Climate change impacts on pistachio cultivation areas in Iran: a simulation analysis based on CORDEX-MENA multi-model ensembles

Abstract

Climate and especially air temperature have a direct and high impact on nut trees in arid regions. In this regard, the use of multi-model ensemble projections as more reliable models is important. In this study, based on multi-model ensembles (MME) from the coordinated regional climate downscaling experiment Middle East North Africa (CORDEX-MENA), the air temperature in RCP8.5 and RCP4.5 pathways in pistachio cultivation areas in Iran was projected. The period 1980 to 2017 was identified as the reference period. Due to the sensitivity of climate change and the existing uncertainties, the hourly temperatures based on the models of chilling hours (CH) and chilling portions (CP) were also used for the reference period. The results of CORDEX simulations for pistachio cultivation areas suggest that the minimum and maximum annual air temperature (MMAT) and growing season temperature (GST) at the end of the current century compared to 1980–2017 as the reference period will increase significantly to 4 °C. The downward trend of winter chill accumulation during the cold season based on observational data will confirm the increase in air temperature in pistachio cultivation areas in Iran. In the output simulation of CORDEX project, the date of flowering pistachio tree for late-maturing varieties by 2080 under representative concentration pathway (RCPs) RCP8.5 and RCP4.5 will occur 16 days and 6 days sooner, respectively. The amount of heat accumulation or growing degree days (GDD) in the future in pistachio cultivation areas will be increased, and deviation from the historical period, based on RCP8.5 and RCP4.5 on average, will occur 3200 and 2600 GDD, respectively.