Scientists are starting to suggest that, in the long run, much of South Florida cannot be saved from climate change-induced sea level rise. They say policymakers should begin planning for how to deal with a massive exodus of area residents in the coming decades.

More than 2.4 million people live within 4 feet of the local high-tide line in the region. The risk of storm surge flooding will be far higher by 2030--within the time frame of many 30-year mortgages.