Associated Press: On a recent afternoon, Scott McKenzie watched torrential rains and a murky tide swallow the street outside his dog-grooming salon. Within minutes, much of this stretch of chic South Beach was flooded ankle-deep in a fetid mix of rain and sea. "Welcome to the new Venice," McKenzie joked as salt water surged from the sewers. There are few places in the nation more vulnerable to rising sea levels than low-lying South Florida, a tourist and retirement mecca built on drained swampland. Yet as other...