Efeitos da subida do nível do mar na inundação costeira na costa leste do Brasil devido às mudanças climáticas

Abstract

Changes on coastal flooding patterns, as well as on regional hydrodynamics, from the beginning to the end of the century were evaluated in the east coast of Brazil, based on the anomalies from two downscaling experiments using the Earth System model HadGEM2-ES outputs for historical and RCP4.5 runs from Coupled Model Intercomparison Project phase 5. Ocean modeling was applied on ten numerical grids (1/3° to 27 m of resolution) focusing on two study areas: the Guanabara Bay surroundings (RJ) and the region between Una and Belmonte Municipalities (BA). It was observed the displacement on Brazil Current (BC) origin, BC intensification, and the increasing of mean sea surface temperatures in 1.44 °C and the mean sea level rise (SLR) in 0.78 m. Spatial variations on SLR rates were observed with an average rate of 7.5 mm/year close to the coast. Two coastal vulnerability indices to climate changes were also proposed based on modeling results. The first index showed more than 75% of the coast between 12 and 30°S with high vulnerability to SLR. The second was applied to the two study areas that mostly exhibited moderated vulnerability to coastal floodings. In both areas, more regions would be submitted to floodings and regions already submitted to wetting and drying processes would be flooded for longer periods, leading to mangrove losses, narrower sandy beaches and larger water surface areas of coastal lagoons. The results highlight the importance of studying climate changes and applying methods to allow the evaluation of its effects on coastal zones.