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patman_007 t1_jdy7x7i wrote

Reply to comment by mperklin in Estimates suggest population growth rate to peak at 8.6 billion by madrid987

Is this not saying that the rate in which our population increases will peak roughly around the time we have 8.6 billion people? And would the rate not be annually?

Obviously the population won't pull a 180 and immediately start shrinking. It will start to grow at a slower rate until the growth rate slows into a decline...

I swear some people just have to be edgy and controversial.

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GetOffMyLawn1729 t1_jdyimvu wrote

no, that is what the headline says, but the first sentence in the article reads "A new projection of the population growth rate highlights that the world’s population could peak at 8.5 billion people by 2050, and decline to 7 billion in 2100".

The person writing the headline is an idiot made a very basic mistake. As others have said, at the point the population reaches its maximum, the rate of change will be 0.

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patman_007 t1_jdzxfql wrote

The article flips back and forth. But looking at some other info it is the population that will peak, not the growth rate.

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turd_vinegar t1_je0t6kh wrote

Growth rate should peak and decline before population peaks. Unless there is some cataclysmic event that drives it down suddenly, like a nuclear war.

Someone could argue that there is a time interval that when tracked in nano seconds displays a sudden drop in growth rate before those hypothetical millions perished, but this is more pedantic than practical and wouldn't give much insight into how society was changing at that time.

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turd_vinegar t1_je0s54q wrote

There is a discrete aspect both in time and in number of humans (not to mention non-linearities to rates due to catastrophes) so it might not be exactly 0 over some time interval, but yes, there should be some identifiable relative maxima in population near rate ~0.

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Mydickradiates t1_je4rkne wrote

I don't know, the word highlights means the growth rate is implied resulting in the peak count of 8.5 billion people. I think you people are being super picky

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mperklin t1_jdy8ccw wrote

No, because if the population tops out at 8.6 billion people then the growth rate is 0 (which is not the peak/highest value)

The population may peak at 8.6 Billion, though.

…

^”Ackshually”

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ExoticSalamander4 t1_jdyj0u4 wrote

This is directly analogous to physics

Population is displacement

Growth rate is velocity

Growth rate peaking means acceleration is 0

So the article *title says acceleration will have fallen to zero by the time displacement is 8.6 billion

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SrpskaZemlja t1_jdz9k83 wrote

You have it off when you're bringing acceleration into this.

That would be the rate of change of the rate of change of population. Aka the rate at which the growth rate itself changes.

This article, beyond the bungled headline, says population will peak at 8.6 billion people.

When the amount of people stops rising and begins falling, at that moment, the growth rate is zero. The headline is totally screwed up and conflicts with the article.

There's no point anywhere here where a second derivative (acceleration) is brought in.

EDIT: Really, downvotes? You guys aren't even gonna try to tell me my math is wrong?

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quokka70 t1_je3hkp5 wrote

You are right. The article is saying that the population will peak in 2050, although its headline, which is gibberish, mentions the growth rate peaking, which is what u/ExoticSalamander4 was talking about.

Many years ago I heard a TV reporter say that inflation was accelerating at an increasing rate of speed. I'm not sure how many derivatives that is, but almost certainly more than intended.

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SrpskaZemlja t1_je3hvip wrote

Relevant funny Wikipedia excerpt:

"When campaigning for a second term in office, U.S. President Richard Nixon announced that the rate of increase of inflation was decreasing, which has been noted as "the first time a sitting president used the third derivative to advance his case for reelection."[2] Since inflation is itself a derivative—the rate at which the purchasing power of money decreases—then the rate of increase of inflation is the derivative of inflation, opposite in sign to the second time derivative of the purchasing power of money. Stating that a function is decreasing is equivalent to stating that its derivative is negative, so Nixon's statement is that the second derivative of inflation is negative, and so the third derivative of purchasing power is positive.

Nixon's statement allowed for the rate of inflation to increase, however, so his statement was not as indicative of stable prices as it sounds."

https://en.m.wikipedia.org/wiki/Third_derivative

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SometimesaGirl- t1_je078rz wrote

> The population may peak at 8.6 Billion, though.

I doubt it. The population of parts of Africa (Nigeria for example) is set to quadruple over the next decade or so.
The counterbalance is Europe + China declining. Both (largely) regions where religion has little sway over the population and birth control and the command of go forth and multiply are meaningless.
Now... getting back to Africa...
Oh, shit.

