Changes in power as world grows up

You might have heard about peak oil, but what about peak child? When I was born in 1965, about one in three of the world's people were children. That will fall to one in five in my lifetime - assuming I make it to the ripe old age of 85.

It might not sound dramatic but the repercussions of that shift are Earth-changing. The number of babies being born around the world is unlikely to ever be higher than now, and that means the domination of the world's population by those in lower age brackets is ending.

<i>Illustration: Kerrie Leishman</i>
Illustration: Kerrie Leishman 

Over the past 50 years, the population aged under 15 ballooned from 1 billion to nearly 2 billion. But revised 100-year population forecasts, released by the United Nations last week, show the number of children will flatten out over the next 15 to 20 years and then fall back to 1.9 billion by 2050.

Swedish public health statistician Hans Rosling, who has popularised the term ''peak child'', said the world was entering an unusual phase when only the adult population would be growing.

Today, the average person is 29 years old but that will rise to 41 years by 2100.

The main reason for this shift is nearly half the global population lives in ''low-fertility'' countries where the average woman has less than 2.1 children (the level required for full replacement of the population).


Most developed countries like Australia have been in that category for some time but we've been joined by some developing country giants, including China and Brazil. Less than one in 10 people live in one of the very poor ''high-fertility'' countries, where the average woman has five or more children, almost all of them in Africa.

Another factor is the rapid worldwide improvement in longevity. In 1950, global life expectancy at birth was 47 years. By the end of this century, the UN predicts it will be 82 years.

Even in the world's least developed countries, which include many nations badly affected by HIV/AIDS, life expectancy will only be about four years less than that.

In developed countries, life expectancy will continue to improve, but at a much slower rate, reaching almost 90 years by 2100.

As fertility declines and life expectancy rises, the proportion of older people across the world will surge dramatically.

The number of over 60s will balloon to nearly 3 billion by the end of the century, the vast majority in developing countries. But many of those nations will have to deal with an ageing population without the same economic growth and living standards that preceded greying populations in Western countries.

These predictions are far more than guesswork. Forecasting future population is one thing at which we've become very good.

For decades combating child poverty, especially in low-income countries, has been a prime humanitarian goal.

But that enduring challenge will be joined by a new global health crisis - the need to care for a massive population of elderly people with limited resources.

These predictions are far more than guesswork. Forecasting future population is one thing at which we've become very good. Rosling points out that in 1958, the UN's population division predicted the world's population would be 6.3 billion by 2000. In that year, the actual population was 6.12 billion meaning the UN's forecast was only out by about 3 per cent over four decades. The latest forecasts predict the global population to grow from 7.2 billion now to 10.8 billion in 2100.

The demographic shifts foretold by the UN will shape the economic and political dynamics of the Asian century. India is forecast to overtake China as the world's most populous country by 2028. Soon after that, China's rapidly ageing population will start to shrink.

By the end of the Asian Century, China's population will be a sixth smaller than it is now. That will leave India as the world's most populous country by a considerable margin in 2100, with a population of 1.5 billion. This may have implications for the strategic balance between Asia's twin giants.

Meanwhile, Europe's population will have shrunk by a seventh by 2100 and Japan's by a third (the average age in both Germany and Japan will be over 50). Australia's population is forecast to keep slowly rising, reaching 41.5 million by the end of the century.

The most eye-catching changes will be in Africa. The population of Nigeria will surpass the US by 2050 and could rival China as the world's second most populous country by the end of the century.

Another four African countries - Tanzania, Uganda, Ethiopia and the Democratic Republic of the Congo - will all have 200 million people, putting them among the world's most populous nations.

With their big, youthful populations, countries like these will become a much bigger source of migrants in Australia as our population ages.

By the end of the 21st century, about 35 per cent of the world's people will be African. That virtually guarantees the African region a far more significant role in the global economy than it currently plays. Great diplomatic and strategic clout will inevitably follow.

If population trends are any guide, Africa will eventually muscle in on the Asian century.

Matt Wade is economics writer.

Ross Gittins is on leave.


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