Wet-Bulb Temperature(en.wikipedia.org)
en.wikipedia.org
Wet-Bulb Temperature
https://en.wikipedia.org/wiki/Wet-bulb_temperature
88 comments
Well, indoor temperatures would still probably not get that hot thankfully in many places so most people would be able to survive. Millions dead from it in a two day period likely wouldn’t happen.
Also peak temps usually only last a few hours with significant drops outside. The hottest day ever in Phoenix hit 122F but the day started at 90 and ended around 100.
Also in places likes this everyone’s AC runs non-stop every day for 6 months a year at peak times and the power grid doesn’t fail. Power grids fail in places that aren’t used to it, like what happened when Dallas froze.
People will die from it, sure, but millions of deaths in a few days from a heatwave isn’t going to happen.
Also peak temps usually only last a few hours with significant drops outside. The hottest day ever in Phoenix hit 122F but the day started at 90 and ended around 100.
Also in places likes this everyone’s AC runs non-stop every day for 6 months a year at peak times and the power grid doesn’t fail. Power grids fail in places that aren’t used to it, like what happened when Dallas froze.
People will die from it, sure, but millions of deaths in a few days from a heatwave isn’t going to happen.
The amount of power an a/c unit requires to maintain a fixed inside temperature grows with the outside temperature. If folks are already running their a/c nonstop, are they actually prepared for significantly higher temperatures? And if they aren't actually running 24/7 at full blast, is the grid prepared for that?
Significantly higher temperatures aren’t what we’re talking about. We’re talking about a 10-15F spike.
Because heat flows at a rate proportional to the delta, it’s useful to think in terms of the delta between outdoor temperatures and desired indoor (let’s say 70 to make the math easy). So Phoenix has a few 120Fcdays a year, so delta of 50, and we’re talking 135F (so delta 65) for a 30% increase.
Most peoples AC is not sized to handle that, so it already runs basically full stop on the hottest days and can’t quite keep up. Maybe your home is 75 instead of 70. Making the exterior hotter has no effect of your power consumption once your AC is running full blast, it just makes the interior warm, so some people are going to have 80+ degree houses. They’ll be annoyed but won’t die and the power might spike let’s say 25%.
The power grids in these places are equipped for that because it’s life or death. You never hear about Vegas or Phoenix having a blackout on a particularly hot day because it’s not unexpected. Same with cold days in Minnesota. (You hear about it in California but that’s due to mismanagement and often unrelated to weather anyway.)
Now in Dallas when they froze you were looking 0F temps or thereabouts in a place where average winter temps are 56 and peak lows around 40. Further complicating it was that supplies of fossil fuels for heating ran out because it went on for so long. So you went from let’s say a 30 degree delta to 70, and electrical demand even higher than you’d expect when they ran out of natural gas and started plugging in space heaters. So you’re looking at like 2-3x previous peak demand, rather than 1.3. Nobody’s grid is prepared for that.
So again I’m fairly confident that if Phoenix hits a peak of 135 it is going to suck and a few hundred people will die for sure. It won’t be millions.
Global warming thankfully grows on 1 degree per decade kind of time scales which sucks ecologically but isn’t faster than we can grow the grid.
Because heat flows at a rate proportional to the delta, it’s useful to think in terms of the delta between outdoor temperatures and desired indoor (let’s say 70 to make the math easy). So Phoenix has a few 120Fcdays a year, so delta of 50, and we’re talking 135F (so delta 65) for a 30% increase.
Most peoples AC is not sized to handle that, so it already runs basically full stop on the hottest days and can’t quite keep up. Maybe your home is 75 instead of 70. Making the exterior hotter has no effect of your power consumption once your AC is running full blast, it just makes the interior warm, so some people are going to have 80+ degree houses. They’ll be annoyed but won’t die and the power might spike let’s say 25%.
The power grids in these places are equipped for that because it’s life or death. You never hear about Vegas or Phoenix having a blackout on a particularly hot day because it’s not unexpected. Same with cold days in Minnesota. (You hear about it in California but that’s due to mismanagement and often unrelated to weather anyway.)
Now in Dallas when they froze you were looking 0F temps or thereabouts in a place where average winter temps are 56 and peak lows around 40. Further complicating it was that supplies of fossil fuels for heating ran out because it went on for so long. So you went from let’s say a 30 degree delta to 70, and electrical demand even higher than you’d expect when they ran out of natural gas and started plugging in space heaters. So you’re looking at like 2-3x previous peak demand, rather than 1.3. Nobody’s grid is prepared for that.
So again I’m fairly confident that if Phoenix hits a peak of 135 it is going to suck and a few hundred people will die for sure. It won’t be millions.
Global warming thankfully grows on 1 degree per decade kind of time scales which sucks ecologically but isn’t faster than we can grow the grid.
> Global warming thankfully grows on 1 degree per decade kind of time scales which sucks ecologically but isn’t faster than we can grow the grid.
I live in BC, which saw all-time record temperatures which killed about 400 people last year. Temperatures were about 10°C higher than a typical year. While average temperatures might grow slowly, peak temperatures are a different story.
I live in BC, which saw all-time record temperatures which killed about 400 people last year. Temperatures were about 10°C higher than a typical year. While average temperatures might grow slowly, peak temperatures are a different story.
I don’t think that’s true of desert climates though. Here’s Phoenix’s highest temp by year. You can see it barely budges at all.
https://www.currentresults.com/Yearly-Weather/USA/AZ/Phoenix...
https://www.currentresults.com/Yearly-Weather/USA/AZ/Phoenix...
The a/c doesn't even have to cool down. It's sufficient to dry the air and that requires much less energy.
I agree, but does that describe the a/c units that folks are equipped with today? There's a big difference between "this problem can be solved" and "this problem has been solved."
Side note, I would love it if more a/c merely dried the air. I hate going into office buildings that are set 20C below the outdoor temperature.
Side note, I would love it if more a/c merely dried the air. I hate going into office buildings that are set 20C below the outdoor temperature.
Sure, this needs coordination - not saying that it's an easy solution.
> Side note, I would love it if more a/c merely dried the air.
Yeah - having a very light breeze and dry (but not too dry) air is all that's needed for the vast majority to not feel sweaty or even hot. I would only ever buy an a/c with an efficient dry-mode.
> Side note, I would love it if more a/c merely dried the air.
Yeah - having a very light breeze and dry (but not too dry) air is all that's needed for the vast majority to not feel sweaty or even hot. I would only ever buy an a/c with an efficient dry-mode.
Right. So in a hypothetical world where everybody can afford to buy a new a/c unit, the risk that millions will die in a heat wave is negligible. Down here in the real world, it's a distinct possibility.
I think it would probably be enough to broadcast on media/news that people are not allowed to cool anymore
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Most people living in places where wet bulb can get 35C have very little insulation from environment in their houses and very few people have means to afford AC.
