بررسی آثار تغییر اقلیم در مناطق نیمه‌خشک بر بازار محصولات کشاورزی

تغییر اقلیم در واقع تغییر برگشت‌ناپذیر در متوسط شرایط آب‌وهوایی است. این پدیده دامنه زمانی و مکانی وسیعی دارد و به دنبال آن دامنۀ اثرگذاری گسترده بر بخش‌های مختلف اقتصادی ازجمله منابع آب و کشاورزی خواهد داشت. قسمت عمده‌ای (77 درصد) از محصولات زراعی کشاورزی تولیدی کشور در مناطق نیمه‌خشک تولید می‌گردد و تغییرات اقلیمی می‌تواند بر تولیدات کشاورزی در این مناطق اثرگذار باشد. در این راستا، هدف مطالعه‌ی حاضر بررسی آثار تغییر اقلیم در مناطق نیمه‌خشک، بر بازار (قیمت، درآمد، تولید، صادرات و واردات) محصولات کشاورزی کشور است. به‌منظور بررسی چالش‌های ناشی از تغییرات آب‌و‌هوا از دیدگاه اقتصادی، رهیافتی که تصویری دقیق از بخش کشاورزی و روابط درون آن را فراهم کند، ضروری می‌باشد. به همین دلیل از الگو چندبازاره کشاورزی استفاده شده است. برای این منظور اقدام به پهنه‌بندی زیراقلیم‌ نیمه‌خشک به روش دومارتن اصلاح شده گردید. همچنین جهت شبیه‌سازی اثرات تغییر اقلیم، عملکرد محصولات زراعی اعم از گندم آبی و دیم، جو آبی و دیم، و ذرت دانه‌ای با استفاده از تغییرات دما و بارش و ضرایب پاسخ عملکرد، محاسبه شد. سپس تابع تقاضای محصولات مختلف با استفاده از کشش‌ تابع تقاضا برآورد گردید. نتایج تحقیق نشان داد که تا سال‌ 2025 (افق 1404) تغییرات آب‌وهوایی، باعث تغییرات متفاوتی مانند تغییر در عملکرد، سطح زیرکشت و آب در دسترس در محصولات منتخب، می‌گردد که این امر باعث تغییر در قیمت این محصولات خواهد شد و اغلب قیمت آن‌ها را افزایش می‌دهد. همچنین نتایج تحقیق نشان داد تغییرات صورت گرفته در محصولات باعث افزایش در درآمد بهره‌برداران کشاورزی شده و میزان خالص صادرات این محصولات را کاهش می‌دهد. در این راستا پیشنهاد می‌شود سیاست حمایتی قیمتی و غیر قیمتی مناسب برای حمایت از تولیدکنندگان و مصرف‌کنندگان این محصولات اتخاذ گردد تا آثار تغییرات اقلیمی بر بخش کشاورزی قابل‌کنترل و برنامه‌ریزی گردد. همچنین تولید محصولات گندم دیم، جو آبی، جو دیم و ذرت دانه‌ای در زیر اقلیم‌های خشک گرم و خشک سرد و محصول گندم آبی در زیر اقلیم خشک گرم و محصولات گندم آبی، جو دیم و ذرت دانه‌ای در زیراقلیم خشک معتدل افزایش یابد.

Investigating the Effects of Climate Change on Agricultural Market in Semi-arid Regions

Introduction: Understanding the temporal and spatial fluctuations of climatic parameters (such as temperature, precipitation, relative humidity, etc.) and its impact on agricultural sector is essential for managing agricultural resources and adopting appropriate strategies. Precipitation directly affects the production of dry crops by supplying the required moisture for the plant, and indirectly affects the production of aquatic crops through supplying surface and underground water resources. Climate change has an effect on temperature and precipitation distribution and consequently affects the plants water requirement and agricultural water consumption. Overall, climate change is influenced by both temperature and precipitation. Due to the changing rainfall pattern and average temperature of the atmosphere, this phenomenon can damage the production of agricultural products that maintain the major food sources of the country. Given the important role of agriculture in the country apos;s economy and the existence of the ongoing water crisis and drought in the country, climate change can have major impacts on their aggravation. The purpose of the present study is to investigate the effects of climate change and water scarcity on agricultural production, price and income in Iran.Materials and Methods: The multimarket model, sometimes referred to as the finite general equilibrium or multimarket partial equilibrium model , has reduced the complexities of computable general equilibrium (CGE) models. The AMM template was used for this purpose. To simulate the effects of climate change, crop yields were calculated using yield response coefficients. Then, the demand function of different products was calculated using estimated elasticities and finally climate change has been simulated for 2025.Results and Discussion: The results showed that climate change would increase, yield of rainfed wheat, blue barley, dry barley and maize grain in semiarid climate and subtropical climate, in addition dry barley and barley products in warm semiarid climate and subtropical climate, and finally rainfed barley and corn products Grain in temperate semiarid climates and subtropicals climate by 2025 relative to current levels. Climate change also would decrease yields of dry wheat and barley in temperate semiarid climates and subtropicals, and also wheat in warm and semiarid climates and subtropicals for 2025 compared to the present value. The results also showed that climate change would expand the water available for the blue wheat crop in the semiarid climate and subclimates, besides the blue barley crop in the semiarid, semiarid, and temperate semiarid climates for 2025 compared to the present value. Climate change also might reduce the amount of water available for the blue wheat crop in the climate and subarid and semiarid subclimates, therefor the corn yield in the cold and semiarid subclimates and subclimates for 2025 compared to the present value. The results also revealed that climate change would diminish cultivation of maize crop in semiarid climate and temperate climates in addition irrigated and rainfed wheat crop in warm and semiarid subclimate and also rainfed wheat crop in semiarid climate by 2025 relative to the present situation. Also the area under cultivation of blue barley and dry barley crops in warm and semiarid climates, cold and semiarid climates, and blue wheat crop in semiarid climates and rainfed wheat crop in temperate and semiarid climates would decrease by 2025.Conclusion: The results also demonstrated that with the climate change, the amount of maize crop production in cold and semiarid climates and subclimates, and the production of blue and dry wheat crops in warm and semiarid climates, cold semiarid, temperate and dry semiarid climates for 20 years would decrease relative to current value. Also, the production of irrigated and rainfed barley in warm and semiarid climates, subclimates and temperate semiarid climates for 2025 would increase compared to the present situation. Thus the first hypothesis of the study: Climate change and water scarcity reduces agricultural production is not approved in Iran. The results also explained that with the climate change the prices of wheat, barley and maize crops in the semiarid and temperate climates for the year 2025 would also rise, so the second hypothesis of the study Climate change and scarcity of water resources will increase the prices of agricultural products in Iran” is confirmed. The results also show that with climate change, farmers apos;incomes in cold and semiarid climates, temperate and warm semiarid climates would increase by 2025 relative to their present value, so the third research hypothesis that climate change and water scarcity reduces farmers apos; income In Iran, is not confirmed. The results also indicated that wheat, barley and maize exports remained negative by the creation of net climate change for 2025 and that the country apos;s climate change created an importer of these products.