Even the most conservative estimates for rising sea levels (five feet at a minimum) would almost completely submerge New Orleans, Miami Beach, and sizable portions of other American cities without engineered protection. With "[m]ore than six million Americans [living] on land less than five feet above the local high tide," the best case for the impact of a warming planet on coastal communities will be substantial.
However, present trends seem to indicate a more dire scenario, say Strauss and Kopp. "If instead we make moderate shifts in energy and industry — using the kinds of targets that nations have contemplated in international talks but have failed to pursue — sea level could still climb past 12 feet just after 2300. It is hard to imagine what measures might allow many of our great coastal cities to survive a 12-foot increase." In a stunning infographic accompanying the article you can explore the impact of various scenarios (5, 12, and 25 ft sea level rises) on America's coastal cities.
Strauss and Kopp outline the two-pronged approach that will be necessary to protect our developed lands from a historic warming phase. "There are two basic ways to protect ourselves from sea level rise: reduce it by cutting pollution, or prepare for it by defense and retreat. To do the job, we must do both."
"We have lost our chance for complete prevention; and preparation alone, without slowing emissions, would — sooner or later — turn our coastal cities into so many Atlantises."