Near-term climate extremes in Iran based on compound hazards analysis

Iran, located in arid and semi-arid regions, has faced significant weather and climate extremes in recent years. This study aims to investigate the climate-related hazards associated with precipitation and temperature in Iran during the Hindcast period (1991-2019) and the Forecast period (2023-2028) using the Near-term Climate Prediction (NTCP) project. We investigate compounding climate-related hazards to assess the severity and importance of weather and climate extremes. To accomplish this, we integrated ten climate extreme indices, namely heavy precipitation (R10mm), the Simple Precipitation Intensity Index (SDII), heat wave frequency (HWF), heat wave duration (HWD), cold wave frequency (CWF), and cold wave duration (CWD), along with the Standardized Precipitation Evapotranspiration Index (SPEI-12), which further encapsulates drought frequency (DF), drought duration (DD), drought severity (DS), and drought intensity (DI). The CMIP6-DCPP models effectively simulate climate extremes and their seasonal cycle across Iran, with minor discrepancies in arid and mountainous regions due to data limitations. The result demonstrates a significant anticipated rise in drought frequency and heat wave events throughout the country within the near-term forecast period. Future projections indicate a shift in precipitation patterns, with increased heavy precipitation in the Zagros Mountains and southwest regions alongside more frequent but less intense droughts nationwide. Heat wave frequency and duration are projected to increase, particularly in southern Zagros and eastern and western Iran, with high-altitude areas experiencing accelerated warming. The results project a shift in climate risk distribution over the next decade, with low to moderate-risk areas decreasing by approximately 15.7% and high-risk areas increasing by roughly 10%, encompassing over 36% of Iran's total area by 2028. Integrated risk maps reveal high to very high compound climate hazard levels across large parts of Iran, necessitating urgent adaptation planning, especially in western, southern Zagros, and eastern regions. Sensitivity analysis confirms that identified multi-hazard hotspots in Iran are spatially robust and statistically significant, reflecting the dominant influence of key climatic extremes.