What Exponential Means: And no... human population growth is not exponential

Let's reiterate the basics (I am adding a basic point since we are now arguing about the definition of the word 'constant;).

1) An population that is growing exponentially has a constant growth rate. This is the definition of "exponential".

2) The human population does not have a constant growth rate.

3) The word "constant" implies a value that is not change. If something has a constant growth rate, it means that the growth rate is not changing.

Does anyone disagree with any of these three basic points?

2 Replies

@maxdancona,

Quote:

Nonsense Hightor.

FFS, I engage with you in good faith and you label my reply "nonsense" – then you cherry pick some arbitrary period of time, completely ignoring my point:

I wrote:

Saying "the world population increased steadily over the past century" isn't the same as saying, "the world population has grown at a steady rate over the past 12,000 years."

Quote:

By what definition is this "steady"?

From 1928 t0 until 2011, the population grew by one billion people every ten years. I call that steady growth. That's what I mean by "bracketing".

1 Reply

@maxdancona,

Let's be clear about what is happening here.

We have an ideological narrative. And we have a set of basic mathematical facts that contradict it. It is interesting, no one is actually disagreeing with the facts (at least they can't tell me which fact they are disagreeing with). They are just ignoring the contradiction.

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@hightor,

Quote:

From 1928 t0 until 2011, the population grew by one billion people every ten years. I call that steady growth. That's what I mean by "bracketing".

This is clearly false. Are you just making stuff up?

In 1910 the population was 1.75 billion
in 1920 it was 1.86 billion
in 1930 it was 2.07 billion
in 1940 it was 2.30 billion
in 1950 it was 2.40 billion

This doesn't even make sense. We have just under 8 billion people now. By your logic how many did we have 80 years ago?

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@maxdancona,

my pop progression dosnt talk in trms of very decennial. Pop dynamics (this is a scientific fact) tries to prsent earlist estimates .In our case it was at about -5K CE. I see where youre trying to push your stats.

1 Reply

@maxdancona,

Quote:

1) An population that is growing exponentially has a constant growth rate. This is the definition of "exponential"

Your errors are in ignoring a math fact. AN EXPONENTIAL GROWTH RATE IS WHERE THE RATE OF INCREASE ACTUALLY INCREASES. This is how the human population has grown in the late plsitocne to today.
Youve really gotta lrn mor about pop systematics. Thats ho w can projct xtinction for an apparently "steady" animal population.
YOURE WRONG ABOUT THIS AN YOU JUST WONT ADMIT IT

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@maxdancona,

https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fourworldindata.org%2Fuploads%2F2018%2F11%2FAnnual-World-Population-since-10-thousand-BCE-for-OWID.png&f=1&nofb=1

Quote:

This is clearly false. Are you just making stuff up?

According to the graph, the population was 2 billion in 1928 and approaching 8 billion in 2019. In 90 years the population increased by six billion. That averages 67,000,000 a year. I call that "steady, rapid growth".

Quote:

We have an ideological narrative.

What is it? Where is the "ideology"?

1 Reply

@farmerman,

I accept your point Farmerman. And I stand corrected.

I suspect that human population growth may have been nearly exponential from 5,000 BC to 1750 AD. I am pretty sure that there was variability during this time betwe0n 5,000 BC and 1750 AD and I think I have read that there were some bottlenecks where human population actually dwindled dangerously. Most of the time population growths were very low (i.e. 0.3%). But this isn't my point.

My point is that Since 1750 AD until now population growth has not even been close to exponential. And population growth isn't exponential now.

If you want to argue about exponential population growth before 1750AD and particularly in prehistoric times, I will concede the point (although I am not actually sure if you are right).

But it hasn't been exponential in the past 300 years.

1 Reply

@hightor,

I will let this silliness slide Hightor. You aren't claiming to be mathematically literate. For you to claim that the population grew 1 billion between 1928 and 1938 is obviously wrong even by your own graph... but I will let it slide.

For anyone who wants to see Hightor's logic is wrong, you can see that we went from 2 billion to 3 billion in 32 years (1928 - 1960) and then from 3 billion to 4 billion in 15 years (1960 - 1975). That disproves Hightor right there; 32 years is not the same as 15 years.

Ironically, Hightor is describing linear growth rather than exponential growth. Linear growth means the same absolute change over equal periods of time. Exponential growth means the same rate of change (i.e. percentage) over equal periods of time. This is an important mathematical distinction (but I think Hightor is making a political argument and the mathematics won't interest him).

Farmerman and Engineer really should know better.

1 Reply

I am going to post this graph again. It is graphing the same data as Hightor's graph. But it is a little easier to read (because Hightor's graph is squished), and the addition of the growth rate adds more information.

https://ourworldindata.org/uploads/2019/06/2019-Revision-%E2%80%93-World-Population-Growth-1700-2100.png

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@maxdancona,

Quote:

For you to claim that the population grew 1 billion between 1928 and 1938 is obviously wrong even by your own graph... but I will let it slide.

I wrote:

In 90 years the population increased by six billion. That averages 67,000,000 a year. I call that "steady, rapid growth".

Quote:

Ironically, Hightor is describing linear growth rather than exponential growth.

It's not "ironic" at all. I never claimed that population growth was "exponential". I did quote someone who said that in one of the articles I posted, and when you objected I said that henceforth I wouldn't use that term. I haven't.

Quote:

Hightor is making a political argument and the mathematics won't interest him

What is the "political argument" I'm making? That the human population increased by 6 billion in 90 years? That isn't a political argument. It's arithmetic.

1 Reply

@hightor,

1. If you now agree with me that global population is now growing exponentially, then there is nothing to argue about here.

