A study published in Science (2014) concludes that world population is unlikely to stabilize this century. Using Bayesian probabilistic methods, the researchers project that the global population, currently 7.2 billion, will reach between 9.6 and 12.3 billion by 2100, with an 80% probability. This is much more certain than previous UN high and low scenarios. Most of the increase is expected in Africa, driven by high fertility and a slowing decline in fertility. The ratio of working-age people to older people is likely to decline significantly in all countries. The study uses probabilistic Bayesian hierarchical models to project population trends, incorporating data on fertility and life expectancy. These models account for correlations between countries and use historical data to set limits on life expectancy growth. The projections show that world population will increase to 9.6 billion by 2050 and 10.9 billion by 2100, with a 95% probability that it will be between 9.0 and 13.2 billion in 2100. This challenges previous assumptions that population growth would end in the 21st century. Africa is expected to see the largest population increase, with its population projected to rise to between 3.1 and 5.7 billion by 2100. This is due to high fertility rates and a recent slowdown in fertility decline. However, fertility in Africa has declined more slowly than in Asia and Latin America, with some countries experiencing stalled declines. The study also highlights the aging of populations in developed countries, with the Potential Support Ratio (PSR) declining in many countries. For example, Germany's PSR is projected to fall from 2.9 to 1.4 by 2100, while the US's PSR is expected to drop from 4.6 to 1.9. In contrast, Nigeria's PSR is projected to decline from 15.8 to 5.4 by 2100. The study suggests that rapid population growth in high-fertility countries could lead to environmental, economic, health, and social challenges. However, it also notes that rapid fertility decline could lead to a demographic dividend, providing opportunities for economic growth. The findings highlight the need for policies to address population aging and ensure the benefits of demographic dividends are used to support future generations.A study published in Science (2014) concludes that world population is unlikely to stabilize this century. Using Bayesian probabilistic methods, the researchers project that the global population, currently 7.2 billion, will reach between 9.6 and 12.3 billion by 2100, with an 80% probability. This is much more certain than previous UN high and low scenarios. Most of the increase is expected in Africa, driven by high fertility and a slowing decline in fertility. The ratio of working-age people to older people is likely to decline significantly in all countries. The study uses probabilistic Bayesian hierarchical models to project population trends, incorporating data on fertility and life expectancy. These models account for correlations between countries and use historical data to set limits on life expectancy growth. The projections show that world population will increase to 9.6 billion by 2050 and 10.9 billion by 2100, with a 95% probability that it will be between 9.0 and 13.2 billion in 2100. This challenges previous assumptions that population growth would end in the 21st century. Africa is expected to see the largest population increase, with its population projected to rise to between 3.1 and 5.7 billion by 2100. This is due to high fertility rates and a recent slowdown in fertility decline. However, fertility in Africa has declined more slowly than in Asia and Latin America, with some countries experiencing stalled declines. The study also highlights the aging of populations in developed countries, with the Potential Support Ratio (PSR) declining in many countries. For example, Germany's PSR is projected to fall from 2.9 to 1.4 by 2100, while the US's PSR is expected to drop from 4.6 to 1.9. In contrast, Nigeria's PSR is projected to decline from 15.8 to 5.4 by 2100. The study suggests that rapid population growth in high-fertility countries could lead to environmental, economic, health, and social challenges. However, it also notes that rapid fertility decline could lead to a demographic dividend, providing opportunities for economic growth. The findings highlight the need for policies to address population aging and ensure the benefits of demographic dividends are used to support future generations.