ARCHIVED= Humanity's Aging | National Institute on Aging
Research and Funding

Global Health and Aging

Humanity's Aging

In 2010, an estimated 524 million people were aged 65 or older—8 percent of the world’s population. By 2050, this number is expected to nearly triple to about 1.5 billion, representing 16 percent of the world’s population. Although more developed countries have the oldest population profiles, the vast majority of older people—and the most rapidly aging populations—are in less developed countries. Between 2010 and 2050, the number of older people in less developed countries is projected to increase more than 250 percent, compared witha 71 percent increase in developed countries.

This remarkable phenomenon is being driven by declines in fertility and improvements in longevity. With fewer children entering the population and people living longer, older people are making up an increasing share of the total population. In more developed countries, fertility fell below the replacement rate of two live births per woman by the 1970s, down from nearly three children per woman around 1950. Even more crucial for population aging, fertility fell with surprising speed in many less developed countries from an average of six children in 1950 to an average of two or three children in 2005. In 2006, fertility was at or below the two-child replacement level in 44 less developed countries.

Most developed nations have had decades to adjust to their changing age structures. It took more than 100 years for the share of France’s population aged 65 or older to rise from 7 percent to 14 percent. In contrast, many less developed countries are experiencing a rapid increase in the number and percentage of older people, often within a single generation (Figure 2). For example, the same demographic aging that unfolded over more than a century in France will occur in just two decades in Brazil. Developing countries will need to adapt quickly to this new reality. Many less developed nations will need new policies that ensure the financial security of older people, and that provide the health and social care they need, without the same extended period of economic growth experienced by aging societies in the West. In other words, some countries may grow old before they grow rich.

Figure 2.The Speed of Population Aging

Chart showing the speed of population aging as indicated by the time it takes for the population aged 65+ to double from 7 percent to 14 percent, in nine countries, with more rapid  doubling seen among less developed countries, often within a single generation. Thus, France took about 120 years to double its population aged 65+ from 7 percent in the 1860s to 14 percent by around 1980. Sweden took about 80 years (beginning in 1890); the UK about 40 years (beginning in the 1930s), USA about 60 years (beginning in the 1950s), Japan about 25 years (beginning in the 1970s), South Korea less than 20 years (beginning in 2000), China and Thailand both about 25 years (both beginning in the early 2000s), and Brazil about 20 years (beginning around 2010).

Time required or expected for percentage of population aged 65 and over to rise from 7 percent to 14 percent
Source: Kinsella K, He W. An Aging World: 2008. Washington, DC: National Institute on Aging and U.S. Census Bureau, 2009.

In some countries, the sheer number of people entering older ages will challenge national infrastructures, particularly health systems. This numeric surge in older people is dramatically illustrated in the world’s two most populous countries: China and India (Figure 3). China’s older population – those over age 65 – will likely swell to 330 million by 2050 from 110 million today. India’s current older population of 60 million is projected to exceed 227 million in 2050, an increase of nearly 280 percent from today. By the middle of this century, there could be 100 million Chinese over the age of 80. This is an amazing achievement considering that there were fewer than 14 million people this age on the entire planet just a century ago.

Figure 3. Growth of the Population Aged 65 and Older in India and China:

Bar chart comparing the population aged 65 and older (in millions) in India and China in 2010, 2020, 2030, 2040, and 2050. China’s population aged 65+ is about twice that of India’s for each time period and is projected to increase from around 110 million in 2010 to 166 million in 2020, 229 million in 2030, 317 million in 2040 and 331 million in 2050. India’s population is projected to increase from around 60 million in 2010 to 87 million in 2020, 126 million in 2030, 172 million in 2040, and 228 million in 2050.

2010-2050 Source: United Nations. World Population Prospects: The 2010 Revision. Available at:

Publication Date: October 2011
Page Last Updated: March 21, 2014