This is true. It is also true that waiting until things bottom out will make things even worse. It will be more expensive and options will be more limited.

There will need to be a federal bailout to relocate everyone who needs help. The government should also probably announce a policy that there will be no future disaster relief that involves rebuilding, only relocating.

New Orleans will be the first, but not the last American city to collapse. Miami is probably next. Salt Lake City could very well run out of water, nevermind the increasingly toxic lakebed. Phoenix too. In the next hundred years people are going to learn why environmentalists use the word "sustainability" so much.

Global warming increases evaporation and consequently increase global rainfall. Although it is true that it can shift the location of rainy spots and dry spots, unless you have some magic way to predict the locations they will shift to, I'm going to assume Phoenix's access to water is going to increase because it seems extremely unlikely to me that the entire watershed of the Colorado River (encompassing most of the American part of the Rockies probably) will become dryer on average.