That’s not been my experience both domestically and internationally. Cities like Vegas and Phoenix didn’t exist (and cities like Lima and Cairo were much smaller) before AC. People simply wouldn’t be here if they couldn’t afford it.
Domestically, it’s a legal requirement. You can’t legally build a home or rent one without it, anymore than you could without heating in Minnesota.
Domestically, it’s a legal requirement. You can’t legally build a home or rent one without it, anymore than you could without heating in Minnesota.
When you say "ended" do you mean sundown or midnight?
Among other things, this is why it’s worrying to see electric grids fail in Texas, hospitals getting overwhelmed during COVID, and the supply chains falling apart for basic supplies - we’re not even scratching the surface of what the world’s got in store for us over the next century.
I am thinking about animals in these superhot regions. yes humans can turn the AC on but such temperatures are effectively death sentences for everyone except human. Now I do not know the exact WB temperature for each animals but 1) their body temperature equilibrium must be around current conditions. 2) for smaller (than humans) surface area/mass equation would tip towards for being worse for them in terms of survivability (think kids needing more layers).
I do not have a good feeling about this!
I do not have a good feeling about this!
This got me wondering, how do humans handle a hot bath? Wet-bulb temp is much higher than 35 °C, right?
I mean, it's probably going to hit moist areas first. So India should be one of the first countries to experience lethal wet-bulb temperatures.
I mean, it's probably going to hit moist areas first. So India should be one of the first countries to experience lethal wet-bulb temperatures.
A hot tub is a little above it. But it’s very important to remember your head is above the water. So the wet bulb temperature for your most vital organs is much lower.
Also you really aren’t supposed to stay in for a long time and it definitely can hurt/kill you to do so. It’s not very common because you can leave at any time and you’ll feel growing discomfort long before the danger zone but people do die that way.
Also you really aren’t supposed to stay in for a long time and it definitely can hurt/kill you to do so. It’s not very common because you can leave at any time and you’ll feel growing discomfort long before the danger zone but people do die that way.
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> (20 or so minutes, even for healthy, fit adults).
As someone who enjoys sitting in a sauna I wonder what physics are at play here. Heat stroke trying to work in >100* heat I get, but death even at rest?
As someone who enjoys sitting in a sauna I wonder what physics are at play here. Heat stroke trying to work in >100* heat I get, but death even at rest?
The humidity is the issue. Wet-bulb temperatures exceeding body temperature means sweating no longer cools you off.
That's why steam rooms peak at ~110 and saunas at ~150. A steam room at 110 is almost unbearably hot, it's hard to last more than 5 or 10 minutes in one.
Think about a human having a fever of 108—that's the temperature at which you'd start to have convulsions.
That's why steam rooms peak at ~110 and saunas at ~150. A steam room at 110 is almost unbearably hot, it's hard to last more than 5 or 10 minutes in one.
Think about a human having a fever of 108—that's the temperature at which you'd start to have convulsions.
I wonder about that myself. I know my limits and can't stay in a sauna for too long, but I've heard that folks in Finland take it really far. But... reading up on the World Sauna Championships, it seems that even the most heat-adapted Finns tapped out after 16 minutes or so. That was in a ludicrous 110C with a steep humidity ramp, and they stopped running the competition after a contestant died and another one nearly died after about 6 minutes.
I've tried to look for better statistics about how much folks in Finland can actually tolerate, but all I found was this spectacular batshit: https://www.reddit.com/r/finlandConspiracy/comments/op97qm/t...
I've tried to look for better statistics about how much folks in Finland can actually tolerate, but all I found was this spectacular batshit: https://www.reddit.com/r/finlandConspiracy/comments/op97qm/t...
The important thing is the moisture level. You need to be able to sweat, which you usually do in a sauna.
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That prompts a lot of questions I'd never thought about before. Assuming a failed grid, are there enough off-grid cooling units to keep the population alive? If such a thing happened in my city people would pile into vehicles and use that AC, but my city has an average car ownership of two per household. The next century will definitely create a market for refrigerated trucks full of bunkbeds.
I wonder how long a fridge-sized freezer filled with water and then frozen could keep you alive in such a heatwave.
I wonder how long a fridge-sized freezer filled with water and then frozen could keep you alive in such a heatwave.
I don't think you need active phase-change cooling to survive a heat wave, there are architectural solutions found in deserts the world over (India and Iran have great examples). Namely, thick stone walls as heat mass so interior stays cool where nights are cool, and encouraging airflow through great public halls (wind will form where-ever there's a temperature gradient, breezeblocks or jaali can aid in increasing airflow while blocking sunlight)
Courtyards with a pool of water will have noticeably cooler ambient temps, these are found all over the middle east.
At the extreme, you get underground cities like Nūshābād.
Courtyards with a pool of water will have noticeably cooler ambient temps, these are found all over the middle east.
At the extreme, you get underground cities like Nūshābād.
One of the things I’m going to be interested to see over the next couple decades is what happens to building design - especially for houses, we’ve switched entirely over to a mode of building that’s effectively optimized for cost and consistency, as opposed to localized to the environment. You’ve got houses built the same in Arizona and Montana, which is insane on the face of it and assumes sufficient energy availability that we can ignore local climates. It would be great to see a move back towards those older building techniques that are tailored better towards their environments.
If we have any architecture buffs here, I’d love a starting point for learning more about climate specific architectural design (that doesn’t center around active climate technologies like HVAC). Keywords?
Check out the wind catchers or wind-towers (burj al hawwa) of Iran [0], as well as Qatar [1] <- some helpful diagrams
Jaali is the latticework that at first glance is merely decorative but is in fact functional, see this paper [2]: "Different names- Takhrima in Yemen, Shanashil or Roshan in Iraq and Saudi Arabia, with differences in design, materials, etc., calls them but the function remained the same as a climate control tool in the harsh deserts."
[0] https://www.bbc.com/travel/article/20180926-an-ancient-engin...
[1] https://www.iloveqatar.net/guide/places/traditional-air-cond...
[2] https://ijseas.com/volume2/v2i2/ijseas20160211.pdf
Jaali is the latticework that at first glance is merely decorative but is in fact functional, see this paper [2]: "Different names- Takhrima in Yemen, Shanashil or Roshan in Iraq and Saudi Arabia, with differences in design, materials, etc., calls them but the function remained the same as a climate control tool in the harsh deserts."
[0] https://www.bbc.com/travel/article/20180926-an-ancient-engin...
[1] https://www.iloveqatar.net/guide/places/traditional-air-cond...
[2] https://ijseas.com/volume2/v2i2/ijseas20160211.pdf
The thing about wet bulb temperature is it means that even pools of water are too hot to survive in.
The pool of water would only be able to keep the temperature down due to the constant evaporation of water taking heat out of the environment. This won't work once the wet bulb temperature crosses a threshold.
Even when it's windy?!
How the windchill effect does work?
I thought it was because it accelerates the evaporation.
Not sure though...
Wet-bulb temperature means equivalent to 100% humidity, at which point there is no evaporation.
