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Chapter 6: The Human Population and Urbanization
Half the World Denied Basic Sanitation, The Brooks/Cole Environmental Science Video Library 2009,
©2011, DVD ISBN-13: 978-0-538-73355-7
Additional Videos
The Habitable Planet, Video 5
A discussion of how demographers measure population size and growth.
http://www.learner.org/resources/series209.html
Web Resources
GapMinder
A collection of statistics and graphs related to humans.
http://www.gapminder.org/
Digital Integration
Correlation to Global Environment Watch
Ecofeminism Limits to Growth Sustainable Cities
Economic Development Migration of People Urban Environment
Family Planning Poverty Urbanization
Human Health Overpopulation Urban Poor
Instructor’s Manual for Environmental Science, 15th edition
Correlation to Explore More
Exponential Growth Mass Transit
Human Population Change Population Dynamics
Indigenous Cultures Urbanization and Urban Planning
Land Use
Suggested Answers to End of Chapter Questions
Answers will vary but these represent phrases from this chapter. The following are examples of the material
that should be contained in possible student answers to the end of chapter questions. They represent only a
Review
Core Case Study
1. Explain how Portland, Oregon has attempted to become a more sustainable city.
o Since the 1970s, Portland has used strong land-use policies to control its growth, reduce
dependence on automobiles, and preserve green space.
o Portland encourages the development of mixed-use neighborhoods with stores, light
industries, professional offices, high-density housing, and access to mass transit, which
Section 6-1
2. What is the key concept for this section? List three factors that account for the rapid increase in the
world’s human population over the past 200 years. Summarize the three major population growth
trends recognized by demographers. About how many people are added to the world’s population each
year? List eight major ways in which we have altered the earth’s ecosystem services to meet our needs.
Chapter 6: The Human Population and Urbanization
o Increasing use of net primary productivity
o Increasing genetic resistance in pest species and disease-causing bacteria
o Eliminating many natural predators
• There are different points to the debate about growth of the human population. Viewpoints
include:
o There are too many people, due to overpopulation or overconsumption. Slowing human
population growth should be an important priority.
o Technological advances have allowed us to overcome environmental limits and increase the
earth’s carrying capacity for our species.
o A growing population means more workers, consumers, and creative people. There is no
developing countries.
Section 6-2
3. What are the two key concepts for this section? List three variables that affect the population change of
an area and write an equation showing how they are related. What is total fertility rate (TFR)? How has
the global TFR changed since 1955? Summarize the story of population growth in the United States.
About how much of the annual U.S. population growth is due to legal immigration? List six changes in
lifestyles that have taken place in the United States during the 20th century, leading to a rise in per
capita resource use.
• CONCEPT 6-2A Population size increases through births and immigration, and decreases through
deaths and emigration.
• CONCEPT 6-2B The average number of children born to women in a population (total fertility
rate) is the key factor that determines population size
dropped from 5 to 2.5.
• Because of China’s strict one-child population policy, the country’s total fertility rate dropped
from 5.7 to 1.5 between 1972 and 2011.
• In 2013, the United States had about 11.5 million illegal immigrants.
• Six changes in lifestyle:
4. List nine factors that affect birth rates and fertility rates. Define life expectancy and infant mortality
rate and explain how they affect the population size of a country. What is migration? What factors can
promote migration?
• Factors that affect birth rates include:
o Importance of children as a part of the labor force.
o Cost of raising and educating children.
o Availability of, or lack of, private and public pension systems.
o Urbanization.
• Life expectancy is the average number of years a newborn infant can expect to live, and the infant
mortality rate is the number of babies out of every 1,000 born who die before their first birthday.
A longer life expectance and a lower infant mortality will increase population.
• Infant mortality rate is the number of babies out of every 1,000 born who die before their first
birthday. It is viewed as one of the best measures of a society’s quality of life because it reflects a
country’s general level of nutrition and health care.
Section 6.3
5. What is the key concept for this section? What is the age structure of a population? Explain how age
structure affects population growth and economic growth. Describe the American baby boom and
some of its economic and social effects. What are some problems related to rapid population decline
due to an aging population?
• CONCEPT 6.3 The numbers of males and females in young, middle, and older age groups
determine how fast a population grows or declines.
• Age structure refers to the number or percentage of males and females in young (pre-reproductive,
ages 0–14), middle (reproductive, ages 15–44), and older (postreproductive, age 45 and older) age
groups.
