We're way past that. Global warming requires (or will, soon enough) heat pumps for survival in many regions of the world. Plenty of regions require large amount of electricity for life critical functions. Degrowth isn't the answer.

Or alternatively, people will need to move to colder regions.

Yes, they will, which will drive conflict, xenophobia and economic destabilization in the countries those people move to, which will exacerbate global political tensions and probably wind up with us all getting wiped out in a nuclear configuration sometime before the century is over, so we might as well have really nice autocomplete before we get there.

Driving up concrete production, a significant carbon contributor as it stands (low carbon concrete is still in its infancy).

Or there are just less people (as we see in developed countries birthrates)

Could you really survive without trucks delivering food to stores on your city? I couldn't.

That’s right (even though you’re probably being facetious).