5mo ago

For the first time, humans were exposed to a deadly combination of heat and humidity. Here's how long they lasted - ABC News

www.abc.net.au For the first time, humans were exposed to a deadly combination of heat and humidity. Here's how long they lasted

Heatwaves loom as a growing threat to humanity in a warming climate. This summer alone, in the northern hemisphere, thousands have died during extreme heat events. It's driving researchers to find out more about the point when heat turns deadly.

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5mo ago

For the first time, humans were exposed to a deadly combination of heat and humidity. Here's how long they lasted

www.abc.net.au /news/2024-09-02/deadly-heat-limits-tested-in-world-first-human-experiment/104242788

89 13

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5mo ago

For the first time, humans were exposed to a deadly combination of heat and humidity.

www.abc.net.au /news/2024-09-02/deadly-heat-limits-tested-in-world-first-human-experiment/104242788

12 3

Climate - truthful information about climate, related activism and politics. @slrpnk.net

poVoq @slrpnk.net

5mo ago

For the first time, humans were exposed to a deadly combination of heat and humidity.

www.abc.net.au /news/2024-09-02/deadly-heat-limits-tested-in-world-first-human-experiment/104242788

28 8

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58 comments

Oh my god this article lay out. Just put sand in my eyes.
What was their conclusion?
- Reader mode of Firefox helped me be able to read the content of the article, despite the unacceptable layout.
  Here's the short version:
  Wet-bulb weather is when, because of a combination of humidity and heat, you can't naturally cool off with things like sweat.
  There are certain combinations where the weather only needs to be 25.8C for a health younger person, or 21.9C for an elderly person for "wet-bulb" to be achieved.
  Climate change is real, and it's causing more instances of "wet-bulb" weather.
  Outside activities may not be possible in the summer in certain parts of the world, people will die, the rich will move.
  
  Wet-bulb weather is when, because of a combination of humidity and heat, you can’t naturally cool off with things like sweat.
  This isn't quite right, even though the gist of it ends up being right. This is one of very few things I'm legitimately an expert in, so I don't want to let it go uncorrected not because it makes a big difference, but because it just feels weird not to and maybe somebody will be interested.
  Dry bulb temperature is what you typically read when you're looking at a thermometer. The bulb, the thing that's checking the temperature, is literally dry. To get a wet bulb reading, you essentially put a wet sock around a thermometer (to get a "psychrometer") and swing it around for a while, because you get a different reading when the water is evaporating off it. So when the air is fully saturated (100% humidity, standing in a cloud), your wet bulb and dry bulb readings will be the same. In all other cases, your wet bulb temperature will be lower.
  "Wet bulb weather" isn't really a phrase people use. High wet bulb, high relative humidity, high absolute humidity - all the same thing (and in fact, if you have just one of those and the dry bulb temperature, you can calculate the others). They just measure how wet the air is in slightly different ways.
  
  i was interested, thank you.
  
  I appreciate the precision AND pedantry of your response. Great, concise explanation of exactly what that term means.
  
  only needs to be 25.8C for a health younger person, or 21.9C for an elderly person
  That's disturbingly low
  
  It’s also at 100% humidity in case that wasn’t clear.
  Edit: ok so what he posted wasn’t wrong but the study said that it could be as low as that for some groups of people. For the average person it’s almost 10 degrees C higher which is lower than it used to be.
  However for heat sensitive people (not sure what that means) it can be disturbingly low
  
  So it’s more like ~35C, but it used to be 40? Is that because of constant heat exposure? Like, is my heat tolerance better in the winter?
  
  It seems like it used to be 35° but now it’s ~34°.
  I don’t have access to the actually study but I would hypothesize that it’s likely because we are seeing more studies about things like this and as we collect more data that’s changing these values to be closer to what we see in the real world.
  
  so are my morals
  
  Meaning you can kill elderly people if you set up air humidifier everywhere 😮🤔 even at normal 22C
  
  can we get these temperatures in freedom degrees?
  
  Depends on which articulation, but I'd say at most 6
  
  25.8, 21.9
  Divide by 5, multiply by 9, and add 32.
  roughly 78.5 and 71.5
  
  So… only slightly related to the headline?
  Headline was obviously false from the start, but it turns out it was just clickbait?
  
