Three months a year

By Gwynne Dyer

I simply do not understand why this statistic is not better known. The average human lifespan in a developed country has been increasing at three months per year ever since the year 1840 – and it is still increasing at the same rate.

Everybody assumes that lifespan grew much faster in the 19th and early 20th centuries, and is growing much slower now. But no. It has plodded along at the same rate, adding about three months to people’s life spans every year, for the past 175 years. And yes, that does mean that a baby born four years from now can expect to live, on average, a whole year longer than a baby born this year.

Some people have always lived to seventy or eighty, but the AVERAGE age at death in 1840 was only forty years. By the year 2000 it was eighty years. That’s forty more years of life per person in 160 years.

In Britain, for example, the average age of a man at death in 1970 was sixty-eight. The average male age at death last year was seventy-nine. That’s eleven more years in the space of forty-four years. Three months per year, just like in the 19th century.

This is why actuaries predict that babies born in the year 2000 will have an average lifespan of one hundred years. Give those babies the eighty years of life that people who died in 2000 enjoyed, then give them an extra three months for every one of those eighty years – and they will have twenty years more years to live. That is, an AVERAGE of a hundred years.

This sounds so outlandish that you instinctively feel there must be something wrong with it, and maybe there is. The fact that it has gone on like this for 175 years doesn’t necessarily mean that it will go on forever. But it’s not stopping or even slowing, so the smart money says that it will continue for quite a while yet

That’s the developed world; what about the developing world? Most of it has been playing catch-up, and by now the gap isn’t very big any more. In China the average lifespan was only forty-two years as recently as 1950 – but then it began increasing by SIX MONTHS per year, so that the average Chinese citizen can now expect to live to seventy-five.

Once you hit an average lifespan of seventy-five years, however, the pace slows down to three months per year, the same as in the developed countries. Average lifespan in India was still forty-two years in 1960 and is only sixty-eight now, so it’s still going up at six months per year. But it will almost certainly fall to three months per year in about 2030, after the average Indian lifespan reaches seventy-five.

Actuaries and demographers now talk about the “young old”, who are in their 70s and 80s and still in reasonably good shape – and the “old old”, in their 90s and 100s, who are mostly frail and in need of care. So we are steadily moving towards a situation where people must work until well into their 70s, because no society can support everybody over 65 when they amount to a third of the population. Give it another forty years, and most people will have to work into their 80s -- but by then it won't be a decrepit 80s.

Is this a bad thing? Well, the alternatives are worse.

Gwynne Dyer is an independent journalist whose articles are published in 45 countries.