cross-posted from: https://slrpnk.net/post/20737457
In the summer of 2023, a dozen people willingly walked into a steel chamber at the University of Ottawa designed to test the limits of human survival. Outfitted with heart rate monitors and temperature probes, they waited in temperatures of 42 degrees Celsius, or 107 degrees Fahrenheit, while the humidity steadily climbed, coating their bodies in sweat and condensation. After several hours, their internal body temperatures began ratcheting upward, as the heat cooked them from the outside in.
“Few people on the planet have actually experienced temperatures like this,” said Robert Meade, a postdoctoral researcher in epidemiology at the Harvard School of Public Health who led the study. “Imagine moisture condensing on the skin like a glass of water on a hot day. That’s how hot it was, compared to skin temperature.”
Their experiment tested the body’s ability to cope with extreme heat by exposing participants to temperatures at which they could no longer cool themselves. Their study confirmed that this dangerous threshold is much lower than scientists had previously thought: a so-called wet-bulb temperature, which accounts for heat and humidity, of 26 to 31 degrees C.
I’m trying to understand what exactly those conditions are more than anything. The articles frames the findings as temperatures of 31c breaking down important proteins in the human body to ill effect, but this cannot be true because there are many regions in the world where temperatures stay up even higher for prolonged periods of time and yet the people that inhabit them are completely fine.
We also know that humidity levels in a given temperature actually impact significantly how we experience it and what the health risks are, due to our bodies’ evaporative cooling.
What I don’t seem to see in the article are specifics, what is the rH % at which 31c has such a negative effect? What rH % is a “wet bulb” temperature equivalent? In human terms, what temperature per rH % did these experiments find to be harmful? Because as I described, 31c at 33% rH does not even feel that warm, nevermind harmfully hot.
I have tried googling this as well but I think I’m just not phrasing it correctly or the question I’m asking is so stupid and obvious that there’s no actual written answer.
Here’s a book that dives very deep into the topic:
https://en.m.wikipedia.org/wiki/The_Heat_Will_Kill_You_First
If you don’t like to buy the book just read and watch the numerous articles and videos about this book and its author.
This seems more like a narrative about the climate crisis and heat deaths. Tragic as they are, it doesn’t seem like it would answer my question.
If you want to quote a passage from the book that explains whether anything has changed with the OP article in terms of lethality and/or harm of certain levels rH% and °C then I’d be happy to take a look.