Lesson 2: Population

Purpose

The issue of global population is at the very center of geographic inquiry. From the use of resources to the density of people in cars on a freeway to the number of children in a region who are malnourished, issues of population size, composition, age, and socioeconomic characteristics are all aspects of geographic study. This lesson will illustrate the breadth of ways that people and their demographic characteristics are of major geographic and global importance.

Learning Objectives

After completing this lesson, you should be able to accomplish the following:

  1. Define density, rate of increase, fertility, and mortality.
  2. Identify the locations of the major concentrations of human population.
  3. Describe the regional distribution of heavily settled as well as unsettled regions.
  4. Explain the various implications of overpopulation.
  5. Define and interpret different population pyramids.
  6. Explain the global significance of demographic transition.
  7. Explain the significance of the writings of Thomas Malthus.
  8. Identify both those who support and argue against Malthus and his beliefs.
  9. Describe how the global population has changed since 1900.
  10. Identify the size of the global population.

Reading Assignment

Contemporary Human Geography

  • Chapter 2 (pages 26–49)

Commentary

The issue of population is at the heart of many discussions in geography. How many people live in a place? What is its population density? What is the average number of people per telephone, per television, or per medical doctor? To understand the dimensions of population, one must know about distribution by age, gender, occupation, fertility, health, and so on. Demography is the term for the scientific study of population characteristics, and many of the elements of this chapter are part of such analysis. Geographers ask the question of where the planet's 6.7 billion people are located and why some regions are more populated than others.

Where Is the World's Population Distributed?

There are three specific perspectives when looking for the regional patterns of population distribution across the globe: (1) population concentrations, (2) sparsely populated regions, and (3) population density. In terms of concentrations, approximately three-fourths of the world's population lives on only five percent of Earth's surface. There are four major regions of concentration: East Asia, South Asia, Southeast Asia, and Europe. Generally, these four regions of high population concentration are characterized by proximity to major rivers and ocean coastlines, broad low-lying areas of fertile soils, and temperate climate. Eastern North America is sometimes included in this description but is excluded by the textbook and therefore only included here for reference.

East Asia
Photo of crowded Chinese streetFigure 2.1. One-quarter of the world's population lives in East Asia, with five-sixths of that population coming from China.

One-quarter of the world's population lives in East Asia at the western edge of the Pacific Ocean. The People's Republic of China, Japan, Taiwan, and the Koreas are all part of this region. China has some five-sixths of the region's population, and the great majority of China's population lives in the eastern part of the country. In China, as in the Koreas and in Japan, population is very imbalanced in its distribution. Mountains, deserts, and highlands all take up much space but afford little geographic base for human settlement.

South Asia

More than a fifth of the world's population lives in India, Pakistan, Bangladesh, and the island of Sri Lanka. A great concentration of settlements occurs along the major river systems in this area, reminding us again of the central importance of freshwater and coastlines for fishing and trade. In both East Asia and South Asia, more than half of the population lives in rural areas.

Southeast Asia

The people of Southeast Asia occupy an abundance of islands, including Java, Sumatra, Borneo, Papua New Guinea, and the Philippines. Almost 125 million people live on the Indonesian island of Java alone. Although East Asia, South Asia, and Southeast Asia represent less than 10 percent of Earth's land area, these regions are home to more than half of the world's people.

Europe

Together, Western and Eastern Europe and the European portion of Russia contain about one-eighth of the world's people. There is great disparity in population densities within this region, but the real difference between this region and the three Asian regions described above is that three-quarters of Europeans live in cities. The Asian regions have lower rates of urbanization.

Eastern North America

The largest population concentration in the Western Hemisphere is located in the northeastern United States and southeastern Canada. This is a mostly urban region, with less than five percent of the people making their living as farmers.

Figure 2.1.2 on pages 28–29 of the textbook shows the distribution of the world's population. Figure 2.1.1 on page 28 shows a population cartogram. Although a cartogram does not reflect the actual shape or size of the countries, it does show approximate locations and shapes that demonstrate the relative size of each country's population. In the cartogram, India is almost as large as China (though its area is much smaller), because their populations are close in size. Canada is shown as only a thin ribbon—even though it is physically larger than the United States—because Canada's population is small, despite its large geographic area.

