Coastal erosion in Rio Grande do Sul, Southern Brazil, has been studied using three methods: analyzing long-term changes in coastal barriers, mapping shorelines annually with GPS, and measuring beach profiles. The research shows that erosion has been happening for the past 5,000 years, mainly in the southern part of the coast. About 80% of the coast is currently eroding, and the lack of sediment is a major reason for this erosion. The data suggests that both short-term and long-term factors contribute to the ongoing erosion along this coastline.