Demography is the statistical study of human populations — the size of a given population (a country, for example), fertility and death rates, the age structure as well as population distribution and density. French philosopher and father of sociology Auguste Comte (1798-1857) noted that “demography is destiny.” While this may be an overstatement, demography is crucial in understanding a nation’s potential and weakness.

Demographers estimate that 12,000 years ago global population was no more than 4 million people, approximately the population of present-day Oklahoma. It took 10,000 years (until the time of Christ) for global population to reach 190 million — 56% of the current U.S. population. Global population did not reach 1 billion until about 1802.

With the industrial revolution came the ability to grow enormous quantities of food, and the rise of modern medicine that dramatically reduced death rates, including infant mortality. As fertility rates remained high and death rates plummeted global population exploded, doubling to 2 billion in 126 years (1928), doubling again to 4 billion in 46 years (1974) and again to 8 billion in 48 years (2022). The United Nations projects global population will reach 9.8 billion in 2050 and 11.2 billion in 2100.

Population growth over the past 50 years as well as population increase through the end of this century is almost exclusively (about 99%) occurring in the poorest Asian and African nations. More than half of projected population increase through 2050 will happen in eight countries: India, Egypt, Ethiopia, Tanzania, Pakistan, the Philippines, Nigeria and the Democratic Republic of the Congo.

Population growth in Nigeria will be especially rapid and disconcerting. With a current population of 224 million, Nigeria is projected to have 377 million people in 2050, equal to the combined present-day populations of the United States and Canada, in a nation the approximate land area of Texas, Oklahoma and western Louisiana.

A recent National Geographic article reports that Nigeria is currently “one of the hungriest countries in the world” with the government spending $22 billion a year on food imports. About 19 million Nigerians experience “critical levels of food insecurity” and about a third of the population lives in “extreme poverty.” Where will food come from to feed another 153 million Nigerians in 2050 in a world increasingly plagued by climate change extremes of heat, drought and flooding?

Nigeria’s population plight can be largely understood via two numbers. First is the total fertility rate or TFR, defined as the total number of children born to each female if she were to live to the end of her child-bearing years. Nigeria’s TFR is 5.4 whereas global TFR was 2.2 in 2023. Second is the median age of the population — half is older and half is younger than that number. The median age in Nigeria is 17. By comparison the median age in the United States is 38.1 and in Europe 44.4.

With half of Nigeria’s population under 17, in 17 years these individuals will be between 17 and 34 years of age — their peak reproductive years. This means that even if Nigeria’s TFR was to drop from 5.4 to replacement level (2.1) the population would still increase significantly because so many people are in their peak reproductive years. The median age of Africa is 19, similar to the median age of the aforementioned eight fastest growing countries.

While many Asian and African countries are growing rapidly, the population of Europe is moving from ZPG (zero population growth) to NPG (negative population growth). Europe’s 2023 population of 744 million will decline to 725 million in 2050. Only immigration prevented much of Europe from falling into NPG years ago. Immigration accounted for 80% of Europe’s meager population growth between 2000 and 2018.

The country with the most prominent population decline to date (with a TFR of 1.3) is Japan. The population of this island nation decreased from 128 million in 2010 to 115 million in 2023 and is projected to be 102 million in 2050. The current median age is 48, and 29% of the population is over 65 (compared to 16.8% in the United States), and will increase to 33% in 2050. An aging population with a low TFR means that fewer people are entering the work force every year to support the elderly. How will Japan maintain its position as one of the world’s economic superpowers?

As serious as the demographic situation is in Japan, the most significant population transition in history is unfolding in China. Fearful that the People’s Republic of China could not feed its 980 million people in 1979, the government instituted a “one-child” per family policy although the TFR was already falling. In 2023 China’s TFR was 1.1 (one of the lowest in the world), significantly less than the replacement rate of 2.1. Annual births declined dramatically from 17.86 million in 2016 to 9.02 million in 2022.

Once a country of large extended families, China now has “4-2-1” family structure: four grandparents, two parents and a single child. Children increasingly have no siblings, no cousins, no aunts and uncles.

The high cost of getting married and raising children as well as residing in small apartments are major factors in China’s population decline as millions of young people decide to remain childless. In 2019 just under 255 million people in China were 60 years of age and older. That figure will increase to approximately 500 million in 2050 while the number of people in the “working age” population required to support the elderly declines significantly because of low fertility.

The Shanghai Academy of Social Sciences predicts that China’s TFR will continue to fall resulting in a population of less than 600 million in 2100, down from 1.41 billion today. At its current rate of growth Nigeria would have a population of approximately 675 million in 2021 as well as catastrophic human misery.

Demography may not be destiny, however, the consequences of population dynamics can be profound and long-lasting.

— — —

George J. Bryjak lives in Bloomingdale and is retired after is retired after 24 years of teaching sociology at the University of San Diego.

–

Sources

–

“2023 World Population Data Sheet” (accessed 2024) Population Reference Bureau, www.prb.org

“Age distribution in China from 2012 to 2022” (accessed 2024) Statista, www.statista.com

Larmer, B. and J. Zhang (2923) “A shrinking China,” National Geographic, April pp. 68-91

“Number of births per year in China from 2013 to 2023” (accessed 2024) Statista, www.statista.com

Nwaubani A. (2023) “A growing Nigeria,” National Geographic, April, pp. 46-57

Peng, X. (2023) “China’s shrinking population brings forward the peak of the world’s population,” January 19, Victoria University Melbourne Australia, www.vu.edu.au

Pere, G. (2020) “Immigrant swan song” International Monetary Fund, March, www.imf.org

“Population ageing in China: crisis or opportunity” (2022) November 26, The Lancet, www.thelancet.com

Roser, M. and H. Richie (2023) “How has world population changed over time?” Our World Data, https://ourworlddata.org

Welch, C. (2023) “Earth’s exploding, shifting population” National Geographic, April pp.34-45

“World population projected to reach 9.8 billion in 2050, and 11.2 billion in 2100” (accessed 2024) United Nations Department of Social Affairs, www.un.org