Wind increases evaporation if it is occurring, basically a multiplier. At 100% humidity no evaporation is occurring because the air is fully saturated. So the wind is multiplying times zero.
There are a few technologies that could help us mitigate this disaster scenario (although laws to address GHG emissions are needed to truly avoid it):
- Smart thermostats which let utility companies cap peoples AC use - you can stop people from cooling down to room temp, keep everyone at 85 wbt instead. You can pre-cool peoples houses before the hottest point in the day (e.g. turn the temperature down to 60 in the morning and then turn the AC off and let it ride back up to 85 wbt during the heat wave). In the worst case scenario, you can shut off peoples AC and make them go to cooling shelters.
- Thermal storage - traditional ice thermal storage uses glycol to freeze ice at night when the condenser temperature is really low, and then stores this ice to cool buildings during the day. The problem is that glycol systems are expensive and impractical on a small scale, so all ice thermal storage systems are huge (take a look at Chicago’s district cooling as an example). New thermal storage materials (e.g. polymer phase change materials) can be frozen/unfrozen at the evaporator temperature of existing AC systems, so they would require less retrofitting to install and could be used for smaller buildings.
- More efficient dehumidifiers - ARPA-E is finding a bunch of projects around this right now. Some, like isothermal membrane-based air dehumidification, could be 4x more efficient than existing vapor compression dehumidifiers.
Many other technologies, like energy recover ventilators, hybrid and adiabatic cooling towers, and inverter chillers, to name a few, are making HVAC more efficient!
- Smart thermostats which let utility companies cap peoples AC use - you can stop people from cooling down to room temp, keep everyone at 85 wbt instead. You can pre-cool peoples houses before the hottest point in the day (e.g. turn the temperature down to 60 in the morning and then turn the AC off and let it ride back up to 85 wbt during the heat wave). In the worst case scenario, you can shut off peoples AC and make them go to cooling shelters.
- Thermal storage - traditional ice thermal storage uses glycol to freeze ice at night when the condenser temperature is really low, and then stores this ice to cool buildings during the day. The problem is that glycol systems are expensive and impractical on a small scale, so all ice thermal storage systems are huge (take a look at Chicago’s district cooling as an example). New thermal storage materials (e.g. polymer phase change materials) can be frozen/unfrozen at the evaporator temperature of existing AC systems, so they would require less retrofitting to install and could be used for smaller buildings.
- More efficient dehumidifiers - ARPA-E is finding a bunch of projects around this right now. Some, like isothermal membrane-based air dehumidification, could be 4x more efficient than existing vapor compression dehumidifiers.
Many other technologies, like energy recover ventilators, hybrid and adiabatic cooling towers, and inverter chillers, to name a few, are making HVAC more efficient!
Interesting. Could you explain why would sitting in front of fan speed up your death though?
The answer everyone missed: boundary layer. Air has friction. When you sit there, a boundary layer of much slower moving (relative to the motion of unobstructed air as connection occurs) air creates an insulating effect around you. The fan removes the boundary layer by blowing it away.
This effect is why food that is boiled cooks so much faster than food at 99C. You’d otherwise expect it to cook only a little over 1% faster but the actual effect is far greater. The boiling churns the water and disrupts the boundary layer. Similar principle in a forced convection oven.
This effect is why food that is boiled cooks so much faster than food at 99C. You’d otherwise expect it to cook only a little over 1% faster but the actual effect is far greater. The boiling churns the water and disrupts the boundary layer. Similar principle in a forced convection oven.
A fan works by speeding up the rate of evaporation from your skin, which cools you off. At these wet bulb temperatures the ratio of heat/humidity is so high that blowing hot air over your skin just heats you up faster. Kind of like turning on the convection feature in an oven.
Yes, exactly. If you pour water on you and sit in front of a fan, why the windchill effect wouldn't work anymore?!
I think this stuff only happens in absence of wind...
I think this stuff only happens in absence of wind...
Because the temperature we're talking about is the wet bulb variety. That means it accounts for evaporation. What is normally a windchill is now a "windwarm" effect.
(Yes, I know that windchill effect isn't solely due to evaporation-cooling. It's also stripping the layer of warm air away from you.)
The environment is hotter than you. Blowing hotter air (laden with moisture, so it won't evaporate your sweat) won't do anything to cool you down.
(Yes, I know that windchill effect isn't solely due to evaporation-cooling. It's also stripping the layer of warm air away from you.)
The environment is hotter than you. Blowing hotter air (laden with moisture, so it won't evaporate your sweat) won't do anything to cool you down.
For a harrowing depiction of what sustained wet-bulb temperatures could look like, check out the opening of Kim Stanley Robinson’s Ministry for the Future.
The entire book is super important. Plausible and scary predictions for the next 40 years with many positive solutions.(Pumping the water from underneath the major glaciers to keep them from sliding into the ocean.) It's heartening to see the world come together over Ukraine, a template for how we could come together over climate change.
> It's heartening to see the world come together over Ukraine
NATO is coming together over the Ukraine to ensure that they control the NG and potential oil reserves there and not Russia. I live in a NATO country and hope my team wins because, ultimately, it will be better for me.
All of the rest of the narratives are propaganda to get the public feeling morally good about another conflict over fossil fuels.
There's nothing heartening about this. The end result of this will ultimately be more burning of fossil fuels, we're just fighting to see who pays what to burn them.
NATO is coming together over the Ukraine to ensure that they control the NG and potential oil reserves there and not Russia. I live in a NATO country and hope my team wins because, ultimately, it will be better for me.
All of the rest of the narratives are propaganda to get the public feeling morally good about another conflict over fossil fuels.
There's nothing heartening about this. The end result of this will ultimately be more burning of fossil fuels, we're just fighting to see who pays what to burn them.
God no. That would be a disaster.
Back here in the real world, not the modelled world, we have to ask is the temperature even rising at all? This shouldn't even be a legitimate question to ask but it turns out it is. In recent years temperature "rises" have sometimes turned out to be the result of data modification and not really existing. See how NOAA has announced that July 2021 broke the previous temperature record set in 2016, and how they also announced that July 2019 was a record breaking year. This happens because climatologists are constantly rewriting the historical record to create new warming trends where none were previously seen. They admit to this in obscure papers but reason, correctly, that the media/political set will not call them on it, so they can get away with making their predictions about the future come true by simply altering the past.
In many cases temperature graphs for massive regions that were flat in the past have become sloped in the present. Consider this front page New York Times article from 1989:
https://www.nytimes.com/1989/01/26/us/us-data-since-1895-fai...
"US data since 1895 fail to show warming trend"
Look at the graph in the lower left hand corner for long term US temperatures and notice that it's flat. The US should certainly have warmed between 1895 and 1989 given GHG emissions in this time frame but it didn't. Now go look up a temperature history of the USA from modern sources like the NOAA website. Observe that it's sloped upwards for the same time frame. The past has been changed.
