Right now, the population of the world is growing, paradoxically, at both ends of the age spectrum, for different reasons and with different results.
In the developed world, the widely reported concern is that fewer births, and longer lives among the old, whose numbers are rising, will altogether wreak havoc on social security and health programs designed for post-retirement generations. Contributions from a smaller work-age population will shrink available funds.
Among developing nations in Africa and Asia, as the United Nations Population Fund stresses in its 2018 “State of World Population,” regions of continued high-fertility rates — the number of births a woman is likely to have in her reproductive years — is swelling the ranks of youth. This can also have negative effects of different kinds.
Unmanageably large populations, particularly in poor nations, hinder sustainable development, contribute to the causes of conflict and reflect low levels of human-rights protections, most notably for women, the Population Fund reported.
The Population Reference Bureau, an independent organization in Washington, D.C., that collects and analyzes global data, recently published its 2018 wall-chart-sized data sheet, statistically measuring all nations by 16 demographic indicators, covering population numbers, health and environment.
The data sheet also includes pages of graphics illustrating some major trends and projections. The 2018 issue of the annual publication focuses on changing age structures and some consequences of these demographic shifts.
In the long term, the world is getting older in many if not most places, though life expectancies vary by region and level of development. The global average for life expectancy at birth is now 70 for men and 74 for women, but those numbers fall to the mid-to-low 60s or 50s (often for both men and women) in the least-developed countries, the Population Reference Bureau found.
In nations with the highest level of development, the life expectancy is 76 for men and 82 for women. (The oldest women in the world live in Hong Kong, where their life expectancy is 88.)
Proportions matter. The percentage of people in the world who are 65 or older, 9 percent in 2018, is expected to reach 16 percent by 2050. The percentage of people under age 15 will drop to 21 percent by 2050, down from 26 percent now, the Population Reference Bureau projects, using data from the United Nations Population Division and other sources.
Among the graphical illustrations of these projections, there is a world map showing where one segment of a society — the old or the young or sometimes both — are dependent on the national population or government. A changing or imbalanced dependency ratio is a challenge to policymakers.
Other graphics show, for example, how older men in developing countries participate less in the labor force than older men or women in developed countries — and why — or how the child poverty rate in the United States has exceeded the adult rate for four decades.
The big numbers: by 2050, India’s population will be the world’s largest, at nearly 1.7 billion, with China still at 1.3 billion, and Nigeria a distant third with 411 million, followed by the US (390 million), Indonesia (320 million) and Pakistan (307 million).
As for fertility rates, which is the current focus of the UN Population Fund, the top 10 countries are African, with Niger at the top at 7.4 births per woman. The countries with the lowest fertility rates, all under the “replacement” level of 2.1 births, are in Europe and Asia, led by South Korea with a fertility rate of 1.1, followed by Singapore and Taiwan, both at 1.2. (China is not in the top 10.)
Successful family planning based on incentives, not coercion, along with good reproductive health care, quality education and economic opportunities for women, make a difference, say policymakers.