World population could shrink from the middle of the century

According to a new forecast, the world population could peak at 8.5 billion people as early as 2040 and decline to around 6 billion by the end of the century. The prerequisite, however, is a "giant leap" in investments in economic development, education and health, according to the international initiative Earth4All. The United Nations (UN) does not expect a peak of around 10.4 billion people until 2080, according to a report from the summer of 2022.

According to the UN, the world population passed the 8 billion mark in November. The last time the world population was six billion people was around the year 2000; in 1960 it was only half that number. Since the middle of the 20th century, the world has experienced immense population growth: according to UN data, the world population more than tripled between 1950 and 2020.

In the working paper "People and Planet" published on Monday, the Earth4All researchers now draw two possible scenarios for the future. In the first, the world continues to develop economically in a similar way as in the last 50 years. Then the population will reach its peak by 2050, according to the analysis. In the second scenario, this could even be achieved as early as 2040 if, among other things, there were larger investments in fighting poverty. The Earth4All experts are convinced that other prominent population forecasts often underestimate the importance of rapid economic development.

In their first scenario - "Too Little Too Late" - the population and economy will grow more slowly through 2050, peaking at around 8.6 billion in 2046 and reaching 7.3 billion by 2100 people shrink. "Current economic growth trajectories are already sufficient to halt global population growth by mid-century," said Beniamino Callegari, a member of the Earth4All modeling team.

If there is more focus on fighting poverty and improving gender equality, the population could even peak as early as 2040, at around 8.5 billion people. According to this “Giant Leap” scenario, there will only be around 6 billion people left on earth in the year 2100.

"Especially in this scenario, the prognosis underscores which adjustment screws need to be turned in order to improve living conditions in the world," said Catherine Hinz, Executive Director of the Berlin Institute for Population and Development. It represents, so to speak, an acceleration of the first scenario. When the world population reaches its maximum depends above all on how countries with particularly high birth rates develop. If the living conditions there improve, the increase shrinks.

"We know that rapid economic development in low-income countries has a huge impact on fertility rates," said Per Espen Stoknes, director of the Earth4All project. "Fertility rates drop when girls have access to education and women are economically empowered and have access to better health care."

In addition to education and health, advances in nutrition in poor countries are also important, explained Hinz, who was not involved in the modeling herself. In their view, it is difficult to achieve the world's trend reversal by 2040. "Even if we invest in the necessary areas now, it will still take time for fertility rates to change around the world."

Although the number of people on our planet has been growing at an overall slower pace for some time, this is not the case in all regions. According to the UN report, by the end of the century there will be about three times as many people living in Africa as today, almost 4.3 billion - about 40 percent of the world's population. The biggest drivers are ten countries from which more than half of all newborns will come in 2050, including Nigeria, Ethiopia and Sudan. In contrast, more and more high-income countries – like Japan already today – will slip into a negative population trend. Countries like Germany would have to rely on migration for stabilization.

According to current knowledge, modern humans, Homo sapiens, appeared about 300,000 years ago. In the past millennia, the number of people has increased steadily, apart from phases of major pandemics such as the plague. About 190 million people lived around the year 0. With longer life expectancy, the curve rose steeply from around the year 1700, and the first billion was probably reached shortly after 1800. It took less than 100 years to go from a world population of two billion in 1928 to eight billion today.

The Earth4All initiative is led by the Club of Rome, the Norwegian Business School and the Potsdam Institute for Climate Impact Research (PIK). Its goal is to develop transformative political and economic solutions for the 21st century that can achieve sustainable development within planetary boundaries. The initiative builds on the report The Limits to Growth commissioned and published in 1972 by the think tank Club of Rome.

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