Rising to the Challenge of Peak Population

In 2011, world population passed the 7 billion mark. While growth will continue, total fertility rates are falling fast and will result in slower population growth and possibly, according to some, declining total population. Lower fertility rates may bring a demographic dividend, significant opportunities but also challenges. Or, we may be doomed, as others would suggest.

What is changing?

The planet welcomed its 7 billionth inhabitant in 2011. Whereas in the past the time needed to add 1 billion has been reducing rapidly, 32 years to go from 2 to 3 billion, but only 12 from 5 to 6; the most recent billion, from 6 to 7, also took 12 years. Growth rates are slowing. The next billion is forecast, for the first time ever, to take longer than the previous billion – albeit by only 2 years less. The cause of the slowdown is a reduction in total fertility rates.

Average global fertility rates, i.e. the number of children on average that a woman is likely to have, have fallen from 4.45 in 1970 to 2.45 in 2010. By 2050, average total fertility rate could be as low as 2. Replacement levels, i.e. the number needed to keep a population static, is about 2.1; higher in countries where infant mortality and the number of other early deaths are higher. In 1970, 24 nations, mostly in the developed west, had fertility rates at or below replacement levels: that number has increased to 70 and many of them emerging / developing nations – such as Brazil, Tunisia, Thailand, India and China.

Why is this important?

On current trends, global population growth will predominantly be the result of increased longevity not fertility from the 2020s onwards. Global population could peak at just over 9 billion. The timing is unclear: about 2070 is slightly more likely than other years, but it could be anywhere between 2052 and 2095; or earlier. Many countries in the west already rely on immigration to maintain population growth and public services: what happens if immigration falters? One forecast even suggests that after peaking, global population could decline to 8 or even 5.6 billion by 2100.

Economists predict a demographic dividend, for some. Falling fertility rates have, in the past, been associated with significant economic growth: the so-called demographic dividend, when the numbers of children fall, but the number in the workforce continues to expand and overall greying and significant ageing has not started, so that dependency ratios remain low. In Europe this occurred between 1945 and 1975; in East Asia between 1980 and 2010; in China it is still going on – for now. India, Africa, many Middle East countries and some of Latin America may all benefit from the demographic dividend. With that demographic dividend, incomes rise, further reinforcing the reductions in fertility rates, but also increasing women’s education, investment in the economy as a whole, as well as in health, savings and consumer spending.

Elsewhere, as fertility falls and longevity rises, so too will dependency, and nowhere more so than China: its dependency ratio will go from 38 today to 64 by 2050, heralding a potential pension and care crisis, the end of cheap labour plus a significant gender imbalance – even with the relaxation of the one-child policy. Those ageing populations will also present opportunities for new forms of care and support technology to enable continued independence; health and wellbeing drugs and nutraceuticals; personalised diets based on genetic profiles and predisposition.

But with growth come challenges. Our global ecological footprint is already about 1.5 planets: i.e. we over consume, to the tune of needing an extra half planet. And that is with most of Africa and many other developing nations consuming at the levels of less than one planet, compared with a European rate needing about 3 planets and a US rate needing about 4.5 planets. With income and economic growth, come increased consumption and rising consumerism. Finding new ways to meet those rising expectations will be a challenge and an opportunity – for clean energy, low carbon technologies, new closed loop production systems, reduced waste and better resource use, quality of life for all. Not meeting the expectations could result in conflict and unrest, especially among the young.

Another of those challenges will be feeding 9 billion people. The current 1.4 hectares of agricultural land could feed a population of 10 billion – vegetarians; but only 2.5 billion US style omnivores. If, as is more likely, meat consumption rises with greater affluence in developing countries, then more land will be needed; or radically new approaches to food production such as vertical farming, meat in a vat and a green revolution.

Some say we are doomed, that the planet cannot cope with 9 billion and more: others look to the innovation and ingenuity of the past to suggest we can survive. Reducing fertility rates indicate that we have reached a turning point, but the jury is out on whether the latter or the former prevails.

By Sheila Moorcroft