In the first part of the century there was a notorious so-called pause in global warming. Temperatures were once again not going up. Scientists fixed this by rewriting the past once again:
https://www.nature.com/articles/nature.2015.17700
If there was actually runaway global warming, they would not need to do this sort of thing. But they do, because otherwise, warming does not appear in the data.
Given that the temperature record is not trustworthy by climatologists own admission it would be incredibly destructive and unwise to do geo-engineering on the basis of such flimsy data. It could easily make things far worse. In fact we just finished up with a global crisis; one that appears to have started in a lab that was tampering with viruses in an attempt to pre-solve a future disease crisis that existed primarily in the heads of the scientists researching it. The scale of it was then exaggerated by modellers who didn't understand what they were modelling and who have utterly refused to accept evidence that their suggested interventions had no effect.
Academia is just not reliable enough to take drastic action on the basis of their predictions and people who keep denying this are, in my view, the real deniers.
Back here in the real world, not the modelled world, we have to ask is the temperature even rising at all? This shouldn't even be a legitimate question to ask but it turns out it is. In recent years temperature "rises" have sometimes turned out to be the result of data modification and not really existing. See how NOAA has announced that July 2021 broke the previous temperature record set in 2016, and how they also announced that July 2019 was a record breaking year. This happens because climatologists are constantly rewriting the historical record to create new warming trends where none were previously seen. They admit to this in obscure papers but reason, correctly, that the media/political set will not call them on it, so they can get away with making their predictions about the future come true by simply altering the past.
In many cases temperature graphs for massive regions that were flat in the past have become sloped in the present. Consider this front page New York Times article from 1989:
https://www.nytimes.com/1989/01/26/us/us-data-since-1895-fai...
"US data since 1895 fail to show warming trend"
Look at the graph in the lower left hand corner for long term US temperatures and notice that it's flat. The US should certainly have warmed between 1895 and 1989 given GHG emissions in this time frame but it didn't. Now go look up a temperature history of the USA from modern sources like the NOAA website. Observe that it's sloped upwards for the same time frame. The past has been changed.
In the first part of the century there was a notorious so-called pause in global warming. Temperatures were once again not going up. Scientists fixed this by rewriting the past once again:
https://www.nature.com/articles/nature.2015.17700
If there was actually runaway global warming, they would not need to do this sort of thing. But they do, because otherwise, warming does not appear in the data.
Given that the temperature record is not trustworthy by climatologists own admission it would be incredibly destructive and unwise to do geo-engineering on the basis of such flimsy data. It could easily make things far worse. In fact we just finished up with a global crisis; one that appears to have started in a lab that was tampering with viruses in an attempt to pre-solve a future disease crisis that existed primarily in the heads of the scientists researching it. The scale of it was then exaggerated by modellers who didn't understand what they were modelling and who have utterly refused to accept evidence that their suggested interventions had no effect.
Academia is just not reliable enough to take drastic action on the basis of their predictions and people who keep denying this are, in my view, the real deniers.
The fact that glaciers are shrinking seems to legitimize the temperature corrections, no?
No, for two reasons.
One: the "glaciers" - I assume you mean something like the Greenland ice sheet here - aren't actually shrinking. See for yourself, data direct from the observation satellites:
http://polarportal.dk/fileadmin/polarportal/surface/SMB_comb...
Note that accumulated surface mass balance for both 2021-2022 so far, and for 2020-2021, is pretty much bob on the 1981-2010 average. In fact last year it was a little over the average. You think they're massively shrinking because scientists and the media like to announce years when it's lower than average, then are silent in years when it's average or above average. This form of soft censorship makes you think they're constantly shrinking when in fact size wanders around.
Even so, we must be careful with interpreting this sort of data because they're all at it. Many claims about changes in ice depth or size are the result of ... more modelling ... which has the exact same problem as temperature modelling, it's too easy to bias in your desired direction by constantly adding convenient fixes. Exactly the same problem as seen in COVID models.
The second reason is more subtle. You refer in your comment to temperature "corrections". By definition, "correcting" observational data to make it conform to your theory (which is the effect of what they're doing) is not scientific. Scientists aren't allowed to "correct" their raw data, period, end of story. If they do it's always fraud when judged by the standards of more normal and rigorous fields. If your historical data is of poor quality then you need to admit that, add error bars and propagate them through to your final confidence intervals, then interpret the CIs honestly i.e. if the CIs are wide enough to incorporate "nothing is changing" then so be it even if that's bad for your grant approval rate.
Climatologists don't do this. Instead what happens is that they collect data, it fails to show warming, and they then spend years coming up with plausible sounding justifications for why their observations need to be changed. So they do it, but their corrections are motivated reasoning so newly collected data of course shows the same problem - no warming (hence why we see stories about the mysterious lack of warming from both 1989 and 2015 in the press, see my citations above). So they come up with yet more reasons to adjust the data and do it again.
This practice has now reached its logical conclusion: they adjust every data point every time a new data point is added. That's why NOAA call their temperature history a reconstructed dataset. They literally reconstruct it every day. Climatology is all about making predictions about temperature but literally according to them, they cannot accurately measure temperatures that were recorded last week, not even at specific weather stations. They cannot read thermometers today, but measuring the temperature of the world as it was 1000 years ago, or predicting what it will be in 100 years, no problem. Obviously no rational person can accept such a claim: it is absurd on its face.
One: the "glaciers" - I assume you mean something like the Greenland ice sheet here - aren't actually shrinking. See for yourself, data direct from the observation satellites:
http://polarportal.dk/fileadmin/polarportal/surface/SMB_comb...
Note that accumulated surface mass balance for both 2021-2022 so far, and for 2020-2021, is pretty much bob on the 1981-2010 average. In fact last year it was a little over the average. You think they're massively shrinking because scientists and the media like to announce years when it's lower than average, then are silent in years when it's average or above average. This form of soft censorship makes you think they're constantly shrinking when in fact size wanders around.
Even so, we must be careful with interpreting this sort of data because they're all at it. Many claims about changes in ice depth or size are the result of ... more modelling ... which has the exact same problem as temperature modelling, it's too easy to bias in your desired direction by constantly adding convenient fixes. Exactly the same problem as seen in COVID models.
The second reason is more subtle. You refer in your comment to temperature "corrections". By definition, "correcting" observational data to make it conform to your theory (which is the effect of what they're doing) is not scientific. Scientists aren't allowed to "correct" their raw data, period, end of story. If they do it's always fraud when judged by the standards of more normal and rigorous fields. If your historical data is of poor quality then you need to admit that, add error bars and propagate them through to your final confidence intervals, then interpret the CIs honestly i.e. if the CIs are wide enough to incorporate "nothing is changing" then so be it even if that's bad for your grant approval rate.
Climatologists don't do this. Instead what happens is that they collect data, it fails to show warming, and they then spend years coming up with plausible sounding justifications for why their observations need to be changed. So they do it, but their corrections are motivated reasoning so newly collected data of course shows the same problem - no warming (hence why we see stories about the mysterious lack of warming from both 1989 and 2015 in the press, see my citations above). So they come up with yet more reasons to adjust the data and do it again.
