Projected climate change impacts on soil erosion over Iran

In the past few decades, there has been increasing interest in studying various environmental phenomena derived from climate change and its social, environmental, and economic serious impacts. It is particularly critical to developing countries where resources are limited, and conditions may worsen in the midst of environmental disasters caused by soil erosion, leading to indispensable costs in resources and human lives. Since no studies have investigated these implications on a regional scale for the case of Iran, here we assessed the impact of climate change on soil erosion across the country. The RUSLE model was employed to estimate potential soil erosion based on historical climate records and projected future data to assess climate change implications. Daily rainfall data (1987-2006) from 103 meteorological stations were used to bias correct the Climate Forecast System Reanalysis (CFSR) rainfall data. Furthermore, CFSR data, as the historical record period data (1987-2006), was used for bias correcting five General Circulation Models (GCMs) to develop rainfall erosivity values for the future climate period (2046-2065) under SSP2-4.5 and SSP5-8.5 scenarios. Based on these data sets, rainfall erosivity maps were developed to compare the variations with projected climate results across Iran. Results show an overall decrease in rainfall erosivity and soil erosion in most provinces. Considering the average outputs of five GCMs and under both SSPs, the most affected provinces with projected soil erosion decrease are P.11 and P.14, whereas the highest increase in soil erosion is likely to occur in P.13 by SSP5-8.5. In the northern provinces, particularly in P.7, the highest increase in soil erosion is expected. It was also noted that the highest range of soil erosion change among the five selected GCMs occurs at P.27, with the maximum increase of above 135% and the minimum decrease of 71% from the historical period. The present study represents the first assessment of soil erosion at a large scale in Iran, providing an overview of soil erosion that may be useful for soil and water conservation planning, hazard mapping, agriculture, and other activities that are subject to soil erosion.