1. The Human Population and Its Impact
Chapter 6

2. Are there too many of us ? Estimated 2.4 billion more people by 2050
about 9.3 billion by 2050, mostly in developing countries
growth rate of world population 1.2% /year
Every week about 1.6 million people are added – 225,000 each day, 2.4 people with each heart beat
Geographically uneven distribution – 1.2 million in developed and 80.8 million in developing nations
Will technological advances overcome environmental resistance that populations face?
Should populations be controlled?

3. Global Connections: UN World Population Projections by 2050

4. Are There Too Many of us ?
Will growing populations cause increased environmental stresses?
Infectious diseases
Biodiversity losses
Water shortages
Traffic congestion
Pollution of the seas
Climate change

5. How Many People Can the Earth Support?
We do not know how long we can continue increasing the earth’s carrying capacity for humans without seriously degrading the life-support system for humans and many other species.

6. Human Population Growth Continues but It Is Unevenly Distributed
Reasons for human population increase
Movement into new habitats and climate zones
Early and modern agriculture methods
Control of infectious diseases through
Sanitation systems
Antibiotics
Vaccines

7. Human Population Growth Continues but It Is Unevenly Distributed
Population growth in developing countries is increasing 15 times faster than developed countries
By 2050, 97% of growth will be in developing countries
Should the optimum sustainable population be based on cultural carrying capacity? - would allow most people to live in reasonable comfort and freedom without impairing the ability of the planet to sustain future generations

8. How Long Can the Human Population Keep Growing?
Thomas Malthus and population growth: 1798
Humans have altered 83% of the earth’s land surface
Can the human population grow indefinitely?
How Long Can the Human Population Keep Growing?

9. NATURAL CAPITAL DEGRADATION
Altering Nature to Meet Our Needs
Reduction of biodiversity
Increasing use of the earth's net primary productivity
Increasing genetic resistance of pest species and disease-causing bacteria
Elimination of many natural predators
Introduction of potentially harmful species into communities
Figure 6.A
Major ways in which humans have altered the rest of nature to meet our growing population’s resource needs and wants. See an animation based on this figure at CengageNOW. Questions: Which three of these items do you believe have been the most harmful? Explain. How does your lifestyle contribute directly or indirectly to each of these three items?
Using some renewable resources faster than they can be replenished
Interfering with the earth's chemical cycling and energy flow processes
Relying mostly on polluting and climate-changing fossil fuels
Fig. 6-A, p. 124

10. What Factors Influence the Size of the Human Population?
Population size increases because of births (fertility) and immigration and decreases through deaths (mortality) and emigration, during a period of time
The average number of children born to women in a population (total fertility rate) is the key factor that determines population size.

11. The Human Population Can Grow, Decline, or Remain Fairly Stable
Population change
Births: fertility
Deaths: mortality
Migration
Population change =
(births + immigration) – (deaths + emigration)
Crude birth rate – number of live births/1000
Crude death rate – number of deaths/1000

12. The World’s 10 Most Populous Countries in 2008
India + China = 36 %
US = 4.5 %
of world’s population

13. Women Having Fewer Babies but Not Few Enough to Stabilize the World’s Population
Fertility rate
Replacement-level fertility rate – average number of children that couples have to replace themselves
2.1 – developed; 2.5-developing
Total fertility rate (TFR) – number of children born to a women in her lifetime
2008 : 2.6 globally
1.6 from 2.5 – developed –down from 1950
2.8 from 6.5 – developing – down from 1950

14. TFR Rates for the U.S. between 1917 - 2008
US fertility rate has declined and remained at or below replacement levels

15. Birth Rates in the U.S. from 1910 to 2008
Drop in TFR has slowed the rate of population growth, but the population is still growing faster than that of any developed country
66% - because births outnumbered deaths
34% from legal and illegal immigration

16. Married women working outside the home 8% 81%
47 years
Life expectancy
77 years
Married women working outside the home 8%
81%
15%
High school graduates
83%
10%
Homes with flush toilets
98% 2%
Homes with electricity
99%
Living in suburbs
10%
Figure 6.6
Some major changes that took place in the United States between 1900 and Question: Which two of these changes do you think were the most important? (Data from U.S. Census Bureau and Department of Commerce)
52%
1900
Hourly manufacturing job wage (adjusted for inflation) $3
2000
$15
Homicides per 100,000 people
1.2
5.8
Fig. 6-6, p. 128

17. Several Factors Affect Birth Rates and Fertility Rates
Children as part of the labor force
Cost of raising and educating children
Availability of private and public pension
Urbanization
Educational and employment opportunities for women

18. Several Factors Affect Birth Rates and Fertility Rates
Infant mortality rate
Average age of a woman at birth of first child
Availability of legal abortions
Availability of reliable birth control methods
Religious beliefs, traditions, and cultural norms

19. Several Factors Affect Death Rates
Why are people living longer and fewer infants dying?
Increased food supply and distribution
Better nutrition
Medical advances
Improved sanitation

20. Two useful indicators of the overall health of people in a country…….
Life expectancy
Infant mortality rate – the number of babies out of 1000 who die before their first birthday. Good indicator, reflects the country’s general level of nutrition and health care
40 countries had lower IMR than US