Section 6-4
6. What is the key concept for this section? What is the demographic transition and what are its four
stages? Explain how the reduction of poverty and empowerment of women can help countries to slow
their population growth. What is family planning and how can it help to stabilize populations?
Chapter 6: The Human Population and Urbanization
Describe India’s efforts to control its population growth. Describe China’s population control program
and compare it with that of India.
• CONCEPT 6.4 We can slow human population growth by reducing poverty through economic
development, elevating the status of women, and encouraging family planning.
• The demographic transition is a hypothesis explaining population change that occurs as countries
become industrialized and their populations tend to grow more slowly.
o Preindustrial.
o Transitional.
o Industrial.
o Postindustrial.
• Family planning includes educational and clinical services that help couples choose how many
children to have and when to have them.
• For over 50 years, India has tried to control its population growth with only modest success. Due
to cultural preferences for large families and male children, only 48% of couples use birth control,
even though 90% have access to at least one modern birth control method.
Section 6-5
7. What is the key concept for this section? What percentage of the world’s people lives in urban areas?
List two ways in which urban areas grow. List three trends in global urban growth. Describe the three
phases of urban growth in the United States. What is urban sprawl? List five factors that have
promoted urban sprawl in the United States. List five undesirable effects of urban sprawl.
• CONCEPT 6.5 Most cities are unsustainable because of high levels of resource use, waste,
pollution, and poverty.
• About 52% of the world’s people, 81% of all Americans, and 53% of China’s population live in
urban areas.
• Urban areas grow in two ways—by natural increase (more births than deaths) and by immigration,
mostly from rural areas.
• Three major trends in urban population dynamics:
o 2. The numbers and sizes of urban areas are mushrooming.
o Poverty is becoming increasingly urbanized, mostly in less-developed countries.
Instructor’s Manual for Environmental Science, 15th edition
• Between 1800 and 2013, the percentage of the U.S. population living in urban areas increased
from 5% to 81%. This population shift has occurred in three phases:
o First, people migrated from rural areas to large central cities.
• Urban sprawl is the growth of low-density development on the edges of cities and towns.
• Urban sprawl is largely the product of ample affordable land, automobiles, federal and state
funding of highways, and inadequate urban planning.
• Some undesirable impacts of urban sprawl:
o Loss of cropland
o Loss and fragmentation of forests, grasslands, wetlands, and wildlife habitat
8. What are the major advantages and disadvantages of urbanization? Explain why most urban areas are
unsustainable systems. Describe the major aspects of poverty in urban areas. Summarize Mexico
City’s major urban and environmental problems and what government officials are doing about them.
• Four advantages of urbanization:
o Are centers of economic development.
• Most cities are not sustainable because they have a high resource input of food, water, and
materials that result in a high waste output.
• The poor who live in urban areas face a lack of medical services, poor sanitation, and increased
poverty.
Section 6-6
9. What is the key concept for this section? Distinguish between compact and dispersed cities, and give
an example of each. What are the major advantages and disadvantages of motor vehicles? List four
ways to reduce dependence on motor vehicles. List the major advantages and disadvantages of relying
more on (a) bicycles, (b) mass transit rail systems, (c) bus rapid transit systems within urban areas, and
(d) rapid-rail systems between urban areas.
Chapter 6: The Human Population and Urbanization
combination of plentiful land and networks of highways have produced dispersed cities whose
residents depend on motor vehicles for most travel.
Section 6-7
10. Describe the eco-city model. Give five examples of how Curitiba, Brazil has attempted to become a
more sustainable and livable eco-city. What are this chapter’s three big ideas? Explain how Portland,
Oregon, and other cities are applying the six principles of sustainability to become more sustainable
urban areas.
• CONCEPT 6-7 An ecocity allows people to choose walking, biking, or mass transit for most
transportation needs; to recycle or reuse most of their wastes; to grow much of their food; and to
protect biodiversity by preserving surrounding land.
• City planners in Curitiba, Brazil focused on mass transit rather than on the car. High-rise
apartment buildings are placed near major bus routes and have stores in the bottom two floors,
reducing the need for residents to travel. Cars are banned from the downtown area, which has a
• The chapter’s three big ideas are:
o The human population is increasing rapidly and may soon bump up against
environmental limits.
• Smart growth encourages more environmentally sustainable development that requires less
dependence on cars, controls and directs sprawl, and reduces wasteful resource use.
• Eight goals of eco-city design:
o Use solar and other locally available, renewable energy resources and design buildings to be
heated and cooled as much as possible by nature.
o Build and redesign cities for people, not cars.
