https://ourworldindata.org/future-population-growth#the-world-is-reaching-peak-child

Lots of info

So here's the explanation, if you care to know.

Population growth is modeled with a "sigmoid function". These are a family of S-shaped curves. Specifically, population is modeled with a logistic function. The characteristics that make these curves useful for modeling and prediction are:

- Growth grows exponentially at inception

- There is an inflection point at which growth slows

- Beyond the inflection point, growth declines exponentially

- There is an asymptotic limit.

- The period of increasing growth and the period of declining growth are symmetric with the logistic function. Other sigmoid curves allow asymmetric patterns.

- S curves are ideal for modelling growth, because they are distinguished by four phases: initiation, contagion, maturity, and terminal limit.

Because of the exponential growth/decline, sigmoids are non-linear. And the non-linearity makes it very, very difficult to predict the inflection point. This is important, because once you know the inflection point, the asymptotic limit can be predicted. To give an example of where this sort of modelling can lead to controversy, consider Covid. Disease progression also follows a logistic pattern. Early in the pandemic, you saw death predictions of varying magnitude, from as low as half a million to as much as 2.5 million. This doesn't indicate that the science was poor just that the confidence interval is enormous during the "contagion stage". Covid followed well-understood patterns of growth, but contagion prediction can't be precise.

With the argument presented in the linked article, the author's source predicts we are close to "peak children." Maybe we are, but you won't know that until we're there. Predicting the asymptote before the inflection point is reached is a dicey proposition.

This method of modeling human growth was popularized from the US Census Bureau's attempts to model US population growth. Prior to 1950, it followed a perfect logistic curve. But the problem is that human behavior isn't all that predictable. Around 1950, the post-war baby boom was in full swing, transportation preference shifted from boats to planes, and immigration patterns changed. So rather than an inflection point, 1950 was the start of another upward swing. Forecasts are difficult, especially about the future.

Seriously, i'm in awe. Your brain has more wrinkles than mine. I've always liked to work with people that know more than I do about a subject and could explain it well.

I think the part about population growth that bothers me most is the consumption of natural resources is ever increasing.

Not sure which site I was reading, but it said that the U.S.A. would need five earths to satisfy the demand for resources. I believe it said India would need .8 earths.

The one thing that always surprises me about the world population is that it doubled between the early 1970’s and now. 50 years isn’t exactly a short period of time, but adding 4 billion over that time period just seems wild.

And it will take even less time to double yet again.

__________________
"It's hard to win an argument with a smart person, but it's damn near impossible to win an argument with a stupid person" - Bill Murray

Eat , sleep , Frank , we’re having a baby .