I’m not sure that Miami is going to be around a century from now. In a well researched and explained piece for The New Yorker, Elizabeth Kalbert lays out the story. Today,

The city of Miami Beach floods on such a predictable basis that if, out of curiosity or sheer perversity, a person wants to she can plan a visit to coincide with an inundation.

That flooding is due in large part to sea level rise.

According to the Intergovernmental Panel on Climate Change, sea levels could rise by more than three feet by the end of this century. The United States Army Corps of Engineers projects that they could rise by as much as five feet; the National Oceanic and Atmospheric Administration predicts up to six and a half feet.

Sea level rise is important in Florida because

In Miami-Dade County, the average elevation is just six feet above sea level. The county’s highest point, aside from man-made structures, is only about twenty-five feet, and no one seems entirely sure where it is. (The humorist Dave Barry once set out to climb Miami-Dade’s tallest mountain, and ended up atop a local garbage dump nicknamed Mt. Trashmore.) Broward County, which includes Fort Lauderdale, is equally flat and low, and Monroe County, which includes the Florida Keys, is even more so.

But South Florida’s problems also run deeper. The whole region–indeed, most of the state–consists of limestone that was laid down over the millions of years Florida sat at the bottom of a shallow sea. The limestone is filled with holes, and the holes are, for the most part, filled with water. (Near the surface, this is generally freshwater, which has a lower density than saltwater.)

As a result, as sea levels rise, you can’t build a dam around the city of Miami to keep the water out because it will simply rise up through the ground.

There’s a lot more to the story. I’d suggest reading Kalbert’s full 6,000 word essay.