Visualizing Environmental Science

174 CHAPTER 7 Human Population Change and the Environment

strains its social security, health, and pension systems.

To reduce such costs, governments with growing elderly

populations may offer incentives to the elderly to work

longer before retiring.

Not all characteristics of an elderly population are neg-

ative, however. Sociologists have observed that in an aging

population the rate of violent crime may decline, as young

adults—those most likely to commit crimes—represent an

increasingly smaller proportion of the population.

1. What is the demographic transition?


2. What is infant mortality rate? How does it vary
   in highly developed and developing countries?

of people in developing countries (including China) in-
creased to 82 percent of the world population. Most of
the population increase during the 21st century will take
place in developing countries, largely as a result of their
younger age structures (Figure 7.14a). These countries,
with their already limited access to resources, will have
economic difficulty supporting such growth.
Declining fertility rates have profound social and
economic implications because as fertility rates drop,
the percentage of the population that is elderly increases
(Figure 7.14b). An aging population has a higher
percentage of people who are chronically ill or disabled,
and these people require more health care and other
social services. Because the elderly produce less wealth
(most are retired), an aging population reduces a coun-
try’s productive workforce, increases its tax burden, and

Percentages of prereproductive and elderly populations for various regions
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Stabilizing World Population

LEARNING OBJECTIVES

1. Relate total fertility rates to each of the
   following: cultural values, social and economic
   status of women, availability of family planning
   services, and government policies.


2. Explain the link between education and total
   fertility rates.

D

ispersal—moving from one place to ano-

ther—used to be a solution for unsustainable

population growth, but not today. As a spe-

cies, we humans have expanded our range

throughout Earth, and few habitable areas remain that

have the resources to adequately support a major

a. Percentages of the population under age 15 in 2011. The higher
this percentage, the greater the potential for population growth.
Note the high percentage of young people in Africa, Latin America,
and Asia, home to many of the world’s developing countries.

Percentage of people under age 15

0

10

20

30

World Africa Latin

America

Asia Oceania North

America

Europe

40

50

Percentage of people older than age 65

World Africa Latin

America

Asia Oceania North

America

(^0) Europe
5
10
15
20
b. Percentages of the population older than 65 in 2011.
Lower fertility rates lead to aging populations. Note the larger
proportions of elderly in North America and Europe, where
population growth rates are typically slow, stagnant, or declining.
Based on data from Population Reference Bureau 2011. Based on data from Population Reference Bureau 2011.