An eye on the history of human population growth

Almost 200,000 years ago, Homo sapiens populated only the African continent. The number of individuals is not known, but they were probably only a few hundred thousand, or even less. One hundred thousand years later, modern humans are moving and migrating to other continents. Studies estimate that there were around 1 million human beings 40,000 years ago. Today, at around 8 billion people, we are 8,000 times more numerous. How can this demographic explosion be explained?

Physical inactivity

The population remained globally stable until the beginning of the Neolithic. However, it doubles in 20,000 years and reaches 2 million individuals, thanks to the invention of tools that improve hunting. It only really increases very late, when humans settled around 10,000 years ago. Then began agriculture, livestock and life in society, which contributed to the growth of the population. Thus, at the beginning of our era a little more than 2,000 years ago, the population rose to 200 million individuals. From there, the almost continuous increase begins. Of the civilizations are formed, which prosper, therefore grow. And are regulated by wars, famines, epidemics… so that in 1200, there were 380 million people. Only big downside: the bubonic plague, or Black Death. This pandemic caused the population to drop to 345 million. Then everything starts again. The exploration and exploitation of the American continent, trade, goods, humans, the beginning of globalization. In 1700, there were 600 million human beings on Earth.

But it was at the beginning of the industrial era that the real population explosion. In 1800, only 100 years later, the billion was reached. And from there, everything is accelerating ! 127 years to double the population and increase to 2 billion in 1927, then only 47 years to double again and this time increase to four billion in 1974. Since then, the rate of increase seems to have stabilized, despite a frightening curve: we are increasing by a billion people every 12 years. Thus, today we are almost 8 billion human beings, the latest data being at 7,953,950 inhabitants.

Population dynamics

The increase in the population passes at the same time by the fall of infant mortality, and by the increase in the birth-rate. Or at least the clear evolution of one of the two factors. However, they are both closely linked to the living conditions of the inhabitants. Health and access to education in particular. Until the recent demographic explosion, the two balanced each other: the population remained globally stable, with an average of two children per woman. But the industrial revolution has enabled technological progress, better food intake, better access to care, and therefore better life expectancy and a decrease in mortality. The population then suddenly increased, hence the evolution on the graph above.

It is only after a long enough period that the birth rate begins to fall, and then rebalances things: we return to a stable population. In question, education and access to contraception : women have fewer children, and have them later. Sometimes the birth rate drops below replacement level, estimated at 2.1 children per woman. In this case, the population becomes aging, and it is migrations that will govern its evolution. Currently the already developed countries have birth rates close to or lower than 2.1 children per woman: they have finished their demographic explosion. It is in developing countries that this sudden increase in population is occurring. The United Nations is also planning a population stabilizationor even a decrease, from 2100.