Just east of the Homestead-Miami Speedway, off Florida's Biscayne Bay, two nuclear reactors churn out enough electricity to power nearly a million homes. The Turkey Point plant is licensed to continue doing so until at least 2032.

At some point after that, if you believe the direst government projections, a good part of the low-lying site could be underwater. So could at least 13 other U.S. nuclear plants, as the world’s seas continue to rise. (See maps below.)

Their vulnerability, and that of many others, raises serious questions for the future. The new UN climate accord, reached over the weekend after two weeks of talks in Paris, prods countries to shift from fossil fuels toward energy sources that emit zero planet-warming