World faces age old problem

By 1971, the diseases of childhood had been largely suppressed. One hesitates to quote Dave Barry, but sometimes you just have to: "Thanks to modern medical advances such as antibiotics, Nasal spray, and Diet Coke, it has become routine for people in the civilised world to pass the age of 40, sometimes more than once."

The most startling statistic I have seen in years is this: since the 1840s, life expectancy in the developed countries has increased by three months per year. That rate of increase continues to apply today. Unless it deviates radically from its historic pattern, now almost two centuries old, the children born in 2000 have a life expectancy of around 100 years.

Of course, you suspect that there's a hidden front-end load in this statistic: that most of the increase in average lifespan came during the first century of this period, when better food, clean water and antibiotics were suppressing the infectious diseases that killed so many people in childhood. And it's true that that's the phenomenon that drove the process in the early decades of the period - but the rate has remained steady right down to the present.

By 1971, the diseases of childhood had been largely suppressed, and as a result life expectancy for a man in Britain, for example, had risen to 68 years. For a woman, it was 72. Most further increases in life expectancy could only come from medical and lifestyle changes that lengthened survival rates in the later decades of life.

But life expectancy at birth went on rising. It is now 77 for a British male, and 81 for a female. British people are living 10 years longer than in 1971, which was only 42 years ago. So average lifespan is still going up at the same old rate: three months per year.

And there's more good news for these longer-lived people: the incidence of crippling diseases and disabilities is still mostly a phenomenon of the last decade of life, even though that last decade is now a lot farther down the road.

The same transformation is now taking place in the rapidly industrialising countries like China and India. Indeed, like the industrialisation process itself, it is happening even faster. Life expectancy in China was only 42 years as recently as 1950. It's now 75 years, which means it was going up at six months per year for most of that period.

However, there is a rather large economic problem hidden in these statistics. The proportion of the adult population that is over 65 years old is now heading up towards one-third of the total. It is not possible for all of them to "retire" and be supported by the two-thirds who are of "working age".

The problem is even bigger for countries where the birth rate has fallen far below replacement level, like China, Japan and Italy. As the elderly population expands, the working-age population in these countries is shrinking, and it is possible to foresee a time when there will be as many retired people as there are workers.

Increasing numbers of over-65s are continuing to work, at least part-time. In fact, the latest statistics show almost half of the increase in employment in Britain since the beginning of the recession in 2008 has been of people over 65. Many other countries are experiencing the same. Welcome to the new world.