Sparsely Populated Regions

Lightly settled landscapes have specific geographical characteristics. Some 20 percent of the Earth's surface is covered by dry lands, which are areas too arid for farming. Deserts are the classic unsettled or very lightly settled landscapes in this category. Even here, though, pastoral peoples sometimes move across such dry landscapes. Other dry lands, such as the Arabian Peninsula, contain major petroleum reserves. In such situations, settlements may be created but at very high expense.

Wet lands are also lightly settled, especially those areas that average more than ninety inches of precipitation annually. Such weather patterns tend to leach soils, making them unproductive. In wet lands, however, people have adopted irrigated rice farming to utilize the abundant rainfall. These tropical farming regions often have very dense population settlements. For example, Bangladesh is a country about the size of Iowa that sustains more than 150 million people, even though it receives heavy monsoonal rains.

Cold lands and high lands also tend to be thinly settled, if they are settled at all. Parts of the Andes Mountains in South America have relatively dense populations of native peoples who adapted to upland locales because of their traditions and the relative cultural freedom (from invading colonizers) such settings provide.

Photo of llamas in the AndesFigure 2.2. Relatively dense populations of native peoples live in parts of the Andes Mountains in South America. Llamas, shown here, are important for their role as pack animals. They graze at high altitudes where productive agriculture is untenable and eventually become a source of meat for the mountain people.

Population Density

The concept of population per unit of land, density, is a very useful demographic and geographic concept. Arithmetic density (also called population density) is the total number of people divided by the area of land. The United States, for example, has an arithmetic density of 80 people per square mile. Bangladesh, a relatively small country with a large population, has 2,750 people per square mile. Canada, a large country with a small population, has only 8 people per square mile. The term for the number of people supported per unit area of arable land (land suitable for agriculture) is called physiological density. A similar term—but with very different implications—is agricultural density. Agricultural density represents the number of farmers per unit of arable land in a specific area. The difference between physiological and agricultural density is a measure of the efficiency of farming in different places. It also provides information about the role of agriculture in the labor patterns of a given place and may indicate the types of crops produced. See Figures 2.2.1, 2.2.3, and 2.2.4 on pages 30 and 31 in the textbook for maps illustrating the different types of population density.

Where Has the World's Population Increased?

Some basic terms must be understood to begin to get a global picture of the issues of population geography. Three of the most fundamental terms are natural increase, fertility, and mortality. Natural increase is the difference between the number of children born in a year and the number of people who died in that year. The difference is usually, but not always, positive—that is, more people are born than die in a year. The natural increase rate (NIR) can be negative in places where there are very low birth or fertility rates and where good health care helps people live longer.

To calculate the NIR, one must know two statistics. The first is the crude birth rate (CBR), which is the total number of live births in a year for every 1,000 people in a country or other political unit. ("Crude" means that the term refers to all people and not just a particular segment of a country's population.) The second statistic required to figure the NIR is the crude death rate (CDR), or the total number of deaths per 1,000 people. The natural increase rate is the percentage by which a population grows (or perhaps declines) annually. If the CBR is 20 and the CDR is 5, the natural increase is 15 per 1,000 people. This means the country is growing at the rate of 1.5 percent annually. It is important to note that NIR does not consider the effect of immigration or emigration.

As of 2008, the world NIR was 1.2 percent. This is a significant decrease from the rate of 2.2 percent in 1963. With a rate of 2.2 percent, the doubling time (the time it would take for the population to double, or increase 100 percent) was 35 years. With the current NIR of 1.2 percent, doubling time has been extended to 54 years. Even with a declining NIR, the population of most countries is growing, just at a slower rate. The actual number of new mouths to feed will continue to grow steadily. If a country has a large population, the economics of such growth can become a threat to political and social stability. If the global NIR rate were to remain steady at 1.2 percent, the world would have a total population of 24 billion by the year 2100. This enormous increase explains why so much attention has been given to population growth and issues related to overpopulation.

