Demographic Upheaval

Author:David E. Bloom

The world will struggle with population growth, aging, migration, and urbanization


Demographic Upheaval Finance & Development, March 2016, Vol. 53, No. 1

David E. Bloom

The world will struggle with population growth, aging, migration, and urbanization

Humankind is being buffeted by the forces of demographic change.

The most prominent changes are rapid population growth in some developing economies and shifting shares of adolescents and young adults in others, increasing longevity and population aging throughout the world, and urbanization and international migration.

All pose formidable challenges—threatening economic growth, fiscal stability, environmental quality, and human security and welfare.

But none are insurmountable. They will be best dealt with if public and private policymakers act decisively, collaboratively, and soon. That includes reform of retirement policy, development of global immigration policy, provision of contraception to many millions of women, and further improvements in child survival and treatment of chronic disease.

World population growsPopulation growth was extremely slow throughout most of human history. It took until the early 19th century for world population to hit 1 billion and until the 1920s to reach 2 billion. But during the past century, world population has grown significantly faster. It reached 3 billion in 1960 and jumped to 7 billion in 2011.

At the beginning of 2016, world population was 7.4 billion, and it is projected to increase another 83 million this year—representing the difference between 140 million births and 57 million deaths. Medium-variant projections by the United Nations Population Division (UNPD), which assume that fertility behavior evolves consistently with past trends and patterns, indicate that world population will surpass 8 billion in 2024, 9 billion in 2038, and 10 billion in 2056. Reaching 10 billion would be the equivalent of adding China and India to the current world population.

Admittedly, there is some uncertainty about these projections. For example, under the UNPD’s low-variant projection (which assumes fertility is half a child lower), world population will not reach 8 billion until 2026; under the high-variant projection (fertility half a child higher), it will reach that level in 2022. But under almost any circumstances, the world is on a historically unprecedented population trajectory (see Chart 1).

Ninety-nine percent of projected 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. Rapid population growth poses significant challenges. Among them is the need to provide jobs for large numbers of people and give them the human capital (quality education, training, and health) they need to be productive. Nations must also lay down the requisite physical capital and infrastructure to support higher employment; otherwise mass suffering and political, social, and economic instability and conflict could become ever more common. Increased inequality across countries could also deter international cooperation, stalling or even reversing the globalization process, which has great potential to elevate standards of living around the world. In addition, rapid population growth tends to impose pressure on ecosystems and natural resources, undermining food, energy, and water security—promoting the degradation of local and global environmental quality and diminishing the prospects for remediation and adaptation.

It has been estimated that a daunting 734 million new jobs are needed globally between 2010 and 2030 to accommodate projected increases in population, account for plausible changes in labor force participation rates, and achieve target unemployment rates of 4 percent or lower for adults and 8 percent or lower for youth.

Where people liveAs the number of people grew over the second half of the 20th century, so did population density, with considerable variation across geographic regions and countries. In 1950, population density ranged from 1.5 people a square kilometer in Oceania to 45 in Asia. Today, it ranges from 5 to 142 across those same regions.

The center of gravity for world population continues to shift to the less-developed regions. It is also shifting from rural to urban areas as a result of migration, rising birth and declining mortality rates in urban areas, and rural settings growing into urban areas. More than half the world’s population now lives in urban areas, up from 30 percent in 1950, and the...

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