(January 2011) The world’s population is growing—and aging. Very low birth rates in developed countries, coupled with birth rate declines in most developing countries, are projected to increase the population ages 65 and over to the point in 2050 when it will be 2.5 times that of the population ages 0-4. This is an exact reversal of the situation in 1950.

In 1950, there were 335 million children in the 0-4 age group and just 131 million people ages 65+. According to United Nations Population Division estimates for mid-2010, there were 642 million persons ages 0-4 and 523 million ages 65+. That is, of course, quite a change. The UN also projects that, for the first time in history, the 0-4 age group will decline between 2015 and 2020, having peaked at around 650 million. The 65+ population is projected to exceed the 0-4 population during that same five-year period, rising from 601 million in 2015 to 714 million in 2020, although precisely when that happens will depend on how fast birth rates in developing countries decline.

The animated graphics show the trends in the growth of the two age groups for the world, more developed countries, and less developed countries.


More Developed Countries

Less Developed Countries

The basic trend is already apparent. According to Richard Suzman, director of the Division of Behavioral and Social Research at the National Institute on Aging, this demographic watershed—for the first time in human history there will be more people in the world over age 65 than under age 5—illustrates the ongoing and profound population transformation that is affecting society in fundamental ways. Although this trend has been apparent in more developed countries for several decades, what is new is how fast the transformation is occurring in less developed countries.

By 2050, the number of people ages 65+ will total just under 1.5 billion, or 16 percent of the global total. In 1950, it was only 5 percent.

While the number of people of retirement age (typically considered 65+) is already beginning to strain retirement financing, a growing number of people ages 75+ will also challenge health care systems, as the proportion of those requiring more frequent medical attention increases along with a need for more nursing home facilities. Europe’s current struggles to raise retirement ages to both reduce the outflow of pension funds and increase the amount of social taxes received is but one symptom of these unprecedented developments.

Aging is no longer the sole province of more developed countries. Longer life expectancy at birth and lower fertility have sharply increased the proportion of elderly in less developed countries. In 1950, 4 percent of the population in less developed countries was ages 65+. Today, that proportion has risen to nearly 6 percent but is projected to reach nearly 15 percent by mid-century. At the same, the 0-4 population would reach a peak of about 585 million around 2015 and then decline. In more developed countries, the number of children in the 0-4 age group was 82 million in 1950 but that number has been declining since the 1970s and is expected to decrease to 65 million by 2050. The proportion 65+, which was 8 percent in 1950, has increased to 16 percent today and will most likely increase to a record 26 percent by 2050.

Carl Haub is a senior demographer at PRB. This article was underwritten through the generosity of the Division of Behavioral and Social Research, National Institute on Aging.