This practice has now reached its logical conclusion: they adjust every data point every time a new data point is added. That's why NOAA call their temperature history a reconstructed dataset. They literally reconstruct it every day. Climatology is all about making predictions about temperature but literally according to them, they cannot accurately measure temperatures that were recorded last week, not even at specific weather stations. They cannot read thermometers today, but measuring the temperature of the world as it was 1000 years ago, or predicting what it will be in 100 years, no problem. Obviously no rational person can accept such a claim: it is absurd on its face.
> By definition, "correcting" observational data to make it conform to your theory (which is the effect of what they're doing) is not scientific.
What about corrections to compensate for known biases? Such as moving a measuring station from the cold to the hot side of a valley.
What about corrections to compensate for known biases? Such as moving a measuring station from the cold to the hot side of a valley.
That corrects data by changing the way it's collected. That's OK if it's properly documented of course, because you're improving the accuracy of your measurements. You may then have difficulties comparing the two periods but there are techniques to deal with that.
Where climatologists go wrong is when they say "and now we'll rewrite the prior observations to what we think they would have been, had the weather station been there all along". That's not scientific. Consider how easy it is to make mistakes that way, or have biases in which only adjustments beneficial for your career are included. Especially when your central claim is about long term trends over time, it should be obvious why editing the past isn't allowed.
Where climatologists go wrong is when they say "and now we'll rewrite the prior observations to what we think they would have been, had the weather station been there all along". That's not scientific. Consider how easy it is to make mistakes that way, or have biases in which only adjustments beneficial for your career are included. Especially when your central claim is about long term trends over time, it should be obvious why editing the past isn't allowed.
Yeah: why would we trust people who go back, verify, and correct their findings later? We should only trust people who never ever change their mind or attempt to correct their previous interpretations of data! Thanks, random internet stranger, for showing that millions of scientists and dozens of government organizations are completely incompetent and/or malicious liars!
Either that or you're spreading misinformation and cherry-picking a few small examples to support a pre-determined conclusion.
Either that or you're spreading misinformation and cherry-picking a few small examples to support a pre-determined conclusion.
Please think about this carefully before making such replies. You cannot "go back" in time and "verify" a weather station reading. It was what it was on a specific day at a specific place, and if the log books say it was X then it was X. You can't say, gee, I wonder what the temperature was in New York on April 1st 1940 if I use my super-duper new thermometer, because time travel is impossible.
"We should only trust people who never ever change their mind or attempt to correct their previous interpretations of data"
Look, I realize what I'm showing you is hard to accept. It was for me too. I did a lot of digging before coming to the conclusion that I couldn't refute what was happening. Nonetheless, please recognize that you're in denial here. These people are not changing their interpretations of the data. They are changing the data itself and I believe I made that extremely clear. It's very hard to get the raw, pre-editing historical datasets. Sometimes it's possible, sometimes it's not. It really depends on the temperature series, the organization that produces it, the time frame in question etc. That's why I'm forced to cite newspaper archives above, because they are one of the places where history is recorded that scientists can't easily rewrite.
"Thanks, random internet stranger, for showing that millions of scientists and dozens of government organizations are completely incompetent and/or malicious liars!"
Unfortunately facts aren't decided by how many people say them or who they work for. Facts are what they are and one person pointing out one fact, can - in fact - show that millions of scientists and dozens of government organizations are doing something highly unusual.
At any rate, there aren't millions of climatologists, lol. It's a tiny field. Even fewer of them produce temperature data sets. Probably fewer than 100 people do that work globally (I'm not counting the people who actually read the thermometers here because they aren't publishing combined temperature series).
With respect to being incompetent and malicious liars, I'm afraid they are something far worse - highly competent and badly incentivized liars. If there was no global warming them climatology would be dusty academic backwater that none of us would ever think about. They wouldn't be the center of a massive cultural industry that venerates them, instead their status and funding would be somewhere near the sort of people who categorize rare species of butterflies.
"We should only trust people who never ever change their mind or attempt to correct their previous interpretations of data"
Look, I realize what I'm showing you is hard to accept. It was for me too. I did a lot of digging before coming to the conclusion that I couldn't refute what was happening. Nonetheless, please recognize that you're in denial here. These people are not changing their interpretations of the data. They are changing the data itself and I believe I made that extremely clear. It's very hard to get the raw, pre-editing historical datasets. Sometimes it's possible, sometimes it's not. It really depends on the temperature series, the organization that produces it, the time frame in question etc. That's why I'm forced to cite newspaper archives above, because they are one of the places where history is recorded that scientists can't easily rewrite.
"Thanks, random internet stranger, for showing that millions of scientists and dozens of government organizations are completely incompetent and/or malicious liars!"
Unfortunately facts aren't decided by how many people say them or who they work for. Facts are what they are and one person pointing out one fact, can - in fact - show that millions of scientists and dozens of government organizations are doing something highly unusual.
At any rate, there aren't millions of climatologists, lol. It's a tiny field. Even fewer of them produce temperature data sets. Probably fewer than 100 people do that work globally (I'm not counting the people who actually read the thermometers here because they aren't publishing combined temperature series).
With respect to being incompetent and malicious liars, I'm afraid they are something far worse - highly competent and badly incentivized liars. If there was no global warming them climatology would be dusty academic backwater that none of us would ever think about. They wouldn't be the center of a massive cultural industry that venerates them, instead their status and funding would be somewhere near the sort of people who categorize rare species of butterflies.
It's not even remotely true that the climate change consensus is based only on 100 climatologists. It has been understood that greenhouse gases could lead to global warming for over 100 years. It's a scientific consensus built on the agreement of many disciplines, from chemists studying how photons interact with methane, agricultural scientists studying how much methane a cow produces, wastewater engineers measuring methane and CO2 output from human waste streams, forestry scientists studying how trees decay over time and analyzing historical tree rings, scientists studying ice levels in the arctic, ecologists studying coral reefs, data scientists and statisticians combining all their data, and on and on and on.
You absolutely are going against the consensus built up over the last 100 years across all of these disciplines. I don't think it's unreasonable to say the number of people that contributed to that consensus is in the millions. You're claiming all of that work is discredited because someone reviewed old data and said "this measurement was odd and their notes are bad; they probably left the thermometer in the sun. Let's throw out this data point". Questionable or not, that's not a counterexample to the well-understood mechanism of the greenhouse effect and atmospheric measurements of CO2, nor to the hundreds of other lines of evidence that have led nearly all science-literate people to accept reality.
It's simple: you are spreading misinformation. Stop it.
