Climate change and the risk of agricultural productions: A case study of wheat, barley and potatoes

Climate change is not only an important determinant of crop average yield and agricultural production potential in a region, but also is an important source of agricultural production risk, which leads to unexpected changes in yield and production levels. This, in turn, it is affects key parameters of the market, supply and demand, and, consequently products prices. Although, the analysis of climate change effects is an important issue in relation to agricultural production from policy making points of view and adaptation strategies (Kundouri et al, 2005), but, little quantitative studies have been conducted in this regard so far. On the other hand, in most researches, the impacts of climate changes on average crops yield is estimated, and less attention has been paid to the effects of this phenomenon on the production risk. In this study, using the random production function introduced by Just and Pop (1979, 1976), the effect of changes in climatic parameters on the average crops yield and yield variance was estimated for three crops including wheat, barley and potatoes in the northwestern ecological zone of Iran for the period of 1999 to 2015 years. The basis of this approach is on the fact that the production function can be separated into two basic components. The first component is related to the average yield of the product, while the second component is related to variance and production-level fluctuations (Sarker et al, 2012). Climatic parameters simulations and hence the change in the average and the variance of crops yield carried out by using the results of two general circulation models of ECHAM3 and EGCM3T63 and two climatic scenarios, GA and B1. The results of climate change simulation of two scenarios B1 and showed that, up to two future decades (2040), the annual rainfall in the northwestern ecological zone was increased and until the year 2070 will decrease compared to the base historical period. Under the scenario B1 in the model , the amount of annual precipitation is predicted incremental over both time intervals. The results of predictions for the temperature parameter also indicate that it tends to increase under both general circulation models and scenarios. The intensity of warming in the model is more predicted than the other model. The results of the crops yield simulation to the predicted climatic variations under different scenarios indicate a significant reduction in the yield of these products. The yield reduction for wheat is estimated to be higher than barley and potato. Comparison of cultivars in the percentage of yield reduction in the scenarios also shows that in the range of predicted changes for climate parameters, increasing temperature is a more effective factor in explaining the reduction of yield performance relative to precipitation. The variance response of crops in relation to climate change for potato production under different scenarios and for wheat under scenario 2040-GA has been estimated incremental. Regarding the reduction of yield of products under different scenarios of climate change, it is recommended to develop agronomic plans in order to shift the crop pattern towards varieties or products that have the least yield loss due to climate change. Further development and research in this field and the introduction of drought and heat resistant varieties can be one of the most effective ways in this regard.