There's been fretting at the prospect of the UK population swelling to 71 million by 2031. But big surges have been predicted before and they haven't always been right.
By Finlo Rohrer
BBC News Magazine
In 1965 the government's demographers and statisticians projected that the population in 2001 would be 75 million.
They were wrong. It was 58,789,194 on census day in 2001.
Or, to be fair, the projection did not come to pass. That's the difference between a prediction and a projection. A prediction is an assertion that a certain event will happen. A projection is a calculation based on certain trends continuing for a certain period.
Four decades ago, those in the know seemed sure the UK was facing a massive population surge and that it would struggle to cope.
In August 1966, Cambridge agriculture professor Sir Joseph Hutchinson warned that the population was already "as great as the environment can support without degeneration".
It was the greatest challenge of the time, he said. "We have mastered the physical world and the world of biology. We ourselves remain untamed. Our greatest need is to master the threat of our numbers."
Paraphrasing his warnings, the Times reported: "What was the density of holidaymakers the recreational areas could support without deterioration of the holiday environment? The Dorset heaths could indeed degenerate into a sandy waste, the Norfolk Broads into a chain of lifeless ponds, under a holiday load little bigger than now."
A terrifying pre-EasyJet prognosis, but one that captures the spirit of the time. Demographics was a burning issue. Senior figures were gripped by a Malthusian fear that Britain might be swamped, unable to produce enough food to sustain its burgeoning population.
"We are in serious danger of becoming the cancer of our own planet," said scientist Sir Julian Huxley at the time, anticipating today's environmental concerns.
Dropping birth rate
But while the UK population has risen in the four decades since, it has been nowhere near the level projected.
Assumptions about fertility were the main culprit, says Mike Murphy, a professor of demographics at the London School of Economics. "They thought that these were all trends which were continuing... everyone did very badly on fertility."
The demographers had looked at earlier marriages and rising prosperity, and projected continued high fertility. But the 60s represented the end of the baby boom. By the end of the decade, effective contraception was a fact of life, abortion had been made available and women were entering the workplace, with many choosing career over children.
Birth rates dropped by the late 60s
In 1965, the UK population of 54,349,500 was being augmented by a much higher total fertility rate [live births per woman] than now. In England and Wales, the rate in 1965 was 2.85. In 2006 the rate, despite recent increases, was only 1.87.
But the mistakes of the past do not mean the projections made this week should be ignored. Some statistical methods have been dropped or changed, Prof Murphy says. In the 60s, demographers estimated fertility within marriage and the marriage rate and multiplied the two together to get the fertility of the whole population.
"If you get both wrong, you have multiplied two sets of errors and the error is compounded."
Demographers did soon realised they had over-cooked the figures. By 1967 the projection for 2001 had been amended to 71 million and two years later to 66.5 million. By 1973, the estimate for 2001 was 59.368 million. Not so far out after all.
Global projections have been much more reliable, says Prof Murphy, with figures from the 60s fairly close to today's population. Perhaps that is what has given the UN the confidence to take its projections as far as 2300.
Demographers can never know what new wave of migration, social upheaval or technological development is around the corner.
At the end of the 18th Century, Thomas Malthus said "the power of population is indefinitely greater than the power in the earth to produce subsistence for man" and predicted catastrophe. Then the industrial revolution happened.
Demography is a difficult business indeed.
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They may have got the numbers slightly wrong but the fears of the 1960s demographers have been realised. We've got so used to living on this overcrowded little island that we now think it's normal to spend 2 hours a day getting to work, normal to wait months for a hospital appointments, normal for a house to cost 8 times average salary, normal for the police not to investigate crime, normal to be unable to park a car in any town or city. Newsflash - it's NOT normal. These are all symptoms of overpopulation, go to less crowded countries and they don't have these problems.
Matt Munro, Bristol, UK
The population which the planet can support, and the population which the planet can support with a good quality of life, are two very different things. The question is not whether we can live, rather it is about how we want to live.
In terms of quality of life the earth is already overcrowded and we are already experiencing degredation of habitat. This will result in shortages of water, food, and energy and, ultimately in war and disease.
Do something about the population problem or be prepared to live with the consequences.
H. D. Burns, Seattle, USA
But we dont all do those things Matt, I don't spend more than 0.75 hours getting to work, my house cost me only three times my salary and I have never had to wait for any hospital appointment. Yes we are crowded, but so were the slums of yesteryear. Now all the proles aspire to decent living space we use up a lot more room thats all. Sing a diff song.
Ron B, London UK
Crowded? We are one of the least urbanised countries in Europe. You want to see crowded travel alittle. Can I suggst Bangladesh, followed by Japan, Gibralter, Hong Kong, Holland, Singapore... and probably others I haven't thought off.....
Ben Shepherd, Farnham, Surrey
Less crowded countries have the same problems because people are obliged to live in cities. Canada has half the population of the UK and 25 times the space. But our problems are identical to the ones cited. Be thankful you have, from a visitors perspective, superb public transport. Ours is 19th Century.
Geoffrey Barnes, Wyevale Ontario Canada
The gist of the article seems to be that we needn't heed the demographic warnings. The estimates might well be wrong- but they could just as well be too small as too large. The problems Mr. Munro points to are very real and are only going to get worse. This country can only offer a good quality of life to a limited number of people. Obviously, something will have to change if we're to avoid an ever more tightly controlled way of life.
Ben Turner, London, UK
Matt - if you go can I have your parking space?