Population Aging in Canada and the United States

Abstract

Population aging is a global phenomenon. The populations of developed nations have aged quickly over the last fifty years, shifting from a median age of 29.0 in 1950 to a median age of 38.6 in 2005 (United Nations 2007). Although the populations of developing nations are younger, with a median age of 25.5, these populations are expected to age rapidly in the future (United Nations 2007). As described in Chapter 1 of this handbook, the aging of the human population is principally the result of worldwide fertility decline, although reductions in old age mortality also play a role. This set of changes is part of the demographic transition, the process by which societies move from high fertility and mortality to low fertility and mortality (Kirk 1996). In turn, these demographic changes are intertwined with social and economic change such that the demographic transition is typically considered a component of modernization.