It's not about optimism, but being factual.
> national borders are unlikely to go away in the next hundred years
That's a strange take, because an argument often raised is that ecological migrants must be accommodated if entire countries become uninhabitable.
As borders are just imaginary lines in the ground, if there is indeed a climate emergency, I do not see why say people from the Indian subcontinent (shown preeminently in the interactive map) would have no rights to settle in the empty eurasian steppes.
Human lives matter more than imaginary lines caused by historical circumstances.
Yes. That is the argument. It is a just and reasonable argument. It does not mean that they will be accomodated.
> if there is indeed a climate emergency, I do not see why say people from the Indian subcontinent, I do not see why say people from the Indian subcontinent (shown preeminently in the interactive map) would have no rights to settle in the empty eurasian steppes
You don't see why? OK. Tell me: who is going to roll tanks into Russia on their behalf when Russia says no?
An ecologically perilous future is one of harder borders and angrier international affairs and is yet another reason to avert it instead of leaping for the quick dopamine pings of "well, actually".