At least a quarter of the houses within 500 feet of coastlines in the U.S. may be lost to erosion in the next 60 years, according to a study conducted for the Federal Emergency Management Agency. The problem, which may hit the Atlantic Coast especially hard, could be made even worse if sea levels rise due to global warming. The study found that property damage could be minimized and coastal environmental quality improved by setting up development-free zones in areas prone to erosion. It also recommended that FEMA include the expected cost of erosion losses when setting flood insurance rates. Critics of FEMA say its current flood insurance program encourages unsound development by offering coverage to coastal homeowners that private insurers wouldn’t provide.