The world's population - led by Europe, North America, and Japan - will grow markedly older in the next 50 years.
This rapid aging will see the number of people over 60 triple by 2050 to nearly 2 billion worldwide. The population over 80 will soar fivefold to 379 million.
The Population Division of the United Nations released the latest predictions this week.
If the UN study proves accurate, it will foreshadow one of the most dramatic demographic changes in modern history.
Many countries, including Japan, Germany, and Italy, will experience unprecedented population challenges. As their citizenry ages, the number of young people in the workforce will decline sharply - a shift that will put unparalleled strains on social services, retirement programs, and healthcare systems.
For example, the UN estimates that by 2050 Japan's population will decline by 17.9 million people to just 109 million. At the same time, the percentage of Japan's people over the age of 60 will climb from just 23 percent of the population today to 42 percent. At least 10 percent of Japan's population will be over 80.
As this is happening, the number of Japanese in their prime working years will sharply decline. While today there are approximately three Japanese of working age for each person of retirement age, by 2050, that could drop closer to 1 to 1.
The UN study highlights a number of other profound changes that could have long-term economic, political, and social implications around the globe. Among them:
* The Russian Federation could lose nearly 1 million people a year for the next half century, and its population could decline to just 104 million. In reaching this conclusion, UN population experts have joined a number of academic experts who have been predicting that Russia's population is about to enter a free-fall because of widespread health problems and a declining birth rate.
* India will pass China to become the world's largest nation, with 1.57 billion people.
* The United States will remain the third most populous country, and will be the only industrialized nation in the Top 10 by 2050.
* The developed world - Europe, North America, Japan, and a few other countries - will see no growth in their total population of 1.2 billion in the next 50 years. Without immigration, their overall populations would decline.
* The developing world, including India, Indonesia, Nigeria, and other fast-growing nations, will expand from the current 4.9 billion to 8.2 billion people by 2050. Growth could be even faster unless birth rates decline.
* Life expectancy will rise almost everywhere. In developed nations, where it is currently 75 years, that will climb to 82 years (82.6 in the US; 88 years in Japan, the highest anywhere). In developing countries, the current 63 years could climb to 75 years.
* Total world population of 6.1 billion is currently rising by 77 million a year (1.3 percent). Six countries are responsible for half the growth - India, China, Pakistan, Nigeria, Bangladesh, and Indonesia.
* Despite serious challenges, including the AIDS epidemic, the 48 least-developed countries are expected to triple in population to 1.83 billion in the next 50 years.
* Thirty-nine countries are projected to lose population over the next 50 years, led by Russia, down 41.2 million. Other important losers, in millions: Ukraine (19.6), Japan (17.9), Italy (14.6), Germany (11.2), Spain (8.6), Poland (5.2), Romania (4.3), Bulgaria (3.4), and Hungary (2.5).
The UN study indirectly notes that because of shifting population trends, the US could soon set itself apart from other industrialized countries.
The US will be the sole nation among the major industrial countries that will grow rapidly during the next 50 years. Many of its traditional rivals, such as Germany, Japan, and Great Britain, will shrink.
In 1950, countries like Russia and Britain were among the 10 most populous nations on earth. By 2050, Russia's population is expected to be about the size of Yemen, and Britain will be smaller than Sudan or Saudi Arabia. Colombia will have more people than Germany.
The US is expected to keep growing - up to 397 million by 2050, or 114 million more than were counted in the 2000 census.
From a global perspective, the UN study finds the world will be a much different place in 2050.
In 1950, Europe had more than twice as many people as Africa and more than three times as many as Latin America. By 2050, the UN projects that Africa will have at least three times as many people as Europe, and that Latin America's population will be approximately twice the size of Europe.
Asia, which has always loomed large in population, will continue to be the biggest. With 5.4 billion people, it is projected to contain nearly 6 out of every 10 people on the planet.
(c) Copyright 2001. The Christian Science Publishing Society