For two generations we’ve been lectured about the dangers of overpopulation. But the conventional wisdom on this issue is wrong, twice. First, global population growth is slowing to a halt and will begin to shrink within 60 years. Second, as the work of economists Esther Boserups and Julian Simon demonstrated, growing populations lead to increased innovation and conservation. Think about it: Since 1970, commodity prices have continued to fall and America’s environment has become much cleaner and more sustainable—even though our population has increased by more than 50%. Human ingenuity, it turns out, is the most precious resource.
Low-fertility societies don’t innovate because their incentives for consumption tilt overwhelmingly toward health care. They don’t invest aggressively because, with the average age skewing higher, capital shifts to preserving and extending life and then begins drawing down. They cannot sustain social-security programs because they don’t have enough workers to pay for the retirees. They cannot project power because they lack the money to pay for defense and the military-age manpower to serve in their armed forces.
There has been a great deal of political talk in recent years about whether America, once regarded as the shining city on a hill, is in decline. But decline isn’t about whether Democrats or Republicans hold power; it isn’t about political ideology at all. At its most basic, it’s about the sustainability of human capital. Whether Barack Obama or Mitt Romney took the oath of office last month, we would still be declining in the most important sense—demographically. It is what drives everything else.
If our fertility rate were higher—say 2.5, or even 2.2—many of our problems would be a lot more manageable. But our fertility rate isn’t going up any time soon. In fact, it’s probably heading lower. Much lower.