Expected climate change impacts on rainfall erosivity over Iran based on CMIP5 climate models

Abstract

Climate change has some important implications for soil resource and sediment loads of rivers which may affect sustainable food production and use of river for water supply. The present study assessed the potential impacts of climate change on rainfall erosivity over Iran. Climate change data from three GCMs under two RCPs 4.5 and 8.5 were statistically downscaled using the LARS-WG model. Regional R-factor regression equations were applied to derive future rainfall erosivity. The results of this study revealed that the average annual R-factor for the observed data was 268 MJ mm ha − 1 h − 1 yr − 1. Projections revealed that in the 2040–2060 period under RCP 4.5, except arid regions in the East, other regions (encompassing 66.1%) of Iran will experience an increase in the R-factor by 2.5–22.5 % mainly in the mountain areas in the North and Northwest. Projections for RCP 4.5 in the period of 2060–2080, showed that in the arid zones in the Southeast, Center and East of Iran, the rainfall erosivity will decrease; however, in RCP 8.5, an increase in rainfall will cause an increase in rainfall erosivity in most parts of Iran. The results also indicated that soil erosion and sediment load in the 2040–2060 period may have some serious implications; therefore new strategies must be developed to attenuate the adverse effects of climate change on soil erosion and sediment deposition in reservoirs.