Chapter Summary

Human populations have grown at an unprecedented rate over the past three centuries. By 1999, the world population passed 6 billion people. If the current growth rate of 1.3 percent per year persists, the population will double in 54 years. Almost all of that growth will occur in the less-developed countries of Asia, Africa, and Latin America. A serious concern is that the number of humans in the world and our impact on the environment will overload the earth’s life-support systems.

Thomas Malthus predicted, some 200 years ago, that populations always outstrip their food supplies unless the negative restraints of starvation, crime, and misery bring numbers into balance with resources. Karl Marx, on the other hand, argued that social justice and equitable distribution of the benefits of technology would provide enough for everyone. In fact, population growth, poverty, injustice, and environmental degradation are all interrelated. We probably can’t solve one of these problems without also addressing the others.

The total fertility rate is the number of children born to an average woman in a population. The crude birth rate is the number of births in a year per thousand persons, while the crude death rate is the average number of deaths per thousand persons. The crude birth rate minus the crude death rate gives the rate of natural increase. When this rate reaches a level at which people are just replacing themselves, zero population growth is achieved. For most developed countries, this rate is an average of about 2.1 children per couple.

In the more highly developed countries of the world, population growth has slowed or even reversed in recent years so that without immigration from other areas, populations would be declining. The change from high birth and death rates that accompanies industrialization is called a demographic transition. Many developing countries have already begun this transition. Death rates have fallen, but birth rates remain high. Some demographers believe that, as infant mortality drops and economic development progresses so that people in these countries are more sure of a secure future, the countries will complete the transition to a stable population. Others fear that excessive population growth and limited resources will catch many of the poorer countries in a demographic trap that could prevent them from ever achieving a stable population or a high standard of living.

While larger populations bring many problems, they also may be a valuable resource of energy, intelligence, and enterprise that will make it possible to overcome resource limitation problems. We have many more options now for controlling fertility than were available to our ancestors. Some techniques are safer than those available earlier; many are easier and more pleasant to use. Sometimes, making family-planning programs successful requires significant cultural changes, including improved social, educational, and economic status for women; higher values on individual children; increased responsibility for our own lives; social security and political stability that give people the means and confidence to plan for the future; and knowledge, availability, and use of effective and acceptable means of birth control.