Global Population and Migration
September 13, 2021
Growth. For most of human history, population growth was slow. The world population required 10,000 years to reach 200 million people, and was 190 million during the time of Christ. The world’s population reached one billion in 1800, 1.6 billion in 1900, and 6.1 billion in 2000.
World population growth accelerated in the 20th century
The population growth rate peaked at 2.2 percent a year in the 1960s and 1970s. The annual increase in population was largest in 1987, when the world’s population rose by 83 million.
World population growth peaked in 1987 at 83 million
The world’s population will continue to increase even as the rate of population growth slows because of population momentum, as large cohorts born 20 years ago have children. By 2100, when the UN expects population growth to be 0.1 percent a year, the world’s population is expected to be almost 11 billion.
The world population is projected to be 11 billion in 2100 as the growth rate approaches zero
Distribution. Asia has 60 percent of the world’s people, including over half in the two population giants, China and India, that each have about 1.4 billion people. India’s population increases by 14 million a year, compared with 5.5 million in China, and India is expected to surpass China in population by 2027.
National populations grow due to natural increase and immigration. A total fertility rate of 2.1, meaning that the average woman has 2.1 children over her lifetime, keeps a population stable in the absence of migration. The total fertility rate peaked at five children per woman between 1960 and 1965, and was 2.5 between 2015 and 2020.
Fertility rates vary by country, with women in some African countries having an average of six or more children and those in China, Korea, and southern and eastern Europe having less than 1.5 children each. In 2020, Korea had the lowest fertility rate of 0.8 children per woman and Niger the highest at seven children per woman.
Fertility rates vary by country, from less than 1 child per woman to over 7
Migration. Low fertility countries such as Canada and Germany have growing populations due to immigration. Most people move from poorer to richer areas, and richer countries are net immigration areas.
A migrant is defined by the UN as a person outside her country of birth or citizenship for 12 months or more, regardless of the reason for being abroad or legal status. If the world’s 280 million migrants in 2020 were collected in one place, “migrant nation” would be the fourth largest (China, India, US, Migrant Nation, Indonesia, Pakistan, Brazil, and Nigeria).
Richer countries are net immigration areas (blue)
Most migrants move to nearby richer countries, that is, most migrants remain in the region in which they were born, as indicated by the thick Africa to Africa arrow in the chart below. There is also significant Latin American and Asian migration into North America, and significant African migration to Europe.
Most international migration between 2010 and 2015 was within one region
International migration is expected to increase because of demographic and economic inequalities that motivate individuals to cross national borders. Revolutions in communications, transportation and rights make it easier to learn about opportunities abroad, travel, and stay abroad. Inequalities are hard to reduce and globalization is difficult to reverse, so policy makers often manage migration by adjusting the rights of migrants.
In 1800, Europe had 21 percent of the world’s one billion residents and Africa had 11 percent, that is, Europe had twice as many people as Africa. In 2000, Africa had slightly more people than Europe. If current trends continue, Europe is expected to shrink to 725 million of the world’s 10 billion residents by 2050, and Africa is expected to increase to 2.5 billion or 25 percent of the world’s people. Will Africans emigrate, as Europeans did?
Worldwide GDP was $85 trillion in 2020 (US $21 trillion), an average of $11,000 per person (US $64,000). The 30 high-income countries had a seventh of the world’s people but two-thirds of the world’s economic output, an average income of $44,000 a year, 10 times more than the $4,800 average in the poorer 170 countries. Will young people migrate to achieve incomes that are an average ten times higher than at home?
The communications revolution makes it easier to learn about foreign opportunities, transportation is more accessible and cheaper than ever, and the rights of individuals vis-à-vis governments have increased. Will governments manage migration by changing the item easiest for them to adjust—the rights of non-citizens?