Coastal sensitivity and population exposure to sea level rise: a case study on Santa Catarina Island, Brazil Carolina Schmanech Mussi 1 & Jarbas Bonetti 1 & Rafael Medeiros Sperb 2 Received: 14 March 2017 /Revised: 22 March 2018 /Accepted: 12 April 2018 # Springer Science+Business Media B.V., part of Springer Nature 2018 Abstract Climate change intensifies the pressure on the coastal zone, endangering ecosystems, socioeconomic activities and coastal infrastructure, with direct impact on the economy of these areas. Although coastal hazard effects have been widely studied, the lack of information in local scale prevents a more effective urban and natural resources management. In order to assess coastal sensitivity and the population exposure to sea level rise, this study evaluated and adapted an index to represent sectors more likely to suffer from the effects of erosion and flooding along the coast of Santa Catarina Island, Brazil. A methodology centred on segmentation and index-based strategies was adapted to the local conditions, using criteria representing coastal geomorphology and dynamics to assess natural sensitivity, which was combined with census data to represent population exposure. Santa Catarina Island was chosen as a test site for three reasons: (a) the existence of a full set of previous data; (b) its diversity of environments; and (c) an important record of erosion and inundation events in several of its beaches. Results showed that the most sensitive areas are located on the island’ s eastern shore, reflecting its higher exposure to the incidence on the ocean waves. Although this west-east contrast had been expected as the key sensitivity feature in the island, its integration with population density allowed the recognition of a more complex pattern. Since variable population densities occur in the both sides of Santa Catarina Island, highly sensible but not urbanized segments were detected in the eastern coast (low exposure), as well as densely occupied sectors in not sensible areas of the western coast (high exposure). The adopted strategy (use of a demographic descriptor to obtain exposure from its integration with sensitivity), was not proposed in the original methodologies of sensitivity assess- ments and improved the representativeness of the spatial model. Obtained results demonstrated the importance of comprehensive coastal management plans, where both physical and demographic aspects should be considered. Keywords Coastal hazards . Physical susceptibility . Social vulnerability . Spatial analysis Introduction The identification and mapping of coastal hazards and their ef- fects are important steps towards coastal management, enhancing the capacity to deal with natural disasters indifferent areas. The coastal sensitivity and human exposure resulting from climate changes are an increasing concern that scientists and govern- ments need to address due to their socio-economic and environ- mental importance. In this context, sea level rise has been con- sidered as one of the main threats resulting from climate change, being responsible for increasing the predisposition of the coast to experience erosion and flooding (Nicholls et al. 2007). Many concepts are related to the identification of threaten- ing elements and to determine how easily a coastal sector could be affected. Recent reviews on this can be found, for instance, in Sharples et al. (2009); Lins de Barros and Muehe (2013); Buitrago and Anfuso (2015); Nguyen et al. (2016) and Bonetti and Woodroffe (2017). Sensitivity (or susceptibility, which is often used as synony- mous) is described by IPCC as the ‘physical predisposition of human beings, infrastructure, and environment to be affected by * Carolina Schmanech Mussi csmussi@gmail.com Jarbas Bonetti jarbas.bonetti@ufsc.br Rafael Medeiros Sperb rmsperb@gmail.com 1 Laboratório de Oceanografia Costeira, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil 2 Universidade Federal do Rio Grande-Rio Grande, Rio Grande do Sul, Brazil Journal of Coastal Conservation https://doi.org/10.1007/s11852-018-0619-8