Southeast Florida's beaches, which are heavily developed and imperiled by rising sea level, continue to be seriously mismanaged and uneconomically maintained and to generate increasing environmental stress for adjacent marine habitats. Broward County heads the list of counties that stretch from St. Lucie southward to Miami-Dade. Five serious problems plague the stability of these barrier-island shorelines: inlet disruption of littoral drift; beach management that enhances shore erosion (lack of shore vegetation, inappropriate vehicular traffic, and structural protections that enhance erosion); historically very poor-quality renourishment sediment (in size and durability); strong resistance by coastal engineering and dredging firms and counties to embrace an understanding of sandy shore dynamics; and a philosophy that renourishment projects are a solve-all management approach to maintaining beaches and protecting infrastructure. This has led to seriously destabilized beaches, overly aggressive beachfront development, major economic waste, and severe environmental degradation to adjacent marine waters and associated valuable sandy bottom and hard-bottom communities. Many of these sandy shorelines may well not survive this global warming century of rapidly rising sea level. It is economically and environmentally critical for both the future risks to be understood and for lessons from the repeated failed history of beach management to be learned. Continued mismanagement will shorten the inhabitable lifetime of this developed sandy coast by decades and at great economic and environmental cost.