You absolutely are going against the consensus built up over the last 100 years across all of these disciplines. I don't think it's unreasonable to say the number of people that contributed to that consensus is in the millions. You're claiming all of that work is discredited because someone reviewed old data and said "this measurement was odd and their notes are bad; they probably left the thermometer in the sun. Let's throw out this data point". Questionable or not, that's not a counterexample to the well-understood mechanism of the greenhouse effect and atmospheric measurements of CO2, nor to the hundreds of other lines of evidence that have led nearly all science-literate people to accept reality.
It's simple: you are spreading misinformation. Stop it.
This is now the second, third and fourth time you're arguing with arguments I never actually made. I'm not sure it's worth continuing with this because you don't seem to be accurately reading what I write.
I said (again, quite clearly) that there are probably 100 or fewer climatologists actively producing aggregated temperature datasets, not 100 climatologists in total. There are many climatologists, but they all use the same set of temperature time series produced by a relatively small group. And that makes sense. Collecting all the data is a lot of work. You have to maintain relationships with many different meteorological agencies, potentially spend lots of time typing in numbers read from old log books, etc. It'd be odd if that work were duplicated by every person who wanted to explore climate data.
Then you go off and talk about how there's consensus that CO2 could lead to global warming, which is nothing I've disagreed with at any point. CO2 could cause that, yes, but how much effect it is actually having in practice is definitely not in agreement, as the numerous different estimates for ECS show.
"You're claiming all of that work is discredited because someone reviewed old data and said "this measurement was odd and their notes are bad; they probably left the thermometer in the sun. Let's throw out this data point"."
Argh, no. I am explicitly not claiming that, I'm claiming the opposite. Faced with measurements they believe are erroneous they do not throw out the data. That would be a scientific thing to do. Instead what they do is keep it, but then apply a large range of "fixes" to it, and present the "fixed" data as if it were the original recordings. This is bad news because actually in the original data no warming is visible, and the trend they are claiming is really happening only appears after their model-driven adjustments. In other words, when observed data doesn't match the theory, the theory triumphs and observed data is modified.
"It's simple: you are spreading misinformation. Stop it."
Someone who can't even correctly understand the things I'm writing is in no position to claim other people are spreading misinformation. None of the points I've responded to in this thread were actually rebuttals to anything I've said!
I said (again, quite clearly) that there are probably 100 or fewer climatologists actively producing aggregated temperature datasets, not 100 climatologists in total. There are many climatologists, but they all use the same set of temperature time series produced by a relatively small group. And that makes sense. Collecting all the data is a lot of work. You have to maintain relationships with many different meteorological agencies, potentially spend lots of time typing in numbers read from old log books, etc. It'd be odd if that work were duplicated by every person who wanted to explore climate data.
Then you go off and talk about how there's consensus that CO2 could lead to global warming, which is nothing I've disagreed with at any point. CO2 could cause that, yes, but how much effect it is actually having in practice is definitely not in agreement, as the numerous different estimates for ECS show.
"You're claiming all of that work is discredited because someone reviewed old data and said "this measurement was odd and their notes are bad; they probably left the thermometer in the sun. Let's throw out this data point"."
Argh, no. I am explicitly not claiming that, I'm claiming the opposite. Faced with measurements they believe are erroneous they do not throw out the data. That would be a scientific thing to do. Instead what they do is keep it, but then apply a large range of "fixes" to it, and present the "fixed" data as if it were the original recordings. This is bad news because actually in the original data no warming is visible, and the trend they are claiming is really happening only appears after their model-driven adjustments. In other words, when observed data doesn't match the theory, the theory triumphs and observed data is modified.
"It's simple: you are spreading misinformation. Stop it."
Someone who can't even correctly understand the things I'm writing is in no position to claim other people are spreading misinformation. None of the points I've responded to in this thread were actually rebuttals to anything I've said!
Coincidentally, Robinson is speaking today at the Long Now Foundation:
https://longnow.org/ideas/02021/11/10/climate-futures-beyond...
Just want to say that the Long Now speaker series has a bunch of interesting talks in their back catalogue.
They really, really do. They do a spectacular job of bringing in people who are at the vanguard without slipping over the edge, so to speak.
Two favorites from the last couple years: Mary Lou Jepsen talking about new modes of cheap, easy medical imaging and their potential impacts: https://longnow.org/seminars/02018/oct/29/toward-practical-t...
Michael Frachetti on the role of nomadic pastoralists in both generating and spreading knowledge along the historic silk roads: https://longnow.org/seminars/02018/feb/26/open-source-civili...
They’re really such a diverse group of speakers and subjects, and all of them have been really high quality and high value.
Two favorites from the last couple years: Mary Lou Jepsen talking about new modes of cheap, easy medical imaging and their potential impacts: https://longnow.org/seminars/02018/oct/29/toward-practical-t...
Michael Frachetti on the role of nomadic pastoralists in both generating and spreading knowledge along the historic silk roads: https://longnow.org/seminars/02018/feb/26/open-source-civili...
They’re really such a diverse group of speakers and subjects, and all of them have been really high quality and high value.
Agreed. They also do a great job of nerding out on a topic without getting so into the technical weeds that a mass audience can’t follow.
Found an excerpt of the first chapter for anyone interested: https://www.orbitbooks.net/orbit-excerpts/the-ministry-for-t...
It is kind of terrifying to realize that large portions of the third world are soon going to become so hot that it will be impossible to do any sort of physical exertion outside for large parts of the day without putting yourself at risk for heat stroke. That's at lower warming scenarios. At even higher temps it becomes damned near impossible to live without AC (which many in the third world don't have)
This opening is truly frightening.
presumably you mean sustained high wet-bulb temperatures? If I understand the concept correctly you can perform a wet-bulb measurement at any temperature, and a wet-bulb temperature of 10 Celsius is presumably not an issue.
This doesn't seem to be mentioned in the article, but an important related concept is delta-t, which is the dry-bulb temperature minus the wet-bulb temperature. It varies roughly inversely with relative humidity.
It's a particularly important metric for farmers/growers who use pesticide spray, as it influences the way the spray behaves when released from the applicator.
If the delta-t is too high, the spray droplets will evaporate too fast, before they land on the plant. Whereas if it's too low, it can remain in droplet form for too long, which can reduce plant uptake, and in combination with other factors (particularly thermal inversions and wind) can lead to spray drift onto other crops, which can be hugely damaging.
https://www.cropsmart.com.au/using-delta-t-for-assessing-spr...
It's a particularly important metric for farmers/growers who use pesticide spray, as it influences the way the spray behaves when released from the applicator.
If the delta-t is too high, the spray droplets will evaporate too fast, before they land on the plant. Whereas if it's too low, it can remain in droplet form for too long, which can reduce plant uptake, and in combination with other factors (particularly thermal inversions and wind) can lead to spray drift onto other crops, which can be hugely damaging.
https://www.cropsmart.com.au/using-delta-t-for-assessing-spr...
Dew point is another measure I like. I find the commonly reported form of humidity (relative humidity) to be the least useful.
