Evaluating the Potential Effects of Climate Changes on Yield and Value-Added in the Agricultural Sector in Hamedan-Bahar Plain

In recent decades, increase in greenhouse gases, especially carbon dioxide (CO2), has caused the global warming as an undesirable phenomenon. Increase in temperature causes rain-decrease and change in crop yields. On the other, increase carbon dioxide can improve yield of agricultural crops through facilitation in photosynthesis. So assess the final effect of increasing this gas in the environment of agricultural crops production has been a controversial subject among agriculture researchers. With this explanation, in this study, the effects of elevated CO2 and climatic changes on crop pattern were examined in Hamedan-Bahar plain. For this purpose, initially, the sensitivity of crop yields in this plain against CO2, temperature and precipitation were estimated by using yield-response regression models and GME method. Then, the regional climatic changes were predicted by using LARS-WG model in the years 2020, 2030 and 2040. Also by using regression models, the CO2 emission was predicted in the mentioned years in the plain. Finally, the conditions of crop pattern were simulated by using of mathematical programming approach and PMP model, and then the effects of CO2 emission and climate changes on crop pattern were investigated in the several scenarios. The results indicated that the climate changes has negative effects on the cultivation pattern and in the most pessimistic prediction, reduce the amount of the agricultural value added about 53 billion Rials will be followed by 2040 in Hamedan-Bahar plain. But the mentioned lose will be offset with adopting strategy improve the productivity of crops the extent of 0.63 percent.