Assessing the Effects of Climate Change on the Prevalence of Food Insecurity with Emphasis on the Role of Water Resources Management in Hamadan-Bahar Plain

The health and food security of a country depends on the production of the agricultural sector, and any disturbance in the production process of this sector can threaten the food security of households. Among the challenges affecting the agricultural sector, climate change is of double importance due to its direct impact on crop yield and water resources. The occurrence of climate change through changes in the supply and price of crops, overshadows the producer surplus in this sector. This is despite the fact that, according to previous studies, climate change in the coming decades will be a visible phenomenon in most plains of Iran, and this issue will have negative consequences on water resources and, as a result, on the production of crops and food security. Therefore, considering the importance of food supply in the process of economic development, it is necessary to investigate the impact of food security on climate change and the welfare effects of this phenomenon in Iran. According to this approach, in the present study, the potential effects of different climatic scenarios on the cultivation pattern of the Hamadan-Bahar plain, considering 2018 as the base year, were investigated, and the impact of water resources, production, income and food security in the agricultural sector of this plain was evaluated.

In this study, the dynamic positive mathematical programming(PMP) approach in endogenous price conditions was used. The experimental model, consisting of 18 crops and two types of irrigation technologies, was developed based on the information of 2018 as the base year and in a 20-year planning horizon. This model's objective function is to maximize the present value of net farm income. Resource constraints used in the experimental model include water, land, capital, labor, and chemical fertilizers, with chemical fertilizer restrictions repeated for each nitrogen, phosphate, and potash fertilizers. Finally, the GAMS software and CONOPT3 algorithm were used for data analysis. In the meteorological dimension of the model, the climatic measurement of rainfall was studied in the form of SSP climatic scenarios. Accordingly, the rate of evapotranspiration of crops and, consequently, the production and yield of crops in the region due to climate change were estimated and integrated into the PMP model. Each of these relationships is responsible for providing some of the information needed in the experimental research model. Finally, the dynamic endogenous price optimization framework was estimated as a unit pattern. After evaluating the changes in the income of farmer households and crop pattern in the face of climate change, the food security index was calculated in the different climate scenarios. In the final stage of the research, management strategies were evaluated in the agricultural sector of the Hamadan-Bahar plain to reduce the negative effects of climate change on the food security.

The results showed that the annual cumulative rainfall values of the Hamadan-Bahar plain in the next 20-year period would have a decreasing trend in all climate scenarios, so that in the SSP1, SSP2 and SSP3 scenarios, the average rainfall would be 303, 272 and 252 mm, respectively. Meanwhile, the amount of precipitation in the base year of this research (2018) is reported as 323 mm. Also, the results showed that with the considering an optimistic approach in predicting climate changes (SSP2 scenario), along with the increase of extraction from underground water sources by 13%, the increase in average price of agricultural products by 34% and the decrease in production by 5% in the 20-year planning period compared to the base year, the present value of net producer income and the food security index in the agricultural sector of the region would decrease by 17 and 11 percent, respectively. However, the adoption of management strategies such as the optimal deficit irrigation would improve the food security of the plain by 11 to 15 percent.

The change in the climate conditions in the coming years would have negative effects on the food security conditions in the agricultural sector of the Hamadan-Bahar plain. In this situation, considering that it is impossible to avoid different forms of climate scenarios, it is necessary to apply strategies to adapt to the mentioned phenomenon. Based on this, the optimal deficit irrigation, as a management strategy, was investigated, and the results confirm the positive effect of this strategy in improving the food security index in the region. Therefore, according to the results, management strategies with emphasis on deficit irrigation in the agricultural sector of Hamadan-Bahar plain should be put on the agenda.