Growing up, when the dew point hit 70, I knew it was going to be a miserable day, even if the relative humidity wasn't as high as other days (where the relative humidity was quite high because of a storm moving through)
Growing up, when the dew point hit 70, I knew it was going to be a miserable day, even if the relative humidity wasn't as high as other days (where the relative humidity was quite high because of a storm moving through)
I think the claim "Even heat-adapted people cannot carry out normal outdoor activities past a wet-bulb temperature of 32 °C (90 °F)" is dubious.
When I lived in Taipei, it would common to have 100F @ 100% RH in July/August and life/activity didn't suddenly stop because of it including people working outdoors. Now they may have modulated or changed how they worked outdoors but it's not absolutely so dire as this line claims. The reality of seeing that is self-evident proof is wrong. I'm wondering where this actually cites from...
When I lived in Taipei, it would common to have 100F @ 100% RH in July/August and life/activity didn't suddenly stop because of it including people working outdoors. Now they may have modulated or changed how they worked outdoors but it's not absolutely so dire as this line claims. The reality of seeing that is self-evident proof is wrong. I'm wondering where this actually cites from...
Obligatory psychrometric chart: [0]. I find it easier to understand how it's all interrelated using a chart.
[0]: https://en.wikipedia.org/wiki/Psychrometrics#Psychrometric_c...
[0]: https://en.wikipedia.org/wiki/Psychrometrics#Psychrometric_c...
This reminds me of swamp cooling. When I describe swamp cooling (evaporative cooling) to somebody who didn't grow up with it, it blows their mind.
They used to make swamp coolers that you would put in your car window and it would blow cool air into the car. I always thought those were really cool. Completely unpowered, no electricity. It's such a simple design compared to AC units.
Hah, I had the same reaction to setting up a siphon. That's for when you need to get a liquid up over a hump and down to a lower point.
You draw the liquid into a tube from the source [1] and drag the outlet to a lower point. Then, as if by magic, the higher pool gets sucked through the outlet until it's drained, without any mechanical pump.
https://en.wikipedia.org/wiki/Siphon
[1] you can do it by sucking it in like a straw, but there are less gross ways like using a flexible bottle to provide pumping action
You draw the liquid into a tube from the source [1] and drag the outlet to a lower point. Then, as if by magic, the higher pool gets sucked through the outlet until it's drained, without any mechanical pump.
https://en.wikipedia.org/wiki/Siphon
[1] you can do it by sucking it in like a straw, but there are less gross ways like using a flexible bottle to provide pumping action
Please describe it
You basically have a fan that sprays a very fine mist. The water evaporates, and in doing so the temperature of the air drops. Note that this only works when humidity is low enough for evaporation to actually happen. If the humidity is too high this doesn't work.
Edit: wiki goes in to way more detail about other methods I was not familiar with: https://en.wikipedia.org/wiki/Evaporative_cooler
Edit: wiki goes in to way more detail about other methods I was not familiar with: https://en.wikipedia.org/wiki/Evaporative_cooler
I dunno, I think that evaporation happens even if there is a lot of humidity in the air. The fastest (hottest) water molecules are going to escape the liquid water. The wind will carry them away.
I think this phenomenon does not take in account the wind. That actually if you have water to wet yourself and a fan you can cool you down.
Not sure though since I seem to be alone to think so.
I think this phenomenon does not take in account the wind. That actually if you have water to wet yourself and a fan you can cool you down.
Not sure though since I seem to be alone to think so.
You've repeated this take twice, but it is still wrong. Yes, the fastest water molecules on your skin escape. But you also have water from the air also latching onto your skin which you aren't accounting for. You're free to see how well evaporative cooling works when there is a lot of water in the air. You can just take a fan into a bathroom and run the hottest shower possible for a few minutes.
[deleted]
I live in Southwest US where it’s common to use a swamp cooler (aka evaporative cooler) for your house. Instead of the normal refrigerated air unit that sits outside your house, there is basically a box with a big fan that pulls air across a big wooden or synthetic “sponge” and pushes it into your house ducts. A small pump like in a fish tank continuously pulls water across the sponge to keep it wet. You leave a couple windows in your house cracked open to leave an exit as new cold air is pushed in. Has a nice humidifying effect which is good in the desert too!
I'm not sure of that.
If you wet your body (or clothes) and sit in front if a fan (or in the wind of there is some) you will cool down.
Why? The fastest molecules tend to jump out of the surface of the liquid water. The wind push them away. So the wind removes the hottest molecules. That's why you are cooler when it's windy.
This mechanism works at any temperature.
Am I wrong?
If you wet your body (or clothes) and sit in front if a fan (or in the wind of there is some) you will cool down.
Why? The fastest molecules tend to jump out of the surface of the liquid water. The wind push them away. So the wind removes the hottest molecules. That's why you are cooler when it's windy.
This mechanism works at any temperature.
Am I wrong?
You can only have a net outflow of water if the air is not saturated with water, which is a function of the air temperature. If it is saturated, a dynamic equilibrium will establish, where water molecules from the air jump back into the surface of the liquid film.
That's why a 100F day in Arizona (dry!) will be much more pleasant than a 100F day in Florida (humid!) - if it's dry, your body can still get rid of the heat. If it's humid, it will just 'stick to your body'.
That's why a 100F day in Arizona (dry!) will be much more pleasant than a 100F day in Florida (humid!) - if it's dry, your body can still get rid of the heat. If it's humid, it will just 'stick to your body'.
At equilibrium, water condenses as fast as it evaporates. So while the fan is blowing water molecules away from you, it’s also blowing water molecules toward you, which condense on your skin. Net heat transport would be zero.
The wet bulb temperature already takes this into account. If you wet your body and sit in front of a fan, your surface skin temperature will be very similar to the wet bulb temperature. Once you know the skin temperature, everything exterior to your body has already been taken into account and it's a question of how many watts of thermal energy can be transferred from your core to your skin.
When your body is warm (i.e. not trying to conserve heat by reducing circulation) then this is essentially linearly related to the difference between core temperature and skin temperature. When the wet bulb temperature is above 95F, then you create more thermal energy than can leave your body when your core is at 99F, so your core body temperature rises and all the bad things that go along with it progress.
When your body is warm (i.e. not trying to conserve heat by reducing circulation) then this is essentially linearly related to the difference between core temperature and skin temperature. When the wet bulb temperature is above 95F, then you create more thermal energy than can leave your body when your core is at 99F, so your core body temperature rises and all the bad things that go along with it progress.
Yes, you are, sort of. The wind will still cool you, but only down to the wet bulb temperature (that's sort of the definition of the wet bulb temperature). So you will no longer be able to keep your core temperature constant, it will rise to lethal levels.
Thanks for the explanation.
I'm still puzzled.
Reminds me of my Army days using the Wet Bulb device to obtain the "Flag" status.
