The Human Population and Its Impact

1
The Human Population and Its Impact

• Chapter 6

2
Core Case Study Are There Too Many of Us? (1)

• Estimated 2.4 billion more people by 2050
• Are there too many people already?
• Will technological advances overcome
  environmental resistance that populations face?
• Should populations be controlled?

3
Core Case Study Are There Too Many of Us? (2)

• Will growing populations cause increased
  environmental stresses?
• Infectious diseases
• Biodiversity losses
• Water shortages
• Traffic congestion
• Pollution of the seas
• Climate change

4
What is the world and U.S. population now?
What is the US and world population now?
Click here for US Census page
5
Crowded Street in China
6
6-1 How Many People Can the Earth Support?

• Concept 6-1 We do not know how long we can
  continue increasing the earths carrying capacity
  for humans without seriously degrading the
  life-support system for humans and many other
  species.

7
Global Connections UN World Population
Projections by 2050
Fig6-2
8
Human Population Growth Continues but It Is
Unevenly Distributed (1)

• 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

9
Human Population Growth Continues but It Is
Unevenly Distributed (2)

• 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? How do we
  pay for cultural luxuries like wine and beef?
  We can feed fewer people when the rich have
  luxuries? Recall Footprint Survey

10
China
1.3 billion
1.5 billion
1.1 billion
India
1.4 billion
304 million
USA
357 million
240 million
Indonesia
292 million
Pakistan
173 million
229 million
195 million
Brazil
229 million
148 million
Nigeria
205 million
147 million
Bangladesh
180 million
142 million
Russia
2008
129 million
2025
128 million
Japan
119 million
Fig. 6-3, p. 126
11
(No Transcript)
12
(No Transcript)
13
United States Population Projections
14
(No Transcript)
15
California Top 10 GrowthCounty by Percent Change
16
California Top 10 CountiesGrowth by Numbers
17
How will State population change?
How will State population change?
Click for table
18
How will California change in the future?
19
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
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
20
6-2 What Factors Influence the Size of the Human
Population?

• Concept 6-2A Population size increases because
  of 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.

21
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 (births/1000)
• Crude death rate (deaths/1000)

22
Women Having Fewer Babies but Not Few Enough to
Stabilize the Worlds Population

• Fertility rate
• Replacement-level fertility rate
• Total fertility rate (TFR)

23
4.0
3.5
3.0
2.5
2.1
2.0
Births per woman
Replacement level
Baby boom (194664)
1.5
1.0
0.5
0
1990
2010
2000
1920
1930
1940
1950
1960
1970
1980
Year
Fig. 6-4, p. 127
24
Some Major Changes That Took Place in the U.S.
between 1900 and 2000
Fig 6-6
25
(No Transcript)
26
(No Transcript)
27
Several Factors Affect Birth Rates and Fertility
Rates (1)

• 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

28
Several Factors Affect Birth Rates and Fertility
Rates (2)

• 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

29
Several Factors Affect Death Rates (1)

• Life expectancy
• Infant mortality rate
• Why are people living longer and fewer infants
  dying?
• Increased food supply and distribution
• Better nutrition
• Medical advances
• Improved sanitation

30
Several Factors Affect Death Rates (2)

• 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

31
Migration Affects an Areas Population Size

• Economic improvement
• Religious freedom
• Political freedom
• Wars
• Environmental refugees

32
2,000
1,800
1,600
1907
1,400
1914 New laws restrict immigration
1,200
Number of legal immigrants (thousands)
1,000
800
Great Depression
600
400
200
0
2010
2000
1980
1960
1940
1920
1900
1880
1860
1840
1820
Year
Fig. 6-7, p. 129
33
(No Transcript)
34
Where are immigrants from in California?
35
6-3 How Does a Populations Age Structure Affect
Its Growth or Decline?

• Concept 6-3 The numbers of males and females in
  young, middle, and older age groups determine how
  fast a population grows or declines.

36
Populations Made Up Mostly of Young People Can
Grow Rapidly

• Age structure categories
• Prereproductive ages
• Reproductive ages
• Postreproductive ages

37
Generalized Population Age Structure Diagrams
Fig 6-8
38
Population Structure by Age and Sex in Developing
and Developed Countries
Fig 6-9
39
Tracking the Baby-Boom Generation in the United
States
Fig 6-10
40
Active Figure U.S. age structure
41
(No Transcript)
42
(No Transcript)
43
(No Transcript)
44
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
Increasing public deficits to fund higher pension
and health-care costs
Pensions may be cut and retirement age increased
Fig. 6-11, p. 133
45
6-4 How Can We Slow Human Population Growth?

• Concept 6-4 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.

46
Planning for Babies Works

• Family Planning
• Responsible for a 55 drop in TFRs
• In developing countries
• Expansion of program
• Include teenagers, sexually active unmarried
  women, and men
• Slow and stabilize population growth
• Invest in family planning
• Reduce poverty
• Elevate the social and economic status of women

47
Women from a Village in Burkina Faso Returning
with Fuelwood
48
Empowering Women Can Slow Population Growth

• Education
• Paying jobs
• Human rights without suppression
• For poor women the only holiday is when you are
  asleep

49
As Countries Develop, Their Populations Tend to
Grow More Slowly

• Demographic transition stages
• Preindustrial
• Transitional
• May lead to a demographic trap
• Industrial
• Postindustrial

50
Four Stages of the Demographic Transition
51
Active Figure Demographic transition model