1. HUMAN POPULATION
Chapter 7

2. Central Case: China’s One-Child Policy
Population posed problems for China’s environment, economy, and political stability
system of rewards and punishments
decreased population growth, but meant government intrusion in private reproductive choices.

4. Is population growth really a problem?
Some say NO:
People can find or manufacture additional resources to keep pace with population growth.
Nations become stronger as their populations grow.
Some say YES:
Not all resources can be replaced.
Even if they could, quality of life suffers.
Nations do not become stronger as their populations grow.

5. Increasing our carrying capacity
Technology has allowed us to raise Earth’s carrying capacity for our species time and again.
Tool-making, agriculture, and industrialization each enabled humans to sustain greater populations.

6. Population size: Future projections
- Demographers project population growth trends to estimate future population sizes. - Different fertility rate scenarios predict global population sizes in 2050 of 7.4 billion, 8.9 billion, or 10.6 billion.
All these projections assume fertility rates below today’s; at today’s rate, the population would reach 12.8 billion.
Figure 7.7

7. * Rule of 70 and doubling time
Doubling time = DT
Growth rate = R
DT = 70/R
If a city’s population grows at 5% each year it will double in ____ years.
DT = 70/5 = 14 years

8. Age structure: Age pyramids
Canada (left) has a much slower growing population than does Madagascar (right).
Figure 7.10

9. Age structure: “Baby booms”
The United States’ “baby boom” is evident in age bracket 45–55. U.S. age structure will change as baby boomers grow older.
Figure 7.12

10. A population’s sex ratio can affect its growth rate.
Sex ratios
A population’s sex ratio can affect its growth rate.
Figure 7.13

11. * Fertility rates affect population growth rates
Total fertility rate (TFR) = average number of children born per woman during her lifetime Replacement fertility = the TFR that keeps population size stable For humans, replacement fertility is about 2.1.

12. Total fertility rates by region
African nations have the highest TFRs. European nations have the lowest TFRs.

13. Demographic transition: Stages
Figure 7.18

14. * Demographic transition: Stages
Pre-industrial stage: high death rates and high birth rates Transitional stage: death rates fall due to rising food production and better medical care. Birth rates remain high, so population surges. Industrial stage: birth rates fall, as women are employed and as children become less economically useful in an urban setting. Population growth rate declines. Post-industrial stage: birth and death rates remain low and stable; society enjoys fruits of industrialization without threat of runaway population growth.

15. Demographic transition: Stages
Figure 7.18

16. Female education and TFR
Female literacy and school enrollment are correlated with total fertility rate: More-educated women have fewer children.
Figure 7.16

17. Family planning and TFR
Nations that invested in family planning (green) reduced TFRs more than similar nations that did not (red).
Figure 7.17a

18. Affluence and the environment
Poverty can lead to environmental degradation… BUT wealth and resource consumption can produce even more severe and far-reaching environmental impacts.

19. The wealth gap
The richest 20% consumes 86% of its resources, and has >80 times the income of the poorest 20%.
Figure 7.25

20. Viewpoints: Population control?
Timothy Cline
Douglas Sylva
“Governments do not have an interest in further reducing fertility. Nor should they have the authority to do so.”
“Access to reproductive health care, including family planning, is a basic human right.”
From Viewpoints