Number of People on Earth

How Good Are Those Young-Earth Arguments?
A Close Look at Dr. Hovind's List of Young-Earth Arguments and Other Claims
by Dave E. Matson
Copyright © 1994-2002


Young-earth "proof" #25: The current population of Earth (5.5 billion) could easily be generated from 8 people in less than 4000 years. If the earth were really billions of years old, the human population would have gone through the roof!

Yes, and by the same reasoning 8 germs could populate every cubic inch of available living space on Earth to the tune of 1 million strong in less than a week! That is, if we allow for a generous die-off rate such that the fourth generation has about 40 germs instead of 128, and if we assume that the population divides every hour, each and every cubic inch of living space on the earth (from 100 feet below ground to a mile above) would have 1 million germs after 158 generations. I guess, by creationist reckoning, the earth must be a week old! If it were a few thousand years old, the germ population would have gone through the roof!


Yes, given unlimited living space, an inexhaustible supply of food, a good deal of luck in the early stages, and a high motivation to travel while having more kids than is practical, eight people could probably populate the earth in a few thousand years. Eight germs could do it in less than a week. Eight bunny rabbits would fall somewhere in between. Eight cats would give us yet another figure. What do any of these figures have to do with the age of the earth? Nothing! What do these figures have to do with actual growth rates? Absolutely nothing!


The human exponential growth rate of the last few hundred years is possible only because of technology. When our ability to stay one jump ahead of starvation and disease fails, when our resources are finally squandered, then you'll see a dramatic change in that growth rate! It will no longer be exponential; it will be disastrous!


When man lived in scattered tribal groups, which is what he did for 99% of his history, the net human population growth was zero most of the time, just as it is for animals today. Animal populations, especially small animals such as rabbits or mice, often undergo cycles of boom and bust but their net growth is zero. No permanent increase in population can be sustained unless it is supported by a permanent change in the environment. Such a change might include the loss of a predator due to the colonization of new territory, a permanent increase in the food supply due to climatic change or a change in dietary habits, or a variety of other factors. In the case of man, hunting technology, the development of agriculture, and the use of fossil fuels have played major roles. After a favorable change in the environment, a population of animals (or people) may record a permanent jump before leveling off at a zero net growth again. Thus, the growth rate, before technology intervened in a major way, necessarily involved a series of plateaus where the population was in approximate equilibrium with the environment. No doubt, many tribal groups died out. Anthropologists can cite several examples of early human or near-human species, side branches on our evolutionary tree, which left no descendants. There was no assurance that early man would even survive. When favorable changes did occur, large jumps between plateau levels would likely have been exponential. Indeed, the human exponential growth rate of the last 300 years or so can be thought of as one long jump to a new plateau, which has been raised artificially high by technology. Those who imagine that eight people gave rise to everyone living today according to a simple exponential growth curve have demonstrated an inability to think things through. Let's look at the equation involved in these growth rate calculations.


P(n) = P(1 + r)n


P(n), called the function P of n, is the population generated after n years. (With the proper adjustment of r, n could be months or generations, etc. For our purposes, years will do nicely and r will be adjusted accordingly.) P (the multiplied factor on the right-hand side of the equation) is the initial population which, in our case, is eight. The growth rate is r which would be close to zero for humanity per year. A negative value would indicate a population decline. Henry Morris used a value for r of 0.0033 [0.33%] in a similar calculation which started with Adam and Eve. However, since the flood supposedly reduced the population to eight people 1656 years after creation, a figure Dr. Hovind gives based on patriarchal ages, we should start our exponential curve at the latter date. If we assume, for the sake of this argument, that the earth is 6000 years old, then we start our calculation with 8 people 4344 years ago. We must wind up with the present population of 5.5 billion people.


It turns out that if r = 0.0047 then after 4344 years we would wind up with about 5.6 billion people (1995), which is close enough. After substituting the values for P and r into the above equation we are at liberty to try out different values for n to obtain the population at different times. At the time the Israelites entered Canaan, for instance, we get a world population of 2024! By the time you divide that up between Egypt, Canaan, the rest of the world, and Israel, that leaves maybe 6 or 7 people for the Israeli army! If we go back to the time that the Hykos were expelled from Egypt, in 1560 BC, we get a world population of 325 people!


We can't calculate the population at the time the Great Pyramid of Cheops was built, around 2500 BC, because it was supposedly washed away by Noah's flood!! Being an antediluvian structure, many people might have been available to work on it. Odd, that the Great Pyramid of Cheops shows no water marks. Stranger still, that the Egyptians should be unaware of Noah's flood! I would think that Noah's flood, coming a mere century or thereabouts after the Great Pyramid of Cheops was built, would have found a prominent place in the Egyptian annals.


As you can see, an exponential growth curve leads to absurdity when we assume that 8 people generated today's population. Creationists, of course, could jack the r value way up at the start, jack it way down in the middle, and jack it up again for modern times, but the ad hoc nature of such an argument becomes a little too obvious. Regarding the foolishness of this whole enterprise, Dr. Alan Hayward had this to say:


Nobody who has ever studied the population explosion would make such an unwise extrapolation. It is well known that growth rates have increased enormously in recent centuries. Population expert Paul Ehrlich gives world average yearly growth rates of 0.9 per cent between 1850 and 1930, 0.3 per cent between 1650 and 1850, and a mere 0.07 per cent in the thousand years prior to 1650. And in the fourteenth century the population increase must have been very small indeed, and it may even have been turned into a big decrease, because of the Black Death. Ehrlich's figures are not just guesses; they are based on historical records. These facts show how misguided it is to extrapolate present population trends into the remote past.


(Hayward, 1985, p.136)


The Times Atlas of World History (1978) estimated that the world population increased 16 times between 8000 BC and 4000 BC. That yields a growth rate (r = 0.069%) which is almost identical to the figure quoted above by Hayward for ancient times.


Try plugging in some real data! It does make a difference. If we assume a growth rate of 0.07% before 1650 (a rate already a bit high because of agriculture), a growth rate of 0.3% between 1650 and 1850, a growth rate of 0.9% between 1850 and 1930, and a growth rate of 2.0% between 1930 and 1994 you will find that Noah and his crew are the ancestors of a whopping 1740 people today!


On that note, I think we can move on to the next point.


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