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6 Billion - A Brief Demographic History Of Humanity
(This is background information only - you do not need to know this to play "6 Billion")
How did our population get to 6 billion? Well, its a long story but Im going to be brief. We can trace our direct ancestry back about 2.5 million years ago to Africas early hominids Homo habilis (Handy Man), although the fossil record beyond that is not clear. For example, the earliest bipedal hominids Australopithecines (Southern Ape) existed in Africa 4 - 5 million years ago but they were more ape-like than man-like. It is not clear if Homo habilis is directly descended from Australopithecines.
Around 1 million years ago the first great diaspora of humanity began, as Homo erectus (Upright Man, descendant of Homo habilis) spread out from Africa through the Middle East throughout the Old World as far afield as China (Peking Man - 500,000 years ago) and Java (Java Man - 900,000 years ago). Europe was occupied around 850,000 years ago. By 500,000 years ago these populations had changed sufficiently to be re-classified as Homo sapiens (Wise Man).
Enter The Very Wise Man
In fact, for the purposes of determining how we got to 6 billion, we need to be clear about who we are counting - Homo sapiens sapiens (Very Wise Man). Between Homo habilis and Homo sapiens sapiens lies a fascinating story. Given the enormous stretch of time involved, and the small numbers of individuals in these early populations, it is often easier to consider the growth rate to be zero. In fact, the growth rate for Homo sapiens sapiens has been estimated at 0.017% up to 8,000 B.C. (doubling roughly every 4,000 years).
Around 130,000 years ago, with Northern Europe in the grip of the Great Ice-Age, Homo sapiens representative there was the anatomically distinct Neanderthal Man. They lived from Spain in the West to the shores of the Black Sea in the East. In Sub-Saharan Africa, around the same time, Homo sapiens sapiens (thats us!) had displaced all other hominids in that region. In South East Asia, a distinct third modern human species may have arisen (although the fossil record is unclear).
In the Middle East, about 100,000 years ago, the dramatic reunion of two of these branches of humanity began as our direct ancestors discovered Neanderthals already living there! The second great diaspora had begun, this time by Homo sapiens sapiens, coming out of Africa just as Homo sapiens had done before them. The genetic and fossil record confirms that Neanderthals and Homo sapiens sapiens were, in fact, separate species descended from a common ancestor, Homo erectus. Any breeding between the two would, at best, have resulted in sterile off-spring (just as breeding a female horse with a male donkey results in a sterile mule).
The Era Of The Hunter Gatherers
Up to 60,000 years ago Northern Europe, Siberia, the Americas, Polynesia and Australia were unoccupied by humanity. Armed with the strategically flexible lifestyle of the hunter gatherer, Modern Man (Homo sapiens sapiens) spread across the globe. They learned to live everywhere, adapting relatively easily to changing conditions, aided by their omnivorous appetite and emboldened by a powerful self awareness and imagination.
Settlement of Australia by Aboriginals is variously dated between 50 - 60,000 years ago. Wave after wave of settlers washed upon Australias Northern shores from South East Asia, helped by the land-bridges created by lowered sea-levels due to the Ice Age in the distant North.
Europe was settled by Cro-Magnon Man (European Homo sapiens sapiens) around 40,000 years ago. Siberia was settled perhaps 20,000 years ago. In the Americas early human fossils dating back 30,000 years have been found as far South as Brazil (recent evidence suggests that these peoples came from Australia). However, the main action in the Americas occurred thousands of years later. It seems that the Mini Ice Age may have assisted human migration across the Bering Straight around 12,000 years ago resulting in the complete settling of the Americas by 11,000 years ago. The smaller islands of Polynesia such as Fiji (3,600 years ago), Hawaii (1,500 years ago) and New Zealand (only 1,000 years ago) were the last the be colonised and settled by our hunter gatherer ancestors.
It appears that we may have co-existed with Neanderthals for up to tens of thousands of years in the Middle East, then Neanderthals became extinct. With the appearance of Cro Magnon in Europe 40,000 years ago, the co-existence there (perhaps a combined total of only 12,000 individuals) lasted up to 10,000 thousand years. Did we wipe them out? Not really, we were better at the population game, thats all. A Darwinian survival of the fittest. Whatever we call it, our annual rate of growth exceeded theirs long enough to see our populations flourish, and theirs decline.
Neanderthals appear to have been creatures of habit. They rarely ranged far from their home bases, and did not adopt the flexible hunter gatherer lifestyle of our ancestors, making their increasingly isolated communities more and more vulnerable. Whilst Neanderthals were undoubtedly sophisticated and fully human, their tools were more primitive than Cro Magnon, changing slowly over longer periods of time. Also, Neanderthals rarely lived beyond 40, Cro Magnons sometimes lived to 60 before Death claimed them. Almost certainly, War, Famine and Pestilence also took their turns with Death in exterminating Neanderthals. War would not have been the organised war of today, but I find it hard to believe that Cro Magnon and Neanderthals lived in perfect harmony! More likely it was a slow war of attrition with individual victims on either side, with the faster breeding and ultimately more numerous Cro Magnon eventually emerging the victor.
