More than 23 countries could see their populations halved by the end of the century, according to a fascinating new study on population, fertility and migration.
The report published in The Lancet predicts that the world’s population will peak at 9.73 billion in 2064 before falling back to 8.79 billion in 2100.
Results from the Institute for Health Metrics and Evaluation at the University of Washington have shown that global fertility rates will drop from almost 2.4 in 2017 to 1.7 in 2100 – largely due to factors such as contraceptive availability and women in education and careers.
The results upset current expectations and suggest that “once the decline in the world’s population begins, it will likely continue inexorably”.
“Our results suggest that due to advances in women’s education and access to contraception which have contributed to declining fertility rates, the continued growth of the world’s population over the century is no longer the most likely trajectory for the world’s population, “said the authors.
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It indicates that 23 countries, including Japan, Spain, Italy, Thailand, Portugal, South Korea and Poland, should see their population halved by the end of the century.
For example, Japan’s population is expected to drop from a peak of 128 million in 2017 to less than 53 million in 2100. Italy is expected to drop from 61 million to 28 million over the same period.
The most populous country in the world, China, is expected to peak at 1.4 billion people in four years before falling to 732 million in 2100, India becoming the largest country.
Sub-Saharan Africa, on the other hand, will triple to reach some three billion people, Nigeria alone reaching nearly 800 million in 2100.
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Australia’s population is expected to peak at 36.38 million in 2096, growth being sustained due to net migration rather than replacement fertility rates, according to the authors.
“Our results show that some countries with fertility rates below the replacement level, such as the United States, Australia and Canada, are likely to maintain their working age population through net immigration.
“Our forecasts for a declining world population have positive implications for the environment, climate change and food production, but may have negative implications for the labor force, economic growth and social support systems in the regions in the world where fertility is falling the most. “
Australia will also increase its economic ranks before the end of the century, going from the 12th world economy in 2017 to the eighth in 2100, placing it just behind the United Kingdom.
The United States is expected to maintain its status as the world’s largest economy until 2050, when it will be overtaken by China. However, this will reverse, with the United States being the largest in the world by 2100, the report said.
“By the end of the century, the world will be multipolar, with India, Nigeria, China and the United States being the dominant powers,” said The Lancet editor Richard Horton, describing the study as describing “radical changes in geopolitical power”.
As fertility declines and life expectancy increases worldwide, the number of children under the age of five is expected to decrease by more than 40%, from 681 million in 2017 to 401 million in 2100, according to the study.
At the other end of the spectrum, 2.37 billion people – more than a quarter of the world’s population – will be over 65 years of age.
The over 80s will drop from around 140 million to 866 million today. The sharp decline in the number and proportion of the working age population will also pose enormous challenges in many countries.
– with son