The End of Youth
Harper, Sarah, The World Today
Advances in medicine and health care mean that people all over the globe are living longer, much longer. At the same time mothers in most countries are having fewer babies. The combination is a demographic timebomb. Sarah Harper looks at the challenges that lie ahead and the changes needed to cope with a grey new world
The past decade has seen a growing public aware- ness of the ageing of the population among most industrialized countries. What is less well under- stood is that this is not just a North American and European phe- nomenon, but is now occurring in Asia and Latin America. In addition, the ageing of populations arises not so much from increased longevity, but through falling fertility. As aresult the 2ist century is like- ly to see not a population explosion, but a cessation of population growth altogether.
Thirty years ago the overwhelming demographic question was how we could prevent world population from growing to more than 20 billion. Now the defining demographic characteristics of the 21st century are likely to be declining births and stabilization in size.
World population is predicted to inc- rease from the current 7 billion to around 10 billion by the middle of the century, the growth flattening and remaining thus until the end of the century.
The global distribution of people will also change, with an overall increase in those living in Asia and Africa, and a fall in European and North American popula- tions. The less and least developed region countries will account for 97 per cent of the growth to 2050. Asia will comprise 55 per cent of the world population by 2050 at 5 billion, Africa is projected to double in size by 2050 from 1 billion to 2 billion, while Europe will decline from 738 million to 719 million.
The age composition of the population will also alter as median ages rise, and there is a proportionate shift from younger to older people across the globe. Around a quarter of the world's population will be over 60 by 2050. Two thirds of these peo- ple will live in Asia, which by then will have more people aged over 60 than under 15.
These changes in the demography of human populations have arisen due to the demographic transition. This started in Europe sometime after 1750, in Asia and Latin America during the 20th century, and now there are indications that Africa will transition during this century. Why the demographic transition occurred when it did, where it did and how it did is strong- ly debated. However, as humans develop economically, mortality falls, populations start to grow and then fertility falls.
The key to the demographic transition is changes in the number of children born to women of childbearing age. The actual drivers of declines in childbearing have long been debated but broadly fall into three positions. One theory is that child- bearing falls in response to a reduction in infant mortality. In other words, an increase in child survival rates reduces the number of births required to achieve the desired number of surviving children.
A second position is that the introduc- tion of modern family planning methods has allowed women to choose the number of births they have. The third broad hy- pothesis is that fertility fall is driven by education. There is a strong association between those countries with a high level of educated women, and those with below replacement fertility levels.
Similarly, those countries with low rates of female education have high rates of childbearing. Educating girls, in particular, encourages later marriage and gives them access to the labour market, which reduces the number of births, but also and crucial- ly, changes the mind set of the women and their communities and enables them to recognize the range of alternative choices they can make.
Two thirds of the world's countries now have childbearing rates that are at or below replacement level - crudely de- fined as 2.1. …