Speaking for the US many populated arid areas are completely unsustainable as population centers (ironically also where most people in the US have been moving for awhile now), especially because water resources haven’t been managed rationally in many arid areas. This story will absolutely be a global one though, see Tehran for one massive example, Lake Mead for another. No water and deadly heat waves are going to make for limitless ghost town tourism attraction opportunities!
The future is bright for abandoned building photography communities!
In the Alps, there are already quite some ghost towns. Small towns either turned into touristic villages or disappeared over the last 50 years. Others were border towns that slowly went out of business. So many are hanging in by a thread, with increasingly old population.