Investigating the Impacts of Climate Change on Water Security in Iran

Water security includes sustainable use and protection of water systems, protection against water-related hazards, sustainable development of water resources, and preservation of water functions and services for humans and the environment. To investigate water security in the past decades, the WSIM-GLDAS water security model was used, and for assessing available water storage, the GRACE satellite data were employed. Then, a multi-model was analyzed using CMIP6 models to investigate future changes in temperature and potential evapotranspiration (PET) over the country's medium-scale under SSP scenarios. The results showed a decreasing trend in available water storage over the past two decades in Iran. The outcome of the water security model indicated a negative return period of water scarcity across the country. The lowest value of WSIM is -10.1 which is seen in the eastern and central regions of Iran, indicating the low water security of these areas. Climate projections show a significant increase in temperature (0.78 oC/decade under the SSP5-8.5 scenario) and evapotranspiration (153.5 mm/decade under the SSP5-8.5 scenario) in the country. To increase water security, it is necessary to take effective adaptation strategies, the purpose of which is to increase the water storage capacity in the soil (green water) and reduce soil erosion in order to increase the quality of the soil and maintain the storage capacity of reservoirs (blue water). Therefore, the adaptation strategies to climate change and its effect on water redistribution from green water to blue water, and the long-term socio-economic consequences of climate change should be considered in future climate plans of Iran.