ABSTRACT
The dynamics of human population—in particular, fluctuating birth and death rates—can be a powerful force. Not only do they influence the overall growth rate, size, and makeup of a population, they also shape its age structure—the proportion of people in each age group relative to the population as a whole. In most cases, a youth bulge is the result of several decades of rapid population growth. It typically occurs in countries at the earlier stages of the demographic transition: though birth rates remain high, infant and child mortality have begun to fall due to advances in health care and nutrition, resulting in higher proportions of children surviving overall. While aging and sustained population decline are unlikely to be as threatening to global security as large numbers of unemployed young men are, policymakers and economists alike are increasingly concerned about the implications of this development for economic growth and military preparedness.
