[jacquesm]

Yes, but not by these quantities of people. Critical infrastructure would be much harder to keep alive without AC and the same goes for the elderly. I would expect the average lifespan of the region to take a serious hit during a prolonged power outage in summer.

[Retric]

People dying of heat in the US tend to have other serious medical conditions so it’s unlikely to change overall life expectancy significantly.

Also, peoples homes have been redesigned for AC. The most obvious being people used to sleep on upper story “Sleeping Porch” in the summers. Those living spaces have almost universally had walls added. There’s many more subtle architectural changes that have gone away such as ventilation above doors, setting homes up for cross ventilation etc. Most of which simple doesn’t make sense in a world with cheap AC.

https://en.wikipedia.org/wiki/Sleeping_porch / https://en.wikipedia.org/wiki/Arizona_room etc

[tfourb]

There are plenty of places where people live in hotter/more humid conditions. US dwellings and lifestyles are simply very badly adapted at natural conditions and the gap is made up for by expending energy.

[dmurray]

"Uninhabitable" becomes meaningless if you dilute it to mean "you couldn't build a city-scale population centre here without some infrastructure". All cities need infrastructure!

[cultureswitch]

Not to diminish your point there, but globally, it is cold that tends to kill the elderly, not heat. Despite being much less newsworthy, illnesses triggered by the cold kill about ten times more than heat strokes and similar health issues from excessive heat.

Meaning that a heating outage in a cold region would have a vastly more devastating effect than an cooling outage in a warm region.

[b112]

People used to die of cold, and so why not heat?

It was just the way things were.

[wil421]

Yea no. Been to Costa Rica many times and no one has AC. People aren’t dying on the streets. My brother in law lived there for 10 years with no AC and it’s hotter, for longer, than my home in the Deep South.

[jacquesm]

It's the combination of temperature, humidity, wind and other factors that poses health risks.

https://www.weather.gov/tsa/wbgt

https://en.wikipedia.org/wiki/Wet-bulb_temperature

This stuff can and does kill and if you're not aware of it then pay attention: this is one of the more direct consequences of climate change, it may well push zones that are currently marginally habitable right into inhabitable.

[lancesells]

Agreed. I would guess some desert areas might not be habitable but that's only a portion of a couple states. You can definitely live in places like Florida without AC.

[Symbiote]

I can see an underground metro requires air conditioning, but for most other things there are people in developing countries with higher temperatures who live without it.