Well, at least part of the Netherlands (approx. 26%) are already below sea level. And it doesn't look that bad.

Netherlands is protected by dams. The solid geology of the area has allowed for durable dams to be constructed over centuries.

Places like Florida are going to be severely hit by rising sea levels because so much of the land is porous. You can't build a dam to stop the sea if it seeps in from underground.

Just out of interest, how tall are the dams?

The dams in the famous Zuiderzee Works [1] are about 13m high, it seems.

[1] https://en.wikipedia.org/wiki/Zuiderzee_Works

Well, given that it predicts half of the Netherlands will be flooded with just a 1m rise in sea level, which happens about twice a day, I'm a bit sceptical.

Well, according to this, my house should already be under water. That's what happens when you live below the water level of the neighbouring canal...