Assessing the climate change impacts on the rainfall erosivity throughout the twenty-first century in the Grande River Basin (GRB) headwaters, Southeastern Brazil

Climate change is always occurring. Its impacts on the environment are still uncertain, especially due to the difficulty of simulating the earth’s climate accurately. However, the global circulation climate models have been the only scientific tool to assess such impacts and their results have been well accepted. This study aimed to analyze the possible impacts on rainfall erosive potential throughout the twenty-first century for the A1B climate change scenario, in the Grande River Basin (GRB) headwaters, Southeastern Brazil. The results from Eta-CPTEC/HadCM3 model were taken into account to calculate the climatic erosivity indicators “Modified Fournier Index” (MFI) and “Precipitation Concentration Index” (PCI). Based on three meteorological stations, which are monitoring the weather in GRB headwaters since 2005, every 10 min, a statistical relationship between annual rainfall erosivity (EI₃₀) and the respective MFI was adjusted to infer about EI₃₀ in the future. The results have showed an increase in annual amount of precipitation for most months of the year, except for September and October, throughout the twenty-first century. The greatest impacts on EI₃₀ are associated with the projected increase in precipitation for December and January, which can reach up to 49 %. A significant increase in MFI and PCI was observed over the twenty-first century in relation to the present climate. These results demonstrate a potential increase in rainfall erosive power, which causes special concerns due to predominance of shallow soils, associated with undulated to strongly undulated relief in the studied region.