It's an interesting thought. Mass displacement will be a huge issue though. While we do have plenty of landmass in theory, migration of major cities is just.. I cannot possibly fathom how that could ever be organized. We'd panic, loot grocery stores, rob pharmacies, etc. I mean look at what this pandemic has done. You can't even buy cans of beans or toilet paper! My local store is out of bags of dry rice. Of _rice_.

I don't recall where I heard it but before I knew it was a quote, I used to say this all the time: humanity is three square meals away from total annihilation. One day without food and humans will revert right back to our caveman "attack other human, take food" lizard brains.

I definitely went a little off topic from your original post but, "adapt to the changes" isn't honestly something I can fathom happening. I don't know where you live - be it a city or suburbs or otherwise - but think about 30 million people showing up and tell me that doesn't end in a massive disaster.