Netherlands has been dealing with flooding even before the US existed. I think they will be fine.
And if we really can't stop global warming, at some point eastern Antarctica is going to start melting (it fortunately isn't yet), and that's going to add another 30 meters to the sea level. I believe if all the glaciers melt, we'll be at about 60 meters.
At some point we're going to have to put up a dome and call ourselves Atlantis.