7 ms·

> fatal even to fit and healthy people, unclothed in the shade next to a fan; This is scary, what's a good way to survive for someone that doesn't have access

> fatal even to fit and healthy people, unclothed in the shade next to a fan; This is scary, what's a good way to survive for someone that doesn't have access to a bunker or AC? Immersing oneself in water in a bathtub?

wrong_variable 7y ago
Yes, the global poor living in high humid areas have always done that. So have Elephants and Hippos.
ajross 7y ago
A tub will work, sure, as long as it's pulled from a large body of water that hasn't warmed up with the air. Hopping in the local lake is an obvious choice. But in a detached demographic sense: effectively everyone lives in a city in the modern world, and while their housing might not be air conditioned most of the major buildings are. In an emergency like this everyone would just crowd into office buildings and shopping malls. That's not to say this wouldn't be horrifying, but it's not the kind of existential social crisis people tend to imagine. Cooling ourselves down in a heat wave, in the modern world, is a solved problem at least as far as keeping ourselves alive goes.
- TheCoelacanth 7y ago
  Offices and shopping malls are upper-middle class things in India. They would not come close to holding the entire population. There would be millions of people dying if temperatures got that high.
  - ajross 7y ago
    I'd want to see cites for that, honestly. Obviously India's commerce centers can't come close to handling a billion shoppers, but there's enough floor space in the urban core of Bangalore to house the at-risk population for a 72 hour heat wave. The point is emergency management here. And I'd bet anything that somewhere there's a workable plan drawn up for exactly this kind of occurrence.
    - TheCoelacanth 7y ago
      India's total retail space is 2 sq ft/person[1]. That's not enough space for someone to sleep in, even assuming that 100% of the retail space there is air conditioned (it's not) and assuming that the AC systems can keep up with that much body heat in temperatures that high (they can't). [1] https://en.wikipedia.org/wiki/Retailing_in_India#The_Indian_retail_market https://en.wikipedia.org/wiki/Retailing_in_India#The_Indian_...
    - lotsofpulp 7y ago
      >The point is emergency management here. And I'd bet anything that somewhere there's a workable plan drawn up for exactly this kind of occurrence. Aside from ACs having a limit on cooling far below “everyone packed in a building”, if you’ve ever done business in India, I don’t see how one could assume there would be a plan drawn up for this grand of a scenario, much less many smaller scale scenarios.
    - Arun2009 7y ago
      > there's enough floor space in the urban core of Bangalore There's vastly more to India than a few metro cities. A quick google search reveals that around 65+ % of Indian population lives in rural areas. India is in for some very dark times if the climate situation gets worse. The positive lining in the cloud is that we have some measure of political stability for the next 5 years.
- wongarsu 7y ago
  Every human is effectively a 100W space heater just from being alive. That means you need at least 30W of air conditioning capacity per human to keep the temperature constant (on top of what you need to counter heat from outside). Unless these buildings are designed as emergency shelters for heat waves their air conditioning systems won't be able to cope with all the people.
  - bloopernova 7y ago
    That's a deeply upsetting mental image. Thousands of people shelter in a building during a heatwave, the electrical grid is overloaded and the AC shuts down. This makes me want to go live in a deep cave somewhere :(
  - newnewpdro 7y ago
    I don't think it's that simple at all. The principal human-appreciated effect of AC is the dehumidifying of the air when it's cooled. The dry interior air allows human perspiration to regulate temperature effectively. The AC doesn't have to cool all the bodies, it just has to keep the air dry enough.
    - the8472 7y ago
      Don't ACs dehumidify by condensing the water? If so then it means they need to get rid of the heat of vaporization, the same amount of energy the humans shed by evaporative cooling.
      - Scoundreller 7y ago
        Right, but it does mean you just need to be in a somewhat sealed room to remove the humidity instead of constantly fighting the ever-warming walls/floors/ceiling. Of course you need to exchange CO2 and O2 to stay alive.
        wongarsu 7y ago
        But the people in the room will create more humidity that you have to constantly remove again. Humans burning calories to stay alive creates heat, and thermodynamics that you spend energy to remove it or see the temperature rise. Whether that heat is hot air or bound as humidity shouldn't make a large difference.
- blensor 7y ago
  Is this really a long term solution. An A/C does not "produce" cold air it just reduces the temperature at one spot by increasing the temperature in another place making the temperature around those buildings even warmer. At some point A/C units will be battling for that little temperature difference that allows them to perform their function with increasingly higher energy demand.
  - TaylorAlexander 7y ago
    Yeah and how much CO2 emissions will that A/C emit?
    - bufferoverflow 7y ago
      Zero if it runs off solar.
      - blensor 7y ago
        I'm not sure if it's an actual issue but solar panels are quite dark and get really hot. I could imagine that a huge solar array does measurably heat the immediate surrounding area.
        bufferoverflow 7y ago
        Even if it were true, it doesn't produce extra CO2.
        TaylorAlexander 7y ago
        Sure, but a solar powered A/C system is well out of the price range of a few billion people on earth.
- jogjayr 7y ago
  > effectively everyone lives in a city in the modern world, and while their housing might not be air conditioned most of the major buildings are. The states of Rajasthan, Madhya Pradesh, and Uttar Pradesh lag the rest of the nation in economic development. This statement is very much not true in those places, and even elsewhere in India. Air-conditioning is still a luxury outside of relatively well-off people's houses, corporate buildings, and malls. > Cooling ourselves down in a heat wave, in the modern world, is a solved problem at least as far as keeping ourselves alive goes. People there can't afford to not work. Sitting in an air-conditioned space for half the working day 4 months a year is not viable for them. A lot of the work is manual or farm labor that must necessarily be done outdoors.
  - machz 7y ago
    These states are also not very humid. Temperatures in Rajasthan have exceeded 50 several times and people have traditional ways of dealing with it. Not saying that #climatechange isn't an emergency; but people won't suddenly die.
- dragonwriter 7y ago
