[lukeschlather]

The NYC seawall depicted in The Expanse seems pretty plausible, it's such a dense area with so many people and so much income. And the seawall isn't really any different from the existing waterfront, so NYC remains recognizably NYC.

Florida though, everything is sprawling, there's no small area you could actually wall off. And the whole point of Florida is living near the beach, not concrete canyons.

[Analemma_]

You can't fix flooding in south Florida with seawalls or levees, because the bedrock is porous limestone: if there's too much water, it literally comes up through the ground. You can't pump floodwater away either, for the same reason.