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THE HUMAN POPULATION CRISIS

Most people would agree chat all people in all countries should have access to the basic require­ments of life: food, shelter, and clothing. Over the next century, however, it will become increasingly difficult to meet these basic needs, especially in countries that have not achieved population stabi­lization. Moreover, it is likely that the social, politi­cal, and economic problems resulting from contin­ued population growth in these countries will affect other countries that have already achieved stabi­lized populations and high standards of living. For these reasons, population growth should be of con-corn to the entire world community, regardless of where it is occurring.

    You may recall from Chapter 8 that when the carrying capacity of the environment is reached, the population will stabilize or crash due to a de­crease in the birth rate, an increase in the death rate, or a combination of both. No one knows whether the Earth can support 10 billion or 6 bil­lion humans. It may be that we have already reached Earth's carrying capacity and that the numerous environmental problems we are experi­encing will cause the worldwide population in­crease to come to a halt.

    On a national level, developing countries have the largest rates of population increase and often have the fewest resources to support their growing numbers. In order for a country to support a certain number of humans over an extended period of time, it must have either the agricultural land to raise enough food for those people or enough of other natural resources (for example, minerals or oil) to provide buying power to purchase food.

Population and World Hunger

In 1985, 30 million people in sub-Saharan Africa starved. Although sub-Saharan Africa has the greatest concentration of suffering, many of the world's people do not get enough food to thrive, and in certain areas of the world people, especially children, still starve to death (Figure 9-2). The cause of world hunger, however, is anything hut clear." Experts agree that complex relationships exist among population, world hunger, poverty, and environmental problems, but they do not agree about the most effective way to stop world hunger.

    Those who think that population growth is the root cause of the world's food problems point out that countries with some of the highest fertility rates are also the ones with the greatest food short­ages. They argue that it is imperative to reduce population growth, even through drastic measures such as the establishment of world population quo­tas. Under such a system, a country that exceeded its 'assigned population size would not be eligible for relief from the international community during times of food shortages.

would provide the appropriate technology for the people living in those countries to increase their food production. Also, once a country becomes more developed, its fertility rate should decline, helping to lessen the population prob­lem.

    A third group of people thinks that neither controlling population growth nor enhancing eco­nomic development alone will solve world food problems. They argue that the inequitable distribu­tion of resources is the primary cause of world hun­ger. According to this view, there are enough re­sources, land and technologies to produce food for all humans, but people on the lower end of the socioeconomic scale in many developing countries do nor have access to the resources they need to support themselves.

    These differing viewpoints indicate that the relationship between world hunger and population is complex and may be affected by economic devel­opment as well as by poverty and the uneven distri­bution of resources. Regardless of whether or not population growth is the primary cause of world hunger, however, it is clear that world food prob­lems are exacerbated by population pressures.

Population, Resources, and the Environment

The relationships among population growth, utili­zation of natural resources, and environmental deg­radation are also complex. We address the details of resource management and environmental problems in later chapters, but for now, we can make two useful generalizations. (1) The resources that are essential to an individual's survival are small, but a rapidly increasing number of people (as we see in developing countries) tend to overwhelm and de­plete a country's soils, forests, and other natural re­sources. (2) In developed nations, individual resource demands are large, far above requirements for survival. In order to satisfy their desires rather than their basic needs, people in more affluent nations exhaust resources and de­grade the global environment through extravagant consumption and "throwaway" life styles.

Types of Resources

When examining the effects of population on the environment, it is important to distinguish between the two types of natural re­sources: nonrenewable and renewable. Nonrenewable resources, which include minerals (such as aluminum, tin, and copper) and fossil fuels (coal, oil, and natural gas), are present in limited supplies and are depleted by use. They arc not replenished by natural processes within a reasonable period of time. Fossil fuels, for example, take millions of years to form.

    In addition to a nation's population, several other factors affect how nonrenewable resources are used—including how efficiently the resource is ex­tracted and processed, and how much of it is re­quired or consumed by different groups of people. Nonetheless, the inescapable fact is that Earth has a finite supply of nonrenewable resources that sooner or later will be exhausted. In time, techno­logical advances may enable us to find or develop substitutes for nonrenewable resources. And slowing the rate of population growth will help us buy time to develop such alternatives.

Renewable resources include trees in forests; fish in lakes, rivers, and the ocean; fertile agricultural

soil; and fresh water in lakes and rivers. Na­ture replaces these resources, and they can be used forever as long as they are not overexploited in the short term. In developing countries, forests, fisher­ies, and agricultural land are particularly important renewable resources because they provide food. Indeed, many people in developing countries are subsistence farmers, able to harvest just enough food so that they and their families can survive.

