The one-child policy in China is coming to an end. It has a few years left to run yet in most of the country, but Shanghai?s city government announced in mid-April that divorced people who remarry can have a child together even if they each have a child from a previous marriage.

The one-child policy has allegedly prevented 300 million births since it was enforced nationwide in 1980, which would certainly make a difference : the current population of China is 1.3 billion, and those missing births would have added an entire United States to the total. However, there are suspicions that peasants in the more remote parts of the country may have concealed the births of up to 200 million second or subsequent children ? and there is no doubt at all that the social costs of the policy have been extreme.

So the one-child policy is gradually going ? and China?s birth-rate will probably still remain below the replacement rate. For the great unsung phenomenon of the past twenty years or so has been the collapse in birth-rates even in relatively poor countries where the government doesn?t provide family planning services. In Brazil, the fertility rate has fallen from over six children per woman to just enough to replace the present population (2.2 children per woman) in only forty years. In Iran, women have accomplished about the same feat in just twenty years. It?s a global phenomenon : Vietnam has gone from 5.8 children per woman to 2.3 in twenty years, and Tunisia has gone from 5 to 2.3. Large parts of India already have birth-rates below replacement level (though other parts still have four children per woman). Exactly what is causing this steep fall in birth-rates is debatable, but the closest correlation is with the very steep rise in literacy in the same period : India, for example, went from 28 percent to 56 percent literacy between 1980 and 2000. China?s birth rate is already below replacement level, and its literacy is well over 90 percent.

Worldwide, the worst fears of the last generation are not being realised either. The birth rate is falling rapidly in most developing countries (Sub-Saharan Africa is a partial exception, but the Aids plague is decimating populations there), and in most developed countries the birth rate has already dropped well below replacement level. Japan?s population will fall by 14 percent by 2050, Italy?s by 25 percent, Russia?s by 30 percent. Indeed, this year probably marks the turning point when more people live in countries where births are below replacement level than above it.

Current projections of world population suggest a peak of 8.9 billion around 2050, followed by a decline that could be equally swift.

Does this avert the many environmental crises that are predicted to occur in the next fifty to a hundred years ? In most cases no, because they have more to do with rising per capita consumption of energy and goods, and rising levels of waste, than with sheer numbers of human beings. But more people would make things that much worse, so it is still very good news.