  Not clickbait at all.
  Wet-bulb is the combination of heat and humidity, and it is deadly in 6 hours. The article is about the first time they have lab tested the conditions on humans to determine the exact numbers, instead of just using the 35C estimate that we have been using.
  
  The headline here has no mention of wet bulb?
  “For the first time, humans were subjected to a deadly combination of heat and humidity.”
  The article is about the first formalized test measuring the relationship between heat and humidity on thermal management in the body, mostly using a single fit thirty year old male. It’s not about how the first human subjected to wet bulb conditions handled them, but about an improved understanding of the relationship of heat and humidity on thermal management of humans.
  
  Wet bulb is an effect thats based on heat and humidity. Which part is confusing you? /g
  
  The part where the headline is supposedly about the first time humans have experienced it?
  The content is fine… the formatting and headline are atrocious.
  
  Ahh gotcha, yeah thats a bit clickbaitey. I read it as "for the first time in a controlled experiment"
- The article is about an experiment, where people are exposed to 35°C wet bulb temperatures, but in different settings. Sometimes lower temperatures but higher humidity, sometimes vise versa, but always 35°C wet bulb temperature.
  So far the assumption was, that humans can't survive a 35°C wet bulb temperature for longer than 6 hours. And at current warming this is unlikely to be naturally the case within this century.
  However the experiment gives hints to believe that humans can't survive at lower wet bulb temperatures either. It looks like with lower temperatures and higher humidity, humans can get very close to that 35°C wet bulb temperature, however people seem to struggle more with higher temperatures and lower humidity.
  A possible explanation could be, that while more sweat evaporates in lower humidity, the body has a limit for how much sweat it can produce. And if you keep raising the temperature, that the human body simply can't produce enough sweat to cool itself.
  That's pretty much what I took away from the article. They mentioned they experiment with several people, however the article was mainly about on person in the experiment, a 30ish year old, athletic male.
  Edit: add some graphs from the article. Sorry for low quality, but as you said, the layout is quite atrocious and on my phone it keeps jumping around on it's own, so I lost patience.
  
  Thanks. Especialy for the graphs. My browser did not like the site!.
  
  It is not your browser, this site is just bad🤧
  
  Is the dashed line the old model?
  
  As I understood it, the dashed line is just the 35°C wet bulb temperature line.
  I think it's the "old assumed border of survivability" and don't know if it is based solely on mathematics or on other experiments as well.
  I also don't know on how many individuals the new line is based and what age group the older people one is.
- “Humid conditions have their own sort of more perceptual limitations, that difficulty breathing, because it feels so claustrophobic,” Dr Cheng says.
  “But in the dry environment, so far, the rate at which [their core temperature] is rising can be one-and-a-half to two times what we’re seeing with the more humid conditions.”
  “It’s really for a lot of those nations, that don’t have a choice but to actually live in these conditions 24/7 … or for people in circumstances where air conditioning is not an option, or areas of the world where manual labour in the field is just sort of their way of life,” Dr Cheng says.
  “A lot of those parts of the world that are most affected by it, are also the ones that have the least resources, I think, to deal with it.”
  The researchers will keep testing the conditions on people until the end of the year.
  But in the meantime, it’s given both the researchers, and Owen, an important glimpse into where the heat threshold of the human body lies.
- I absolutely hate when the ABC does these scrolling articles, they are by the far the worst thing to read.
- Hot temperatures are bad, humidity is bad, but it turns out hot temperatures at lower humidity is seemingly even worse. And we're all fucked because climate change models show us likely hitting the temps this guy was exposed to if we don't fix some shit fast.
  
  No, it's the high humidity that's bad. The temperature can be relatively low to reach wet bulb if the humidity is high.
- Oh my God what is this shit
  
  Some team is getting their bonus by some fucked up metric of engagement and so they are getting points for people scrolling?
  I dont know. i miss the plaintext web sometimes.
- If you scroll down, you'll find out!
  
  I will not.
  
  Then I guess you'll live in suspense.
  
  Instead I am going to draw a picture of a toe:
  https://lemmy.world/post/19314508?scrollToComments=true
  
  That looks like family to me and not a toe

58 comments