Population Growth

One of the more amusingly wrong creationist arguments is that, if the world is really so old, why aren’t there trillions of us? I mean, evolutionists have to propose millions of years without any population growth at all! How could this be true, if population grows in the geometric pattern P(t) = P0ert?

This is the question asked by the latest B.T. DpSU, Earth Hit the 7-Billion Mark Too Late. Mr Thomas is objecting to a paragraph in a paper called When the World’s Population Took Off: The Springboard of the Neolithic Demographic Transition from a three-month old edition of Science which said:

After the members of the genus Homo had been living as foragers for at least 2.4 million years, agriculture began to emerge in seven or eight regions across the world, almost simultaneously at the beginning of the Holocene.

This must clearly be wrong, as “according to the Bible and historical records, there was never a time when humans weren’t engaged in agriculture.”*

Estimated Population curve, from 10000 BCE to 2000

The problem is that in this projected timeline, people (“genus Homo”) must have had virtually no population growth “for at least 2.4 million years.” Bocquet-Appel [The author of the aforementioned paper] wrote, “The world’s population on the eve of the emergence of agriculture is estimated to have been 6 million individuals.” Thus, the first human couple that supposedly evolved from ape-like ancestors would have had only 6 million descendants after 2.4 million years. This requires a population growth rate of about 0.000000009—essentially zero. Virtually no growth for 2.4 million years?

For one, the idea that a single ‘couple’ evolved from “ape-like ancestors” is cartoon-evolution, and wrong. Nobody is saying that an ape gave birth to a human. Well, the creationists might be…

It’s perfectly possible (though unlikely), then, that the population would have been 6 million at the start, too. I say unlikely because I haven’t seen any evidence that that was so, but you get the picture. What then is the problem?

In contrast, the average historically observed growth rate has been at least 0.4 percent, at times spiking to above two percent. Even a “pre-industrial farming population” growth rate of 0.1 percent per year—Bocquet-Appel’s number—would have yielded today’s seven billion people in only 7,062 years. As the late Dr. Henry Morris, founder of the Institute for Creation Research, asked, “How could it be that the planet only now is experiencing a population crisis—why not several hundred thousand years ago, soon after man first appeared on earth?”

To try and explain this slow growth, Bocquet-Appel stated, “An increase in the birth rate was closely followed in time by an increase in mortality.” And the cause of all this death was “infectious diseases” such as “Rotavirus and Coronavirus.”

But this only invokes more unlikely events. How could such diseases maintain a near zero balance of birth and death rates for so long without randomly killing the whole population at some point? And why would these diseases suddenly lose their population-reducing effect after so many supposed eons? Plainly, the infectious disease idea, along with unrealistically slow growth rates, are ad hoc add-ons that prop up long-age thinking.

From this we can reasonably conclude that Mr Thomas has absolutely no knowledge of population dynamics at all. Exponential growth can only really occur when there are enough resources to support it. If these aren’t there – for example, in a hunter-gatherer or subsistence-agriculture community – the population will not, can not grow. We observe ‘developing’ countries, which begin with a flat, equal birth and death rate, first have “an increase in the birth rate” which is, at least geologically speaking, “closely followed in time by an increase in mortality.” The diseases are density dependant facts, which means that they have a greater impact on the population when the population is larger and a smaller impact when it is smaller, which means that it is highly unlikely to eradicate humanity as a whole and will, in fact, work to keep the population constant. They “lose their population-reducing effect” once a) there is enough food for the population to grow anyway and b) when modern medicine is invented. They are still as intrinsically virulent as before, it just no-longer matters so much over the population as a whole.

But the current world population aligns completely with biblical history, with no added stories. Using census records from the last 400 years and a bit of algebra, and assuming a natural logarithmic growth, eight Flood survivors 4,500 years ago produce 7 billion people almost exactly. This is powerful evidence that biblical history is accurate, and man-made evolutionary history is not.

