Where in the world would this event take place? In the hottest parts of the US the temperature gets to 46ºC regularly during the summer and people have lived there for hundreds of years. Do people die of heat stoke? Sure, at a rate of hundreds per year. Elsewhere in the world there are places where people love in the same heat with less means of cooking and less access to water.

Millions of people may have to adapt. Fortunately, people are good at that.

Where would this take place? In places where the wet bulb temperature is already getting close to the limits of human endurance:

https://www.theguardian.com/science/2022/jul/31/why-you-need...

People can survive amazingly hot temperatures, as long as they can sweat - once the wet bulb temp gets far above 31c people are in trouble - the theoretical maximum is 35c.

We won't hit these wet bulb temps in places like the US or even much of Europe, but built up China, India etc are at risk of approaching these in our lifetimes, potentially far sooner.

Thank you! It is really important to emphasize that heat and humidity have both to be taken into account. To quote a relevant passage from the article you linked:

> Concern often centres on the “threshold” or “critical” WBT for humans, the point at which a healthy person could survive for only six hours. This is usually considered to be 35C, approximately equivalent to an air temperature of 40C with a relative humidity of 75%. (At the UK’s 19 July peak temperature, relative humidity was approximately 25% and the wet-bulb temperature about 25C.)

(WBT is Wet Bulb Temperature)

KSR's novel "The Ministry For the Future" starts with a graphic account of a 35C wet bulb event in India. The heat initially raises the demand for air conditioning, the demand for air conditioning over-stresses the electrical grid, the electrical grid fails so no one has air conditioning, millions die. I don't remember exactly when it's set; in the 2030s?

The others have pointed out the humidity, dry heat doesn’t just kill hundreds. The 2003 heat wave likely killed 70000 people in Europe. You know, a developed country. https://www.france24.com/en/environment/20230717-parisians-a...

Texas, maybe? If the power grid goes down because of excess AC usage?

Yes, I read that people have been living for 100s of years (pre-AC) through temps regularly hitting 46 degrees, but see also the response on wet-bulb temps and survivability. 46 degrees for 5 days straight without AC (as in, backup power is gone...) and I think we'll see some losses.

Europe regularly sees large deaths due to heat during summers already today, true mostly in elderly.

Yeah it might be wise to invest into some backup solar and an inverter to run off-grid in a pickle, after all max heat will also typically mean max solar output at the same time.

A billion people in India could die and US elections would still be determined by gas prices.

But what would India do? It might be something hard to ignore.

India will attempt to geoengineer the sky way before that happens, international pleading or possible other dire consequences be damned.

Millions died in the pandemic - didn’t do much to affect any opinion really. Just see in the replies to my comment here. Deniers out to prove desperately that this is all going just fine.