Used a dry bulb, wet bulb, and a black bulb fed into a slide rule calculator to determine the heat index and thus working conditions.
http://www.wetglobe.com/
Used a dry bulb, wet bulb, and a black bulb fed into a slide rule calculator to determine the heat index and thus working conditions.
http://www.wetglobe.com/
Hi Everyone,
I am a researcher that studies the interface between human heat stress and climate change. I list some news articles I was involved in and some peer reviewed manuscripts I coauthored below.
Tw at ~35°C (95°F), what does this mean? Putting it terms that may be more relatable, like the NWS Heat Index: whether at low or high relative humidity, a 95°F Tw is ~160°F Heat Index. A Finnish sauna (dry) temperature is ~160-190°F. However, a steam sauna is usually between 90-120°F, aka Tw of 90-120°F. Generally, you do not want to be in a steam sauna for more than 20 minutes, because it will very likely kill you. But, you do sweat a lot, and that can be quite relaxing, for short periods of time.
Tw 35°C is extremely rare in the outdoor environment. Persian Gulf/Pakistan area, if they occur (the veracity of those measurements are difficult to confirm). What happens more often (although, still quite rare) is Tw of 32°C (89.6°F). Heat waves, such as the Chicago 1995 (>700 dead) or the Indian-Paksitan Heatwave of 2015 (>2500 dead) peaked at those temperatures. Humans cease being able to function/perform labor at 32°C (89.6°F) Tw, regardless of the air temperature or humidity. And this is the real concern we have a climate scientists. Wet bulb temperatures peaking for extended periods of time (>6 hours) rarely exceed 28°C (82.4°F) today.
But, the major work that’s come out recently (some of it mine, but is also verified by independent statisticians), is that global maximum Tw is tied to global mean surface temperatures, and scales readily with global mean changes. In the tropics, this change is reliably projected to be ~0.9°C (1.6°F) Tw per 1°C (1.8°F) of global warming.
So, you can do thought experiments. At what point of global warming will there be sustained (>6 hours) of Tw at 32°C (89.6°F)?
Current max Tw at >6 hours is 28°C in the tropics: Y = mx +b b = 28°C (today) Y = 32°C (future) m = 0.9°CTw / 1°C global T change x = (Y - b) / m X = ~4.4°C global T change.
32°C (future) = (0.9°CTw / 1°C global T change) 4.4°C global T change + 28°C (today)
4.4°C change in global temperature is equivalent to ~8°F of global change.
This is a lot of global warming. But, not unlikely, given our current trajectories. Our estimate of global change by 2100 is about +4°C (7.2°F).
Cheers, -Jonathan R. Buzan PhD Climate and Environmental Physics and Oeschger Centre for Climate Change Research University of Bern, Switzerland
Some News Articles: https://www.bbc.com/sport/olympics/57904094
https://www.theverge.com/2017/9/14/16290934/india-air-condit...
https://www.nytimes.com/2015/06/07/opinion/sunday/the-deadly...
Some Peer review manuscripts: https://iopscience.iop.org/article/10.1088/1748-9326/abeb9f
https://www.annualreviews.org/doi/abs/10.1146/annurev-earth-...
https://gmd.copernicus.org/articles/8/151/2015/
I am a researcher that studies the interface between human heat stress and climate change. I list some news articles I was involved in and some peer reviewed manuscripts I coauthored below.
Tw at ~35°C (95°F), what does this mean? Putting it terms that may be more relatable, like the NWS Heat Index: whether at low or high relative humidity, a 95°F Tw is ~160°F Heat Index. A Finnish sauna (dry) temperature is ~160-190°F. However, a steam sauna is usually between 90-120°F, aka Tw of 90-120°F. Generally, you do not want to be in a steam sauna for more than 20 minutes, because it will very likely kill you. But, you do sweat a lot, and that can be quite relaxing, for short periods of time.
Tw 35°C is extremely rare in the outdoor environment. Persian Gulf/Pakistan area, if they occur (the veracity of those measurements are difficult to confirm). What happens more often (although, still quite rare) is Tw of 32°C (89.6°F). Heat waves, such as the Chicago 1995 (>700 dead) or the Indian-Paksitan Heatwave of 2015 (>2500 dead) peaked at those temperatures. Humans cease being able to function/perform labor at 32°C (89.6°F) Tw, regardless of the air temperature or humidity. And this is the real concern we have a climate scientists. Wet bulb temperatures peaking for extended periods of time (>6 hours) rarely exceed 28°C (82.4°F) today.
But, the major work that’s come out recently (some of it mine, but is also verified by independent statisticians), is that global maximum Tw is tied to global mean surface temperatures, and scales readily with global mean changes. In the tropics, this change is reliably projected to be ~0.9°C (1.6°F) Tw per 1°C (1.8°F) of global warming.
So, you can do thought experiments. At what point of global warming will there be sustained (>6 hours) of Tw at 32°C (89.6°F)?
Current max Tw at >6 hours is 28°C in the tropics: Y = mx +b b = 28°C (today) Y = 32°C (future) m = 0.9°CTw / 1°C global T change x = (Y - b) / m X = ~4.4°C global T change.
32°C (future) = (0.9°CTw / 1°C global T change) 4.4°C global T change + 28°C (today)
4.4°C change in global temperature is equivalent to ~8°F of global change.
This is a lot of global warming. But, not unlikely, given our current trajectories. Our estimate of global change by 2100 is about +4°C (7.2°F).
Cheers, -Jonathan R. Buzan PhD Climate and Environmental Physics and Oeschger Centre for Climate Change Research University of Bern, Switzerland
Some News Articles: https://www.bbc.com/sport/olympics/57904094
https://www.theverge.com/2017/9/14/16290934/india-air-condit...
https://www.nytimes.com/2015/06/07/opinion/sunday/the-deadly...
Some Peer review manuscripts: https://iopscience.iop.org/article/10.1088/1748-9326/abeb9f
https://www.annualreviews.org/doi/abs/10.1146/annurev-earth-...
https://gmd.copernicus.org/articles/8/151/2015/
[deleted]
> A sustained wet-bulb temperature exceeding 35 °C (95 °F) is likely to be fatal even to fit and healthy people, unclothed in the shade next to a fan; at this temperature human bodies switch from shedding heat to the environment, to gaining heat from it.
The important thing is that passive/evaporative cooling simply stops working. In fact, sitting in front of a fan would actually speed up your death. You'll also die shockingly quickly (20 or so minutes, even for healthy, fit adults).
The only thing that can save you is:
- air conditioning
- getting in a cold tub
- going somewhere cooler (obviously) like a basement or parking structure
There are two thing that make this frightening:
1. We have already, for the first time in history, started seeing spikes of wet-bulb temperatures that exceed these values. Fortunately so far they have been in uninhabited areas.
2. If we ever see these temperatures in a city, odds are that the electrical grid would fail on account of the strain by A/C units.
So picture this: a heat wave of this magnitude hits a large city. Bangkok, Phoenix, Melbourne. It lasts for 48+ hours. The grid fails on account of the strain. We're looking at a mass casualty event with millions of dead in a matter of hours/days.