  > effectively everyone lives in a city in the modern world, and while their housing might not be air conditioned most of the major buildings are. In an emergency like this everyone would just crowd into office buildings and shopping malls. Heat waves spur increases in violent crime, limited in some degree by the fact that people stay in their own homes in really hot (but not uninhabitably so) heat waves. Heat waves that go further to where the only survivable solution is pulling people out of their homes into large communal shelters (whether they otherwise serve as offices or shopping malls or whatever) is...going to be very ugly. And that's even before considering whether the facilities or supporting infrastructure (plumbing, electrical systems, etc.) are adequate to support these places being used as shelters. Almost certainly they won't be until it's happened and failed a few times, and even after that the places that most need it will be the least able to finance the necessary upgrades.
- YeGoblynQueenne 7y ago
  Air conditioning itself is a significant contributor to greenhouse gas emissions, via energy consumption: https://www.rehva.eu/knowledge-base/rehva-journal/chapter/air-conditioning-environmental-challenges https://www.rehva.eu/knowledge-base/rehva-journal/chapter/ai... See the pie chart on page two: eletricity consumption from cooling systems is 17% of global consumption. The IPCC expects this usage to rise as temperatures rise. I would also like to challenge the notion that human beings understand how to use air conditioning units. In pretty much every building I visited or vehicle I boarded with air conditioning, if the unit was on, the windows were also wide open at the same time. In Greece, where I'm from, in the summer, you can cool down just by walking past stores, with their doors thrown wide to signal they're open for business and their air conditioning blasting cool air onto the street. It may be 42°C in the shade, but in front of our shop, it's 15°! Come on in and buy our stuff! But put on your coat first. Contemplate for a second the futility of this behaviour: air conditioning pumps heat out of a room, into the environment; leaving the windows open allows the heat to circulate back into the room. The unit typically has a thermostat, also typically set at an unrealistically low value, that would cause the user to turn on the heating in winter. The unit goes to work and pushes the warm air out trying to reach its target temperature. The warm air cycles back in from outside and tries to raise the temperature. The unit keeps working, and working, and working, wasting energy all the time. Eventually, this contributes to warming, which causes more people to buy and misuse air conditioning. We might know how to survive a heat wave, by our clever use of technology, but we don't know how to use technology to avoid more and more severe heat waves.
  - ricardobeat 7y ago
    Air curtains can be extremely efficient and allow doors to stay open. That sounds like an insane waste of money and energy if store owners are not using one - are you sure you're not just feeling the 10-20% lost cold air when walking past?
    - YeGoblynQueenne 7y ago
      Yes, I'm sure. Edit: because obviousy I also go into shops to buy stuff and I've never seen an air door used. If air doors are used, they are very, very rare.
deleted 7y ago
[deleted]
myself248 7y ago
The water is only cooler because it's evaporating, meaning the wet-bulb temperature also describes the water's own limit. 35°C is slightly cooler than body temperature, so it would work just a little bit as a heatsink, but another degree or two and even that becomes ineffective.
- leereeves 7y ago
  The water is cooler because the specific heat of water is very high, meaning it takes more heat energy to increase the temperature of water. So a large body of water stays cool for a long time, and then stabilizes around the daily average temperature, not the high.
  - wongarsu 7y ago
    > and then stabilizes around the daily average temperature, not the high. However the acceptable temperature range in water is also much smaller because under water we exchange heat quickly and don't have a way to cool below the temperature of the water. Water above ~38°C would be dangerous to stay submersed in. Not a problem for huge bodies of water, but important to keep in mind on the small scale.
- jniedrauer 7y ago
  The phase change of water from liquid to gas is an endothermic reaction. In an emergency, if you had water and a fan, you could continually soak yourself and then accelerate water evaporation using the fan. This would keep you significantly cooler than the water temperature itself.
wongarsu 7y ago
Large bodies of water, mine shafts or just holes in the ground. Just a few meters below the ground temperatures are effectively constant, barely effected by weather. Ocean temperatures are similiarly stable. Of course you can't start digging while dying of heat stroke and you can't crowd people into any places (people are great space heaters). With education about proper measures a few days should be survivable for rural populations. In cities you just need air conditioning, there's no other viable way to cool large amounts of people.
phonypc 7y ago
I credit drinking copious amounts of ice water and frequent urination for helping me avoid hyperthermia for 10+ hours working in a kitchen where the air temperature read 52C + radiative heat from various equipment and high perceived humidity. Granted I don't know the wet-bulb temp actually exceeded 35C
vishnugupta 7y ago
I've experienced this heat wave in various degrees and in different situations (long distance cycling, shopping, trekking, etc.,) and places (Bangalore, Bombay, and Delhi). The most effective preventive measure, in my experience, is to drink (~200ml of) mineral-filled water once every half an hour. The body's heat regulation mechanism works best when provided with sufficient amount of water. The problem only begins to manifest once the body water levels aren't good enough to dispose of heat as well as maintain blood circulation in which case the body prefers to give up heat regulation over fluid circulation. Under normal circumstances, we are used to drinking water only when we get thirsty. Under extreme heat, however, by the time thirst signal kicks in it could be too late. I learned this the hard way during long-distance cycling. Since then I've followed cyclists' mantra of eat-before-hungry and drink-before-thirsty. Another thing to keep in mind is to drink mineralized water (such as Gatorade, juices, tender coconut water, etc.,). When you sweat you also lose a lot of minerals so replenishing just water isn't good enough. Most of the heat wave death in India doesn't occur in an urban setting as people have access to water within walking distance. It is the farmers who are in the most danger as a) They are directly exposed to sun b) They are engaged in strenuous physical activity. By the time they realize the danger they are in it'd be too late and they lose consciousness with no one around them to help out in vast agricultural fields.

