چکیده:
تغییرات اقلیم به تغییرپذیری‌های بلندمدت در الگوی رفتاری میانگین سنجه‌های آب و هوایی یک منطقه در شرایط نبود تغییر در وضعیت عمومی اقلیم منطقه اطلاق می‌شود. نظر به اجتناب ناپذیری اثرات تغییرات اقلیم بر بخش کشاورزی، ارزیابی اثرات آن می تواند بستر‌‌ساز انطباق با شرایط محتمل دوره آتی باشد. هدف از این تحقیق تحلیل اقتصادی اثرات تغییر اقلیم بر رانت زمینهای کشاورزی گندم آبی در ایران می‌باشد. آمار و اطلاعات مورد نیاز از دادههای سازمان هواشناسی کل کشور و بانک اطلاعات وزارت جهاد کشاورزی گردآوری شده است. به منظور بررسی اثر نهایی تغییر اقلیم بر رانت گندم‌کاران در ایران از رهیافت ریکاردین و تکنیک دادههای تلفیقی برای17 استان تولیدکننده عمده گندم آبی استفاده شد. به منظور پیش‌بینی اثر متغیرهای اقلیمی بر رانت گندم‌کاران در آینده از سه سناریوی تغییر اقلیمA1، B1و ABکه بیانگر افزایش سه درجه‌ای دما و کاهش 5/2 درصدی بارش برای ایران تا سال 2100 است، استفاده شد. نتایج نشان می‌دهد که رابطه بارش تجمعی سالیانه و رانت مثبت و معنی‌دار می‌باشد. بر اثر تغییر اقلیم میزان رانت را در سال 2025، 07/2 درصد، در سال 2050، 34/2 درصد و در سال 2100 تا 41/3 درصد کاهش خواهد یافت.
Introduction There are assessing the impact of environmental change to internalize the externality. Climate change is the environmental change that needs to evaluate the impact on various sectors in the economy. Climate change refers to the long-term variability in the behavioral pattern of the average climate measures of an area in the absence of a change in the general climate of the region. Climate change occurs when changes in Earth's climate system result in new weather patterns that remain in place for an extended period of time. Agriculture is a climate-sensitive sector, and climate-smart agriculture is the way forward to increase agricultural productivity in a sustainable manner. Based on the reanalyzed index of global land-ocean temperature prepared by National Aeronautics and Space Administration combined land and ocean skin temperature represents warming approximately to 1.35 °C between 1880 and 2018. The climate change fact is intensive among the Middle East countries and especially Iran. According to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, climate change (CC) will amplify existing stresses on agricultural systems, particularly those in Asia for several reasons. Given the inevitability of the effects of climate change on the agricultural sector, the assessment of its effects can be a basis for compliance with the uncertain future conditions. Some of the research has investigated the potential impacts of climate change on agriculture crops across different geographical locations. Regarding the importance of wheat in Iran‘s food security, The purpose of this research is to assess the effects of climate change on wheat crops in Iran. In this way, Partial goals are including: 1-Determination of irrigated land rent in Iran. 2-Investigation the impact of climate variable on irrigated land rent in Iran 3-Determination of climate change impacts on irrigated wheat lands rent in Iran Materials and Method Because of the potential for global warming, there are widespread concerns about the impact of changing climate upon the productivity of land in farming and other sectors. The needed statistics and information were collected using secondary data. The main wheat production province in Iran are West Azarbaijan, East Azarbaijan, Ardebil, Esfahan, Ilam, Razavi Khorasan, Khuzestan, Sistan and Balouchestan, Fars, Qazvin, Kordestan, Kerman, Kermanshah, Golestan, Lorestan, Markazi and Hamedan Province. About 70 percent of total wheat production is related to irrigated wheat and 30 percent is related to rain-fed wheat. In recent year, land area of irrigated wheat in recent year is about 2.2 hectar in Iran. Also, The yield of irrigated wheat is about 3.5 Ton per hectar in Iran. To accomplish the research objectives, using the panel data and Ricardian approach, the final effects of climate change on wheat rent in major provinces of the country wheat production during 2000-2015 were investigated (relation 1 to 4). In relation (1) to (4), where the Quantity of production, P is is the market price of the crop, L land, and Pl is the agricultural land value. In order to predict the effect of climatic variables on the rent in the future of climate scenarios (A1, B1, and AB) was used. Climate change scenarios or socioeconomic scenarios