A wet bulb event, occuring over multiple hours, would be that signal. Piles of dead bodies from folks who either were misinformed or weren't able to move to safety would be quite the wake up call.
With these wet bulb events and the breathless death counts in the media people get the impression that heat waves are bigger killers than cold winters, when it's the opposite (and if you include indirect and long-term deaths by an order of magnitude).
There are also some serious and well connected organizations advancing plans that I can only see as attempted mass murder. If your plan projects no cargo ships by 2035 you will kill millions from the fragility of food supply chains alone.
If you want to reduce fertilizer use, fine. Better targeting and smarter application can reduce the consumption by at least 30%. But if you want to use no fertilizer you will kill billions.
Even the more grounded and non-murderous proposals have some serious question marks. Electrify almost all energy use by running 300% overproduction of renewables, to be stored in batteries and pump storage that isn't even planned yet while at the same time increasing electricity demand by 400%? Yea sure that will get done in 30 years, no problem.
The climate doomers always insist that the extinction event will be caused by climate change destroying food supply. But crops can be bred, new areas can be cultivated and ressource use reduced. The fact that 6 billion of us only exists thanks to chemical fertilizer, mechanized agriculture and amazing seed variants is not open to argument though.
The Republican Party just held their first primary debate among the presidential candidates. They were asked about climate change and only one of them was willing to recognize it as a problem, and my understanding is that she directed action towards China and India. The candidate leading the pack, Trump, was not present, but has called Climate Change a Chinese hoax.
If you are not encountering people like this in real life, you are living in a bubble yourself.
A wet bulb event is a period of complete local inhabitability due to the temperature/humidity rising above the threshold where the human body can cool itself by sweating. These events are so far almost unheard of.
Anyone who is in the affected area during such an event would only survive if they had air conditioning and uninterrupted power. Anybody without AC would die, unless they found some non-evaporative way to cool themselves.
It’s the most terrifying natural disaster conceivable.
Could you survive in a basement?
Keep in mind that we're now seeing sea surface temperatures above 38°C (100°F).
If the river itself is slow-moving and is in an area of prolonged heat, it will also be warm.
The areas most prone to high temperatures often also have little surface water, or at least, not enough to shelter all persons affected.
Water refuges being too warm for human survival is an early plot point in Kim Stanley Robinson's Ministry for the Future.
Note that for a small poorly-ventilated basement, the humidity will rise from respiration, thus increasing the wet-bulb temperature. For a well-ventilated basement, the air temperature will approach the outdoor temperature, thus increasing the wet-bulb temperature.
If you have a giant, well-shaded, pool of water, the water temperature will usually be below the peak air temperature (water has high thermal mass, so it will take a long time for it to come up to the ambient temperature, even at high humidity, where evaporation effects are negligible) so that's another non-AC method of staying cool.
In any event pools of water and basements don't scale to densely populated areas.
Couldn't you just eat ice to keep cool? Heat from blood transfers to the ice as it melts and warms in the stomach, then it leaves the body completely through urination.
Similarly you could put a giant block of ice in front of a fan and sit there; most people would call this a from of AC though.
A ton of cooling being defined as 12000 BTU/hr, or the rate implied by the latent heat of fusion of 1 ton of ice at 0°C being consumed via melting over 24 hours.
It won't. People you are talking about have access to air conditioning. They will not care about people dying in distant places, whom become an annoyance after a while. They will just wish people die silently without complaining.
In 2003, 70,000 people died in the EU from a heat wave [1]. A fact that is never really comes up in talks about climate change.
The death toll could be millions and we'd still see deniers clamoring that we need to burn more coal for grid stability or whatever.
[1] https://www.france24.com/en/environment/20230717-parisians-a...
Obviously there's a limit, but based on the data about lives lost due to cold vs. warm temps, we should expect increased global temps to first save human lives since a lot more people freeze to death.
> "This was 10 days [with temperatures reaching] 90 degrees at street level and 90 percent humidity, with temperatures not even dropping at night,"
https://www.npr.org/2010/08/11/129127924/the-heat-wave-of-18...
It wasn't necessarily a wake-up call then. But it may have at least been the crisis that spurred one guy...
Seems like in this case most of the mortality was due to young men who had no choice but to work in those conditions. This event, among many other work-related disasters of the time, probably helped spur the push for better working conditions during the Progressive Era.
It’s not THAT hard to cool down even if you’re incapable of sweating to do so. People aren’t idiots either. Despite imaginations of cultural hubris, people can tell when it’s deathly, disgustingly hot, and do not casually tank it until they die. And even if they did, they’re not idiots. If one person collapses, they’re not going to ignore them and continue to assume the heat is negligible. You don’t have to realize the nuances of your circumstances and the probability of death to understand that you are intolerably uncomfortable.
Yes of course heat waves are bad and can kill people. But wet bulb events are not a magic threshold that completely change the game.
How would you recommend cooling down for hundreds of thousands of people at a time? I have to assume that those affected wouldn't have easy access to AC.
However there is a limit to how long you can live in the bath.
You also have to worry about power when it comes to having access to sufficient water to cool a person in the first place.
Hence mentioning a bath tub.
Some interesting reading to go along with this topic:
https://ntrs.nasa.gov/api/citations/19750007244/downloads/19...