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patman_007 t1_jdy8onm wrote

But the growth rate won't immediately decline to 0 or a negative. It will first rise, then peak, then slow then reverse. And that peak will be at roughly 8.6 billion people....

This isn't saying our population will max out at 8.6 billion.

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SrpskaZemlja t1_jdz967u wrote

But the article is saying the population will max out at 8.6 billion. The headline was written wrong, as the article clearly goes on to say that our population will peak at 8.6 billion.

When you reach the peak of the amount of something over time, at that moment your growth rate is zero. That is not only common sense but also basic calculus.

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patman_007 t1_jdzwlm4 wrote

I'm chalking this to the author not understanding what they were writing. Because if you read the article they flip back and forth between stating the growth rate will peak at that population marker, followed by that the population itself will peaked then. And those are two totally seperate peaks, honestly don't think they could predict the highest possible population that would be harder to determine. NOW, looking through some other info it does appear it is the population that peaks around 8.6 billion.

You need to restudy calculus. Because that's exactly what my point is derived from - see what I did there?? The growth peak will not be the same time as the growth rate peak ( a secondary difference). The growth rate will peak, and THEN when the growth rate hits 1 to 1 the population will begin to decline.

What your stating would be true if humans had kids on a 1:1 ratio, but if the population growth rate peaks at 4 children per 2 adults than there will be a period of time when the growth rate declines from 4 children per to 2 children per and that will still see an increase in population, even post peak growth rate.

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spovax t1_jdya49r wrote

You are correct. The growth rate could peak when the population is 8.9B. Odd thing to point out.

Too lazy to read the article, but I assume they’re saying population growth will stop and the population will be 8.9 billion at the top.

Just because the peak is a growth rate doesn’t mean we can’t reference other numbers at the same time. I realize I’m being nitpicky, but so is the dumbass above you who’s being nitpicky.

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patman_007 t1_jdyb9x8 wrote

No, they're saying the rate at which the population will grow will peak at 8.6 billion people LMAO. It will continue to grow for a bit after, but just at a smaller rate. Then finally it will decline which will shrink the population.

You are not nitpicky, you are misunderstanding what they are saying. And I don't know what other numbers you are referencing... But I do agree It's an odd thing to state, we can agree about that.

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Norwester77 t1_jdyni8l wrote

No, they’re saying the population is projected to top out at 8.6 billion, so the population growth rate must already be well off its peak.

If this graphic is to be believed, the global population growth rate hit its maximum somewhere around 1980-1990:

https://upload.wikimedia.org/wikipedia/commons/e/eb/Absolute_increase_in_global_population_per_year%2C_OWID.svg

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quokka70 t1_je3ian0 wrote

And that's the absolute change.

The growth rate, relative to the population at the time, topped out in 1963.

https://ourworldindata.org/grapher/population-growth-rates?tab=chart

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Plastic-Wear-3576 t1_jdyyetq wrote

The confusion is that the headline and opening sentence of the article itself are different.

The headline says what you're saying, the highest rate of population growth will be at 8.6 billion people, then that rate will taper off, but their will still be growth.

The first sentence in the article says that at current growth rates, the highest POPULATION, not growth rate, will be at 8.6 billion people, where the population will then begin to decline.

Simplified:

Headline -> Population will grow past 8.6 billion. Article -> Population will not grow past 8.6 billion.

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SrpskaZemlja t1_jdz9nko wrote

I'm disappointed both with journalists and with redditors' confidently wrong calculus knowledge this morning.

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patman_007 t1_jdzxbdy wrote

I'm amazed at some people's confidence in things they are wrong about.

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phunkydroid t1_je075v9 wrote

I'm amazed you keep commenting without reading past the headline.

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patman_007 t1_je0ntl3 wrote

I'm not commenting on what the article was stating, just pointing out that growth rate and population total are two separate things.

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phunkydroid t1_je0rrq0 wrote

>I'm not commenting on what the article was stating

Then why did you say:

>No, they're saying the rate at which the population will grow will peak at 8.6 billion people LMAO.

​

> just pointing out that growth rate and population total are two separate things.

Which is what the first person in this thread said when you got snarky with them. The headline says rate, but the article clearly talks about the overall population, despite the word rate being incorrectly used.

The rate peaked already. It's in decline now. The article is about the population peaking in 2050 and then declining for the second half of the century to 7 billion by 2100. Total, not the rate.

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