are projections of future greenhouse gas emissions used by analysts to assess future vulnerability to climate change. Producing scenarios requires estimates of future population levels, economic activity, and the structure of governance, social values, and patterns of technological change. The climate change scenarios for Iran are published by the Intergovernmental Panel on Climate Change (IPCC). Change in precipitation and Temperature will happen to 2100. Temperature and precipitation respectively increased and decreased. Based on Climate change scenarios in Iran between 2025 to 2100, change in Temperature will happen one degree centigrade in 2025, 1.7-degree centigrade in 2050, 2.3 degrees centigrade in 2075 and 3 degrees centigrade in 2100. Also, precipitation will decrease by 0.9 % in precipitation in 2025, 1.3% in 2050, 1.4% in 2075 and 2.5% in 2100. Also, Iran will experience an increase of 3 °C in mean temperatures and a 2.5% decline in precipitation in the next Century. Also, Iran by total greenhouse gas emissions nearly 616,741 million tons of CO2 is the first responsible country to climate change in the Middle East, and seventh in the world. Results and discussion & Conclusions The results showed that the first and second-degree coefficients of variables indicate the effects of U or reverse U on net agricultural income, which indicates that the average precipitation of spring season up to 91.5 mm leads to an increase in agricultural land rent and after this, the spot decreases with increasing precipitation. The results of the fall season were similar to those of spring season precipitation, i.e., rainfall increase up to 112.2 mm in this season, will increase the rents, but if rainfall is higher than this, the rent will decrease. The results of the fixed effect by using Generalized least squares (GLS) show that the fixed effect is the best model for investigating climate change impacts on irrigated wheat land rent in Iran. F-test is applied to select between the pooled model and panel model. Also, the Hausman test is applied to select between the random effect model and the fixed-effect model. The quantity of F and Hausman test is respectively 3.14 and 49.58. the result indicates that the panel model is better than the pool model. Also, the fixed-effect model is better than the random effect model to evaluate the climate variable on agricultural land rent in Iran. The quantity of JB shows that the model has normality. However, we applied GLS to resolve the heteroskedasticity in the fixed-effect model. Log-lin is the best form of this model. First, 72 proposed variables including Temperature and precipitation in spring, fall, and interaction between variable, latitude, above mean sea level and quantity of inputs Were estimated by stepwise regression. Then, based on the fixed-effect model, Workforce, Seed, spring temperature, fall precipitation, and total precipitation are significant and R2 is equal to 65 percent. When Spring precipitation increases, first agricultural land rent increases and then decreases. Also, When fall precipitation increases, first agricultural land rent increases and then decreases. Both fall precipitation and Spring precipitation have a two-degree effect on agricultural land rent in Iran. Besides, by one millimeter increasing in spring precipitation agricultural land rent increases 0.05 percent. The negative-coefficient Squared spring precipitation indicates after the maximum spot rent decreases. Aso, the seed coefficient shows that by one Kilogram per hectare increasing in wheat seed, agricultural land rent increases by 0.01 percent. The Workforce indicates when one labor increases, agricultural land rent increases by 0.04 percent. The results of the final effect of climate change on agricultural land rent using scenarios of climate change in the future years showed that climate change has a significant negative impact on wheat yield rents and will lead to lower product rents in the future, So that the climate change will decrease the rent by 1.35,4.51 and 10.41 percent in 2025, 2100 and 2050, respectively. As a result, it could be mentioned that consideration of the effects of climate change on food security and farmers needed can decrease the negative effects of climate change
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