Australia has millions of km^2 in the subtropics. Why would they move due to heating requirements? Also there will be many, many climate refugees from floods,

Australia has millions of km^2 in the subtropics. Why would they move due to heating requirements? Also there will be many, many climate refugees from floods, famines, droughts, super storms, fires, dust storms, and so on. Most of these issues are much harder to overcome than adding insulation, living in a reasonably sized home, sharing a wall or two, installing a heat pump, and putting on a jumper.