Population Aging: A Demographic and Geographic Overview

Read “Population Aging: A Demographic and Geographic Overview” by Richard Cincotta, published in the National Intelligence Council’s Global Trends 2030 blog, and in the New Security Beat, July, 2012. Download “Population Aging: A Demographic and Geographic Overview” here …

This GT2030 blog, focused on population aging, begins with this introductory essay aimed at familiarizing readers with some of the demographic and geographic particulars of this phenomenon, and with several key demographic terms. The term most in need of definition is, of course, population aging. Strictly speaking, aging is any shift in the population’s age structure (the distribution of individuals, by age) that produces an increase in the median age (the age of the individual for whom one-half of the population is younger). Generally, advances in a population’s median age are associated with increases in the proportion of seniors (aged 65 years and older), and declines in the proportion of children (younger than 15). Sustained population aging leads to a relatively older workforce, slowed workforce growth and slowed growth among school-age children.
While various age-specific patterns of birth, death and migration can induce change in the median age, over the past century two demographic processes have contributed most powerfully to country-level population aging. First and foremost is declining fertility (fertility is usually measured by computing the total fertility rate (TFR), an immediate estimate of the number of children that women are bearing over their reproductive lifetime). The second most influential factor has been increasing longevity. Not all trends associated with modernization, however, contribute to aging. Declines in childhood mortality have served to slow aging’s pace or make it retreat, as have waves of youthful immigrants (until the immigrants themselves age) and occasio
nal baby booms.

Is an advance in the median age bad news? That depends on “where you are” the broad diversity of age structures suggested by today’s lengthy spectrum of median ages—which in 2012 stretches from around 16 years (Niger, Uganda, Mali) to around 45 (Japan, Germany). For states in the youthful phase of the age-structural transition (median age 25.4 years or less; see Figure 1), the near-term net economic, social, political outcomes of aging are overwhelmingly positive. Getting to the next next age-structural phase— the intermediate phase (25.5 to 35.4)—is crucial; it is associated with very high support ratios (working-age adults per child), diminished risk of intra-state conflict, the accumulation of human capital, and higher savings (among “saver” societies).
There are growing indications that states might develop more quickly by sustaining their intermediate phase—which, for very-low-fertility states, has been rather fleeting (for example, China recently departed the intermediate phase after entering 25 years ago). In fact, states that have achieved near-universal secondary education and sustained a lengthy period of economic prosperity and liberal-democratic stability, including the US, have done so during their population’s presence within the so-called age-structural sweet spot: starting in the their intermediate phase and finishing during the first half of the mature phase (the mature phase ranges from 35.5 to 45.4 years).

The forthcoming essays in this blog are focused “beyond the sweet spot.” It is concerned with the challenges and possible outcomes of “advanced aging”—a condition never before encountered—that will evolve in the so-called post-mature phase (median age >45.5 years) of the age structural transition. Countries approaching the end of the mature phase, most in Europe and East Asia, are accumulating large proportions of seniors, most of whom are moving out of the workforce, drawing on pensions, drawing down personal savings and other accumulated assets, and accepting transfers from their children, other relatives, and other public and non-profit sources. As they age, seniors face an increasing risk of morbidity due to chronic illness and declining physical mobility, as well as an increasing risk of poverty.

While improvements in healthcare and nutrition promise to compress the late-in-life period of high morbidity and permit the extension of workforce participation, the projected declines in the number of working-age adults per retiree (the old-age support ratio) in European and East Asian states over the coming two decades is unprecedented. These projections suggest that those states heading for a post-mature future need to deftly manipulate a full range of social and fiscal policy levers in order to mediate, and adapt to, the cost burdens that are poised to descend upon their pension and healthcare systems. Simultaneously, most of these states will likely wrestle with the challenging and politically delicate task of encouraging the reestablishment of near-replacement-level TFR.

The four age-structural phases experienced by Japan (1935, 1970, 1990, 2025 (projected).

As of 2012, only Japan and German have attained the 45-year median-age mark—and just within the past year or two. Significantly, both countries face “negative momentum”; in other words, because of several decades of annual TFRs below 1.5 children per woman and steadily increasing life expectancies, these and other very-low-fertility states are projected to continue to age for the foreseeable future—until old-age mortality dissipates their populations’ currently broad bulges of seniors and middle-agers, and fertility or migration significantly enlarges their childhood and young adult cohorts. In other words, advanced aging is not a momentary inconvenience.

By 2030, advanced aging will have spread widely through Europe (see figure 2: world maps, 2015 and 2030). Current projections by demographers at the US Census Bureau’s International Program Center (International Data Base, June 2011) suggest that the populations of 29 states (each over 1 million residents) will experience a median age over 45.0 years by 2030. Of these, the Census Bureau indicates that 26 will be located in Europe and 3 in East Asia (Japan, Taiwan and South Korea). Despite China’s rapid pace of aging, US Census Bureau projections place its 2030 median age at 43 years, very similar to the UN Population Division’s medium fertility-variant projection for the PRC. The UN Population Division, using a somewhat different set of projection assumptions to produce its medium fertility variant, projects that by 2030 this post-mature group of countries (median age >45.0 years) will consist of 19 states: 14 European, 4 East Asian (including Singapore), and Cuba.

Richard Cincotta is Demographer-in-residence at the Stimson Center in Washington, DC, and a consultant on political demography for the Woodrow Wilson Center’s Environmental Change and Security Program. From 2006-09, he served as a long-range analyst for the National Intelligence Council.


