Evaluating and projecting extreme meteorological droughts over two strategic regions of Brazil: the Brazilian Pantanal and Southern Minas Gerais

Abstract

Brazil contains the largest volume of freshwater of any country in the world. However, this important natural resource is threatened by increases in water demand and water quality degradation, mainly as a result of anthropogenic pressures. As a result of this pressures, natural hazards, such as droughts are probably becoming more common in the future. In recent years, droughts have affected different regions of Brazil, impacting energy security, food production, and water consumption. In this study, the severity of droughts that hit two strategic regions of Brazil, Southern Minas Gerais and the Brazilian Pantanal were analyzed and were projected up to the end of the XXI century. The first, is well-known by its coffee crop production (more than 30% of country’s production) and hydroelectricity generation. The second, it is one of the largest wetland in the world and home for species and unique animals and plants. To access the severity of the droughts, the Standardized Precipitation Index and the Standardized Precipitation Evapotranspiration considering the hydrological years (SPI12) were investigated over time and space. Two different datasets were considered as observaded data in this study: data from the National Water and Sanitation Agency (ANA) and from the Climate Research Unit (CRU). Also, severe droughts were projected up to 2098/2099 using two RCM ensembles, from Eta project (BESM, CanESM2, HadGEM2-ES and Eta-MIROC5) and CORDEX project (CSIRO, IPSL-CM5A, GDFL, NorEMS1) under two Representative Concentration Pathways, RCP4.5 and RCP8.5. The 2013/2014 hydrological year was the driest ever recorded in South of Minas Gerais. Projections have shown that this event might occur again in the future, with several consectuve events possibly happening more often. In Pantanal, in 80 years of observed data, the hydrological year of 2019/2020 was the driest observed in Pantanal, with 1960s decade been the worst. SPI projections have shown different results, with CORDEX projecting extreme droughts until 2040, and Eta models not showing extreme events. SPEI projections, otherwise, have shown extrem drought events in the end of the XXI century, for both, Eta and CORDEX. Observed data and projections give information that will help decision makers and stock holders in the detection of drought anomalies in short terms and for long term analyses.