Low fertility helps the species but threatens cultures and some dreams.
Weddings get me thinking about reproductive success. I went to two this week, both outstanding professional couples, and I couldn't help wondering if and when they might make a contribution to the next generation's genetic and cultural mix.
And I do mean "if."
The New York Times Magazine last week had an article called "No Babies?" about increasingly childless Europe, but the same point could be made about the most educated Americans. The U.S. overall has 2.1 children per couple, the replacement rate. Southern and Eastern Europe are now below 1.3.
We used to cluck our tongues about population doubling times; 1.3 gives you a 45-year halving time. Northern Europe is celebrating with 1.7 or 1.8, believed due to the greater support for working moms in those countries. But that is just postponing the inevitable.
As population ages, Europe must import youth, unlikely to be assimilated by shrinking native populations. Italy will cease to be Italian before Sweden stops being Swedish, but both will happen soon.
The one-child family edict in China is causing similar shrinkage, but Thailand, with no such policy, is down to 1.5 and South Korea and Japan are about tied for lowest at 1.1. According to UN data, 25 countries in the developing world are below replacement.
Worldwide, birthrates themselves have halved since 1972, from an unsustainable 6 to a still expansive 2.9. This rate will continue to drop, but the species will grow until mid-century, when it is slated to stabilize at around 9 billion.
But meanwhile, there will be drastic and transformative shrinkage in Europe. Biologist Paul Ehrlich, who wrote The Population Bomb back in the ‘60s, was interviewed for the Times piece: "It's insane to consider low birthrate as a crisis. Basically every person I know in my section of the National Academy of Sciences thinks it's wonderful that rich countries are starting to shrink their populations to sustainable levels. We have to do that because we're wrecking our life-support systems."
I agree that it's good for the planet and the species. "ZPG," for Zero Population Growth, became a watchword after Ehrlich's book; we need that and more. Some naïve scientists have decided Malthus was wrong, since the nine billion we will have when the species crests can be fed by the world's grain.
But it's not just about grain production. It's about getting the grain to the hungry bellies, fraught with politics and conflict. It's about oil and other commodities, fresh water, garbage, pollution, and global warming.
And it's about whether nine billion can attain even a modest Western life style-a one-bedroom apartment, a refrigerator, a TV set, and a Prius-without, as Ehrlich put it, "wrecking our life-support systems." No one thinks the answer to that is yes.*
So what we need after mid-century is NPG, Negative Population Growth, which in a century or two might reduce our species to true sustainability. But while some places are in rapid NPG, others are still expanding. No one can predict future evolution, but we know some things.
Religiosity is rather heritable, and religious people have more children. So the future is religious, not necessarily a bad thing. The overall shrinkage will in due course save the world, and God will get some credit.
But remember the law of unintended consequences; there will be economic and social consequences both foreseeable and unforeseen. Aside from having an elderly species for the first time in history, we will have lost the extended family. Think of those large Italian and Chinese family dinners; in one generation they will be gone, because there will be no aunts, uncles, or cousins. And the rapid shrinkage of Europe, Japan, and South Korea will eliminate many specific cultural traditions.
At lunch after the wedding yesterday-it was a beautiful Hindu ceremony, joining an Indian to a Polish family-I sat with yet another former student and his new wife. She is thirty-five; both are in the prime of their productive professional lives. When they asked me if I had read the Times article I talked about the need for NPG.
But when she said that she has always dreamed of having a family, I felt my doctor hat settling on my head. This happens when I know something that might be help the person in front of me, the welfare of the species notwithstanding.
I told this loving couple that the thirties are a decade of marked decline in the receptivity of the uterus, independent of the aging of the ovaries. I told them that postponement of childbearing is fine, if you accept a growing risk of permanent failure. I told them that I have seen terrible disappointments.
I would not have made these statements if she had not told me her dreams. To lighten things up before I left, I looked at my watch. I knew they had a great hotel room upstairs. "You have five and a half hours before we have to be back here for the reception."
When I saw them at the reception, they had talked about it.
*Ehrlich's excellent new book, The Dominant Animal: Human Evolution and the Environment, co-authored with Anne Ehrlich, summarizes the details.