The total fertility rate (TFR) is the average number of children a woman is likely to have during her childbearing years (from about age 15 to 49). The TFR varies a great deal globally. In many sub-Saharan African countries the TFR is greater than six, while in most European countries it is less than two. Such variation has a great deal of economic and social significance.

The infant mortality rate (IMR) is the number of deaths of children under the age of one year. IMR is usually expressed as the number of deaths per 1,000 births. The lowest IMR is found in Western Europe (the region with the lowest TFR), and the highest IMR is in sub-Saharan Africa.

Life expectancy is another index of population health. At the extremes of this index, the life expectancy for children born in sub-Saharan Africa averages in the forties, while Western Europeans have an average life expectancy in the upper seventies. The demographic with the highest life expectancy at birth are Japanese women, who are expected to live to an average age of eighty-six years.

Population Pyramids

A population pyramid is a demographic chart that shows age and gender characteristics of a given population (such as that of a country). Population pyramids have good illustrative value in showing the demographic structure of different places and different times. These graphics generally divide the population into five-year age groups, with the youngest at the base of the pyramid and the most senior at the top. By convention, females are generally shown on the left side of the pyramid and males on the right.

Population pyramids take on distinctive shapes at different stages in the demographic transition. (Demographic transition is discussed below.) A country having a population with a very large and young population will have a wide base. A country with a low CBR, well-developed medical facilities, and associated long life expectancy will have a relatively wide cohort at the top of the pyramid. The term used to describe the ratio of younger people (at the base of the pyramid) and older people (at the top of the pyramid) to people in their productive working years is the dependency ratio. Those at the top and bottom of the pyramid tend to need significant social services and are not generally involved in productive, gainful employment. The youthful cohort at the bottom needs schools, daycare centers, and medical services. The older cohorts need medical services as well as nursing-care centers and living facilities. The dependency ratio is shorthand for the percentage of a country's population that depends on the incomes and taxes of the working population (those who are generally between the ages of 15 and 65).

The sex ratio shown by population pyramids expresses the number of females to males in a given population cohort. The pyramid also shows balance or imbalances from age group to age group. This ratio changes from place to place and time to time. For example, places that attract large numbers of immigrants tend to have more males, because it is generally the male who migrates initially, often in search of economic opportunities. His family may join him later, which helps bring the ratio back into balance, but continuing immigration often keeps the male numbers higher. In Alaska, for example, there are 111 males for every 100 females. Frontier areas tend to have imbalances such as this. A postcard from Alaska shows a woman saying, "In Alaska, the odds are good…but the goods are odd!" This means that a woman hoping to meet a man benefits from the abundance of men. But, as the humorous observation suggests, the frontier demands in Alaska mean that the men who migrate there are, well, special in many cases!

Reasons for Different Global Population Growth Rates

The demographic transition, one of the most important concepts of this entire course, is shown in Figure 2.5.2 on page 36 of the textbook. Study the characteristics of the four stages and associated changes. Pay attention to the three lines that illustrate the change in crude birth rates, crude death rates, and natural increase. No other chart has as much significance in explaining the global population patterns that you will see for the rest of your life. Population plays a vital role in the whole fabric of the world around you, as does the demographic transition in the changing patterns of population growth and human well-being. There are four stages of demographic transition. Each is defined by the rate of population growth. The relationship of fertility, mortality, NIR, and impact on human settlement to each of these stages is described below.

Stage 1: Low Growth

This stage is characterized by both high crude birth and death rates. In terms of a time line, it is sometimes suggested that stage 1 took place from about 8,000–10,000 years BC to the AD 1600s. After the Agricultural Revolution (the discovery of the power of the seed), a population's capacity to feed itself and even generate surplus changed a great deal. With the domestication of plants and animals (the major act of the Agricultural Revolution), people began to develop a farming landscape. Fields were sometimes plowed, sometimes fenced, and sometimes irrigated. Most important, though, farmers could choose what crops to grow based on their knowledge of plants and local climate conditions. Prior to this development, people obtained food by hunting and gathering. People who practiced hunting and gathering tended to live in small groups and travel through landscapes in which they knew the timing of food plants coming to ripeness. They also knew animal migration patterns well enough to hunt with some success. When times were good, the people ate well. When there were too many people or when one or two exceptionally dry years came in a row, the availability of food declined, and the population would die or move away. As Figure 2.5.3 on page 37 of the textbook shows, birth rates and death rates fluctuated a great deal during stage 1 of the demographic transition, but the overall rate of net growth was low.

