Figueiredo, S.A., 2013. Modeling climate change effects in southern Brazil.Along the coast of Rio Grande do Sul state, southern Brazil, differences on coastal configuration are generally accompanied by changes in substrate slope, where steeper gradients characterize coastal projections and gentle gradients the coastal embayments. This study focus on coastal response to climate change effects at two sectors along RS coast: Cassino embayment and Conceição lighthouse projection. The former has been under very high rates of progradation, on the order of at least 3 m/yr at geological and historical time scales. Whereas Conceição region has been undergoing rates of recession reaching −3.6 m/yr. In order to forecast coastal response to the effects of climate change at these sites over several time horizons (2030–2070–2100), model simulations using the DRanSTM (Dilating Random Shoreface Translation Model) were performed. Simulation results have demonstrated that Cassino sector is particularly vulnerable to such effects, and therefore presents extremely high recession distances (102–103 m). Despite the historical erosion trend at Conceição lighthouse region it presented lower recession rates in comparison to Cassino sector. Hence a possible inversion on shoreline historical trends can be expected for the future. These results are in line with the expectations, that sectors characterized by low gradient shoreface profiles are at very high risk of future shoreline erosion. The high degree of vulnerability in Rio Grande do Sul coast is further highlighted when compared to other embayments around the world, such as those at SE Australia, which when subjected to similar rates of sea level rise (max. 1.1 m) presented recession distances that were orders of magnitude lower (10–102). The results presented here express the urgent need for the development and implementation of coastal management and adaptation plans to climate change that account for site specific characteristics.