In 1950, there was not a single country where the population was not growing rapidly, the average woman had more than five children in her lifetime, and the birth rate was not dropping significantly anywhere. Then came the new birth-control technologies and the rise of women’s liberation ideologies, and in many Western countries the birth rate dropped by half in ten years. As recently as 1974, however, the median birth rate worldwide was still 5.4 children per woman, so the pessimists were still winning the arguments.
They believed that only literacy could spread the ideas and techniques that made birth rates fall, and that literacy would not grow fast enough. Well, literacy has grown a lot faster than they expected – between 1980 and 2000, literacy rose from 18 percent to 47 percent in Afghanistan; from 33 percent to 64 percent in Nigeria; from 66 percent to 85 percent in China; and from 69 percent to 87 percent in Indonesia. But birth rates have dropped even faster than literacy has risen: the global average is now 2.7 children per woman.
Some of the most startling recent drops have been in places where women’s illiteracy is still quite high – Bangladesh and parts of India, for example – so we clearly need a broader criterion than mere literacy. In fact, any form of mass media, including broadcast media that do not require literacy, seems to have the same effect on the birth rate. (Though purely local cultural factors also play a role: Pakistan and Bangladesh both had a birth rate of 6.3 in 1981; now Bangladesh’s is 3.3, while Pakistan’s is still 5.6.)
The global birth rate may be no more than a decade away from dropping to replacement level, 2.2 children per woman. Most developed countries have already dropped well below that rate. This does not immediately stop population growth, since all the children who have already been born will have a child or two themselves, and then live for another fifty years afterwards. It does not solve the environmental crisis either, since all of these seven or eight billion human beings will aspire to the kind of lifestyle now enjoyed only by the privileged billion or so.
But it does mean that populations almost everywhere will start graying within the next decade, and in due course, the old will come to outnumber the young. (The exceptions are almost all in African and Arab countries which together amount to only a tenth of the world’s population.) Based on historical precedent, countries where the average age is rising are unlikely to become aggressor nations. Peace through exhaustion, perhaps?