Stage 2: High Growth

For nearly 10,000 years after the Agricultural Revolution, world population grew at a modest pace. People were switching from hunting and gathering to an agricultural pattern of land use. Farming villages became more popular as settlement centers all across the globe. The real change that brought about stage 2 in the demographic transition was another so-called revolution. This was the Industrial Revolution, which began in the middle of the eighteenth century. Small-scale craft enterprises were replaced by large textile factories and other mechanized enterprises. Large numbers of people began to move away from the farming lifestyle of rural areas and toward the city and industrial labor. The wealth that came from this transition allowed cities to reshape their landscapes profoundly. Sewer systems and water delivery systems were installed. Slowly, public health centers were created, at least in part to serve public-health needs of the people. This process slowly and irregularly began to extend the life expectancy of some urban populations. A medical revolution is associated with this transition. Medical discoveries from major centers of research spread to other parts of the world, as medical missionaries, academics, doctor-explorers, and ambitious merchants began to connect cities on a global scale. This diffusion of medical knowledge resulted in a drop in global mortality rates, meaning that more people were living longer. At the same time, fertility levels stayed as high as they had been in stage 1. Consequently, the NIR went higher and higher. The net change in stage 2 was enormous population growth. Many countries today are still in stage 2, because they have access to modern medicine and farming methods, but they have not seen a change in cultural values and educational attainment that often results in having fewer children.

Population pyramid for Angola, a country in stage 2 growthFigure 2.3. This population pyramid shows the population of Angola, a country in stage 2 of the demographic transition. Note the large number of younger Angolans and the relatively small number of older ones. Source: U.S. Census Bureau.
Stage 3: Moderate Growth

In stage 3 of the demographic transition (see Figure 2.5.2 on page 36 of the textbook), the three lines representing the crude birth rate, crude death rate, and natural increase all begin to shift downward. The crude death rate declines because of the continued expansion of medical care, the improvement in living conditions in many urban centers, and the expanding global network of trade in foodstuff and other commodities. For the first time, there is also a decline in the crude birth rate. Most countries easily accept medical innovations that extend life and opportunities to improve water and sewage systems. These countries also develop transportation networks that enable more efficient movement of agricultural commodities, manufactured goods, and human populations searching for employment. However, the other critical factor in the rate of natural increase, the crude birth rate, is more resistant to change. It is in stage 3 that such changes begin to occur more widely, and this change in mindset occurs because of the nature of city space. In the countryside, having more children is seen as an asset because there are always farm chores with which even young children can help. As children grow older, they become even more essential in the household farm economy. When children reach the age of marriage, they usually continue the same pattern as their parents. They may even live in the same expanding farm household. The size of the farm household is disposed to expansion.

The city world, on the other hand, has a very different landscape. Urban children are generally not as productive a part of the family pattern as those in the countryside. Finding space for more children often means less space for the parents and anyone else living in the city apartment or tenement. At the same time, the city setting provides expanded opportunities for education. Generally, the more education a young father or mother has, the smaller the family they will be inclined to have. There are many reasons for this—and it is not universally true—but the pattern expressed in the demographic transition illustrates that the more urban a population is, the lower the NIR will be. This is the great significance of the demographic transition. Today, many countries are rapidly industrializing and urbanizing, which places them in stage 3 of the demographic transition.

