What is the hottest temperature that a human can survive without dying? I’ve heard people are in certain parts of California and it 122 degrees Ferenheit. Is it physically possible for a human body to withstand that type of heat?
In: Biology
It’s not just heat. It’s heat + humidity. The human body can only remove heat effectively through sweating, and sweating is only possible when the wet bulb temperature is below 95 F. A wet bulb temperature is measured by taking a piece of cloth soaked in water and placing it on a thermometer. The water will evaporate so long as the ambient air is sufficiently dry, cooling the thermometer and thus reading a lower overall temperature than what would be measured without the wet cloth (think of it as all of the “hot” water molecules get up and fly away, leaving behind only the “cold” ones). The evaporation will continue until the thermometer is so cold that it would start to condense water back onto it, like a glass full of ice condenses humidity in the air. This is the wet bulb temperature.
When this wet bulb temperature is above 95 F, it means no amount of sweat generated by a person’s skin can evaporate and cool them. They will just keep getting hotter and hotter until their body reaches the wet bulb temperature, which will cause their organs to start failing and eventually death. Shade won’t help. Fans won’t help. Night time won’t help. The only escape is air conditioning, and for people in poverty who can’t afford it or don’t even have access to it, they’ll just die.
This condition has already been seen in India for longer and longer durations, and people invariably die. As the length of these events increases, until eventually it’s perpetual, people simply can’t live there.
https://www.independent.co.uk/climate-change/news/wet-bulb-temperature-india-heatwave-2024-b2552395.html
Note that the critical wet bulb temperature is only 95 F… but people live in much hotter climates. How? Those climates are drier. Think the desert southwestern US. Super hot, but also super dry, so sweat will still evaporate. If humid places like Florida start to see 110 F, people will just die.
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