University of Sistan and Baluchestan Journal of Natural Environmental Hazards 2676-4377 14 46 2025 12 22 Projection of Future Drought Trends in Iran Using the CMIP6 Multi-Model Ensemble Projection of Future Drought Trends in Iran Using the CMIP6 Multi-Model Ensemble 43 74 9183 10.22111/jneh.2025.50138.2075 FA Mahyar Ahadi PhD Student of Climatology, Faculty of Social Sciences, University of Mohaghegh Ardabili. Ardabil, Iran Batol Zeynali Professor of Climatology, Faculty of Social Sciences, University of Mohaghegh Ardabili, Ardabil, Iran Bromand Salahi Professor of Climatology, Department of Physical Geography, University of Mohaghegh Ardabili, Iran Faeze Shoja Associate Professor in Climatology, Department of Physical Geography, University of Tehran, Iran Amin Fazl Kazemi PhD Student of Meteorology, Department of Space Physics, Institute of Geophysics, University of Tehran, Tehran, Iran Iman Babaeian Professor of Climatology, Atmospheric Science and Meteorological Research Centre, Climate Research Institute, Mashhad, Iran Mansoureh Kohi Professor of Climatology, Atmospheric Science and Meteorological Research Centre, Climate Research Institute, Mashhad, Iran Journal Article 2024 10 28 Ongoing global warming has caused unprecedented changes in climate systems, leading to an increase in the intensity and frequency of weather and climate extremes. This study uses the sixth phase of the Coupled Model Intercomparison Project (CMIP6) data to investigate projected changes in drought events over Iran under two Shared Socioeconomic Pathway emission scenarios. The observational period of 1985-2014 and the next three 25-year periods, are the near future 2020-2026, 2075-2051 and far future 2100-2076, were considered as study periods. The standard precipitation evapotranspiration index (SPEI) was used to estimate drought over a 12-month timescale. According to the results, under SSP2-4.5, the average precipitation of the country increases by 20%, 12%, and 16% in the near-, medium-, and far-future periods, respectively, and by 15%, 13%, and 21% in the pessimistic scenario. In terms of temperature, the most severe increase is related to the pessimistic scenario and in the far future at 3.7 degrees Celsius. The average 12-month SPEI drought index shortly under the SSP2-4.5 and SSP5-8.5 scenarios will be equal to 0.53 and 0.80, respectively, in the medium future, -0.1 and zero, and in the far future, -0.45 and -0.84. According to the results, by applying the pessimistic scenario, the severity of droughts in the near and medium future will decrease by 96% and 49%, respectively, and in the future, it will increase by 300%. However, if the SSP2-4.5 scenario occurs, there will be a 61% decrease soon and an increase of 64% and 234% in the medium and long term, respectively. Examining the trend of average temperature and drought severity using the Mann-Kendall test indicated an increase in average temperature and drought severity at 100% of the stations with a confidence level of 99%. Ongoing global warming has caused unprecedented changes in climate systems, leading to an increase in the intensity and frequency of weather and climate extremes. This study uses the sixth phase of the Coupled Model Intercomparison Project (CMIP6) data to investigate projected changes in drought events over Iran under two Shared Socioeconomic Pathway emission scenarios. The observational period of 1985-2014 and the next three 25-year periods, are the near future 2020-2026, 2075-2051 and far future 2100-2076, were considered as study periods. The standard precipitation evapotranspiration index (SPEI) was used to estimate drought over a 12-month timescale. According to the results, under SSP2-4.5, the average precipitation of the country increases by 20%, 12%, and 16% in the near-, medium-, and far-future periods, respectively, and by 15%, 13%, and 21% in the pessimistic scenario. In terms of temperature, the most severe increase is related to the pessimistic scenario and in the far future at 3.7 degrees Celsius. The average 12-month SPEI drought index shortly under the SSP2-4.5 and SSP5-8.5 scenarios will be equal to 0.53 and 0.80, respectively, in the medium future, -0.1 and zero, and in the far future, -0.45 and -0.84. According to the results, by applying the pessimistic scenario, the severity of droughts in the near and medium future will decrease by 96% and 49%, respectively, and in the future, it will increase by 300%. However, if the SSP2-4.5 scenario occurs, there will be a 61% decrease soon and an increase of 64% and 234% in the medium and long term, respectively. Examining the trend of average temperature and drought severity using the Mann-Kendall test indicated an increase in average temperature and drought severity at 100% of the stations with a confidence level of 99%. https://jneh.usb.ac.ir/article_9183_3f5b3aa9e638a9a530694aecedd7889c.pdf