Population pyramid for Turkey, a country in stage 3 growthFigure 2.4. Turkey, whose population pyramid is shown here, is rapidly urbanizing, and people are having fewer children. It is in stage 3 of the demographic transition. Source: U.S. Census Bureau.
Stage 4: Low Growth

Stage 4 is the current pattern in countries with the lowest NIR. A large percentage of the population lives in cities. Rural settlement and farm employment decline because fewer farmers can produce more food with new practices and technological advancements. With a greater percentage of people living in cities, there are more educational opportunities for women, more information on family planning and contraception, and frequent examples of small families or families without children. Young couples become aware of pulls other than children that are exerted on their time and income. Consumer goods, for example, may have been a small consideration for a young rural family, but a young couple in a city may see other ways to spend their money and play out their lives. This results in an intellectual transition as well as a demographic transition. Urban influences change patterns of preference, and these changes may even lead to zero population growth (ZPG). ZPG occurs when the TFR is so low that the total population does not change over time. A TFR of 2.1 children per woman tends to lead to ZPG unless a country experiences a steady immigration rate. New immigrants may cause the total population to grow even though the majority of the population has a low TFR. Stage 4 varies greatly from country to country, but it reflects the significant cultural and demographic influences that urban and rural lifestyles have on population growth.

Population pyramid for Japan, a country in stage 4 growthFigure 2.5. Japan is a country in stage 4 of the demographic transition. Notice in the population pyramid that a large portion of the population is past the reproductive age, and the number of people in the younger age groups is smaller. Japan will probably see a population decline over the next several decades if its TFR stays the same. Source: U.S. Census Bureau.
Demographic Transition in England

Initially, England provided much of the observation and study of the demographic transition. The textbook provides dates and specifics for this transition. Stage 1 ends approximately in 1750, when the Industrial Revolution began to change labor and technology patterns in English manufacturing. Population growth prior to that date had been very low and was affected by the Black Plague and associated famines, erratic farm yields, and wars. In 1750, the crude birth rate and the crude death rate were both about 40 per 1,000 people. This combination produced a low rate of population growth.

Stage 2 is marked by the fact that in 1800, the CBR had dropped only to 35, while the CDR had dropped to 20. This means the national population had gone from an NIR of about 0 in 1750 to 1.5 percent just half a century later. England stayed in stage 2 from about 1750 until 1880, and the national population grew from six million to thirty million in that time period. This represents an annual growth rate of 1.4 percent.

Stage 3 began in England in about 1880, when the CBR dropped from 34 to 33, and the CDR was 19. However, the CBR dropped to 18 by 1930 and to 15 in 1970, while the CDR dropped to 12 in 1970. These two significant changes meant that the total population changed from twenty-six million in 1880 to forty-nine million in 1970, or an average growth rate of 0.7 percent per year. England has been in stage 4 from about 1970 to the present. The CBR has varied between 12 and 14 births per 1,000 people. The CDR is at about the same number. This means that in England the TFR has fallen well below the rate needed to maintain a steady population (2.1 children per woman in her childbearing years). Between 1970 and 2000, the English population grew only by one million, largely due to immigration.

Migration

Perhaps the most important aspect of the demographic transition is the impact that migration from the countryside to the city has on patterns of fertility and mortality. The textbook suggests that few countries have reached stage 4, but many countries in Western Europe are getting very close. In many of these countries, the native-born population has moved steadily toward ZPG, but many of the countries are destinations for immigration flows. Families that are a part of this long-distance migration are generally inclined to have more children. This leads to an increase in the national population growth rates and, consequently, keeps the countries more like stage 3 countries than stage 4 countries. The United States has a low natural increase rate of around 0.6 percent, but when immigration is added to the total, the increase rate is closer to 0.9 percent.

Thomas Malthus and Population Growth

Will growth one day outpace the ability of a population to feed itself? This issue comes up because of the writing of the English economist Thomas Malthus. In 1798, he published An Essay on the Principle of Population. This essay—now more than two centuries old—is still at the heart of the Malthusian Doctrine. Malthus proposed that human reproduction is expressed by geometric growth. This means two people give birth to four; four beget eight; eight beget sixteen; sixteen beget thirty-two, etc. Food increases, on the other hand, are expressed by arithmetic growth; one unit of food might be turned into two units of food with very careful farming. Two units might lead to three. And with much care, three units might lead to nearly four units. The pattern, known as the Malthusian Scenario, suggests that this difference in the rates of growth will cause the world's population to outstrip resources and space, and the increases in the food supply will not keep up with population growth.