wrong_variable 7y ago

Yes, the global poor living in high humid areas have always done that. So have Elephants and Hippos.

ajross 7y ago

A tub will work, sure, as long as it's pulled from a large body of water that hasn't warmed up with the air. Hopping in the local lake is an obvious choice. But in a detached demographic sense: effectively everyone lives in a city in the modern world, and while their housing might not be air conditioned most of the major buildings are. In an emergency like this everyone would just crowd into office buildings and shopping malls. That's not to say this wouldn't be horrifying, but it's not the kind of existential social crisis people tend to imagine. Cooling ourselves down in a heat wave, in the modern world, is a solved problem at least as far as keeping ourselves alive goes.

TheCoelacanth 7y ago
Offices and shopping malls are upper-middle class things in India. They would not come close to holding the entire population. There would be millions of people dying if temperatures got that high.
- ajross 7y ago
  I'd want to see cites for that, honestly. Obviously India's commerce centers can't come close to handling a billion shoppers, but there's enough floor space in the urban core of Bangalore to house the at-risk population for a 72 hour heat wave. The point is emergency management here. And I'd bet anything that somewhere there's a workable plan drawn up for exactly this kind of occurrence.
  - TheCoelacanth 7y ago
    India's total retail space is 2 sq ft/person[1]. That's not enough space for someone to sleep in, even assuming that 100% of the retail space there is air conditioned (it's not) and assuming that the AC systems can keep up with that much body heat in temperatures that high (they can't). [1] https://en.wikipedia.org/wiki/Retailing_in_India#The_Indian_retail_market https://en.wikipedia.org/wiki/Retailing_in_India#The_Indian_...
  - lotsofpulp 7y ago
    >The point is emergency management here. And I'd bet anything that somewhere there's a workable plan drawn up for exactly this kind of occurrence. Aside from ACs having a limit on cooling far below “everyone packed in a building”, if you’ve ever done business in India, I don’t see how one could assume there would be a plan drawn up for this grand of a scenario, much less many smaller scale scenarios.
  - Arun2009 7y ago
    > there's enough floor space in the urban core of Bangalore There's vastly more to India than a few metro cities. A quick google search reveals that around 65+ % of Indian population lives in rural areas. India is in for some very dark times if the climate situation gets worse. The positive lining in the cloud is that we have some measure of political stability for the next 5 years.
wongarsu 7y ago
Every human is effectively a 100W space heater just from being alive. That means you need at least 30W of air conditioning capacity per human to keep the temperature constant (on top of what you need to counter heat from outside). Unless these buildings are designed as emergency shelters for heat waves their air conditioning systems won't be able to cope with all the people.
- bloopernova 7y ago
  That's a deeply upsetting mental image. Thousands of people shelter in a building during a heatwave, the electrical grid is overloaded and the AC shuts down. This makes me want to go live in a deep cave somewhere :(
- newnewpdro 7y ago
  I don't think it's that simple at all. The principal human-appreciated effect of AC is the dehumidifying of the air when it's cooled. The dry interior air allows human perspiration to regulate temperature effectively. The AC doesn't have to cool all the bodies, it just has to keep the air dry enough.
  - the8472 7y ago
    Don't ACs dehumidify by condensing the water? If so then it means they need to get rid of the heat of vaporization, the same amount of energy the humans shed by evaporative cooling.
    - Scoundreller 7y ago
      Right, but it does mean you just need to be in a somewhat sealed room to remove the humidity instead of constantly fighting the ever-warming walls/floors/ceiling. Of course you need to exchange CO2 and O2 to stay alive.
      - wongarsu 7y ago
        But the people in the room will create more humidity that you have to constantly remove again. Humans burning calories to stay alive creates heat, and thermodynamics that you spend energy to remove it or see the temperature rise. Whether that heat is hot air or bound as humidity shouldn't make a large difference.
blensor 7y ago
Is this really a long term solution. An A/C does not "produce" cold air it just reduces the temperature at one spot by increasing the temperature in another place making the temperature around those buildings even warmer. At some point A/C units will be battling for that little temperature difference that allows them to perform their function with increasingly higher energy demand.
- TaylorAlexander 7y ago
  Yeah and how much CO2 emissions will that A/C emit?
