The demographic disaster facing the planet today is not a population explosion but rather depopulation. As I wrote last week, for world population to replace itself, the birthrate per woman (Total Fertility Rate or TFR) needs to be at least 2.1. While the current world TFR is just above 2.5, it has declined from 2.8 in just the past six years. Virtually all developed countries, with the notable exception of the United States, and most developing countries are experiencing sharp declines in birthrate.

"Yet we still do face a 'population bomb' of a different sort," notes New American Foundation senior fellow, Phillip Longman in "The Empty Cradle." "But what makes today's economic growth unsustainable is not that it is about to exhaust the Earth's bounty, but that it is consuming more human capital than it produces." Longman continues, "The eventual result, if the (below-replacement level fertility rate) trend continues to run its course, is an exhaustion of human capital — a harried, overworked society in which there are too few people to support the old or tend to the young."

Notwithstanding official and unofficial voices that continue to raise concerns about overpopulation, a number of countries that recognize the severe consequences of depopulation are experimenting with pro-natal policies to increase birthrates. For example, Singapore (TFR 1.58) has established a"baby bonus" policy, which deposits money into a savings account for newborns. The bonus applies only to second and third children.

Michael Balter, writing in Science Magazines, notes that Russian President Vladimir Putin "proposed a fistful of incentives to boost the country's flagging birthrate (TFR 1.25)." Russian population is declining by 700,000 a year. A number of other developed countries have put in place or are working on incentive programs to increase birthrates. According to Balter's sources, however, the baby bonus programs have little effect on birthrates.

What has caused this precipitous decline in birthrate? It turns out that there are pretty standard answers in the academic studies looking at this. Generally, the higher the education the lower the birthrate. The same is true of increased social status. The move to cities from farms decreases fertility. Government policies have an effect. Though it is worth noting that China's barbaric one-child policy only marginally increased its fertility free fall over some of its Asian neighbors.

Simply put, one cause of low birthrates is selfishness and desire for material goals. One study states that "below-replacement fertility levels in developed countries resulted from social changes associated with the pursuit of post-materialist values such as self actualization, individual autonomy and recognition of individual achievement." Having children also declines where "children are seen to reduce individual freedom and self-fulfillment."