The Europeans In The Americas And Australia
The story of the rise of Cro Magnon and decline of Neanderthals is a similar story to what occurred in the Americas and Australia as the hunter gatherer peoples there faced the challenge of the European empires from 1500 A.D. to 1900 A.D. These hunter gatherers were first devastated by disease (particularly small-pox and influenza). Then many local groups were deliberately wiped out, or displaced. Having no central government, the American and Australian native tribes would have seen one local treaty after the other broken, and their lands taken. Displacement, and a general disruption to their way of life, caused famine and further deaths.
Certainly this explains the decline of these hunter gatherer populations, assisted by the rapid population growth of the invading civilized populations. Our civilized populations had centralized government, medicine, agriculture and technology to assist their rapidly expanding populations in their invasions, and an attitude hardened by centuries of European organised conflict.In the Americas (North & South) an estimated native population of 100 million was reduced to 10 million from 1492 Ad to the early 1900s (around 400 years). For a more detailed examination of Australia's demographic history, and to understand the impact of the Europeans on Australian Aboriginals, read Australia In Detail.
It was a similar story again in Africa, as the Europeans divided that continent up between their modern empires. Perhaps the key differences to the impact of the Europeans here were the enormous expansion of the slave trade (and consequent displacement of Africans to other continents), the larger African populations and a greater resistance to the European germ pool.
The demographic conquest by the Europeans in Africa was never as complete as it was in the Americas and Australia. Indeed, estimates indicate that 3 million slaves were sold to Mediterranean countries and a staggering 12 million to the European colonies in the Americas. These black Africans have, in turn, now changed the demographic nature of the Americas enormously.
India and China
In India and China civilization flourished early and, whilst they had their fare share of pestilence, they probably caused Europe more harm from disease than visa versa. The Black Death of the Middle Ages ravaged Europe ,causing a reduction of up to a third of the population. It is believed to have spread along the trade routes from China.
Europeans once again made their appearance as invaders ; India was conquered for a while, though China only conceded small territories to the Europeans (now all reclaimed). Demographically, however, China and India were largely unaffected by the Europeans Their vast populations are testimony to the age and effectiveness of their respective civilizations, as well as the fertility of the lands that they occupy.
A New Malthusian Scale
Using my New Malthusian Scale, here is an overview of Earth's demographic history with rough dates (obviously, the further back we go, the more guesswork comes into the date):
Time 98,000BC Kilopops 1 2 4 8 16 32 64 128 256 512 1024 Time 10000BC 1500BC 800BC 450BC 1000AD 1600 Megapops 1 2 4 8 16 32 64 128 256 512 1024 Time 1800+ 1930+ 1974+ Gigapops 1 2 4 8 16 32 64 128 256 512 1024
Note: 1KP = 1024 individuals, 1MP = 1024KP, 1GP = 1024 MP and 1 Terapop = 1024GP.
We've gone from a population doubling time for hunter gatherers of 6,769 years to as little as 44 years for the civilized world between 1930 and 1974. In fact, our doubling time peaked between at 39 years with 3 billion in 1960 and 6 billion in 1999. It seems that my game 6 Billion™ was released on the crest of a population wave. You might like to read my Exponentialist article The Mechanism Of Population Doubling for an explanation of how population doubling works.
It is extremely unlikely that Earth can go back to the doubling times of the hunter-gatherer populations. You might like to read my article The Cassandra Prediction for my views on what happens next.
Homo sapiens spread throughout the Old World and survived for close to a million years. Homo sapiens sapiens spread from Africa only 100,000 years ago. By 35,000 years ago Homo sapiens was gone and Homo sapiens sapiens was on the way to colonising the entire globe. Rapid population growth began with 10 million hunter gatherers at the dawn of the Agricultural Revolution 10,000 years ago. Prior to that moment our doubling rate was estimated at 4,000 years.
As civilization flourished, so history records the rise and fall of empires. During that time it took until 1800 to get to our first billion, and a further 130 years to double to 2 billion. From a population of 3 billion in 1960 it took just 39 years to double to 6 billion in 1999.
The hunter gatherer way of life, looked upon nostalgically by so many, could never have supported todays global population. Cities, civilization, agriculture - love them, or hate them, they are necessary to support the numbers of people alive today.
I often think of the changes that may be necessary to support our future populations. Will the changes be as marked as the differences between the hunter gatherer and civilized populations? With the challenge of living and flourishing in space ahead of us, the future will belong to those can face this challenge and adapt to life in space. In time, I believe that their numbers will dwarf Earth's population.
The Times Atlas Of Archaeology
The Third Chimpanzee - Jared Diamond
Guns, Germs And Steel - Jared Diamond
The Origin Of Humankind - Richard Leakey
The Ascent Of Man - J Bronowski
Future Plagues - biohazard, disease and pestilence - Peter Brookesmith
Historical Estimates Of World Population from the US Census Bureau.
For a list of articles by me, see the Articles page.
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