  - bufferoverflow 7y ago
    Zero if it runs off solar.
    - blensor 7y ago
      I'm not sure if it's an actual issue but solar panels are quite dark and get really hot. I could imagine that a huge solar array does measurably heat the immediate surrounding area.
      - bufferoverflow 7y ago
        Even if it were true, it doesn't produce extra CO2.
        TaylorAlexander 7y ago
        Sure, but a solar powered A/C system is well out of the price range of a few billion people on earth.
jogjayr 7y ago
> effectively everyone lives in a city in the modern world, and while their housing might not be air conditioned most of the major buildings are. The states of Rajasthan, Madhya Pradesh, and Uttar Pradesh lag the rest of the nation in economic development. This statement is very much not true in those places, and even elsewhere in India. Air-conditioning is still a luxury outside of relatively well-off people's houses, corporate buildings, and malls. > Cooling ourselves down in a heat wave, in the modern world, is a solved problem at least as far as keeping ourselves alive goes. People there can't afford to not work. Sitting in an air-conditioned space for half the working day 4 months a year is not viable for them. A lot of the work is manual or farm labor that must necessarily be done outdoors.
- machz 7y ago
  These states are also not very humid. Temperatures in Rajasthan have exceeded 50 several times and people have traditional ways of dealing with it. Not saying that #climatechange isn't an emergency; but people won't suddenly die.
dragonwriter 7y ago
> effectively everyone lives in a city in the modern world, and while their housing might not be air conditioned most of the major buildings are. In an emergency like this everyone would just crowd into office buildings and shopping malls. Heat waves spur increases in violent crime, limited in some degree by the fact that people stay in their own homes in really hot (but not uninhabitably so) heat waves. Heat waves that go further to where the only survivable solution is pulling people out of their homes into large communal shelters (whether they otherwise serve as offices or shopping malls or whatever) is...going to be very ugly. And that's even before considering whether the facilities or supporting infrastructure (plumbing, electrical systems, etc.) are adequate to support these places being used as shelters. Almost certainly they won't be until it's happened and failed a few times, and even after that the places that most need it will be the least able to finance the necessary upgrades.
YeGoblynQueenne 7y ago
Air conditioning itself is a significant contributor to greenhouse gas emissions, via energy consumption: https://www.rehva.eu/knowledge-base/rehva-journal/chapter/air-conditioning-environmental-challenges https://www.rehva.eu/knowledge-base/rehva-journal/chapter/ai... See the pie chart on page two: eletricity consumption from cooling systems is 17% of global consumption. The IPCC expects this usage to rise as temperatures rise. I would also like to challenge the notion that human beings understand how to use air conditioning units. In pretty much every building I visited or vehicle I boarded with air conditioning, if the unit was on, the windows were also wide open at the same time. In Greece, where I'm from, in the summer, you can cool down just by walking past stores, with their doors thrown wide to signal they're open for business and their air conditioning blasting cool air onto the street. It may be 42°C in the shade, but in front of our shop, it's 15°! Come on in and buy our stuff! But put on your coat first. Contemplate for a second the futility of this behaviour: air conditioning pumps heat out of a room, into the environment; leaving the windows open allows the heat to circulate back into the room. The unit typically has a thermostat, also typically set at an unrealistically low value, that would cause the user to turn on the heating in winter. The unit goes to work and pushes the warm air out trying to reach its target temperature. The warm air cycles back in from outside and tries to raise the temperature. The unit keeps working, and working, and working, wasting energy all the time. Eventually, this contributes to warming, which causes more people to buy and misuse air conditioning. We might know how to survive a heat wave, by our clever use of technology, but we don't know how to use technology to avoid more and more severe heat waves.
- ricardobeat 7y ago
  Air curtains can be extremely efficient and allow doors to stay open. That sounds like an insane waste of money and energy if store owners are not using one - are you sure you're not just feeling the 10-20% lost cold air when walking past?
  - YeGoblynQueenne 7y ago
    Yes, I'm sure. Edit: because obviousy I also go into shops to buy stuff and I've never seen an air door used. If air doors are used, they are very, very rare.