Changes in technology, the settlement of new farmlands, and a general decline in the rate of global population growth have shown Malthus's predictions to be unrealized. For example, the Malthus projection from 1950 to 2000 would have global population go from 2.5 billion at the 1950 level to 10 billion in 2000. In fact, the world population was just over 6 billion in the year 2000. A Malthusian Scenario is more likely to occur in a less developed country (LDC) where high population growth rates have the potential to outpace economic growth that brings technological advances in agriculture and food production.

Neo-Malthusians are present-day supporters of Malthus's theories. They say the population growth and development in more and more countries could deplete not only food but other resources as well. Geographers and others continue to discuss Malthus and his predictions.

Strategies for Slowing Population Growth

The textbook points out that there are only two ways for countries in stage 2 of the demographic transition to alter the pattern of high population growth. The first is to lower birth rates through economic development. This approach is valued both by more developed countries and less developed countries, because it is accompanied by a better standard of living and longer life expectancy. The second approach is to lower birth rates using contraception or family planning programs. This option is often more difficult, because many cultures still value having many children, and there may be resistance to interference with this very personal decision.

Lower birth rates will be most critical in changing the demographic transition stage of these countries. The most widely considered strategy is promoting economic development. The stronger the development efforts in less developed countries, the stronger the role of education becomes. With more education comes new information about contraception and family planning, careers, children's health needs, and other innovations. A second strategy is the distribution of contraceptives and family-planning information. Money spent in such programs has been shown to change patterns of childbearing more quickly than trying to stimulate economic development. While the social responses to expanded birth-control promotion can be quite varied, most societies seem to accept programs that utilize elements of both economic change and information on family planning.

India versus China

A comparison of how India and China, the world's two most populous countries, have responded to their population situations provides a strong lesson. Each of these countries is home to more than a billion people.

India has had more than fifty years of government support for family planning programs. Although sterilization was an early method of birth control, efforts now focus on education, distribution of contraception devices, and legal abortions. Despite these efforts, India's progress in reducing its population growth has been only modest.

China, on the other hand, has been quite effective in reducing the NIR from two percent in 1950 to one percent today. This has been done largely through government programs that encourage couples to marry later and to have no more than one child. The One Child Policy has been promoted by the government, media, and the country's leaders. It appears likely that India's population will surpass that of China within twenty years unless India is able to substantially reduce its NIR.

Population pyramids for China and IndiaFigure 2.6. As shown in their population pyramids, China and India have different population patterns. China's population is likely to level off and achieve ZPG in the near future, while India's is likely to grow for decades to come. Both have experienced economic development, but China's One Child Policy has moved that country into stage 3 of the demographic transition sooner. Source: U.S. Census Bureau.

Study Questions

These study questions are for your own benefit and should not be submitted to your instructor. You can check your answers against those provided.

  1. Describe the factors that affect the population growth of a place.
  2.  

    Population growth is affected by the age of the population, fertility and mortality (birth and death) rates, the health of a population, and the cultural traditions of a people. When people live in cities, they are likely to have fewer children than people who live in farm settings. The quality of health care also has an impact on mortality rate, and this, too, shows up in growth patterns. Generally, the largest factor is the level of development. Less developed countries are more likely to have higher population growth rates. Immigration also affects population growth.
  3. Explain why it is often easier to lower the crude death rates than the crude birth rates.
  4.  

    Crude death rates (CDR) can be lowered by improvements in sanitation, medical care, education, and food supply. These changes tend to be welcomed universally in any culture. Lowering crude birth rates (CBR) means the introduction of contraception, promotion of family planning, or otherwise encouraging young couples to have fewer children. These steps often contradict traditional cultural or religious practices and are more difficult for people to embrace. CBR tends to decline with increasing development and a growth of urban populations. Large numbers of children in an urban family are not as economically beneficial as the same number of children on a farm.