There are numerous problems with this closing paragraph. For one, at the present rate of population growth a population equal to that of the present could be attained from a mere 8 individuals in less than 1800 years. This population growth rate – currently 1.14% – is dropping. Clearly, we cannot assume that population is following a simple “natural logarithmic growth.” Secondly, we don’t have accurate “census records from the last 400 years” – even our figures for the population in 1800 is just guesswork. Finally, he implies that he is able to accurately calculate the time it would take for the population to rise to 7 billion given an average population increase, but he is instead doing quite the opposite – he is calculating an average growth rate assuming the population was 8 4,500 years ago. His figure of .456% does indeed produce an output of 4515.3 years, but if we imagine for a moment that he actually used some data to calculate this number it can be simply demonstrated that using numbers that would frankly be well within the error bars for average population growth – .4% and .5% – we get a massive variance in numbers. He could pick, then, any number he liked, and in this case it was .456%. Thus, on the subject of his allegations of “ad hoc add-ons that prop up long-age thinking,” I will say that a model that takes into account real and observable phenomenon is to be infinitely preferred over one that does not and which takes its conclusion as its premise.

Brian Thomas is apparently obliquely referencing Dr Morris’ article Evolution and the Population Problem, which incidentally uses the simpler Pn = P (l + r)n equation to calculate population numbers. He calculated that an average population growth rate of .5% could have produced the population of that time (the 70’s, when the population of the world was around half of what it is now) from the afore-mentioned 8 people. This article has many of the same problems, but Dr Morris at least admitted the unreliability of the data. However, he too is evidently just playing with the numbers.

See why I called this argument “amusingly wrong”?

*Thus, we can conclude that Genesis 4:1 (“And Adam knew Eve his wife…”) is the originator of “sowing seeds” as a euphemism.


10 thoughts on “Population Growth

  1. I read the population ICR article about 14 hours ago (was going to say “yesterday” but you and I are in such different time zones that’s meaningless) and was thinking to myself, “Brian, you are ignoring KNOWN HISTORY with this $–‡.” And not understanding BASIC evolutionary theory (I at least try to understand creationist arguments so I can talk intelligently about them, but I find that most creationists don’t bother to understand anything about what they write on science-wise). Sigh.

    I mean, the guy apparently doesn’t even play computer games! My latest obsessession has been Civilization and you learn very quickly that with agriculture, your cities experience a population boom that levels off; same with fertilizer. Same can be said in real history, and also with things like tighter knit cloth developed through time that allowed more people to survive winter (again, these things are KNOWN HISTORY). It’s also a basic differential equation you learn in fourth semester college math, but I don’t really expect Thomas to know that.

    • You mean this equation that I stumbled across while doing calculations? That does look like a number of future population prediction graphs I’ve seen, now I come to notice…
      Which Civilisation, BTW? I’ve only got III, and haven’t played in a while – but I think I remember that it wasn’t quite that true-to-life 😀

    • Actually, it was more in the context of the hunter and the hunted – rabbit and fox populations oscillating until a steady-state was reached.

      And Civ III was SO 5 years ago. Civ V is where it’s at. Though it’s annoying that each new release is two steps forward and one step back. And no, it’s not quite true to life, but those basic things like once you figure out a new technology (dawn of agriculture, bronze working, mining, etc.) you see boosts in population and production that then taper off until the next one is researched. It’s the same basic idea in real life — going to an agrarian society bumped our numbers until we reached a steady state that could survive on it. The next change in technology saw a rapid boost that then tapered off again. Etc.

  2. because we only have have in the last century or so changed the conditions we exist in.

    before, the size of the population was limited by infant mortality rates, and death rates owing to communicable diseases.

    With birth control, modern medicine, including dentistry, and mass production of foods – we no longer live on a human scale of within the labour we could do by hand.

    More of us are born and live to adulthood because of improved nutrition, medicine and sanitation.

    If we lived the way the Christian god wanted, we’d all be naked in the forest and not overpopulated the planet.

  3. Pingback: Cycads « Eye on the ICR

  4. Pingback: Jawbone Length… Proves Creationism? « Eye on the ICR


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