Blog Post Published September 2013

Our World's Population is Ageing

The age demographic of the world we are living in is changing at a dramatic rate unprecedented in human history. This will have widespread implications for future generations.

What is population ageing?

As fertility declines and life expectancy rises, the proportion of the population above a certain age rises. This phenomenon, known as population ageing, is occurring throughout the world.

In 1950, the median age in the developed World was 29. This is expected to reach 46 by 2050. This is a permanent change and will have dramatic implications on the economy and social structure.

What causes population ageing?

The ageing population is the result of two factors: people having less children and people living longer. With fewer babies being born, and more people living longer, it is inevitable that the population will get progressively older.

Fertility Decline (decrease in birth rates)

People are having less children. Fertility decline has been the largest contributing factor to our ageing population. Low birth rates largely reflect increased choices available to women, including access to birth control, access to education and employment, and higher living standards.

The total fertility rate of a population is the average number of children born to a woman in her lifetime. This assumes that she survives from birth through to the end of her reproductive life.

Replacement level fertility is the number of babies a female would need to have over her reproductive life to replace both herself and her partner. The global average is 2.1.

Fertility is well below the replacement level in all developed regions of the world. It is estimated that 48 per cent of the world’s population live in “low-fertility” countries, where women have fewer than 2.1 children on average over their lifetimes. 

Low-fertility countries now include all of Europe except Iceland, plus 19 countries of Asia, 17 in the Americas, two in Africa and one in Oceania. The largest low-fertility countries are China, the United States, Brazil, the Russian Federation, Japan and Viet Nam.

Fertility decline in the less developed regions of the world started later but is occurring at a much faster rate than was the case for the developed world. This means they will have a much briefer opportunity to prepare for an older population.

Increase in Life Expectancy

People are living longer. The chances of surviving to old age has improved dramatically in the past century - in fact the 20th century witnessed the most rapid decline in mortality in human history. 

Over the past 50 years, global life expectancy has increased by almost 20 years, from 47 years in 1950-1955 to 69 years in 2005-2010. 

By 2050, life expectancy is expected to have risen to 82 years in the developed regions of the world and 75 years in less developed regions.

Life Expectancy
in 2011 (years)
Fertility Rate
in 1955-1960
Fertility Rate
in 2011
Australia 81.85 years 3.41 1.87
Brazil 73.44 6.15 1.81
Canada 80.93 3.88 1.63
China 73.49 5.48 1.58
France 81.67 2.7 2.03
Germany 80.74 2.3 1.36
India 65.48 5.9 2.59
Japan 82.59 2.16 1.39
Italy 82.09 2.29 1.41
New Zealand 80.9 4.07 2.10
Portugal 80.72 3.12 1.35
Spain 82.33 2.7 1.36
UK 80.75 2.49 1.98
USA 78.64 3.71 1.89

Red indicates that the number of children born per woman is below the replacement rate of 2.1

Interesting data about population ageing

The total fertility rate for Australia has been below the replacement level since 1976, the US since 1972.
The proportion of Australia’s population aged over 65 years has grown from 8 per cent in 1970-71 to 13 per cent in 2001-02. The IGR projects that over the next 40 years, the proportion of the population over 65 years will almost double to around 25 per cent.
By 2050, it is estimated that there will be 2 billion people aged 60 and older globallhy.
By 2050, the oldest population is expected to be that of Spain, where one in every two persons is projected to be at least 55 years old.
Over the past 50 years, labour force participation of persons aged 65 or over declined by more than 40 per cent at the global level.
By 2050, the number of centenarians is expected to increase eighteen times
The population of India is expected to surpass that of China around 2028, when both countries will have populations of around 1.45 billion. Thereafter, India’s population will continue to grow for several decades to around 1.6 billion and then decline slowly to 1.5 billion in 2100.
The population of China, on the other hand, is expected to start decreasing after 2030, possibly reaching 1.1 billion in 2100.
Nigeria’s population is expected to surpass that of the United States before the middle of the century. By the end of the century, Nigeria could start to rival China as the second most populous country in the world.
By 2100 there could be several other countries with populations over 200 million, namely Indonesia, the United Republic of Tanzania, Pakistan, the Democratic Republic of the Congo, Ethiopia, Uganda and Niger.

What impact will population ageing have on our society?

Population ageing will present widespread implications for future generations.

Read more: Implications of an Ageing Population

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