Think about if we had the other “problem”, climatic cooling. An ice age REALLY would impact the amount of land humans could inhabit and farm. Unless you want to build a house on top of a shifting hunk of ice miles deep. Other than that it is no problemo.
Somewhere in some article I read, during some icy period, mankind nearly bit the spear tip and the number of human(oids?) declined to some ridiculously low number. I think the projection was less than 100K. These asshats don’t even want to try to deal with another ice age. Although we know one is coming despite their stupid lies and forecasts. It’s call earth cycles I think. It’s been hotter and it’s been colder with zero input from us mere humans.