Future projection of the effects of climate change on saffron yield and spatial-temporal distribution of cultivation by incorporating the effect of extreme climate indices

In this study, precipitation- and temperature-related indices were considered using Rclimdex software to study trend of climate extreme indices. Daily minimum and maximum temperature data retrieved from MPI-ESM-LR and ACCESS1-0 global climate model were used to predict future climate extreme events over the next three periods of 2026-2050, 2051-2075, and 2076-2100 based on IPCC scenarios of RCP4.5 and RCP8.5 of studied area covering South Khorasan province and southern part of Razavi Khorasan province, located in east of Iran; furthermore, future saffron yield was predicted based on the yield-extreme indices model. Results showed an increasing trend of warm climate extreme indices and a decreasing trend in precipitation indices as important factors in the decrease of saffron yield. Considering multiple regression yield model of saffron based on climate extreme indices, it was concluded that saffron yield decreases in future periods over studied area with the highest reduction of 31% in period of 2076-2100 under RCP8.5 scenario. Results also confirmed that yield reduction in all three periods under RCP8.5 scenario was greater than the same periods under RCP 4.5 scenario.