Of particular note is the need to remove about 1k BTU/hour when walking/doing light work, and that's only from metabolic heat generation.
And 1 BTU raises 1 pint of water 1 degree, so 1k BTU/hour would raise 5 gallons of water by an unrealistic 25° every hour.
Can you survive wet bulb temperatures given a bucket of water indefinitely? No. Can you survive working hard labor with the water bucket? No. Can you survive wet bulb events significantly higher than the threshold? No.
Can you survive several hours in a typical (current typical) wet bulb event? Yes, definitely. Bucket of water is fine.
I'm going to vote maybe. At best, it'll be close.
Resting metabolic output is about half the active value I provided (per NASA's PDF). That means for a bucket of water that starts at 32°, you have 5 hours before the bucket is also 95° if you discount ambient heating from the air, circulatory constriction, and assuming no prior conditions.
Since you can't discount those (and are unlikely to find barely-not-frozen water for an entire city's population), survival for more than an hour or two is nowhere near guaranteed.
Does that pass your personal sniff test for reasonability? Have you ever soaked in a 104°F (40°C) hot tub for an hour or more? Was your survival in serious doubt?
Wet bulb temperatures in excess of 35°C need to persist for around 6 hours to represent a serious hyperthermia risk. This is not a "you will die inside of 1-2 hours" scenario.
There's no need for the bath. The shower will probably work better actually since it's constantly disposed down the drain after picking up some heat, and replenished with subterranean-temp fresh water running across your person.
The point to take away is that humidity matters in addition to raw temperatures. Not that there is a specific threshold at which things matter or didn’t matter.
In some countries electricity becomes unavailable quite regularly, so relying on A/C during a crisis like that might fail. And that is assuming that A/Cs are common (they are not, in large parts of the world).
Cooling yourself down by using water from a tap may also fail, if, in such a situation, everyone in a city tries to do that. You are assuming a very high level of infrastructure and no critical failures.
Heatwaves and infrastructure failures can undoubtedly be serious threats. But the vast, vast majority of people survive wet bulb events when they encounter them.
That's maybe 2 hours of cooling per person and it's not at all obvious that during such a heat event that you'll have access to a continued source of 70°F/21°C water. If you only have access to 82°F/28°C water, 5 gallons only lasts you an hour or less.
If this imaginary graph has an inflection point, I can't think of a better one.
Also, IMO most of deaths will come from decimation of food crops brought on by climate change induced 'weather randomization'. our world currently is super optimized for supporting 8B people. any one of the optimizations in the chain fail and we wont be able to easily recover. when multiple fail realistically the world economy sill settle into a non-globalized setup. that will support far fewer people than exist today.
I know you threw babies in here but it feels like I have to point out that the old and sickly dying have a negligible effect on man years lost.
> Also, IMO most of deaths will come from decimation of food crops brought on by climate change induced 'weather randomization'. our world currently is super optimized for supporting 8B people. any one of the optimizations in the chain fail and we wont be able to easily recover. when multiple fail realistically the world economy sill settle into a non-globalized setup. that will support far fewer people than exist today.
I don’t really agree that the world is as fragile as you propose. But I feel like need to clarify that I’m not arguing against the threat posed by climate change broadly.
I live in the Chicago area, and in the winter working from my heated home and traveling between heated places in my heated car, it's sometimes possible to forget how uninhabitable it is outside! But you need to carry emergency jackets and other things in the car in case it breaks down and you lose your climate control. And I remember how scary it was when my furnace broke during a winter cold snap!
In the hot climates, we cool our spaces, but in the process we pump extra heat outside, making it warmer when it's already too warm.
I'm not sure it'd look like the "bodies in the street" image GP likes to call up, but yes, a prolonged wet bulb event would result in mass casualties.
All that's needed is an intersection of high-humidity heat wave + densely populated area + extended power outage.
And/or too few buildings that have A/C or other places to escape the heat like swimming pools, metro tunnels or whatever.
Probably more likely to occur in less-developed areas like India or Africa. But regardless, could happen in many places. Just a few degrees might be the difference between 1000s or 100k+ deaths.
That said, in more general terms, this is a relatively new concern for many people, even in Texas or Arizona, where these wet bulb events were rare. All told, I can understand how people really don't grok it because 10+ years ago, they could keep working in the heat taking relatively simple precautions.
However since 2021 web bulb events have been increasing in regularity and many models suggest that starting this year and going forward, these extreme heat events are going to become the norm, with increasing intensity, making this a permanent concern now. This makes a lot of simple previous precautions folks take less effective or even worthless.
Hundreds of deaths in a single day will lead to... nothing. Same politicians will be voted in and the deaths will just be counted as the price of freedom
I have been surprised by the resilience of the grid this summer. Thank god for solar.
"It has been thought that a sustained wet-bulb temperature exceeding 35 °C (95 °F)—given the body's requirement to maintain a core temperature of about 37°C—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"
Even if you are the fittest, healthiest human being alive, standing in the shade in a thorough breeze, your core body temperature can only go up. Let it go up, and you get heatstroke and eventually death. And if you're not the fittest, healthiest being alive, or not standing in the shade? It's only going to go up faster, and heatstroke and death will beckon much sooner.
"Wet bulb events" are, in short, when "no A/C means outdoors = death"