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Comment by mikorym | Hacker News Reader

> the human population growing exponentially

This is not true as of 2019. The only continent that possibly does not show logistic growth (yet) is Africa. [1]

[1] https://en.wikipedia.org/wiki/Population_growth#/media/File:...

Those are gently flattening lines on a logarithmic scale. No, growth is no longer exponential, but it’s still greater than linear.

While it’s likely true that we will end up with a sigmoid curve, population is still growing at a high rate

A high rate?

Population in the world is currently (2019-2020) growing at a rate of around 1.08% per year.

https://www.worldometers.info/world-population/

By the rule of 72, that's doubling in 66 years. Under a lifetime seems to qualify as high.

That's a 108% increase in a century, which is a relatively short time in historical terms. Imagine the damage to the planet with double the current human population. This could be around the corner, historically speaking.

Err, no it isn't, it's 100% in approximately 66 years. It's compounded growth.

See https://en.wikipedia.org/wiki/Rule_of_72

The source I provided shows that the growth rate has been consistently dropping. In 2015,2016,2017,2018 it was 1.19,1.14,1.12,1.10

Not sure you can extrapolate out 100 (or 66) years when there's been a 0.11% (1.19 -> 1.08) change in the growth rate in just the last 5 years.

It still sounds pretty bad, like doubling the current population or close to that in 100 years. If not 100, make it 150 or 200 it's still not much on historical terms.

With modern medicine, modern agriculture and the tendency to reduce warfare around the world, there is no reason to believe the growth will stop, by the contrary.

I think you've misunderstood the change in growth rate. It has dropped from 1.19% to 1.08% growth in the last five years or down 0.11%. If this trend held in the next five years it would drop to 0.97% growth by 2024 and in ~50 years it would be 0% growth, ie the population would stabilize.

That's exponential.

Indeed! One has got to appreciate how words in the English language are not always (read: never) the best way to describe math.

By the way, this reminds of the series 1/n^s and the fact that the sum converges exactly for s > 1, but diverges for 1/n. Personally, I prefer to call the latter s = 1 case the infinite pizza series, since it can ensure that you have free pizza for the rest of your life by choosing an interval for n large enough to be ~1 in the sum; every day.

And by the way again, this is also the Riemann Zeta! [1]

[1] Provided that complex exponentiation is explained to you in a way that doesn't lead the same sensational misgivings written about Heisenberg uncertainty in Medium articles...

Oh yeah and more more thing: 1% on it's own is exponential, but the key fact is that in logistic growth the exponential factor (or rather compound factor) goes down over time... much like changing the s over time in the above example of 1/n^s.

The logarithmic scale is not a problem. I did not say linear; I said logistic.

On a logarithmic scale, an exponential function is linear, making the test easy!

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