[pfbtgom]

I'm less confident that a mass migration wouldn't result in millions of deaths. An example might be the partition of India and Pakistan in 1947. Only 14 million displaced, yet an estimated 200k-2 million deaths and another 2 million people missing[1]. In many ways, this planned displacement was a more favorable scenario than a chaotic climate refugee situation.

If we don't have a good answer to the relatively simple refugee migrations now (eg. Central America, Syria), then I have extreme pessimism that we will be able to manage a larger-scale, persistent event. Whereas with economic + political refugee situations we can always hope to resolve the root cause, with climate change it is simply the new normal.

[1] https://en.wikipedia.org/wiki/Partition_of_India