21. Major reasons for decline in Infant Mortality Rate
inadequate health care for poor women during pregnancy and for their babies after birth
drug addiction among pregnant women
high birth rate among teenagers (dropped to half between 1991 and 2006)

22. Several Factors Affect Death Rates
U.S. infant mortality rate high due to
Inadequate health care for poor women during pregnancy and their infants
Drug addiction among pregnant women
High birth rate among teenagers

23. Migration Affects an Area’s Population Size
Economic improvement
Religious freedom
Political freedom
Wars
Environmental refugees

24. Legal Immigration to the U.S. between 1820 and 2003

25. How Does a Population’s Age Structure Affect Its Growth or Decline?
The numbers of males and females in young, middle, and older age groups determine how fast a population grows or declines.

26. Populations Made Up Mostly of Young People Can Grow Rapidly
Age structure categories
Prereproductive ages
Reproductive ages
Postreproductive ages

28. Generalized Population Age Structure Diagrams
Male
Female
Male
Female
Male
Female
Male
Female
Expanding Rapidly Guatemala
Nigeria
Saudi Arabia
Expanding Slowly United States Australia
China
Stable
Japan
Italy
Greece
Declining
Germany
Bulgaria
Russia
Figure 6.8
Generalized population age structure diagrams for countries with rapid (1.5–3%), slow (0.3–1.4%), zero (0–0.2%), and negative (declining) population growth rates. A population with a large proportion of its people in the prereproductive age group (far left) has a large potential for rapid population growth. See an animation based on this figure at CengageNOW. Question: Which of these figures best represents the country where you live? (Data from Population Reference Bureau)
Prereproductive ages
0–14
Reproductive ages
15–44
Postreproductive ages
45–85+
Fig. 6-8, p. 131

29. Population Structure by Age and Sex in Developing and Developed Countries

30. Figure 6.9
Global outlook: population structure by age and sex in developing countries and developed countries, Question: If all girls under 15 had only one child during their lifetimes, how do you think these structures would change over time? (Data from United Nations Population Division and Population Reference Bureau)
Fig. 6-9a, p. 131

31. Figure 6.9
Global outlook: population structure by age and sex in developing countries and developed countries, Question: If all girls under 15 had only one child during their lifetimes, how do you think these structures would change over time? (Data from United Nations Population Division and Population Reference Bureau)
Fig. 6-9b, p. 131

32. Age-Structure Information used to Make Population and Economic Projections
Baby boomers – added 79 million people, looks like a huge bulge moving up through the country’s age structure. Almost half of the US adult population
Graying of America – 2011 onwards
Shortage in work force

33. Tracking the Baby-Boom Generation in the United States

34. Populations Made Up of Mostly Older People Can Decline Rapidly
Slow decline
Manageable
Rapid decline
Severe economic problems
Severe social problems, larger share of medical care, social security funds
shortage of health workers
labor shortages
Japan,Russia,Germany, Bulgaria,Poland, Ukraine, Greece, Italy, Spain

35. Some Problems with Rapid Population Decline
Can threaten economic growth
Labor shortages
Less government revenues with fewer workers
Less entrepreneurship and new business formation
Less likelihood for new technology development
Figure 6.11
Some problems with rapid population decline. Question: Which three of these problems do you think are the most important?
Increasing public deficits to fund higher pension and health-care costs
Pensions may be cut and retirement age increased
Fig. 6-11, p. 133

36. Populations Can Decline from a Rising Death Rate: The AIDS Tragedy
25 million killed by 2008
Many young adults die: loss of most productive workers
Sharp drop in life expectancy
International community called upon to
Reduce the spread of HIV through education and health care
Financial assistance and volunteers

37. How Can We Slow Human Population Growth?
Experience indicates that the most effective ways to slow human population growth are to encourage family planning, to reduce poverty, and to elevate the status of women.

38. As Countries Develop, Their Populations Tend to Grow More Slowly
Demographic transition stages
Preindustrial
Transitional
May lead to a demographic trap
Industrial
Postindustrial

39. Four Stages of the Demographic Transition

40. Planning for Babies Works
Family Planning
Responsible for a 55% drop in TFRs
In developing countries-42% unplanned pregnancies
Expansion of program problem lack of access
Include teenagers, sexually active unmarried women, and educate men
Slow and stabilize population growth
Invest in family planning
Reduce poverty
Elevate the social and economic status of women

41. 1994 Conference 0n Population and Development in Cairo
encourage actions to stabilize the world’s population at 7.8 billion by 2050, instead of the projected 9.2 billion
Many women in the developing world are trapped in poverty by illiteracy, poor health and unwanted high fertility

42. Empowering Women Can Slow Population Growth
Education
Paying jobs
Human rights
without suppression
“For poor women the only holiday is when you are asleep”

43. Slowing Population Growth in China: the One-Child Policy
Encourages fewer children: TFR from
Literacy Rate : 91%,Life expectancy :73 years
Gender imbalance : million surplus males by 2020
Fast-growing economy
Face serious resource and environmental problems

44. Slowing Population Growth in India
Population control: gender bias
Poverty
Malnutrition
Environmental problems