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Population growth rate (percent)
Population Growth Rates of Countries
0.0
1.0
– 1.0
2.0
3.0
2.5
3.5
1.5
0.5
– 0.5
Afghanistan
Brazil
BulgariaGermanyHonduras
India
Indonesia
KenyaNiger
Nigeria
United States
Table 1Population Growth Rates of Countries
Country Population GrowthRate (percent) Location
Afghanistan 2.63
Brazil 0.98
Bulgaria –0.81
Germany –0.04
Honduras 2.02
India 1.58
Indonesia 1.18
Kenya 2.76
Niger 2.88
Nigeria 2.38
United States 0.88
Population growth models predict that the total number of people added to the world
population in developing countries will be greater than the total number of people added
in the industrially developed countries. For example, between now and 2050, the develop-
ing country Niger—shown in Table 1—will be one of the fastest growing countries. Assum-
ing that the growth rate remains the same, its population is expected to expand from 13
to 53 million people. The industrially developed country Bulgaria is expected to have a
population decline from seven to five million people in the same time period.
Zero population growth
Another trend that populations can experience is zero population growth. Zero population
growth (ZPG) occurs when births plus immigration equals deaths plus emigration for a
generation. This will mean that the population has stopped growing, because births and
deaths occur at the same rate. Once the world population reaches ZPG, the age struc-
ture eventually should be more balanced with numbers at pre-reproductive, reproduc-
tive, and post-reproductive ages being approximately equal.
Zero population growth is a goal of many countries and societies. Many population
planners and environmentalists believe that ZPG will contribute to the sustainability of
Earth’s ecosystems.
CROSSCUTTING CONCEPTS
Scale, Proportion, and QuantityCarefully study the data presented in
Table 1. Research to find the current population of each of these countries.
Assuming that the growth rate remains the same, determine what the population
of these countries will be in 10 years. Select a country that you think has a
problematic trend and prepare a report for its government summarizing the
population trend for the next decade. Use your evidence to identify potential
problems and suggest solutions for these problems.
STUDY TIP
Interactive ReadingAs you read, write
three questions about human popula-
tion dynamics. The questions should
begin with why, how, where, or when.
Ask a partner the questions about the
content in the module.
90 Module 4 • Population Ecology