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.
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.
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.
https://www.currentresults.com/Yearly-Weather/USA/AZ/Phoenix...
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.
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.
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.
I do not have a good feeling about this!
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.
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.
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?
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'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 wonder how long a fridge-sized freezer filled with water and then frozen could keep you alive in such a heatwave.
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.
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...
- 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!
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.
I think this stuff only happens in absence of wind...
(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.
> 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.