Extreme climate events under global warming in Iran

Extreme climate events and precipitation depths are assessed for Iran with minimal uncertainties, considering three sources of uncertainty: general circulation models (GCMs), future scenarios, and downscaling method. The frequency, duration, severity, and intensity of extreme events, along with extreme precipitation depths for 2- to 50-year return periods, are evaluated for the baseline period (1980-2014) and three Shared Socioeconomic Pathways (SSPs): SSP1-1.9, SSP2- 4.5, and SSP5-8.5 (2021-2080). Daily precipitation and temperature data from multi-model ensemble of the Coupled Model Inter-comparison Project phase 6 are statistically downscaled for 51 stations across Iran. Extreme precipitation depths increase under SSP1-1.9, whereas the precipitation anomaly depends on location under SSP2-4.5 and SSP5-8.5. The southern coastal and southeastern regions (remaining stations) will experience more-frequent shorter (less-frequent longer) extreme events. The GCM and downscaling method are the main sources of uncertainty in projected precipitation, while climate scenario significantly contributes to the uncertainty in projected temperature.