Humans cannot long survive above certain temperatures because the body becomes incapable of dissipating heat above body temperature. We die of hyperthermia as the body temperature elevates and stays there, causing heat stroke and destroying our organs. I can vouch that being just temporarily overheated and unable to cool down is very uncomfortable.
The temperature at which we will die depends on the humidity and the length of time we are exposed to it. If we experience 122˚F at moderate humidity of 10%-25%, we will probably die after two or more days. That is why thousands of people, shut-in elderly people in particular, died during the European heat wave of 2007. They were often found at home with all windows closed and no air conditioning or fan, which elevated the temperature even further. It’s also why so many people die in the Mexican and American deserts while desperately trying to reach El Norte.
The temperature at which we will die
depends on the humidity and
the length of time we are exposed to it.
People can and do live at temperatures approaching the intolerable. I have experienced temperature of about 115˚F in Fez, Morocco. I found it tolerable for a day, since humidity was very low. But I would never have been able to sleep, and I found it necessary to drink water nearly continuously, which never generated a drop of urine. Without this constant water I would have quickly dehydrated and my body temperature would have risen, after which my life could only have been saved by intravenous saline. Once seriously dehydrated, I could not restore body fluids by drinking.
Death Valley, CA holds the record for the highest directly recorded temperature, at 134˚F. A number of other places have had temperatures up to 154˚F, recorded from space. There are a dozen or so cities in the US that experience at least several days a year at 100˚F or higher. Phoenix always leads such lists, with over 100 days 99˚F or higher every year. The summer heat wave of 2012 afflicted a large part of the US. Temperatures in some places stayed well above 100˚F for days, or even weeks. Some 82 deaths were recorded.
None of the accumulated data
suggests anything other than
continuous planet-wide warming.
Now, what can we expect from global warming? We could be optimistic, and believe as climate skeptics do, that there is no such thing. Temperature records show more-or-less constant temperatures for some time, after all. This hiatus is taken as proof positive by climate change deniers that they are right, “the greatest fraud in world history”, according to one congressional fool. We should be so lucky.
Unfortunately, there is a vast accumulation of climate data, including explanations of the warming hiatus, and virtually none of it suggests anything other than continuous long-term planet-wide warming. The Greenland and Antarctica ice sheets are melting at twice the rate of five years ago. In the US it is probable that our temperatures will increase by at least 4 or 5˚F by 2100. The arctic will increase about 8 degrees, and record loss of sea ice at both poles is readily observable fact. This cannot but spell disaster for the entire planet, not only because of the heat itself, but because the change in heat will have—and is already having—radical effects on living things.
In the US,
temperatures will probably increase
by at least 4 or 5˚F by 2100.
Consider what this warming will mean in future heat waves. Places that have experienced long periods above 100˚F, such as Oklahoma, which had several weeks of it two years ago, will now have periods that are 4-5 degrees hotter than before, and maybe longer as well. Places that stood at 112˚F for a week will be at 116˚F. That’s what I experienced in Fez, that required near constant water intake. But recall that this was at very low humidity, and humidity in the US is typically at least 10% higher and less tolerable. That means people will simply not be able to survive without constant water intake and artificial ways to cool the body.
Also unfortunately, each new climate report brings only worse news. We are approaching half a dozen tipping points, each one of which will potentially create accelerating conditions that cannot be reversed. The loss of sea ice is one of the most obvious. Loss of reflective ice cover creates a feedback loop as the open water absorbs the heat the ice no longer reflects. This, in turn, causes temperature increase everywhere. This means warmer water, and warmer water increases in volume. The scariest ice condition, however, is Greenland. The ice melt is continually increasing. If it reaches a tipping point, as eventually seems likely, it will by itself add 22 feet to ocean depth. Vast areas of coastal land everywhere would be under water, and major storm crests would be twenty to thirty feet deeper than the current sea level.
We are approaching half a dozen tipping points.
Glacier and other ice has been melting at rates not seen for tens of thousands of years. Photos of literally every glacier on earth show radical retreat compared to historic photos. Kilimanjaro, Everest, and numerous other mountain peaks are becoming bald, bereft of snow. Permafrost is melting. Low islands flood with every high tide. Coastal cities find seawater in their streets. Today. These are things we can see.
We animals, as we have seen, cannot long survive in temperatures much above those we evolved to tolerate. We humans are ingenious animals, though, and will devise ways to survive even high temperatures. But we must remember that high temperatures will be only one of our new problems, and there are over seven billion of us, with an additional three billion expected by century’s end. Out of control warming would eventually melt all ice, covering the planet with an extra 65 feet of water—well inland everywhere.
All human life will perish
when temperatures stand at 125˚F.
Long before that happened, the hot places would no longer support animal life. These temperatures already exist in the hottest places on the planet, which can reach 154˚F. High temperatures will become increasingly common in hot US cities like Phoenix, and all of them will eventually not support life. People would move en masse inland from flooded coastal areas, and northward from hot desert areas. They would find little relief, because the heat will move northward too. They will seek higher elevations, which are cooler, but less supportive of human life. Where would we all go?
If the temperature march isn’t checked by some as yet unknown mechanism (perhaps greatly increased reflective cloud cover?), temperatures everywhere in the world will at some point top 125˚F, and all animal life will die, including every human. This is the future we are flirting with in a couple of centuries. It’s no joke.