Human beings have built-in air conditioning. Your body can regulate its temperature, but only to a point. When temperatures rise above 35C, roughly body temperature, you sweat to cool down. However – That 35C is also a benchmark. If your body can’t keep your temperature below 35C, it’s in trouble. This means it can’t cool down and overheats.
Humidity is one of the deadly factors which can tip people over the limit. Most people loathe humid weather, with good reason. It does make it extremely difficult to cool down, and working in that sort of weather is murderously unpleasant. Any kind of exertion triggers heating.
There’s a very interesting explanation of how this works on Inverse.com, which explains the process in depth.
The good news so far is that even in massive heatwaves, getting into that condition isn’t easy to do. Most people can survive simply by sweating and reducing body temperature. The bad news is that cases of hitting this brick wall are becoming more common, and are raising obvious health risks.
Heatwaves and history
The big heatwaves of the last decades or so tell a very grim story. If you check out this list of heatwaves, you’ll see a range of patterns. One of those patterns is emerging large-scale heatwaves covering very large areas. This is the simplest way to define the heat risk factor for humans.
There’s another factor which isn’t as well-known, and it’s called residual heat. Air and physical objects don’t automatically lose heat or lose it rapidly in a hot ambient environment. The hot temperatures don’t “just go away”. Heat transfer is slower than usual. Temperatures remain high overnight, adding further physiological stress. Then the hot night becomes a hotter day.
This puts a lot of strain on heat regulation by the body. Losing sleep on ridiculously hot nights doesn’t help a lot, either, adding more physiological stress, and worse, reducing the effectiveness of sleep as a recovery method.
Sustained heat stress, therefore, is now statistically likely to become more common, more widespread, and last longer. The human body simply isn’t designed for this type of climate.
New risks for new generations
There are clear large-scale risks for the very young, in particular. It’s quite impossible to predict how abnormally high temperatures will impact the next generations, but there are clear risk factors.
Babies may well be on the wrong end of this situation. Immature physiology can be tricky enough without added risks, and how it reacts to extreme heat isn’t at all clear. The possibility of serious health damage to infants can’t be ignored. This is the age when things need to go right, and this new heat is a big possible risk.
According to the WHO, 166,000 people died worldwide from heatwaves in the years 1998-2017. To scale, with increasing populations, that number could go up drastically, and soon. The future is looking way too sunny.
there’s another issue – More heat means people need more water. Thanks to massive global maladministration of water supplies for decades, water must now be considered an existing high risk factor for future generations. This is just one example of the huge threats to future humanity posed by heat.
Good luck, kids. You’re going to need it. You might try some sanity, too. At the very least, it’d be a nice change.