1. Applying Population Ecology: The Human Population and Its Impact
Chapter 7
Applying Population Ecology:
The Human Population and Its Impact

2. Is the World Overpopulated?
The world’s population is projected to increase from 7 billion to 9 billion between 2013 and 2050.
The debate over interactions among population growth, economic growth, politics, and moral beliefs is one of the most important and controversial issues in environmental science.

3. Is the World Overpopulated?
Some argue that the planet has too many people.
Some feel that the world can support billions of more people due to technological advances.
There is a constant debate over the need to reduce population growth.
Must consider moral, religious, and personal freedom.

4. human population has grown rapidly: expansion of agriculture & industrial production - lower death rates from improvements in hygiene & medicine.

5. Is the World Overpopulated?
Much of the world’s population growth occurs in developing countries like China and India.
Figure 9-1

6. Where Are We Headed?
We do not know how long we can continue increasing the earth’s carrying capacity for humans.
There are likely to be between billion people on earth by 2050.
97% of growth in developing countries living in acute poverty.
What is the optimum sustainable population of the earth based on the cultural carrying capacity?

7. Where Are We Headed?
U.N. world population projection based on women having an average of ___ children
2.5 (high),
2.0 (medium),
1.5 (low)
Figure 9-2

8. Developed countries grew at 0.1% per year.
Developing countries grew at 1.5% per year. (15 times greater)
2006

9. Factors that Drive Human Population Growth
Demography- the study of human populations and population trends.
Changes in Population Size
Fertility
Life Expectancy
Age Structure
Migration

10. Doubling time- The time it takes for the population to double the number of people Rule of 70 Doubling time = Growth Rate

11. If a population of a country grows at a rate of 5% a year, the number of years required for the pop to double is what?

12. If a population of a country grows at a rate of 5% a year, the number of years required for the pop to double is what?
Rule of 70:
Doubling time = = 14 years 5

13. Changes in Population Size
Immigration- the movement of people into an area
Emigration- the movement of people out of an area
Net migration rate- the diff between immigration and emigration in a given year per 1,000 people in the country.

14. Changes in Population Size (Growth Rate) Crude Birth Rate: (births per 1000 people per yr) Crude Death Rate: (deaths per 1000 people per yr)
Ideal: GR = 0

15. POPULATION SIZE
Population increases because of births and immigration and decreases through deaths and emigration.
Instead of using raw numbers, crude birth rates and crude death rates are used (based on total number of births or deaths per 1,000 people in a population).

16. Growth Rate- includes birth rate, death rate, immigration and emigration Using Raw Numbers: G.R. = (Births – deaths) + (Immigration – Emigration) X Total Population If a population of 10,000 experiences 100 births, 40 deaths, 10 immigrants and 30 emigrants in a year, what is the net annual percentage growth rate?

17. Growth Rate- includes birth rate, death rate, immigration and emigration Using Raw Numbers: G.R. = (Births – deaths) + (Immigration – Emigration) X Total Population If a population of 10,000 experiences 100 births, 40 deaths, 10 immigrants and 30 emigrants in a year, what is the net annual percentage growth rate? G.R. = (100 – 40) + (10 – 30) X 100 = ,000

18. Growth Rate- includes birth rate, death rate, immigration and emigration Using Raw Numbers: G.R. = (Births – deaths) + (Immigration – Emigration) X Total Population If a population of 10,000 experiences 100 births, 40 deaths, 10 immigrants and 30 emigrants in a year, what is the net annual percentage growth rate? G.R. = (100 – 40) + (10 – 30) X 100 = (-20) X , ,000

19. Growth Rate- includes birth rate, death rate, immigration and emigration Using Raw Numbers: G.R. = (Births – deaths) + (Immigration – Emigration) X Total Population If a population of 10,000 experiences 100 births, 40 deaths, 10 immigrants and 30 emigrants in a year, what is the net annual percentage growth rate? G.R. = (100 – 40) + (10 – 30) X 100 = (-20) X , , = 40 = 0.4%

