Fertility Rates Are Falling and the Global Population Is Aging, But That's Good for the Planet I worked in Japan for a year as a journalist for TIME in 2006 and 2007, and here's what I realized: the Japanese do do everything first. Cameraphones, Zen Buddhism, little fuel-efficient cars, huge public debt, a stagnant economy, the literary acceptance of comic books-what happens first in Japan eventually makes its way to the rest of the world. And that includes declining birth rates. One of the biggest social issues I covered in Japan was the increasingly low marriage rate among young people and the vanishingly small birth rate, which translated to an aging - and eventually shrinking - population. The issue dominated the media, and I wrote about it several times. But the public angst made little difference. Most young Japanese women simply didn't seem interested in having many children - at least not under the conditions of Japanese society. Now what began in Japan is happening globally. As David Brooks wrote in his New York Times column yesterday, fertility is on the decline in much of the world, from Iran - 1.7 births per woman - to Russia, where low fertility combined with high death rates mean the population is already shrinking. To Brooks the world is facing what the writer Philip Longman has called the gray tsunami - a moment the population over 60 swamps those under 30. And that includes the U.S., which has long had higher birth rates than most developed nations: But even that is looking fragile. The 2010 census suggested that U.S. population growth is decelerating faster than many expected. Besides, it's probably wrong to see this as a demographic competition. American living standards will be hurt by an aging and less dynamic world, even if the U.S. does attract young workers. For decades, people took dynamism and economic growth for granted and saw population growth as a problem. Now we've gone to the other extreme, and it's clear that young people are the scarce resource. In the 21st century, the U.S. could be the slowly aging leader of a rapidly aging world. To Brooks this is a slow-motion disaster. Aging countries will face the burden of caring for large elderly populations without a large resource of young workers to draw on. But here's the thing: a Centrum Silver world may have a silver lining for the planet. MORE: Has Shinzo Abe Lost His Way? First of all, as Amanda Marcotte points out in Slate, it's a little hard to separate Brooks's "concern-trolling" about fertility from the recent political battle over contraception. After all, fertility rates are declining not because people are suddenly having less sex - well, in most countries at least - but because women are exercising the ability to control if and when they become pregnant. And it turns out that once women have the means to control reproduction, they will almost always choose to have fewer children. From Marcotte: Yes, while the rest of the world is noticing that every year, the actual number of human beings on the planet gets bigger and bigger-recently surpassing 7 billion people, many times larger than it was just 100 years ago-conservatives have decided that we're actually suffering a crisis of too few people, a concern that conveniently has implications for women's basic reproductive rights. Brooks manages to get through his entire hand-wringing op-ed without mentioning contraception or abortion, but he doesn't really have to. Even though he stupidly guesses women are having fewer children for mysterious reasons, he can't really be unaware that it's because women don't have to be constantly pregnant anymore. It's true that global aging is going to present some major challenges. Who will take care of the elderly - and more importantly, who will pay for it? Will an older world be less dynamic, slower to change and adapt? Marcotte's colleague, Rachael Larimore, brings up some of those points in a post of her own for Slate: As a society, we have a choice. We can reduce our expectation of what the entitlement state should provide us in our old age. But if we don't reduce our demands, if we want enough money to live on AND free health care AND prescription drugs, we have to look at how we're going to achieve that without bankrupting ourselves. It's all true. Sometimes I worry about a coming generational war over resources, just as I worry about how I'll take care of my own parents in their old age, just as I worry who might take care of me. No kids up. Right now the old are winning in a landslide - it helps to vote in huge numbers - but how long can that imbalance remain? MORE: Population: Is the World Ready for 7 Billion People? Still, I think it's far more likely that we'll rewrite parts of the social contract than suddenly see fertility jump back to pre-contraception levels. Nearly everywhere around the world - in different countries with different religions and different cultures - fertility is declining, often quite rapidly, as women become richer, more educated and as they move to cities. It's not hard to understand why. As people become richer and healthier, the infant mortality level drops - and suddenly parents no longer need to produce many children in hopes that a few will survive to a healthy adulthood. In colonial New England, up to a quarter of all children died before the first year of life - by comparison, the figure is about 10% in modern Somalia. As people move from rural areas to the cities - something happening around the world - extra children go from an economic benefit for farm work to an economic penalty. As women enter the work force - and come to value their leisure time - the oppourtunity and perhaps desire to raise large numbers of children shrinks as well. This isn't just happening in godless Northeastern American cities. The transition is happening almost everywhere - and I don't see it changing, nor do I see why it should. The freedom to control reproduction seems pretty basic to me - it's certainly exercised almost everywhere, even among groups whose religious beliefs are supposedly against it. We're simply going to have to adapt to an aging world. And there's a plus side for the planet. Overpopulation isn't the human catastrophe it was made out to be in the 1970s, when it seemed like we were just a few people away from eating Soylent Green. But the number of people on the planet - and the amount of the stuff they use - is the basic multiplier for nearly all environmental woes, from deforestation to climate change. As I wrote when the global tally hit 7 billion people late last year: the environment is the real victim of overpopulation. So maybe a world that grows slower - and grows older - will put less pressure on the environment, and buy us a few more years to ensure that our energy use, along with our birthrates, reaches a sustainable level. After all, we're supposed to get smarter as we get older. Hopefully that holds true for the planet as well. MORE: The Environment Will Be the Real Victim of Overpopulation MORE: A Post-American World in Progress SPECIAL: The World at 7 Billion