Will the earth be overpopulated by 2100?

Peak reached worldwide in 2064 Population forecast 2100: Germany will shrink to 66 million

Globally, the fertility rate is expected to decrease from 2.37 in 2017 to 1.66 in 2100, which is further below the minimum rate of 2.1. The rates would be particularly low at 1.2 in Spain and Italy and only 1.17 in Poland. That doesn't sound like much, but it has a significant impact. An increase in the rate by just 0.1 births per woman would correspond to about 500 million more people on the planet in 2100.

But most of the expected declines in fertility rates, the team expects for countries with high fertility - especially sub-Saharan Africa. In Nigeria, for example, the birth rate was the highest in the world in 2017 with 7 births per woman. By 2100 it is expected to drop to 1.8 births per woman. Nevertheless, the researchers expect the population of sub-Saharan Africa to triple over the course of the century: from an estimated 1.03 billion to 3.07 billion in 2100. The reasons for this are falling mortality rates and more women who have reached childbearing age.

Only in two other regions of the world does the study forecast a larger population for 2100 than in 2017: North Africa and the Middle East. Many of the fastest shrinking populations will be in Asia and Central and Eastern Europe. Even China will almost halve its population by 2100 - as will South Korea, Japan and Thailand.

Southern Europe is shrinking - Germany less severely affected

If the US research team's prognosis is correct, then Europe will experience significant losses. Especially in the south: The population of Italy and Spain is expected to halve over the course of the century - from 61 million people in 2017 to 30.5 million in Italy in 2100 and from 46 million in 2017 to 23 million in 2100 in Spain . As a result, the two countries would also slip in the ranking of the world's largest economies - Italy from ninth to 25th and Spain from 13th to 28th in 2100. And Portugal is hardly any better.

In the UK, Germany and France, on the other hand, the situation looks somewhat more stable. They are also expected to remain in the top 10 of the world's largest gross domestic product by the turn of the century. But in Germany, too, the population is expected to decrease from 2035 - from 83 million people in 2017 to only 66 million in 2100. The fertility rate will drop from 1.39 children per woman to 1.35 children over the same period.

More and more old people

The researchers emphasize that their forecast highlights the challenges facing the economy and health and social systems in particular.

Because people are not only becoming fewer, but also getting older - while in many places there are few young people of working age who follow suit. So if you have more young people in the country, you have an economic advantage.

In 2100 there will be an estimated 2.37 billion people over the age of 65, the study predicts. In contrast, there are only 1.7 billion people under the age of 20. For this reason, countries with significantly declining working-age populations would necessarily have to rely on a liberal immigration policy, according to the researchers.

The continued growth in world population over the century is no longer the most likely path for world population.

Dr. Christopher Murray, University of Washington

The study provides an opportunity for governments in all countries to rethink their migration, labor and economic development policies to address the challenges of demographic change, Murray said. And first author Prof. Stein Emil Vollset also emphasizes that there will be considerable social, economic and geopolitical effects.

In particular, our results suggest that the decline in the number of working-age adults alone will reduce GDP growth rates, which could lead to significant shifts in global economic power by the end of the century.

Prof. Stein Emil Vollset, University of Washington