Streamflow projections for the Brazilian hydropower sector from RCP scenarios

Streamflow projections were estimated for river basins of relevance to the Brazilian hydroelectric sector from monthly precipitation projections from global models of the fifth report of the Intergovernmental Panel on Climate Change – IPCC-AR5 from 2010 to 2098 for RCP4.5 and RCP8.5 scenarios. Streamflow were computed using the Soil Moisture Accounting Procedure (SMAP) hydrological model, which was forced by bias-corrected precipitation from the monthly rain data of the Climatic Research Unit and by the estimation of potential evapotranspiration according to the Penman–Monteith method. The impacts on average annual streamflow were analyzed for the periods 2010–2039, 2040–2069 and 2070–2098 in comparison with the observational record (historical experiment) from 1950 to 1999. Most IPCC-AR5 models agree in terms of the impact on the electrical sector in the southeastern/midwestern and northern regions, showing that streamflow may be reduced up to 15% in each 30-year period on Furnas basin and approximately 30% by the end of the century in Tucuruí basin under RCP8.5 scenario. In the northeastern sector, the divergence of the models suggests great uncertainty, emphasized in the Xingó basin. In the southern sector, results show increasing streamflow over southernmost Brazil and decreasing over intersection between southern and southeastern regions.