Reading: Demography and Population Growth

People walking in New York City

At over 7 billion, Earth’s population is always on the move. (Photo courtesy of [“NewYorkStreetScene-People” by Moncrief is in the Public Domain]

Between 2011 and 2012, we reached a population milestone of 7 billion humans on the earth’s surface. The rapidity with which this happened demonstrated an exponential increase from the time it took to grow from 5 billion to 6 billion people. In short, the planet is filling up. How quickly will we go from 7 billion to 8 billion? How will that population be distributed? Where is population the highest? Where is it slowing down? Where will people live? To explore these questions, we turn to demography, or the study of populations. Three of the most important components that affect the issues above are fertility, mortality, and migration.

The fertility rate of a society is a measure noting the number of children born. The fertility number is generally lower than the fecundity number, which measures the potential number of children that could be born to women of childbearing age. Sociologists measure fertility using the crude birthrate (the number of live births per 1,000 people per year). Just as fertility measures childbearing, the mortality rate is a measure of the number of people who die. The crude death rate is a number derived from the number of deaths per 1,000 people per year. When analyzed together, fertility and mortality rates help researchers understand the overall growth occurring in a population.

Another key element in studying populations is the movement of people into and out of an area. Migration may take the form of immigration, which describes movement into an area to take up permanent residence, or emigration, which refers to movement out of an area to another place of permanent residence. Migration might be voluntary (as when college students study abroad), involuntary (as when Syrians evacuated war-torn areas), or forced (as when many Native American tribes were removed from the lands they’d lived in for generations).

The 2014 Child Migration Crisis

Children have always contributed to the total number of migrants crossing the southern border of the United States illegally, but in 2014, a steady overall increase in unaccompanied minors from Central America reached crisis proportions when tens of thousands of children from El Salvador, Guatemala, and Honduras crossed the Rio Grande and overwhelmed border patrols and local infrastructure (Dart 2014).

Since legislators passed the William Wilberforce Trafficking Victims Protection Reauthorization Act of 2008 in the last days of the Bush administration, unaccompanied minors from countries that do not share a border with the United States are guaranteed a hearing with an immigration judge where they may request asylum based on a “credible” fear of persecution or torture (U.S. Congress 2008). In some cases, these children are looking for relatives and can be placed with family while awaiting a hearing on their immigration status; in other cases they are held in processing centers until the Department of Health and Human Services makes other arrangements (Popescu 2014).

The 2014 surge placed such a strain on state resources that Texas began transferring the children to Immigration and Naturalization facilities in California and elsewhere, without incident for the most part. On July 1, 2014, however, buses carrying the migrant children were blocked by protesters in Murrietta, California, who chanted, “Go home” and “We don’t want you.” (Fox News and Associated Press 2014; Reyes 2014).

Given the fact that these children are fleeing various kinds of violence and extreme poverty, how should the U.S. government respond? Should the government pass laws granting a general amnesty? Or should it follow a zero-tolerance policy, automatically returning any and all unaccompanied minor migrants to their countries of origin so as to discourage additional immigration that will stress the already overwhelmed system?

A functional perspective theorist might focus on the dysfunctions caused by the sudden influx of underage asylum seekers, while a conflict perspective theorist might look at the way social stratification influences how the members of a developed country are treating the lower-status migrants from less-developed countries in Latin America. An interactionist theorist might see significance in the attitude of the Murrietta protesters toward the migrant children. Which theoretical perspective makes the most sense to you?

Population Growth

Changing fertility, mortality, and migration rates make up the total population composition, a snapshot of the demographic profile of a population. This number can be measured for societies, nations, world regions, or other groups. The population composition includes the sex ratio, the number of men for every hundred women, as well as the population pyramid, a picture of population distribution by sex and age.

Male and female population numbers are compared by age range.

Figure 1. This population pyramid shows the breakdown of the 2010 U.S. population according to age and sex. [USpop2010.svg by Ro4444 is in the Public Domain]

As the table illustrates, countries vary greatly in fertility rates and mortality rates—the components that make up a population composition. (Chart courtesy of CIA World Factbook 2014)
Varying Fertility and Mortality Rated by Country
Country Population (in millions) Fertility Rate Mortality Rate Sex Ratio Male to Female
Afghanistan 31.8 5.4% 14.1% 1.03
Sweden 9.7 1.9% 9.6% 0.98
United States of America 318.92 2.0% 8.2% 0.97

Comparing the three countries in the table above reveals that there are more men than women in Afghanistan, whereas the reverse is true in Sweden and the United States. Afghanistan also has significantly higher fertility and mortality rates than either of the other two countries. Do these statistics surprise you? How do you think the population makeup affects the political climate and economics of the different countries?

Think It Over

  1. Given what we know about population growth, what do you think of China’s policy that limits the number of children a family can have? Do you agree with it? Why, or why not? What other ways might a country of over 1.3 billion people manage its population?
  2. Describe the effect of immigration or emigration on your life or in a community you have seen. What are the positive effects? What are the negative effects?
  3. What responsibility does the United States have toward underage asylum-seekers?


1. The population of the planet doubled in fifty years to reach _______ in 1999?

  1. 6 billion
  2. 7 billion
  3. 5 billion
  4. 10 billion