glaciers of the Pamir-Alay Mountains supply water to the Amudarya, and the glaciers of the Tien Shan Mountains supply water to the Syrdarya. Both rivers are transboundary and supply water to the countries of the Aral Sea basin. The average annual water resources of the two rivers are 115-120 km3.
The size of Central Asian glaciers has shrunk by a third since the beginning of the 20th century. Furthermore, their size is projected to shrink by up to 60% (Fig. 1). Due to the melting glaciers and the reduced precipitation, less water enters the Aral Sea basin during summer. With expected climate change and reduction of precipita-tion, the rate of reduction of glaciers in the Aral Sea basin is anticipated to be from 0.2% to 1% per year. Uzbekistan is a country with a shortage of water resources, and this problem is expected to be exacerbated by climate change, population growth, and the growing redistribution and use of water flow between countries of the Aral Sea Basin. Due to the negative impact of climate change, water flow in rivers is expected to decrease by 2050; in the Syrdarya River basin it can be reduced by 2-5%, and in the Amudar-ya River basin by 10-15%.
If additional water-saving measures and methods are not used in the future, the risk of water shortages, increasing droughts and other dangerous hydrometeorologi-cal events that lead to instability of agricultural production in the country and threaten food security may increase.

Discussion
The degree of climate change impact in Aral Sea Basin countries varies. The highest rates of climate change were recorded in Uzbekistan between 1950 and 2005 at rate of 0.29 °C and in Kazakhstan at 0.26 °C  per decade [6]. In addition, the climate change rate in Kirgizstan (1883Kirgizstan ( -2005 and Tajikistan  were 0.08 °C and 0.10 °C per decade, respectively [7]. In Kirgizstan and Tajikistan the area of forests and mountain ranges is comparatively more and the possible negative impact of climatic factors is relatively small. Analysis of long-term temperature changes in Tashkent and in Nukus region (the Aral Sea) for 80 years, showed an increase in temperature average by 2 °C degrees (Fig. 2). These indicators are much higher than the indicators of global climate change. According to the moderate climate change scenario, the direct impact of climate change on irrigated crops, including cotton, wheat, apples, tomatoes, and potatoes, is projected to decrease by 1-13% by 2050 [8].

Conclusions
Modern problems of water use in the Aral Sea Basin countries in the context of cli-mate change include: a limited and growing scarcity of water resources; uneven distribution of water resources in the basin countries; relatively low water use effi-ciency (especially in agriculture) deterioration of water quality; degradation of water and land resources; Population growth in the Aral Sea Basin is higher than world rates; Intensification of economic processes, increasing use of water resources.
In the region, key adaptation measures to climate change are: developing regional principles and sensible solutions that apply to all water consumers of transboundary rivers; introducing a system of efficient use and conservation of water resources; improving monitoring of water resources; strengthening the legal framework for water use; watersaving and improvement of irrigation and drainage system infra-structure; and, improvement of irrigation technologies.