One of the most powerful movements of the last half-century directed its energeis toward avoidance of what it termed the “population explosion.” Some leaders in the movement were ideologues driven by contremporary environmental theories. Others were leftward thinkers with a basic antipathy toward large families and “pro-natalist” worldviews.

Yet others were motivated to concern by the realization that limited resources could threaten human healthy, welfare, and happiness. This is not a ridiculous concern, but the evidence often claimed as proving a resource crisis was dubious at best. Separating ideology and evidence should be an intellectual concern and moral priority for both liberals and conservatives.

In any event, the warnings of activists like Paul and Anne Ehrlich now look not only wrong, but foolish. The Ehrlichs predicted world-wide famine by the 1970s, a global age of scarcity by the 1980s, and “smog disasters” in Los Angeles and New York that would kill hundreds of thousands over thirty years ago. Their book, The Population Bomb, became a symbol of the age and a manifesto for their movement.

But now, almost 40 years after the Ehrlich’s wrote their book and fear of a population explosion became a hot political issue, it is clear that the real population crisis is low population growth — even birthrates below replacement levels — in much of the world.

The Globe and Mail [Toronto] offers an interesting analysis of this phenomenon in “The Growing Problem of a Shrinking Population,” published in the October 8, 2005 issue of the paper.

France is now paying for couples to have a third child. Scandanavian countries are dropping their population-control policies in favor of having more children. Without a large number of young people, the population crisis becomes how to support an aging population, feed the people, sustain the economy, and pay the bills.

A word from Britain, courtesy of The Guardian [London]: [S]tatisticians point to a simple, stark fact: people are having fewer and fewer children. In the 1970s global fertility rates stood at about six children per woman. Today the average is 2.9 – and falling. Such a rate will still see the world’s population rise to 9 billion by 2050, an increase of 50 per cent on today’s figure. That is not good news for the planet, but it is far less alarming than the projections of 15 billion that were once being made. More to the point, statisticians predict that, after 2050, the number of humans will go down, the first major long-term fall since the Black Death.

As sociologist Ben Wattenberg states in his book, Fewer: How the New Demography of Depopulation Will Shape Our Future: ‘Never in the last 650 years, since the time of the Plague, have birth and fertility rates fallen so far, so low, for so long, in so many places.’

So the urging by Trade Secretary Patricia Hewitt that it is now the patriotic duty of the nation’s women to have children makes some sense. As she told the CBI last week: ‘We won’t have a workforce if people do not have children.’

She has a point. By 2050 we will have stopped replacing ourselves with enough youngsters. At present the median age of people on this planet is 26; within 100 years, if current trends continue, that will have doubled. More and more old people will have to be supported by fewer and fewer young people. Populations will go down and also become badly unbalanced. Today 10 per cent of the world’s population is 60 years or over, a figure set to rise to more than a third by 2100.