Changing shape of the age pyramid: towards a cowbell?
The world population is growing: from 7.7bn people today, it will climb to almost 9.8bn in 2050 and exceed 11.1bn in 2100. This growth goes along with a significant change in the age structure of the global population.
The population pyramid below visually represents the age distribution of the world population from 1950 to 2018 and projected until 2100 (data from the UN Population Division: medium projections to 2100). The pyramid plainly fattens over the years, representative of the ongoing global demographic transition. In 1950, a high number of births broadened the base layer, while a continuously high risk of death throughout life narrowed the pyramid toward the top. In 2100, notwithstanding potential large-scale health issues linked to lifestyles (e.g. diabetes), the pyramid is expected to become box-shaped, because of the increasing life expectancy with less risk to die before old age.
Figure: The demography of the World Population from 1950 to 2100.
Although the number of births increases globally over the whole period, projections show that the base of the age pyramid will begin to narrow near 2100, meaning that the number of children born will start to decrease. Indeed, after a peak at 2.1% in the 1960s, the annual population growth rate is experiencing a downtrend, and the global increase in population is more driven by an ageing of citizens than by an increasing number of births. According to projections, the number of people aged 65+ has already surpassed children under 5 years old in 2018 and could surpass those younger than 15 by the 2070s. Different factors such as falling fertility rates, governments’ policies, rural flight, and improving healthcare can explain this.
Moreover, the diagram does not show the disparities behind this global demographic transition. Developed economies may already be closer to a 2050 or 2100 shape, whereas emerging countries still follow a less advanced stage of the age pyramid. Yet, both ends of the spectrum (low-income countries with a very young population or high-income countries with a large elderly population) generate challenges for the working-age populations, which have the responsibility to support young and elders alike.