Assessment of Climate Change Impacts on Optimum Cropping Pattern: A Case Study of Ghareso Basin in Golestan Province

This study was carried out to evaluate the economic and technical effects of climate change on the agricultural sector of Ghareso basin in Golestan province. In the first part, using the IHACRES rainfall-runoff model and rainfall, temperature, and monthly runoff data during the base period (1994-2010), the Ghareso river flow was simulated during the period of 2011-2040. Then, the probabilistic status of water resources allocation and provision of agricultural sector was evaluated by WEAP model. In the second part, in order to reduce the negative effects of climate change on the agricultural sector, using the goal programming economic model, optimal cultivation with the goals of minimum water consumption and maximum future profits was determined. The results of the first part showed that runoff decreases in the upcoming periods by 31.34% compared to the base period. In addition, the results of the WEAP model indicate an increase in the unmet need of the agricultural sector in the region under study. This result suggests that with the continuation of climate change in the future to reduce the negative effects in agriculture, the region's cultivation pattern should be changed to remove cotton and increase barley and rice. These changes were identified in the results of the second part of the model through the Goal Programming Model. In the optimal cultivation pattern, the gross profit of farmers in the studied area in the period of 2011-2040 increased from 1386 billion Rials to 1991 billion Rials compared to the base year.