Monday, March 28, 2005
Two other comments re: demographic change.
First, anti-natal policies work. Iran has experienced what I think is the steepest, certainly among the steepest, declines in fertility in any country in recent years. In 1985, the average Iranian woman had 5.6 children; now, the number is below 2. The change is not just in urban areas; the decline is even more dramatic in rural areas. The only part of the country that now has >3.0 children/woman fertility is the remote, ethnically distinct, deeply impoverished and rather wild region of Baluchistan. One reason for this dramatic decline: the aggressive promotion of contraception and birth-spacing by, yes, the government of the Islamic Republic, which did a 180-degree reversal from their early pro-natalist policies. China, obviously, is the, well - I won't say poster child because that would be in poor taste - classic example of a country that dramatically changed its demographic profile through conscious anti-natalist policymaking, but there are other, less dramatic instances in the Islamic world, including Indonesia and Bangladesh. It's notable that Indonesia has experienced faster fertility-rate declines than neighboring Malaysia, and Bangladesh faster fertility declines than "nearby" Pakistan (actually, they are nowhere near each other, but they used to be the same country, so what the heck), because in each case the *poorer* country experienced faster fertility declines than the richer country, because of government anti-natalist policies.
Second, I hope this isn't too obvious, but a major reason why demographic change can happen quickly is the constraints of female biology. A woman's most fertile years are from her late teens through her early twenties. If the age of first marriage for women is 18, the average fertility in that society is going to be a lot higher than if the age of first marriage is 22, just because of the facts of biology. Similarly, if women just space births out by 1 additional year, that dramatically lowers their lifetime fertility. And because there's no opportunity to catch up, any discontinuity in female fertility - caused by economic dislocation, or war, or what-have-you - moves along like a pig in the python. If times are bad for a few years, and the men can't find jobs and so can't marry, so the women of marriageable age in that society therefore marry a few years late, fertility will take a noticeable blip south. Take a look at U.S. fertility trends since 1940 for an illustration of just how big the swings can be. Note further that most of the change on this graph - from just over replacement fertility in 1940, to over 3.5 children/woman in the mid-1950s, and back down to replacement by 1970 - happened before the sexual revolution, before widespread use of the birth-control pill (introduced in the early 1960s), before abortion was legalized generally (abortions didn't take off until the late 1970s, well after the bulk of the decline in fertility), and so on. The point is not to contradict my first point above, but to show that you can have big swings in fertility without dramatic changes in birth-control technology because there is so much "leverage" in the system. You only have to change women's childbearing behavior at the margins to dramatically change the demographic trajectory of a society.
That's all. Not sure why I'm even bringing this all up.