Ahh, I see.
So the level of technology doesn't exist to say, move people inland a mile or so? Everyone will just drown along with the polar bears?

There you are - off on the wrong track again. No, we don't have technology capable of diverting atmospheric rivers to where we want them. We can build irrigation aqueducts, but we don't direct the whether. The desertification of the West is a low confidence area - we don't know what is going to happen. It can be a sever problem if we don't have enough water to fill the aqueducts. So



The snowpack. Hmm. What to do.
Do you know of a way to somehow magically separate salt from the ocean's water? Has anyone ever invented a way to do that before?

Science does that, and , AFAIK it's expensive for crops. No, I think we may have major shifts in population within the US northward, and Canada's bleak regions may become popular as they warm. There will be continued migration from Latin America as areas desertify there. So there may be hardships, extreme hardships to go through in the West and West Coast. We'll adapt, but there may be an awful lot of pain and hardship, which I'd prefer everyone avoided. But I won't be there.

If the Gulf Stream stops pumping, we lose 3 feet or more on the North East coast, and we can deal, it's just a PITA. But if farms become impractical in areas and we can't solve it - dustbowl time.