Critical Thinking
1. Portland, Oregon (Core Case Study) has made significant progress in becoming a more environmentally
sustainable and desirable place to live. If you live in an urban area, what steps, if any, has your community
taken toward becoming more environmentally sustainable? What further steps could be taken?
2. Do you think that the global population of 7.1 billion is too large? Explain. If your answer was yes, what do
you think should be done to slow human population growth? If your answer was no, do you believe that
there is a population size that would be too big? Explain. Do you think that the population of the country
where you live is too large? Explain
Answers will vary but most students will express that the population is too large. They may talk about
China’s one-child rule, but may object to the level of constraint. This is a good place to talk about resource
consumption.
Here is one possible response:
3. If you could say hello to a new person every second without taking a break and working around the clock,
how many years would it take you to greet the 87 million people who were added to the world’s population
in 2013? (Hint: start by dividing 87 million seconds by 60 to find the number of minutes, and go from there
to find the number of years.) How many years would it take for you to greet 7.1 billion people?
4. Identify a major local, national, or global environmental problem, and describe the role that population
growth plays in this problem.
Answers will vary. One possible answer is that overfishing is a major environmental problem in our
5. Some people think that our most important environmental goal should be to sharply reduce the rate of
population growth in less-developed countries, where at least 92% of the world’s population growth is
expected to take place between now and 2050. Others argue that the most serious environmental problems
stem from high levels of resource consumption per person in more-developed countries, which have much
larger ecological footprints per person than do less-developed countries. What is your view on this issue?
Explain.
One possible answer is that both are important and should be addressed. People in less-developed
Chapter 6: The Human Population and Urbanization
If you own a car or hope to own one, what conditions, if any, would encourage you to rely less on your
car and to travel to school or work by bicycle, on foot, by mass transit, or by carpool?
These are a few of the many possible answers: saving money, price of gasoline, parking and/or
7. Do you think the United States (or the country in which you live) should develop a comprehensive and
integrated mass-transit system over the next 20 years, including an efficient rapid-rail network for travel
within and between its major cities? Explain. If so, how would you pay for such a system?
Possible answers would be that we should not develop a comprehensive a mass-transit plan because of
8. Consider the characteristics of an eco-city listed on p. 000. How close to this eco-city model is the city in
which you live or the city nearest to where you live? Pick what you think are the five most important
characteristics of an eco-city and, for each of these characteristics, describe a way in which your city could
attain it.
Answers will vary depending on where the student lives. But the important characteristics to plan for
are:
• Limit building permits
• Draw urban growth boundaries
• Create greenbelts around cities
• Promote mixed use of housing and small businesses
Global Environment Watch Exercise
Find three different projections for the size of the global population in 2050 (Core Case Study). Explain
how the projections were made. To do this, try to find out the assumptions behind each of the projections
with regard to total fertility rates, crude death rates, infant mortality rates, life expectancies, and other
factors. Based on your reading, choose the projection that you believe to be the closest to reality, and
explain why you chose this projection.
Projections for global population in 2050 can be found the following websites:
Instructor’s Manual for Environmental Science, 15th edition
Data Analysis
The chart on page 127 shows selected population data for two different countries, A and B. Study the chart
and answer the questions that follow.
1. Calculate the rates of natural increase (due to births and deaths, not counting immigration) for the
populations of country A and country B. Based on these calculations and the data in the table, suggest
whether A and B are more-developed or less-developed countries and explain the reasons for your answers.
Country A
Rate of natural increase = crude birth rate –crude death rate
r = 43/1000 - 18/1000 = 25/1000 = 2.5%
2. Describe where each of the two countries may be in terms of their stage in the demographic transition
(Figure 6-11). Discuss factors that could hinder country A from progressing to later stages in the
demographic transition.
Country A is probably in stage 2 or the transitional phase of the demographic transition. Birth rates
are still high and the death rates are lower because of advancing living conditions.
3. Explain how the percentages of people under 15 years of age in country A and in country B could
affect the per capita and total ecological footprints of each country.
Chapter 6: The Human Population and Urbanization
In Country A the large number under 15 can have many negative effects on the country as a whole.
Not all of these individuals will be able to find jobs when they try to enter the workforce and many
may not be able to provide for themselves. Poverty rates are likely to increase. Hunger and
malnutrition would become a problem for many people in this large population as land is degraded by
overgrazing or overuse for raising food. Water use issues will get worse. Much of the country’s