2. We seem to disagree on the meaning of the word "steady". The word "steady" means the same amount each year (which has nothing to do with the average). I still don't know what your definition of "steady" is.

The growth rate of human population has varied wildly in the past 90 years; starting at about 0.5% in 1930 it rose to 2.2% at its peak in 1968 and then declined to a current rate of 1.05%. This is not "steady" by my definition of the word.

1 Reply

@maxdancona,

Quote:

If you now agree with me that global population is no[t] growing exponentially...

I don't "now" agree with you. I never claimed that there was exponential growth. You didn't convince me of anything. I don't care whether it's exponential or linear. I want to see it reversed.

Quote:

The word "steady" means the same amount each year...

It could also refer to the general direction of change. If someone says, "the population has increased steadily" they might simply mean that it has always increased, independent of the varying rates of increase.

1 Reply

@hightor,

You are in luck. Population growth is being reversed. If you look at the graph of growth rate, it went up (to a peak in 1968). Now it is coming down. That is what "reversed" means.

You probably want it reversed faster, but the amount that the human population growth rate is going down is actually pretty impressive.

1 Reply

Let's talk about the causes of population growth. There are two things that cause population growth.

1) High birth rates
2) Low early mortality rates.

Birth rates have been dropping since the 1700s. The cause of the rampant population growth in the 19th and 20th century is not a rise in the birth rate.

The "problem" that caused the rapid increase in population growth is that people stopped dying early. The child mortality rate dropped rapidly (as prosperity increased thanks to the industrial revolution and trade). We got better agricultural practices (so fewer people starved) and better sanitation practices (so fewer people died of disease).

That population growth rate peak you see, where the population growth rate increased precipitously until 1968 and then started falling, is caused for a time with a high birth rate and low early mortality.

The easiest thing to do is to let people start dying early again. If we stopped modern agriculture so there would be famines, or if we stopped people's access to clean water, or if we stopped vaccinating people... any of these things would slow down population growth.

The much more difficult path is to lower birth rate dramatically. And we have to lower birth rate by a huge amount, because agriculture and medicine and access to clean water keep getting better.

And that is what we have been doing. The amount that population growth rate has been falling means that we are dramatically lowering the birth rate year after year.

1 Reply

@maxdancona,

Yeah, it's sort of funny. I was putting together a post about something I'd observed looking at one of the graphs. I didn't finish it, had supper, and just came back to it. I decided to check the thread to see if anyone had made a comment. This is the unfinished post I was working on:

Quote:

Looking at the human population graph, it's interesting:

1 billion to 2 billion - about 125 years
2 billion to 3 billion - 32 years
3 billion to 4 billion - 15 years
4 billion to 5 billion - 12 years
5 billion to 6 billion - 12 years
6 billion to 7 billion - 12 years
7 billion to 8 billion - if we add another .3 billion by 2023 it would be 12 years

The rate of increase has leveled off and begun to decline [...]

I was going to point out, once again, that when the baseline is 8 billion people it takes a long time to turn things around and lowering the rate of increase isn't the same as reducing the net load of human input on the living planet. Population growth isn't being reversed; we're not losing population. There's a lower rate of growth but the number of people keeps increasing.

1 Reply

@hightor,

This is a good analysis, Hightor. I have no mathematical problem with it.

You are describing linear growth (it is not exponential). And it seems that population growth in the past 40 years has been close to linear (using a rough approximation).

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@maxdancona,

Quote:

The easiest thing to do is to let people start dying early again.

I wish you people would at least practise what you preach. Perhaps you would find what you're looking for if you were honest. Start with yourself, then, if you wish others to die off!

Quote:

if we stopped vaccinating people...

Hey! That's what we've been saying! But Bill Gates has other ideas for limits to growth... once you take the Mark of the Beast, you can't UN-take it, and no, that's not the United Nations of enslavement to satan-world.

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@maxdancona,

pop growth dynamics has been mostly run wrt bactria an Malthus. In a bactee growth curve, it has been definitionally placed into 4 stages

1 lag phase (where the number of initial cells increases arithmtically then geomtrically)
2,,anexponntial growth (where ^n+1 is the increasing xponent.(for humans it is holocene through 1980)_
3 a stationary phase (growth effectively ceases)
4 aSenescence phase, where apoptosis kicks in and th population begins to succumb to a decline in one of the resources that life needs (Malthus kicks in here)

I hadda dig up one of my microbio texts

were in a sort of early senescence with the exception of a few african and asian rsource minimum populations (This used to be called " LEIBIG's
nd SHELFORD'S LAWS OF THE MINIMUM and LAWS OF TOLERANCE)

in English it sorta says that Population growth an stability of an organism (or a population) occurs wrt to that nutritive and environmental resource that is LEAST available. That was maybe 50 yars Before Malthus

2 Replies

@farmerman,

Farmerman, you are being absurd.

1. Exponential growth means population growth with a constant "growth rate". If the growth rate is changing than it isn't exponential growth.

2. The growth rate of the human population has swung wildly. It was less than 0.4% in 1700. It shot up to 2.2% in 1968 and declined after that.

I don't know whether you are failing to understand the definition of exponential growth, or if you are making up data. But what you are claiming is simply untrue.

The claim you are making is ridiculously untrue. My teenaged daughter is learning about exponential growth in high school Algebra. You have a scientific career, Farmerman. You should know this basic math. It is difficult for me to understand why you are getting this wrong.

In mathematics there are right answers. This isn't a matter of opinion. Anyone in high school Algebra can look at the growth rate per year and see that it isn't even close to exponential.

0 Replies

What Exponential Means: And no... human population growth is not exponential

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