What is the greatest moment of mankind

Demographic change

Bastian Berbner

Bastian Berbner is the editor of DIE ZEIT's dossier. He studied politics and history.

In the future, overpopulation could no longer be the problem for mankind, but population decline. According to Bastian Berbner, this could affect not only the rapidly aging industrialized countries but also the still growing regions of the world such as Africa.

The South Korean capital Seoul is one of the largest metropolitan areas in the world. At the same time, South Korea's population has been shrinking for years. (& copy picture-alliance, YNA)

Nigeria

While the men flock to the streets of Agege outside and roll out their prayer rugs, while they bow their heads towards Mecca a thousand times at the same time and the traffic, the noise and the hustle and bustle of this city in southwest Nigeria come to a standstill for a moment, Hadizatu Ahmed sits behind her house and thinks out loud about when she gave birth to her first child.

She is around 70 years old, says Hadizatu Ahmed, but she doesn't really know. She married when she was fifteen. A tailor. A year later she gave birth to a girl, Habiba. A year later a miscarriage. Two years later came Danjuma, a boy.

Then her husband took a second wife. Hadizatu Ahmed got the two rooms to the right of the hall, which she still lives today. The other woman, the two on the left. Hadizatu Ahmed's goal was to have more children for her husband than the other.

Shortly afterwards she gave birth to Tiggani, the second boy. That same year the other woman gave birth to a girl.

A year later Hadizatu had a girl, Ladi. And the second wife a boy.

Hadizatu: another daughter, Teni. Then another, Mariam. The second wife: a son, then a daughter.

Hadizatu: another daughter, who soon caught malaria. The second wife: a boy.

Hadizatu: Another girl, Fatima. And the second wife shortly afterwards the last child in this family, also a girl.

Hadizatu Ahmed won the family competition, eight to six, but it felt like a defeat, she says, because she only had two sons and the other three.

Fourteen children - her husband was doing well in the neighborhood, she says, but it was nothing against old Bello, he had thirty, albeit with four wives. And certainly nothing against Kabii, he must have had around forty children.

After the prayer is over, the men in front of Hadizatu Ahmed's house start their motorbikes again. Women balance plastic bowls on their heads. Small children walk by the hands of the older ones. People hang on the outside of a yellow shared taxi that rumbles in and out of the potholes. People sit on the roof of a truck. People wave, people laugh, people scream. People everywhere.

When Hadizatu Ahmed was young, there was a forest here. Today Agege is part of the 21 million metropolis Lagos, the largest city in Africa. Since Hadizatu Ahmed had her first child, Nigeria's population has quadrupled to 200 million.

Each Nigerian has an average of 5.4 children.

That's just Nigeria. The numbers are similar in neighboring countries. Niger has the highest birth rate in the world: 7.2 children per woman. Mali: 5.9. Chad: 5.8. Burkina Faso: 5.2. And that's just Africa. Afghanistan: 4.4. Yemen: 3.8. Papua New Guinea: 3.6.

Every second, somewhere in the world, four children are born while two people die. Since you started reading this dossier, the world population has increased by about 200 people. People have long suspected that they might one day become too many. Painters have captured the threatening confinement of the earth in oil. Hollywood has made films in which colonies arise on distant planets because there is no longer enough food on earth. In a novel, writer Dan Brown described a gang of conspirators spreading a virus that makes a third of humanity sterile. The book is called Inferno.

It's true: a person needs food. The food has to thrive somewhere. A person needs clothes. The cotton has to grow somewhere. A person needs a roof over their head. The house has to be somewhere.

Space on earth is limited. It can only carry a finite number of people. Currently there are 7.7 billion.

How long until the inferno?

A mother poses for the camera as part of the "First Baby of the Year 2020" campaign in Lagos, Nigeria. Lagos is the largest metropolis in Africa. (& copy NurPhoto)

Eleven billion - the maximum

new York

On the 19th floor of a skyscraper in Midtown Manhattan, twelve scientists are working to predict the future of mankind. Your boss, Frank Swiaczny, is a 52-year-old German who was once a photographer for Mannheimer Morgen. When he got tired of taking pictures of car accidents, he studied geography. Today he heads a team of statisticians and demographers for the United Nations that calculates how the world's population will develop.

