It all starts with a paradox. In November 2022, the world had 8 billion human beings for the first time in history, three times more than the 2.5 billion counted in 1950. And this figure will continue to grow with around 9.7 billion people in 2050, before a potential peak at 10.4 billion in the 2080s and stagnation until the end of the century, according to UN projections. However, at the same time, a large number of countries, particularly developed ones, are facing an unprecedented birth crisis since 1945. Last January, the figures for France had the effect of a bomb: the number births fell by 6.6% in 2023 in the country, falling below the symbolic bar of 700,000 for the first time since the end of the Second World War. South Korea, Japan, Spain, Italy and Germany are following the same path. Consequence: the rate of growth of the world population, although it continues to progress, has declined radically since the peak of the 1960s, falling below 1% in 2020. And the situation is not likely to improve according to a study published this Thursday March 21 by The Lancet, which states: “The world is moving closer to a future with low fertility.”
According to this article published in the very serious British magazine and conducted by the Institute for Health Metrics and Evaluation (IHME) of the University of Washington’s School of Medicine, more than three-quarters of states will not have sufficient fertility rates (i.e. less than 2.1 children per woman) to maintain the size of their population by 2050. A proportion that will increase to 97% in 2100. In 2021, the average fertility rate was 2.2 children per woman, compared to around 5 in 1950. Today, almost half of the states are already below the threshold of 2, 1 child per woman. A particularly worrying trend in countries like South Korea and Serbia, where this rate is less than 1.1 children per woman. But in many sub-Saharan African countries, fertility rates remain high: the average fertility rate in the region is almost twice the global average, or 4 children per woman in 2021. In Chad, it is the highest highest in the world with 7 children.
Over the coming decades, global fertility is expected to decline further, reaching 1.8 children in 2050, and 1.6 in 2100. This is a rate well below the population replacement level. By 2100, only six countries are expected to have fertility rates above 2.1 births per woman: Samoa, Tonga, Somalia, Niger, Chad and Tajikistan, American researchers estimate. Conversely, this rate should fall below one child per woman in 13 countries, including Bangladesh, Bhutan, Nepal and Saudi Arabia. In Western Europe, specify the authors of the report, this average fertility rate should be 1.44 children in 2050, then fall to 1.37 in 2100. France, where this rate stands at 1.68 children per woman in 2023, should benefit from the highest rates in the Old Continent with 1.56 children in 2050 and 1.43 in 2100. Concretely, only 26 countries will see their population grow at the end of the century, with a number of deaths lower than that of births, notably Angola, Zambia and Uganda, according to these projections.
A two-speed world
Continuing what we observe today, developed countries would be the most affected, when those with low incomes would see their share of the number of births in the world increase from 18% in 2021 to 35% at the end of the century. In detail, one in two children will be born in sub-Saharan Africa in 2100 (compared to 29% in 2021). We are therefore heading towards a world divided in two, to summarize: rich states with a low fertility rate on one side; “poor” states with an increasing number of births on the other. In the former, the authors warn, governments will have to adopt policies to support parents and encourage “ethical and efficient” immigration in order to maintain the size of the population and the strength of the economy, because the lack of labor This work coupled with the aging of the population will put a strain on growth, health and social security systems. In the latter, we will favor better access to contraceptives and education for women in order to reduce birth rates.
“A major challenge for sub-Saharan African countries with the highest fertility is managing the risks associated with increasing population growth or risking a potential humanitarian catastrophe,” said co-senior author and acting assistant professor of the IHME, Dr. Austin E. Schumacher. “We will face astonishing social changes during the 21st century,” declared Professor Stein Emil Vollset, lead author of the study. “The world will be faced simultaneously with a ‘baby boom’ in certain countries and a ‘baby bust’ [NDLR : un déclin de la natalité] in others”, he continues. Which could also result in a possible shift in geopolitical relations, with a fairly high average age in Europe, for example, of 41.7 years in 2050 compared to 17.6 years in Sub-Saharan Africa.
At the same time, life expectancy will only increase: it was 72.8 years in 2019 and will reach 77.2 years in 2050, according to the UN. As a result, combined with the decline in fertility, the proportion of people over 65 is expected to increase from 10% in 2022 to 16% by mid-century. Aging which will have effects on the labor market, retirement systems and even the care of the elderly.
Increase in infertility
Several reasons can explain the drop in the fertility rate: economic difficulties, pessimism about the future or the fact that women are having children later and later. In four decades, the age at motherhood has increased by five years in France, knowing that fertility gradually declines after 30 years. On the scientific side, the increase in infertility is also explored. It affects one in six people in the world, according to a report from the World Health Organization published in April 2023. In France, the inability to procreate affects more than three million citizens, and one in four couples wishing to children fail to achieve pregnancy after twelve months or more of trying, according to a report submitted to the executive in February 2022 and co-led by Professor Samir Hamamah, head of the reproductive biology department at Montpellier University Hospital. Medical causes (endometriosis affecting one in six women worldwide, polycystic ovary syndrome in women, etc.), factors linked to lifestyle (tobacco, alcohol, obesity, etc.) but also a drop in sperm quality which can be partially linked to environmental factors (chemical pollution) are mentioned.
Last January, Emmanuel Macron announced a plan to combat infertility, described as “the taboo of the century” by the President of the Republic. Its conclusions should be known by July, according to the Elysée. In terms of content, “several avenues are already being considered”, including: relying on the new prevention appointments accessible to key ages, in this case during the appointment at 25 years old, where doctors will suggest carrying out a gynecological examination or spermogram, fully reimbursed by Social Security. The future plan will also include a section on endocrine disruptors, which are part of the elements explaining the increase in infertility, according to the presidential palace. In other reflections: support for people on PMA journeys, which can seriously affect life at work.