Anyway, I don’t want to act like this fact makes it not a problem; I simply can’t imagine all of lower manhatten wanting to raze every skyscraper and start over either. I’m pretty sure most of these city-on-a-city situations are after major fires kinda force everyone’s hand, so it really is a huge catastrophe!
hence, the levee solution. in the future future even that’s probably not going to work (at least not for NYC) and it’s pretty likely then people will just have to abandon levels of buildings to rising sea level if they want to continue using them, but for right now most cities just want to buy their populations time to adapt further. (and for residential structures it’s probable people will move or be forced to move)