If you believe the World population clock, there are now just under 7.4 billion humans on this planet. Since the clock is mostly based on official figures, chances are that the real number is even higher.
Tenthousand years ago, at the dawn of the agricultural revolution, it is believed that the count was somewhere in between 5 and 10 million. At this time all scientific research also suggests that homo sapiens had already spread out all over the planet. Actually, the Mayan Civilisation was already about 2000 years old.
If we go back another 60000 years, to the time when members of our species started leaving central africa, it is widely believed that the number was between 1000 and 10000 individuals. It might have been more before, especially since geneticists claim that mitochondrial adam and eve date back to at least 250000 years ago, but the so-called Toba catastrophe, a volcanic explosion of apocalyptic dimensions not only wiped out a huge chunk of higher life-forms on Earth but also created what we call a population bottleneck-effect, thus partly explaining the lack of genetic diversity in modern day humans.
So how did we get from a few thousand individuals to almost seven and a half billion?
Let’s do the math:
If 70000 years ago the population was 1000 to 10000 and tenthousand years ago it was 5 to 10 million, that means that within this time period the population doubled about 9 to 13 times, roughly once every 4500 to 6700 years.
With the start of the agricultural revolution numbers seem to explode.
According tho HYDE, the History Database of the Global Environment, which estimates that there were 5 million humans at 8000 B.C., the next doubling takes less then 2000 years, then little more than 1000, by the year 0 the human world population is already estimated to be 200 million. By the year 1200 A.D. most estimates put it to over 400 million. 550 years later, around 1750 A.D. we reach 800 million. At the start of the 20th century, after only 150 years there are 1.65 billion people populating the Earth. In 1959 we reach 3 billion, in 1999 6 billion. That means that the population doubled in only 40 years and almost twice within the 20th century.
In 1970 it was less than half of what it is now… .
What we have here is not only an exponential growth. Look closely. The exponent itself has grown exponentially. From an initial growth rate of an annual 0.05 percent, we have gone up to maximum of 2.14 percent in 1963. In 2015 the rate is roughly at one percent annually. It is estimated that we will reach 8 billion by 2020.
Now think of the damage 8 billion people will cause to the environment. Think of water consumption, Think of energy consumtion, Think of food production. Of forrests being burned down to make space for fields and pastureland for cows and sheep. Think of fishing. Think of cosmetics, pharmaceutical products, plastics, cars and car-manufacturing. Think of wars and weapons, nuclear, chemical and biological ones. And on the impact all these things have on the environment when there are 8 billion people as opposed to 4 or 1 or just ten million.
The biggest risk for the survival of our species is our own over-population.
Of course there is the risk of a nuclear war. But do you honestly think that risk would be an issue without the imperialistic conflicts of the 20th century? And were these not fuelled by the needs of the rapidly growing population of the World’s industrialized Nations?
So how could this have happened? How and why did we manage to go from 5 million to 7.4 billion in only tenthousand years? Tenthousand years equals 500 generations… . And how is it that recently the growth rate seems to be declining again?
These are the questions i will address in the next posts on this blog. Keep reading, subscribe or add this site to your favourites, because this will take a while.