The world population is expected to peak in 2064 at 9.7 billion people, then decline to 8.8 billion in 2100. These predictions are based on improving access to contraception and education women who will lead to generalized and lasting declines in fertility.
- The number of people over 65 should be 2.37 billion in 2100 against 1.7 billion today.
- The decline in fertility should accelerate and the world average will be around 2.1 children per woman.
- The fastest declining populations will be found in Asia and Europe.
The world population is not expected to reach 10 billion this century. The year 2064 is expected to mark the peak of the number of people on Earth, at around 9.7 billion, before slowly declining to fall back below 9 billion at the start of the next century. These estimates are the result of modeling carried out by American researchers from the Institute for Health Metrics and Evaluation (IHME) of the School of Medicine at the University of Washington (United States). They used data from the Global Burden of Disease Study conducted in 2017 to project the future world population and used new methods to predict mortality, fertility and migration. The results were published on July 14 in the journal The Lancet.
More old people
These estimates contrast with those made previously and bet on a future decline with around 2 billion fewer people. By 2100, 183 of 195 countries will have total fertility rates, which represent the average number of children per woman, below 2.1. This means that in these countries, populations will decline unless low fertility is compensated by immigration. “Continued global population growth throughout the century is no longer the most likely trajectory for global populationadvances the director of the IHME, doctor Christopher Murray, who led the research. This study provides an opportunity for governments of all countries to begin rethinking their migration, labor and economic development policies to meet the challenges posed by demographic change..”
The study also predicts huge changes in the global age structure. It estimates that about 2.37 billion people will be over 65 in 2100, compared to 1.7 billion under 20. According to statistics from the State of the World Population Report, carried out by the UN, the over 65s represented only one in 11 people in 2019. This upheaval will have many economic consequences. “Our results suggest that the decline in the number of working-age adults alone will reduce GDP growth rates that could drive major shifts in global economic power by the end of the century.predicts Stein Emil Vollset, first author of the article. Responding to population decline is likely to become a paramount political concern in many countries, but must not undermine efforts to improve women’s health or advance women’s rights..”
An acceleration in the decline in fertility
The decline in fertility is expected to accelerate worldwide. Much of this anticipated decline is expected in countries with high fertility, particularly those in sub-Saharan Africa, where rates are expected to fall below replacement level for the first time, from an average of 4.6 births per woman in 2017 to 1.7 in 2100. In Niger, where the fertility rate was the highest in the world in 2017, with women giving birth to seven children on average, the rate is expected to drop to around 1.8 in the next century. However, the population of sub-Saharan Africa is expected to triple over the course of the century, from about 1.03 billion in 2017 to 3.07 billion in 2100. North Africa and the Middle East are the only regions that are expected to have a larger population in 2100 (978 million) than in 2017 (600 million).
As fertility declines and life expectancy increases globally, the number of children under age 5 is expected to fall by 41%, from 681 million in 2017 to 401 million in 2100. The number of people over 80 is expected to increase sixfold, from 141 million to 866 million. Similarly, the global ratio of adults over 80 for each person aged 15 or younger is projected to increase from 0.16 in 2017 to 1.50 in 2100, in countries where the population has declined by more than 25 %.
Countries will see their population halved
The fastest declining populations will be found in Asia and Europe. Populations are projected to more than halve in 23 countries and territories, including Japan (from about 128 million people in 2017 to 60 million in 2100), Thailand (71 to 35 million), Spain (46 to 23 million), Italy (from 61 to 31 million), Portugal (11 to 5 million) and South Korea (53 to 27 million). There are 34 other countries expected to see population declines of 25-50%, including China (1.4 billion in 2017 to 732 million in 2100).
This demographic decline should also have the effect of redistributing the cards in the geopolitical game. “The XXIand century will see a revolution in the history of our human civilizationresponded Dr. Richard Horton, editor-in-chief of The Lancet. Africa and the Arab world will shape our future, while Europe and Asia will recede in their influence. By the end of the century, the world will be multipolar, with India, Nigeria, China and the United States as the dominant powers. It will truly be a new world, which we should prepare for today.”
Limits of the study
The authors note some important limitations, including that the predictions are constrained by the amount and quality of data used. They add that past trends are not always predictive of what will happen in the future, and that certain factors not included in the model could alter the rate of fertility, mortality or migration. For example, the Covid-19 pandemic has affected healthcare systems around the world and caused more than half a million deaths. However, the authors believe that the additional deaths caused by the pandemic are unlikely to significantly alter long-term forecast trends for the world’s population.
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