Evaluation of the Effects of Greenhouse Gas Emissions on the Yield and Cropping Pattern of Selected Products in Tehran Province

in the present study evaluation of the effects of greenhouse gas emissions on the yield and cropping pattern of selected products in Tehran province were investigated. In order to assess the potential effects of drought, global warming and the establishment of local or regional water markets. To achieve this goal, first using general circulation models (GCM) the effects of greenhouse gases on the average climatic variables of temperature and precipitation under the emission scenarios A1B, A2 and B1 were investigated. This was done with the help of GCM/RCM data system and LARS-WG microscale model. Then, using econometric approach and regression analysis, the effects of climatic variables of temperature and precipitation on the average yield of selected products were evaluated. A positive mathematical programming (PMP) model to investigate changes of products yields on cropping patterns was used. The results showed that the behavior of climatic variables of temperature and precipitation during the future periods in Tehran province compared to the base period will increase (0/27 to 3/75 °c) and decrease (0/63 to 41/1 mm) respectively. Increasing the farmers’ desire to develop the acreage of irrigated wheat, corn and canola and reducing the acreage of irrigated barley, tomato, watermelon and sunflower in the cropping patterns of of Tehran province is an important result of application of integrated climate scenario (2 °c increase in temperature and 20 mm decrease in precipitation) in this study. Under the terms of climate change occurrence, watermelon and sunflower with the most decreasing changes in yield (13/1 and 17/7 %) and acreage (68/8 and 31/9 %) as the most sensitive products in cropping pattern of Tehran province were identified. Therefore, planning to reduce or develop the their acrage in the cropping pattern of Tehran province is recommended to farmers and relevant officials in the agricultural sector during future periods.