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United States Department of Agriculture

Agricultural Research Service

Research Project: Understanding Water-Driven Ecohydrologic and Erosion Processes in the Semiarid Southwest to Improve Watershed Management

Location: Southwest Watershed Research

Title: Projected climate change impacts in rainfall erosivity over Brazil

Author
item Almagro, A.
item Sanches Oliveira, P.
item Nearing, Mark
item Hagemann, S.

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/2017
Publication Date: 8/15/2017
Citation: Almagro, A., Sanches Oliveira, P., Nearing, M.A., Hagemann, S. 2017. Projected climate change impacts in rainfall erosivity over Brazil. Scientific Reports. 7:8130. doi:10.1038/s41598-017-08298-y.

Interpretive Summary: Rainfall erosivity is the power of rainfall to cause soil erosion by water. As the climate changes it is expected that rainfall erosivity will also change. This study looked at the way that rainfall is expected to change in Brazil as a function of future climate change scenarios. Data from large-scale climate change models were downscaled to finer areas across the whole of Brazil to look at how this might happen. The results show that certain areas of Brazil might expect increases, and other areas decreases in soil erosion by water. Most affected regions included the northeastern and southern parts of the country, where rates of erosion could increase by as much as 100% over the next century. Soil erosion degrades soil and tends to reduce the productivity of crops in affected areas, hence these results have important implications for the long-term production of crops in Brazil.

Technical Abstract: Climate change projections and historical analyses have shown alterations in global precipitation dynamics, and therefore, it is also expected that there will be associated changes to soil erosion rates. The impacts of climate change on soil erosion may bring serious economic, social, and environmental problems. However, few studies have investigated these impacts in continental scales. Here we assessed the influences of climate change on rainfall erosivity across Brazil. We used observed rainfall data (1980-2013) and downscaled climate models (projected, 2007-2099) resulting from HadGEM2-ES and MIROC5 GCMs, forced by RCP4.5 and RCP8.5 scenarios to estimate and map rainfall erosivity and its projected changes across Brazil. We found an average rainfall erosivity of 10,089 ± 3,489 MJ mm ha-1 h-1 year-1 and 10,585 ± 3,420 MJ mm ha-1 h-1 year-1, using the HadGEM and MIROC models, respectively. Our analysis suggested that the most affected regions, with projected rainfall erosivity increases ranging as high as an estimated 109%, were the northeastern and southern parts of Brazil. Decreases of as much as -71% were estimated for the southeastern, central and northwestern parts of the country. Our results provide an overview (past and projected) of rainfall erosivity in Brazil that may be useful for planning soil and water conservation, and promoting water and food security.

Last Modified: 09/20/2017
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