    Rapid population growth can cause renewable resources to be overexploited. For example, when fisheries are over harvested to the point where fish populations are so low that they cannot recover, then there will be too few fish to serve as a food source. A similar problem arises when land that is inappropriate for farming (such as mountain slopes or tropical rain forests) is used to grow crops. Although this prac­tice may provide a short-term solution to the need for food, it does not work in the long run, because when these lands are cleared for farming, their agri­cultural productivity declines rapidly and severe environmental deterioration occurs. Renewable resources, then, are not always renewable. They must be used in a sustainable way—that is, in a manner that gives them time to replace or replen­ish themselves.

    Whereas developed countries waste their re­tries the effects of population growth on natural resources are particularly critical. The economic growth of developing countries is often tied to the exploitation of natural resources. These countries are faced with the difficult choice of exploiting nat­ural resources to provide for their expanding popu­lations in the short term or conserving those re­sources for future generations. (It is instructive to note that the economic growth and development of the United States and of other highly developed nations came about through the exploitation—and in some cases the destruction—of their resources.)

Population: Numbers versus Resource Consump­tion

Whereas it is true that resource issues are clearly related to population size (more people use more resources), an equally if not more important factor is a population's resource consumption. People in developed countries are conspicuous consumers; their use of resources is greatly out of proportion to their numbers. A single child born in a developed

country such as the United States, for example, causes a greater impact on the environment and on resource utilization than do a dozen or more chil­dren born in a developing country. Many natural resources are needed to provide the air conditioners, disposable diapers, cars, video cassette recorders, and other "comforts" of life in developed nations. Thus, the disproportionately large consumption of resources by developed countries affects natural resources and the environment as much as does the population explosion in the de­veloping world.

Population and Environmental Impact: A Simple Model

Although human impact on the environ­ment is complex, we have identified the three factors that are most important in determining this impact: (1) the number of people in a particular area, (2) the effect on the environment of obtain­ing and using the resources in that area, and (3) the resource utilization (amount of resources used) per person. A country is overpopulated if it has more people than its resource base can support without damage to the environment. If we combine our three factors in order to compare human impact on the environment in developing and developed countries, we see that a country can be overpopulated in two ways. People overpopulation occurs when the environment is worsening from too many people, even if those people consume few resources per person. People overpopulation is the current problem in many developing nations. In contrast, consumption overpopulation occurs when each individual in a population consumes too large a share of resources. The effect of consumption over­population on the environment is the same as that of people overpopulation—pollution and degrada­tion of the environment. Many affluent developed nations suffer from consumption overpopulation: developed nations represent only 20 percent of the world's population, yet they consume about 80 per­cent of its resources.

Economic Effects of Continued Population Growth

The relationship between economic development and population growth is complex and difficult to evaluate. Some economists have argued that popu­lation growth stimulates economic development and technological innovation. Others hold that developmental efforts are hampered by a rapidly expanding population. At the present time, most major technological advances are occurring in countries where population growth is low to moder­ate, an observation that seems to support the latter point of view.

    The National Research Council of the U.S. National Academy of Sciences published a report in 1986 that examined whether large increases in population were a deterrent to economic develop­ment. Their panel of experts took into account the complex interactions among world problems such as underdevelopment, hunger, poverty, environ­mental problems, and population growth. While concluding that population stabilization alone would not eliminate other world problems, the panel determined that for most of the developing world economic development would profit from

slower population growth. Thus, population stabili­zation would not guarantee higher living standards Kit would most likely promote economic develop­ment, which in turn would raise the standard of living.

    Illustrating the greater urban growth of developing nations is the fact that most of the world's largest cities today are in developing countries. In 1950, three of the world's ten largest cities were in developing countries: Shanghai (China), Buenos Aires (Argentina), and Calcutta (India). In 1990,

    Urban growth contributes to the deterioration of the nonurban environment, which must provide the large quantities of food, water, energy, building supplies, minerals, and other materials required to maintain a concentrated population. In addition, cities and towns are the sources of water and air pollution that contaminates the surrounding rural areas as well as the cities themselves.

Does urbanization affect the rate at which pop­ulation grows? Urbanization appears to be a factor in decreasing fertility rates, perhaps because family planning services, including access to contracep­tives, are more readily available in urban settings.