On a predictably gorgeous South Florida afternoon, Coral Gables Mayor Jim Cason sat in his office overlooking the white-linen restaurants of this affluent seaside community and wondered when climate change would bring it all to an end. He figured it would involve a boat.
When Cason first started worrying about sea-level rise, he asked his staff to count not just how much coastline the city had (47 miles) or value of the property along that coast ($3.5 billion). He also told them to find out how many boats dock inland from the bridges that span the city’s canals (302). What...