Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The emergence of heat and humidity too severe for human tolerance (2020)

advances.sciencemag.org

Post reply on HN
Print view View original

171–180 of 414 posts

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#171

Post by csomar »

boplicity wrote: post #2

Kim Stanley Robinson's recent book The Ministry For the Future starts with a very disturbing scenario: A heatwave with a "web bulb" temperature of 35 Celsius. It turns out, in those temperatures, even young and healthy people can't survive. Combined with power outages, as happens in the book, everyone living under such a heat wave will likely die. It's looking increasingly likely that such heatwaves are possible in t…

Edit: didn't know about wet-bulb temperatures (was confusing it with perceived temperature). Here is a link for a wet-bulb temp. map: https://meteologix.com/th/observations/701-e-263-n/wet-bulb-...

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#173

Post by Sharlin »

zabatuvajdka wrote: post #43
boplicity wrote: post #2

Kim Stanley Robinson's recent book The Ministry For the Future starts with a very disturbing scenario: A heatwave with a "web bulb" temperature of 35 Celsius. It turns out, in those temperatures, even young and healthy people can't survive. Combined with power outages, as happens in the book, everyone living under such a heat wave will likely die. It's looking increasingly likely that such heatwaves are possible in t…

If there’s a heat wave and drought the only way is to dig tunnels and build cities underground. Water can be imported from the ocean (rising sea levels) and desalinated using solar/thermal power above ground and feed an aquifer!

What is actually going to happen is displacement. The hundreds of millions of people most vulnerable to the consequences of climate change don't have much choice but to start walking. The 2015 refugee crisis in Europe was nothing compared to that, never mind the tiny trivial inconvenience that is current illegal immigration across the Mexico–US border.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#174

Post by lmilcin »

csomar wrote: post #171
boplicity wrote: post #2

Kim Stanley Robinson's recent book The Ministry For the Future starts with a very disturbing scenario: A heatwave with a "web bulb" temperature of 35 Celsius. It turns out, in those temperatures, even young and healthy people can't survive. Combined with power outages, as happens in the book, everyone living under such a heat wave will likely die. It's looking increasingly likely that such heatwaves are possible in t…

Edit: didn't know about wet-bulb temperatures (was confusing it with perceived temperature). Here is a link for a wet-bulb temp. map: https://meteologix.com/th/observations/701-e-263-n/wet-bulb-...

I think you don't understand what wet bulb temperature is.

Wet bulb temperature is a combination of humidity and temperature.

Wet bulb temperature of 35C means your body physically cannot get rid of heat and you WILL die, rather quickly, even in shade. There is no escape unless you have ability to control humidity (ie. remove some humidity from the air).

Up until recently we did not have situations on earth where wet bulb temperature would reach 35C. Even in the most hot places the air would be dry enough to bring wet bulb temperature down under 35C meaning, things can cool below human body temperature.

The issue is that a lot of people in hot places simply do not have the means to control their climate in their houses, assuming they have any.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#175

Post by Sharlin »

rvn1045 wrote: post #34
boplicity wrote: post #2

Kim Stanley Robinson's recent book The Ministry For the Future starts with a very disturbing scenario: A heatwave with a "web bulb" temperature of 35 Celsius. It turns out, in those temperatures, even young and healthy people can't survive. Combined with power outages, as happens in the book, everyone living under such a heat wave will likely die. It's looking increasingly likely that such heatwaves are possible in t…

A lot of new technology could potentially solve this problem. There are certain types of roofs being installed called cool roofs that reflect heat and don’t absorb it that keeps the inside of building a little cooler.

For people who can afford new technology. For hundreds of millions to billions of people that's not an option.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#176

Post by beowulfey »

jiggawatts wrote: post #143
boplicity wrote: post #2

Kim Stanley Robinson's recent book The Ministry For the Future starts with a very disturbing scenario: A heatwave with a "web bulb" temperature of 35 Celsius. It turns out, in those temperatures, even young and healthy people can't survive. Combined with power outages, as happens in the book, everyone living under such a heat wave will likely die. It's looking increasingly likely that such heatwaves are possible in t…

> Combined with power outages, as happens in the book, everyone living under such a heat wave will likely die. That's an exaggeration. Extreme heat (including heat waves that exceed this threshold) happen semi-regularly, and the death rate when they occur is nowhere near 100%. More like 0.1% or less. Electrically-powered air conditioning is not the only way to cool a human body. Simply escaping to an underground or s…

Wet bulb of 37C does not happen semi-regularly. Table S2 of the article shows a TW of 35+ has only happened 14 times in their ~30 year dataset so I would even hazard a guess that TW of 37 has not yet happened.

These events are usually short (for TW >35, majority only last an hour, see Sup fig 2), which is perhaps why we are not seeing many deaths associated with them.

With regards to immersing oneself in water, a bathtub is good so long as groundwater is available; if everyone starts filling their tubs for every heat wave it might start becoming more scarce. I would have thought natural bodies of water like the sea would have been a good choice, but the authors point out that in one region where wet bulb temps >35 were happening they also observed frequent sea surface temps >35 too (sup fig 16).

