Future projection of early fall and late spring frosts based on EC-earth models and shared socioeconomic pathways (SSPs) scenarios over Iran plateau

Climate change and its effects on the Earth are one of the most significant challenges in the twenty-first century. Understanding and modeling climate phenomena are essential for exploring their characteristics, impacts and prediction of their changes in the future. One of these phenomena is frost affecting society and the economy directly and indirectly. Therefore, in this study, future changes in the occurrence of early fall and late spring frost, frost frequency and frost period were studied and projected based on climate change in the Iranian plateau. In the future period (2021–2050), the output of EC-Earth system models from Coupled Model Intercomparison Project phase 6 (CMIP6) under four ocioeconomic pathways (SSPs) scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5) were used, analyzed and compared with the base period (1985–2014). The results showed that the early fall frosts are likely to start 2 to 21 days later, and late spring frosts end between 1 and 8 days earlier in the future period in the study area. Compared to the base period, the frequency and period of frost days will decrease between 11 and 44 days and 4 and 42 days, respectively. Moreover, early fall and late spring frost days will start later and end sooner. The changes in the start dates of frosts were more than the changes at the end dates of frosts. The study of different climate zones also revealed that variations in the cold region were more than changes in the warm region. These variations will severely affect agriculture, energy consumption and transportation in the region. Therefore, it is required to adopt necessary strategies to deal with the consequences and manage the effects of extreme events in this study area.