Natural earth system confront grand challenges due to climate change. Soil erosion and sediment transport are the key components functioning natural ecosystem. A special report from the Soil and Water Conservation Society indicated that the projected climate changes may increase the overall risk of soil erosion. The amount of change and repercussion is not known for most parts of the world. Iran located in arid and semi-arid part of the world might become one of the most vulnerable regions to climate change. Any change in soil loss and sediment load in this country may have significant implications for water resources development as well as water productivity and food security. A quantitative assessment of climate change impacts on the soil erosion and water resources availability is required to study the potential options in dealing with climate change. The Gorganroud river basin (Golestan Province, Iran) was considered as case study. The Soil and Water Assessment Tool (SWAT) was used to simulate the hydrologic regime in this basin. The SUFI-2 algorithm in the SWAT-CUP program was used for parameter optimization using the daily river discharges and sediment loads. Future climate data of multi-model ensembles were downscaled and fed into hydrologic model to predict the impact on hydrologic regime and sediment load, presenting also the uncertainty resulting from structural differences in the global climate models (GCMs), CO2 emission scenarios and uncertainty due to variations in initial conditions or model parameterizations. This study lay the basis to assess feasibility of protecting the soil and water resources and in an advanced study for water productivity and food security issues in the future.

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