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Comment by ashoeafoot | Hacker News Reader

I wonder what adaptions humans could develop to survive overheating in a wet bulb szenario. Some thermal shutdown of metabolism or almost all muscles could make those temperatures surviveable?

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Bergmann’s rule: animals in colder climates have larger bodies than members of the same species (or subspecies) in warmer climates.

Allen’s rule: limb lengths vary according to climate. Limbs are longer in warmer climates.

Both rules observed in human populations over time.

https://en.wikipedia.org/wiki/Cold_and_heat_adaptations_in_h...

Low hanging fruit probably would be smaller body sizes, and early onset baldness in both sexes.

I expect housing & behavioral adaptations would carry the most weight. E.g. you'd want to dig a basement in a moderate weather season, so you'll have somewhere survivable in the hot season. And of course have redundant backup power for A/C if you can afford it.

Some of the adaptations camels use could theoretically be useful, like dropping temperature at night & letting it rise throughout the day, tolerating higher temps overall, etc. But I doubt there's time for humans to naturally evolve those abilities very far in the next several thousand years.

The only thing to do is hvac management. We don’t have enough time to accumulate sufficient favorable mutations across the population given the speed we are affecting the earths climate.

Migrating north (or south, in the southern hemisphere). Which is going to increasingly collide with the man-made borders preventing people from doing so.

This is in the back of my mind as my spouse and I ponder emigration.

Many orders of magnitude too few time to adapt naturally to the coming climate crash.

This is wrong thinking about evolution. The potentially beneficial mutations are already out there in the population. They gain dominance in the population after a large die-off of folks who don't have them and the remaining survivors reproduce.

Yeah but the selection for who survives is going to be based not on a specific gene, but on membership in the group with the will and power to kill for the remaining arable land.

The selection is going to be based on wealth, not on genes.

That's pretty much it yes.

Wealth as an abstraction can fall apart too

Not all potential traits are going to be present in the population. If this were true nothing would go extinct as there would be enough diversity in this theoretical population to see some individuals with the right combination of traits.

It it somewhat more likely to happen when you have say a flask of bacteria where they grow logarithmically by the hour in terms of generational time and have much simpler single cell systems vs us poor multicellular well differentiated humans that are waiting until our thirties when reproductive systems start failing to have our 0.6 kids or whatever the rate is in western countries where diversity is already quite low due to a lack of significant african demography in most populations out of africa. Even in places with significant african background population numbers, social history means these alleles have not yet dispersed across the population homogeneously and are maintained in their demographic subset.

I think given the option of a mass die-off, and moving into your still-habitable back yard, most people would take the latter.

Do thinner people fare better than obese people?

Based on my experience gaining and losing weight and the amount I sweat when I'm heavier, I'd guess yes.

Square cube law would say so. The more surface area per volume to dissipate heat the better.

The inverse can be seen in arctic animals that are basically baubles to conserve heat.

Not a genetic adaptation like OP is considering, but if you're a big westerner and spend a lot of time in a tropical country you're likely to lose weight.

Edit: tried to find some peer reviewed evidence to back up my anecdote but came away empty handed. Still i stand by my claim. :)

Evolution will select for humans intelligent enough to buy air conditioners.

Do air conditioners matter if you don't have crops or livestock?

See the CO2 fertilization effect:

https://en.wikipedia.org/wiki/CO2_fertilization_effect

What about rain and temperature?

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