I’ve been warning about this for years: 143 Million People May Soon Become Climate Migrants
Worth reading. The actual number is 2 billion or so. But not before the first several hundred million show up… somewhere.
The United States is not immune to climate refugees of our own, either. The entire Deep South and Southwest will become uninhabitable as wet-bulb temperatures exceed human survivability. No amount of cooling will be possible to make living in these locations doable.