Friday, March 4, 2016

Global Demography: Tectonic Shifts

Demographic change is a relatively slow and gradual process, but then, so are the shifts of tectonic plates that can lead to earthquakes and volcanoes. The March 2016 issue of Finance & Development, published by the International Monetary Fund, contains five articles on various major population shifts. David Bloom contributed the lead article, called in "Taking the Power Back." He writes:
The world continues to experience the most significant demographic transformation in human history. Changes in longevity and fertility, together with urbanization and migration, are powerful shapers of our demographic future, and they presage significant social, political, economic, and environmental consequences.
Bloom backs up the big claim ("most significant ... in human history") with some vivid examples o shifts that are underway. Here are a few that especially caught my eye.

Some Shifts in Global Population
"Ninety-nine percent of projected [population] growth over the next four decades will occur in countries that are classified as less developed—Africa, Asia (excluding Japan), Latin America and the Caribbean, Melanesia, Micronesia, and Polynesia. Africa is currently home to one-sixth of the world’s population, but between now and 2050, it will account for 54 percent of global population growth. Africa’s population is projected to catch up to that of the more-developed regions (Australia, Europe, Japan, New Zealand, and northern America—mainly Canada and the United States) by 2018; by 2050, it will be nearly double their size. ...
Between now and mid-2050, other notable projected shifts in population include:
  • India surpassing China in 2022 to have the largest national population; 
  • Nigeria reaching nearly 400 million people, more than double its current level, moving it ahead of Brazil, Indonesia, Pakistan, and the United States to become the world’s third-largest population; 
  • Russia’s population declining 10 percent and Mexico’s growing slightly below the 32 percent world rate to drop both countries from the top 10 list of national populations, while the Democratic Republic of the Congo (153 percent increase) and Ethiopia (90 percent) join the top 10; and 
  • Eighteen countries—mostly in eastern Europe (and including Russia)—experiencing population declines of 10 percent or more, while 30 countries (mostly in sub-Saharan Africa) at least double their populations." 
Urbanization: From Megacity to Metacity
"More than half the world’s population now lives in urban areas, up from 30 percent in 1950, and the proportion is projected to reach two-thirds by 2050 . ... The number of megacities—urban areas with populations greater than 10 million—grew from 4 in 1975 to 29 today. Megacities are home to 471 million people—12 percent of the world’s urban population and 6 percent of the world’s total population. The United Nations recently introduced the concept of metacities, which are urban areas with 20 million or more residents. Eight cities had reached “meta” status in 2015. Tokyo heads the list, with 38 million residents—more than the population of Canada. No. 2 Delhi’s 26 million exceeds Australia’s population. Other metacities are Shanghai, São Paulo, Mumbai, Mexico City, Beijing, and Osaka. By 2025, Dhaka, Karachi, Lagos, and Cairo are projected to grow into metacities."
Life Expectancy
"The number of global deaths annually per 1,000 people has declined steadily from 19.2 in 1950–55, to 7.8 today. ... It corresponds to a 24-year gain in global life expectancy—from 47 in 1950–55 to 71 now. Given that the average newborn lived to about age 30 during most of human history, this 24-year increase, an average of nine hours of life expectancy a day for 65 years, is a truly astonishing human achievement—and one that has yet to run its course."



In 1950, 8 percent of the world’s population was classified as old (that is, age 60 or over). Since then, the old-age share of world population has risen gradually to 12 percent today, about 900 million people. But a sharp change is afoot. By 2050 about 2.1 billion people, 22 percent of global population, will be older than 60. The United Nations projects that the global median age will increase from about 30 years today to 36 years in 2050 and that, with the exception of Niger, the proportion of elderly will grow in every country. ...
Japan’s median age of 47 is the world’s highest and is projected to rise to 53 by 2050. But by then South Korea’s median age will be 54. In 2050, 34 countries will have median ages at or above Japan’s current 47. The world’s 15- to 24-year-olds now outnumber those ages 60 and above by 32 percent. But by 2026 these two groups will be equal in size. After that, those over age 60 will rapidly come to outnumber adolescents and young adults. This crossover already took place in 1984 among advanced economies and is projected to occur in 2035 in less-developed regions.
For insights into the possible implications of these trends, the imaginations of science fiction writers may be as relevant as the social science research literature. I'll just say that a number of assumptions that we take more-or-less granted for granted--say, about patterns of immediate family, extended family, age distribution of population, the shape of communities, and location of world population--are going to be transformed. Much of the change will happen in my own lifetime, and it will shape the world in which my children live.

For a post from a few weeks back on how demographic shifts will affect the future global workforce and make the distinctions between GDP and GDP per capita ever more important, see "Demography is Destiny: Global Economy Edition" (February 23, 2016).