Risk analysis of agricultural drought characteristics under current climate and changing climate conditions in various climates of Iran

According to the studies from Hadley Center for Climate Prediction and Research (HCCPR), it is predicted that in the 21st century extreme droughts would threat millions people due to global warming. Researches have been showed that the areas affected by extreme droughts have increased in the country in the 20th. This study was performed to answer this question that "how would various climates of Iran respond to global warming in case of drought?" For this purpose, monthly precipitation and temperature data for the selected stations of the country (representing various climates of Iran including Bandar Anzali, Bushehr, Gorgan, Tehran, Mashhad, and Zahedan) were produced using statistical downscaling of CGCM3 model under two scenarios A1B and A2 for 2011-2040 via change factor method. Next, a representative index of agricultural drought, i.e., the adjusted Reconnaissance Drought Index (RDI, based on precipitation and temperature data) were calculated for the base period 1971-2000 and future periods (2011-2040) under two scenarios A1B and A2 in stations of interest. Probabilistic analyses of drought characteristics for present and future climate conditions were done and compared. The results showed that in the period 2040-2011, the likelihood of duration and intensity of droughts will increase in all stations under investigation. Also, it was found that the sensitivity of extreme climates (very wet and very arid) to global warming is more than the other climates (arid, semi-arid and Mediterranean).