The Course of the Age-structural Transition

The Course of the Age-structural transition. 

Figure 1.  The course of the age-structural transition is pictured by positioning the world’s states (in 2015) in terms of their proportion of young people (less than 30 years of age) and seniors (65 and older).


Initiated by fertility decline, the age-structural transition entails gradual shifts in the relative size of age cohorts through a lengthy, relatively predictable series of configurations. The Age-structural Theory of State Behavior owes much of its predictive potential to: (a.) the power of these configurations to influence, amplify, control, and reflect, a broad range of interacting demographic, social and economic conditions; and (b.) the ability of demographers to predict future configurations using cohort component methodologies.

To describe the age-structural transition (Fig. 1) with some narrative clarity, I employ the classification system published in the (U.S.) National Intelligence Council’s Global Trends series of publications (National Intelligence Council [NIC], 2012, 2017). Although the age-structural transition is continuous, this system intuitively divides the transition into four discrete phases, based on country-level median age (the age of the “middle person”, for whom 50 percent of the population is younger): the youthful; intermediate; mature; and post-mature phases.

Why does Age-structural Theory provide a useful estimate of the current and future behaviors of states?  Clearly, there is more to political action and risk than a country’s demography (isn’t there?).  Indeed, there is. However, the chain of causality that ends in intra-state conflict, democracy, or economic development is varied and complex. Using population age structure, analysts can take a step back and take a statistical view of state behavior, moving away from the close-up determinism that typically pervades country analyses.  An analysis using age structure reflects the state of a system of mutually re-enforcing effects that move between fertility decline (which drives age-structural change), educational attainment and income (Fig. 2). And, because the UN Population Division projects the configurations of every country’s age structure into the foreseeable future (and, some would argue, beyond it), age-structural models, which have been developed with past data, can be applied to the future.

Figure 2.  A graphic representation of the feedbacks that ultimately drive age-structural change.



The Four Age-structural Phases

The four age-structural phases are described in the (U.S.) National Intelligence Council’s Global Trends reports (2008, 2012, 2016). The phases (youthful, intermediate, mature, and post-mature) are described by ranges of median age (the age of the person in the population for whom precisely 50.00 percent of the population is younger). While no hard-and-fast borders exist between these categories, analysts find them useful for mapping and for narrative descriptions of conditions and processes.


The four age-structural phases. From left to right, they are youthful, intermediate, mature and post-mature. The graph shows the positions of of the world’s states in 2015, in terms of median age, and the 5-year rate of change in median age (2010 to 2015). 

The path of the age-structural transition can be described as a non-linear influence on state capacity—in colloquial terms, a “bad-news, good-news, bad-news” story (Cincotta, 2012). Countries in the earliest, high-fertility portion of the transition experience youthful age-structures that present obstacles to attaining high levels of institutional capacity and state legitimacy (Dyson, 2010). In the intermediate and mature phases, working-age adults proportionately dominate the population. Then, in the post-mature phase of the transition, population aging.

With more than half of their population composed of newborns, infants, school-age children, adolescents, and women in their peak childbearing years, demand for health and educational services in youthful states (so-called youth-bulge countries, median age <25.50 years) typically outstrips the state’s institutional capacity. Because annual growth rates among youth cohorts run high, children typically face school placement insufficiency and crowding, and low levels of societal investment per pupil (Lee & Mason, 2011). Meanwhile, young adults in these countries typically endure intense competition for jobs and underemployment (Easterlin, 1968). Politically difficult to manage, youthful populations tend to feature locally powerful extended family and patronage networks (Wusu & Isiugo-Abanihe, 2006), and an elevated risk of intra-state conflict and other forms of political violence (Goldstone, 2012; Urdal, 2006; Goldstone, 2002; Mesquida & Weiner, 1999; Möller, 1968).

The four age-structural phases experienced by Japan (1935, 1970, 1990, 2025 (projected).

Countries that advance into the intermediate phase of the age-structural transition (median age 25.50 to 35.49 years) experience lower proportions of their population among cohorts of dependent children, and higher proportions in the productive, and taxable, working ages (a worker bulge). This transformation, typically the result of fertility decline below 2.5 children per woman, has been associated with improvements in health status, increased per-child investment in schooling (Lee & Mason, 2011), growth in savings (Higgins & Williamson, 1997), increased participation of women in the economy (Bauer, 2001), and often a faster pace of economic development—what has been termed the “demographic dividend” (Bloom et al., 2002; Birdsall & Sinding, 2001).

Economic growth rates tend to slow as states enter the third phase of the age-structural transition, the mature phase (median age 35.50 to 45.49 years). Despite an aging workforce and a growing group of retirees in mature states, favorable economic and political conditions often prevail—a so-called “second demographic dividend” (Lee & Mason, 2006), a situation typically associated with states that amassed human capital during the intermediate phase.

In the final phase of the age-structural transition, states incur another challenging set of distributions: a series of post-mature age structures (median age 45.50 or greater) characterized by a large proportion of seniors and dependent elderly, and declining numbers in the younger working ages. Whereas by 2016 only three states—Japan, Germany, and Italy—have entered this category, some researchers hypothesize that, as a group, future post-mature states will face declining per-capita productivity, fiscal imbalances (Jackson & Howe, 2008), substantial foreign debt (Eberstadt & Groth, 2010), and constrained participation in the international system (Haas, 2007).