15.1 Demography and population

Comparing these three countries 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 impacts the political climate and economics of the different countries?

Demographic theories

Sociologists have long looked at population issues as central to understanding human interactions. Below we will look at four theories about population that inform sociological thought: Malthusian, zero population growth, cornucopian, and demographic transition theories.

Malthusian theory

Thomas Malthus (1766–1834) was an English clergyman who made dire predictions about earth’s ability to sustain its growing population. According to Malthusian theory    , three factors would control human population that exceeded the earth’s carrying capacity    , or how many people can live in a given area considering the amount of available resources. He identified these factors as war, famine, and disease (Malthus 1798). He termed these “positive checks” because they increased mortality rates, thus keeping the population in check, so to speak. These are countered by “preventative checks,” which also seek to control the population, but by reducing fertility rates; preventive checks include birth control and celibacy. Thinking practically, Malthus saw that people could only produce so much food in a given year, yet the population was increasing at an exponential rate. Eventually, he thought people would run out of food and begin to starve. They would go to war over the increasingly scarce resources, reduce the population to a manageable level, and the cycle would begin anew.

Of course, this has not exactly happened. The human population has continued to grow long past Malthus’s predictions. So what happened? Why didn’t we die off? There are three reasons that sociologists suggest we continue to expand the population of our planet. First, technological increases in food production have increased both the amount and quality of calories we can produce per person. Second, human ingenuity has developed new medicine to curtail death through disease. Finally, the development and widespread use of contraception and other forms of family planning have decreased the speed at which our population increases. But what about the future? Some still believe that Malthus was correct and that ample resources to support the earth’s population will soon run out.

Zero population growth

A neo-Malthusian researcher named Paul Ehrlich brought Malthus’s predictions into the 20th century. However, according to Ehrlich, it is the environment, not specifically the food supply, that will play a crucial role in the continued health of planet’s population (Ehrlich 1968). His ideas suggest that the human population is moving rapidly toward complete environmental collapse, as privileged people use up or pollute a number of environmental resources, such as water and air. He advocated for a goal of zero population growth    (ZPG), in which the number of people entering a population through birth or immigration is equal to the number of people leaving it via death or emigration. While support for this concept is mixed, it is still considered a possible solution to global overpopulation.