Climate change projections of soil erosion in South America in the XXI century

Abstract

Global climate projections indicate that continental South America (SA) can experience significant changes in soil erosion caused by water in the coming years due to changes in the precipitation spatial and temporal patterns, threatening food security and biodiversity and impairing agroecosystems to provide services. This study aims to quantify future impacts on soil erosion in the SA provoked by changes in precipitation from climate change scenarios using the Revised Universal Soil Loss Equation (RUSLE). A 20 km spatial resolution of annual precipitation projected from the ensemble of four global climate models (BESM, CanESM2, HadGEM2-ES, and MIROC5 models) was used to assess impacts between 2010 and 2099, sliced every 30 years. The Eta/CPTEC model dynamically regionalized the datasets, and the RCPs 4.5 and 8.5 scenarios were selected to quantify rainfall erosivity and soil erosion rates. The projected average soil erosion over the continent was 37% above the present estimation (3.8 Mg ha−1 year−1), reaching 5.2 Mg ha−1 year−1 at the end of the 21st century. The projections indicate an increase in soil losses across the Andes Cordillera with less severe impacts on lowlands commonly used for crops and livestock. Contrastingly, soil erosion rates tended to decrease by the end of the century in northern SA due to the reduced precipitation projected by most climate models. Overall, the most significant impacts on soil erosion caused by climate change were found for the last time slice (2071–2099) in the RCP 8.5 scenario, with mixed results, i.e., an increase in some regions and a decrease in others.