There are ways to survive and you have provided good ones, but they won’t be available to all who experience these events if they continue to increase in number. And excellent point about wildlife! That’s a whole additional side of it that will probably get lost in the mitigation effort…

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#177

Post by lmilcin »

I see a lot of uninformed people on this thread thinking 35C wet bulb temperature isn't such a big deal and proposing various ineffective tips to cool down.

Let me explain what the issue is, in simple words:

WET BULB TEMPERATURE IS NOT TEMPERATURE YOU SEE ON A THERMOMETER. (please, don't nitpick, I am aware of wet bulb thermometers)

Wet bulb temperature is combination of temperature and humidity.

The simple layman way to understand it is it says what minimum temperature an object can attain by evaporating water off it, in perfect conditions (forced airflow, full shade, no internal heating, etc.)

When air is dry, even if it is hot you can evaporate sweat and cool down -- the wet bulb temperature is low in dry air.

You can survive on Sahara because while the air can be very hot, it is also dry. You sweat and you cool down.

As the humidity rises, the wet bulb temperature approaches dry bulb temperature and at 100% humidity they are both the same.

When air is 100% humid you cannot cool down by sweating at all -- the sweat will not evaporate in 100% humidity regardless of temperature.

Meaning that an air with 35C and 100% humidity has 35C wet bulb temperature but so can hotter air that has less than 100% humidity. The hotter air the lower humidity is needed for the object to cool down to 35C.

Wet bulb of 35C is a limit of human endurance. Even if you lie down in shade and do nothing and are completely healthy, your body is barely able to remove enough heat to survive. Any higher temperature and you WILL eventually die.

People who need to work (like move around at all) or are sick or are small (kids) will die faster.

The only way to resolve this issue is to dry the air somehow.

Things that don't work:

-- going into shade. You are still going to die, just a little bit slower.

-- having a fan. It can't cool you down, because water will not evaporate to cool anything below wet bulb temperature. You are going to die.

-- going into cellar. The air will get cooler but the humidity will rise. You are going to die, unless you can cool the air DRY BULB temperature below 35C. At which point your cellar will have water condensing on its walls which means you can remove humidity from air. It will be shitty, wet, 100% humid, hot place, to sit half a day in with your family, kids and neighbors that don't have an expansive cellar like you, but at least you will survive. Yay...

The issue is in areas that tend to be very hot and susceptible to this phenomenon, people tend to not have means to dry the air. They either don't have money for equipment or they have open homes (who keeps their home shut in a climate like that) assuming they have home at all.

From economic point of view, the problem is that even under wet bulb temperature of 35C some people will already be dying and others will have to stop whatever they are doing, which is not good for your economy.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#178

Post by nicoburns »

ghshephard wrote: post #122
poorjohnmacafee wrote: post #116

Earlier quoted context omitted.

That's contradictory to leading sleep scientists like Matthew Walker, Peter Attia, etc. which is clear about need for chilly environment for sleep quality, eg < 21C. Granted, sleep science isn't oriented towards the genetics of the tropics yet, but there's plenty of evidence about temperature and sleep quality for more northern genetics anyway.

I agree with the parent. Killing the AC for weeks on end really helped me acclimate to the local temperature. I'm not saying it resulted in quality sleep (as a Canadian - I set the thermostat to 13 degrees in the winter when sleeping, and my ideal temperature in the summer is about 18 degrees) - but you get used to the outdoor climate reasonably quickly (in my case, about 4-6 months).

Is 18 degrees assuming a fairly warm duvet covers / blankets? When I was staying hostels the dorms would sometimes be air conditioned and only a sheet would be provided for cover, and I struggled to sleep in anything colder than 21, and I'd have had it up to 22-24 if I could.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#179

Post by burntoutfire »

14 wrote: post #146
fencepost wrote: post #77

Earlier quoted context omitted.

On a purely technical basis that may seem reasonable. On a "we're talking about human beings here" basis what do you do about all the people who feel that the selection and admission process was corrupt and that they've been robbed of their chance at safety? Do you expect them to meekly acquiesce?

I imagine once the first big wave where a nation hits the wetbulb temperature and there is a mass die off you will see panic in surrounding nations and they will scramble to a border. What will nations do with millions of people knocking at the fence wanting in? Uncertain times for sure.

I imagine this happening only in the least well-run countries. In any country with a functioning military, they'll probably organize a mass operation of moving people into temporary refugee camps in cooler areas of the country or into caves, underground structures etc. For people who won't be moved, they'll provide food and water for them so that people don't need to leave their hiding places during the day. (Also, I suspect that, after first major killer heat wave hits an area, people will have their own contingency strategies - be it digging a cellar for themselves to stay in, move to relatives in cooler areas for the duration etc.). However, I'm not sure if for example India is organized enough to pull this off, given their absolutely massive population.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#180

Post by neolog »

poorjohnmacafee wrote: post #116
andi999 wrote: post #75

Earlier quoted context omitted.

When you use AC during nighttime you never get adapted to the heat. Try slowly phasing it out.

That's contradictory to leading sleep scientists like Matthew Walker, Peter Attia, etc. which is clear about need for chilly environment for sleep quality, eg < 21C. Granted, sleep science isn't oriented towards the genetics of the tropics yet, but there's plenty of evidence about temperature and sleep quality for more northern genetics anyway.

https://guzey.com/books/why-we-sleep/
Post reply on HN