Optimal Earth temperature

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I’m sure by now you have at least heard of Global Warming.

Many people disagree exactly on what is global warming, or climate change. But most people agree that it exists in some form, regardless of whether it is a problem or not.

I drew this little chart (not to scale) that should convince everyone that uncontrolled global warming will eventually kill us all.

So we definitely have a good reason to stop global warming before we reach the death zone. After all, I assume none of you are particularly fond of melting instantly when you step outside of your AC-cooled house.

But if we manage to stop global warming and fix it in some way. Whether it is by stopping all bad emissions, or by using some technological means to cool down the Earth, there is still a risk. I drew a little chart (not to scale) demonstrating this.

So we have to be careful with cooling down too. There is also a death zone on that side, and it is pretty deadly too.

Now you’re probably saying “I get it, change is bad, let’s all go brag about our conservative beliefs and march against any kind of change whatsoever.” I won’t tell you what to do during your free time, but that was not my point.

Imagine you are driving on an highway. If you accelerate to 600 Km/h somehow, you will most likely die in a violent accident. If you suddenly brake when you were going 100 Km/h, you will probably cause an accident, and you may or may not die in it. If you brake then instantly start going backwards, what the hell is wrong with you?

But if you go slightly faster, let’s say 105 instead of 100, you might reach your destination several minutes earlier. On the other hand, if you go 95 instead of 100, you might have an extra valuable second to react to unexpected events, and in some rare cases this could prevent an accident. neither of these decisions will instantly kill you, and they both have upsides and downsides.

According to science, Earth’s temperature is extremely vulnerable to change. Lowering the temperature 10 degrees could be enough to trigger an ice age. Even just a few degrees of difference could have catastrophic consequences. The death zones in my charts above are probably a lot wider than I drew them.

But we still have some range to move.

My point is not that global warming is irrelevant because we can go slightly warmer and survive. My point is not that considering the proximity of the death zones we should do everything in our power to stop climate change. You and I both know I won’t change your mind today, so you keep believing what you want and we’ll both be happier.

But let’s say that 200 years from now, we successfully obtained control over global temperature somehow. We stopped the threat of too much warming or too much cooling, but we are still able to tweak it. Maybe 1 degree hotter would have the effect of the average person being in better physical shape (many sports are played outside!). Maybe, on the other hand, people would wage more wars because the climate is more tolerant to sleeping outside and fighting day and night.

Maybe 1 degree cooler would make people reproduce more, since they would stay inside more. Maybe 1 degree cooler would kill part of the homeless population, or raise consumption of food while lowering farm output.

Within this “we can stay alive” range, there are a large number of temperatures, which all have their strengths and weaknesses. One of those temperatures if most likely optimal for human survival. Another one is optimal for human productivity. Another is optimal for human intelligence, or physical fitness, or kindness, etc.

But all those optimal temperatures are definitely not the same one. We’d have to choose.

What’s better between avoiding the most deaths and birthing the most babies? What’s better between being as smart as possible or being as happy as possible? What temperature makes people more likely to pull the lever?

If we had control over global temperature somehow, imagine we can set a earth thermostat somehow, and within 5 years average temperature is changed to what we chose, and we had done the necessary studies to know the optimal temperature, within our staying alive range, for any criteria you could possibly have, what would guide your choice?

You would, of course, have to keep in mind that as every facet of human society would have an optimal temperature, some would depend a lot more on it than others. The ability to grow food has an optimal temperature, and changing it would have a huge effect, while our ability to solve rubik’s cubes also probably have an optimal temperature, but switching it up or down a bit would probably make a very small, if noticeable, difference. So you not only have to take into account your priorities as to what’s good for humans, but also what is worth it. If you can slightly reduce (<5%) world hunger, at the expense of creating 60% more armed conflicts, it might not be worth it.

There are also some temperatrues that would be in our death zone, but allow many animals to still survive and even thrive. I doubt the ideal temperature for penguins is the same as ours. Some nihilistic or very cynical people might say that the criteria should depend on animals or nature more than it depends on humans. That’s allowed too, of course, but I happen to think that if they wanted to choose the temperature, they should have invented the tech first.

  • Kingfisher

    For the sake of simplicity, let’s assume that we’ve got the science and technology to set a global average temperature and keep it there, it’s not going to spark a natural feedback loop that results in runaway cooling or heating.

    But even if we’ve got such advanced technology, I think the right answer is always about robustness. How many variables outside out control can we absorb before we lose control completely. There might be an ‘optimum’ point for any definition we choose that sits on a razors edge, where the very best temperature sits right next to “We’re all dead”. That’s not a very good place to be.

    So in that case, I think the best way to go about it is to figure out exactly where the “All Dead” threshold is in both directions, and pick a point close to right between those two thresholds.

    I think (I am not saying this is correct), that this middle temperature is one where there are some glaciers, and some frost-free regions both in the temperate regions between the tropics and the arctic zones. My understanding is that this range isn’t actually very big.