Projections of severe droughts in future climate in Southeast Brazil: a case study in Southern Minas Gerais State, Brazil

Abstract

South of Minas Gerais state, in Southeast Brazil, is known for the coffee crop production (more than 30% of country’s production) and hydroelectricity generation (1216 MW installed power). Droughts are natural climate phenomena that may strongly affect a region during a certain period. In this study, the severity of the droughts that hit southern Minas Gerais state was analyzed in the period from 1970 to 2020 and was projected up to 2098/2099 using four global circulation models (HadGEM2-ES, MIROC5, BESM, CanESM2), downscaled by Eta model to 20-km resolution, under two Representative Concentration Pathways (RCP4.5 and RCP8.5). To access the severity of the droughts, the Standard Precipitation Index considering the hydrological year (SPI12) was investigated over time and space. The results demonstrated that the 2013–2014 hydrological year was the dryest in southern Minas Gerais, followed by 2014/2015, which led to water shortage, reduction of the hydroelectricity and reduction of coffee crop production. Future projections indicate that extreme droughts will continue occurring, but with similar rarity. However, the RCM downscaling pointed out the possible occurrence of several dry consecutive years, which can collapse the hydrology and put at risk the economy of the region. Except from the Eta-MIROC under RCP 8.5, that simulated most of the droughts in middle to the end of XXI century, the other RCMs projected recurrent droughts for the next two decades, supporting the detection drought anomalies and helping in adoption actions to anticipate and mitigate drought effects in the future.