To predict the future, Swiaczny's people must first understand the present - and the past.

Since 1950, new information has been added to the United Nations database every year, including birth and death rates, immigration and emigration figures from 235 countries and territories. Sometimes the data is very precise, like that from Norway, where you can always check how many inhabitants the country currently has at the push of a button. Sometimes the data is very imprecise, like those from Lebanon - last census in 1932 - or from Syria and the Congo, where wars have made it impossible to count the population for years.

Swiaczny's people verify the data, clean it up, even rummage through surveys trying to pinpoint people who are hard to pinpoint, like the homeless on the streets of New York and the nomads in the deserts of Arabia.

The computer forms all of these numbers into lines of development, and they usually point upwards.

The world population has been growing for thousands of years. When hunters and gatherers settled down 12,000 years ago, there were probably less than ten million people in the world. Jesus of Nazareth already had 300 million people around him. William Shakespeare in the 16th century 400 million. All over the world, women had many children at that time. But since many of them died early, the population size remained stable. Sometimes epidemics or wars even caused a decline.

Then the numbers rose all at once in the 18th century, starting from Europe. Thanks to more productive agriculture and better medical care, many more children now survived. Around 1800 there were a billion people in the world for the first time. Revolutions followed that made people live longer: vaccinations, health insurance, antibiotics.

1928 two billion.
1959 three billion.
1973 four billion.
1986 five billion.
1998 six billion.
2010 seven billion.

In order to predict the further development of the world population, Frank Swiaczny's team uses a model that is very complicated in detail, but very simple in essence: The population of the next year corresponds to that of the current year plus births minus deaths. This can then be calculated year after year based on probabilities. The United Nations is forecasting the numbers up to the year 2100.

They announce new predictions every two years, and so in June this year Frank Swiaczny takes his seat in the back of the United Nations press center, while his boss sits in front on the podium. Two dozen journalists are there, a camera broadcasts live on the Internet.

Swiaczny's boss says the world population will continue to grow, reaching 11 billion by 2100.

Eleven billion. Almost three and a half billion more.

The next day, Frank Swiaczny is sitting in his office, and the news has already spread around the world.

Euronews from France: "In the last half century the number of people has exploded. This growth will continue."

RTVE from Spain: "There are two protagonists in the demographic explosion: Africa and Asia."

Spiegel Online from Germany: "The world population continues to grow rapidly."

However: The word "rapid" was not used at the press conference, nor was the word "explosion". It does not correspond to the forecasts, which is why Frank Swiaczny can only shake his head about it.

The truth is already in the numbers of the past, you just have to take a closer look. It took mankind 128 years to go from one billion to two billion. It took her 31 years to make the next billion. For the next 14, then 13 and finally only 12. Humanity grew faster and faster. But then it took another 12 years for another billion, the one that brought it to seven billion. It will take another 13 years to reach the next billion, the next 14, and then even 20 years.

Growth didn't accelerate, it slowed down.

The eleven billion, which Swiaczny's boss also said at the press conference, will not be another stop on the way to another record, according to United Nations calculations. You are the maximum.

One of the greatest events in human history is imminent, the moment when Homo sapiens will have reached its greatest expansion. Over the millennia, people became more and more. Soon they will be less.

The cause for this will not be war, nor disease, or famine, as it has sometimes slowed down population growth in the past, no, the cause will be much more powerful than all that. The shrinking of humanity will be a conscious decision of human beings. Or better: it is a conscious decision. Because it fell a long time ago.

"First the school died, then the village"

South Korea

At the mouth of the Tamjin River, in the far south of the Korean Peninsula, stands the two-story, bright yellow painted elementary school of the village of Daegu. The soccer field in front of the building is deserted and weeds are sprouting in the penalty areas. Long corridors in the building, strangely quiet.

In a room on the first floor, the second grade students sit in front of their teacher and quietly sing a song. There are five of them. On the first floor the third class (two students), the fourth (one), the fifth (also one). In the classroom of the sixth, five children are working on posters on the theme of chrysanthemums.

14 students - in one building designed for 200.