deleted 7y ago

[deleted]

myself248 7y ago

The water is only cooler because it's evaporating, meaning the wet-bulb temperature also describes the water's own limit. 35°C is slightly cooler than body temperature, so it would work just a little bit as a heatsink, but another degree or two and even that becomes ineffective.

leereeves 7y ago
The water is cooler because the specific heat of water is very high, meaning it takes more heat energy to increase the temperature of water. So a large body of water stays cool for a long time, and then stabilizes around the daily average temperature, not the high.
- wongarsu 7y ago
  > and then stabilizes around the daily average temperature, not the high. However the acceptable temperature range in water is also much smaller because under water we exchange heat quickly and don't have a way to cool below the temperature of the water. Water above ~38°C would be dangerous to stay submersed in. Not a problem for huge bodies of water, but important to keep in mind on the small scale.
jniedrauer 7y ago
The phase change of water from liquid to gas is an endothermic reaction. In an emergency, if you had water and a fan, you could continually soak yourself and then accelerate water evaporation using the fan. This would keep you significantly cooler than the water temperature itself.

wongarsu 7y ago

Large bodies of water, mine shafts or just holes in the ground. Just a few meters below the ground temperatures are effectively constant, barely effected by weather. Ocean temperatures are similiarly stable. Of course you can't start digging while dying of heat stroke and you can't crowd people into any places (people are great space heaters). With education about proper measures a few days should be survivable for rural populations. In cities you just need air conditioning, there's no other viable way to cool large amounts of people.

phonypc 7y ago

I credit drinking copious amounts of ice water and frequent urination for helping me avoid hyperthermia for 10+ hours working in a kitchen where the air temperature read 52C + radiative heat from various equipment and high perceived humidity. Granted I don't know the wet-bulb temp actually exceeded 35C

vishnugupta 7y ago

I've experienced this heat wave in various degrees and in different situations (long distance cycling, shopping, trekking, etc.,) and places (Bangalore, Bombay, and Delhi). The most effective preventive measure, in my experience, is to drink (~200ml of) mineral-filled water once every half an hour. The body's heat regulation mechanism works best when provided with sufficient amount of water. The problem only begins to manifest once the body water levels aren't good enough to dispose of heat as well as maintain blood circulation in which case the body prefers to give up heat regulation over fluid circulation. Under normal circumstances, we are used to drinking water only when we get thirsty. Under extreme heat, however, by the time thirst signal kicks in it could be too late. I learned this the hard way during long-distance cycling. Since then I've followed cyclists' mantra of eat-before-hungry and drink-before-thirsty. Another thing to keep in mind is to drink mineralized water (such as Gatorade, juices, tender coconut water, etc.,). When you sweat you also lose a lot of minerals so replenishing just water isn't good enough. Most of the heat wave death in India doesn't occur in an urban setting as people have access to water within walking distance. It is the farmers who are in the most danger as a) They are directly exposed to sun b) They are engaged in strenuous physical activity. By the time they realize the danger they are in it'd be too late and they lose consciousness with no one around them to help out in vast agricultural fields.