# Extrapolating Human Population to 5000 B.C

amt
The Earth's current Human population is 6 Billion. Some time in 1940 the world population was 3 billion and around 1750 the population was about 500 million. Is there a scientific method to extrapolate the Human population for the date 5000 b.c?

Thanks.

Gold Member
not realistically... Various diseases, technologies, etc all contribute to human population

amt
Yes I agree-
But let's consider a linear extrapolation function based on statistics known in 2005, 1940 and 1750. Let's ignore abnormal population growth or population shrinkage due to war, famine, decease, weather etc.

Homework Helper
Certain population models are very close to being exponential, that's often used to work out the approximate population between various points of data you already have. However 5000 BC is way out of the realistic range of sensibility given the data points you have.

fourier jr
off-topic: i think the biggest city in the world until rome was mohenjo daro in western india. the population was something like only 20,000-30,000

kant
amt said:
The Earth's current Human population is 6 Billion. Some time in 1940 the world population was 3 billion and around 1750 the population was about 500 million. Is there a scientific method to extrapolate the Human population for the date 5000 b.c?

Thanks.

Yes. You can use the logistic model of population growth( found in most calculus and differential equations textbooks)

The problem with this model is the inherent need for a constant K which is defined to be the upper limited that a population can reach. If a population were to exceed that limit of K, then the rate of population growth would be negative.

Staff Emeritus
Gold Member
And in the case of humanity, there have been many occasions in which, due to new technologies (for food production, processing, trnasportation and storage), the upper limit has suddenly changed.

Homework Helper
I'd start with the simplest model possible. Then perhaps think about using some kind of random scheme to obtain "disasters" and "prosperity" at random times throughout the history that would have changed the upper limit. Then integrate the disaster model and the simple model together in a simulation algorithm.

kant
ahrkron said:
And in the case of humanity, there have been many occasions in which, due to new technologies (for food production, processing, trnasportation and storage), the upper limit has suddenly changed.

Some say the upper limit might be 9.1 billion by mid-century.

Homework Helper
Why 5000 BC, anyways?

natty1905
It interests me. Some sources say 10,000 BC was 1 million people and it seems to have increased steadily since then. If this is true presumably shortly before 10,000 BC it would have been 0!

Homework Helper
It interests me. Some sources say 10,000 BC was 1 million people and it seems to have increased steadily since then. If this is true presumably shortly before 10,000 BC it would have been 0!

No. From as far as we know, human population grows at an exponential rate so it is preposterous to think it would have been 0 before 10k BC and obviously it hasn't been else we wouldn't be here today would we.

natty1905
Oh right sorry. I had assumed that exponential meant increases in proportion to the quantity present which is what meant in the first place. A more useful theory is that the ice age occurred around 12,000 BC which may have killed a lot of people.

Staff Emeritus
Gold Member
2021 Award
No. From as far as we know, human population grows at an exponential rate so it is preposterous to think it would have been 0 before 10k BC and obviously it hasn't been else we wouldn't be here today would we.

Well, at some point it was zero

Homework Helper
Well, at some point it was zero

If we're assuming evolution, then the fine line between a human and its ancestor makes that answer a fuzzy one.
Yes natty, that would be a better theory

natty1905
I guess what I'm actually trying to say is that if population increases fairly progressively at a fairly steady rate, which it seems to, and the population at 10,000 BC was 1-4 million then unless there was some kind of catastrophic event preceding this the population would have been zero quite close to this date unless we are assuming that man evolved from a lesser form somewhere around 14,000 BC which I sincerely doubt.

Homework Helper
I want to stay on the topic of science, and steer clear of religion - since I think you're subtly trying to mention Adam and Eve.
Crocodiles have been on this Earth for millions of years and I doubt their population was booming at one point. They don't have the intelligence to sustain such a population, such as domesticating animals and planting and harvesting crops for food. Humans do, which is why we have such a large population today.
I believe there is a natural equilibrium where under a certain population density in anyone region on the globe, the food chain isn't unbalanced so there is a sustainable number of such species. Before 10,000 BC humans could've just been idling in these low population numbers, doing what all animals do, spend each and every day hunting for food and occasionally mating. Births = deaths.

Indigenous Americans and Australians are a good example of such an equilibrium with nature. My intentions aren't to be racist, but they did live off the land like all animals do. With little advancements in shelter, weaponry and domestication, they were on their way to slowly moving beyond the limits of what nature can provide us.

natty1905
Sorry I guess I was bored with the ludicrous and religious claims of science after my Bsc. I will leave you to it.