20. Growth rate: Using Crude Rates
Instead of using raw numbers, crude birth rates and crude death rates are used (based on total number of births or deaths per 1,000 people in a population).
(Birth rate - death rate) + (immigration rate – emigration rate) X 100
1000

21. Growth rate: Using Crude Rates
Instead of using raw numbers, crude birth rates and crude death rates are used (based on total number of births or deaths per 1,000 people in a population).
(Birth rate - death rate) + (immigration rate – emigration rate) X 100
1000
G.R. = (Birth rate - death rate) + (immigration rate – emigration rate) 10

22. Growth rate: Using Crude Rates
If the birth rate is 20, the death rate is 30, immigration is 40, and the emigration rate is 10, what is the growth rate for this country?

23. Growth rate: Using Crude Rates
If the birth rate is 20, the death rate is 30, immigration is 40, and the emigration rate is 10, what is the growth rate for this country? G.R. = (B.R. – D.R.) + (I.R. – E.R.) 10

24. Growth rate: Using Crude Rates
If the birth rate is 20, the death rate is 30, immigration is 40, and the emigration rate is 10, what is the growth rate for this country? G.R. = (B.R. – D.R.) + (I.R. – E.R.) 10 = (20 – 30) + (40 – 10)

25. Growth rate: Using Crude Rates
If the birth rate is 20, the death rate is 30, immigration is 40, and the emigration rate is 10, what is the growth rate for this country? G.R. = (B.R. – D.R.) + (I.R. – E.R.) 10 = (20 – 30) + (40 – 10) = = 10 10

26. Growth rate: Using Crude Rates
If the birth rate is 20, the death rate is 30, immigration is 40, and the emigration rate is 10, what is the growth rate for this country? G.R. = (B.R. – D.R.) + (I.R. – E.R.) 10 = (20 – 30) + (40 – 10) = = 20 = 2%

27. Average crude birth rate Average crude death rate
Ideal: CBR = CDR
Average crude birth rate
Average crude death rate 21
World 9
All developed
countries 11 10
All developing
countries 23
Figure 9.3
Global connections: average crude birth and death rates for various groupings of countries in (Data from Population Reference Bureau) 8
Developing
countries
(w/o China) 27 9
2006 data
Fig. 9-3, p. 174

28. 2006 data Africa Latin and Central America Asia Oceania United States38 15
Latin and
Central America 21 6
Asia 20 7
Oceania 17 7
United
States 14
Figure 9.3
Global connections: average crude birth and death rates for various groupings of countries in (Data from Population Reference Bureau) 8
North
America 14 8
Europe 10 11
2006 data
Fig. 9-3, p. 174

29. The 12 Most Populous Countries in the World

30. Life Expectancy Life expectancy- the average age an infant born
can be expected to live

31. Life Expectancy
Infant mortality rate- the number of deaths of children under 1 year of age per 1,000 live births.
Child mortality rate- the number of deaths of children under age 5 per 1,000 live births.

32. Life Expectancy

33. Fertility Rates:
The Replacement-level Fertility the number of children a couple must bear to replace themselves to stabilize a population is ideally 2.0 children.
It is actually slightly higher because some children die.
2.1 in developed countries
2.5 in developing countries because of higher infant mortality

34. Fertility Rates:
Total fertility rate (TFR): the average number of children a woman has during her reproductive years.
In 2006, the average global Total Fertility Rate was 2.7 children per woman.
1.6 in developed countries (down from 2.5 in 1950).
3.0 in developing countries (down from 6.5 in 1950).

35. Declining Fertility Rates: Fewer Babies per Women
The average number of children that a woman bears (TFR) has dropped sharply.
This decline may not be low enough or fast enough to stabilize the world’s population in the near future.

36. Total Fertility Rate: # of babies avg
Total Fertility Rate: # of babies avg. woman will have Replacement Level Fertility: # children to replace parents
Ideal: TFR = Replacement

37. Fertility Rates (notable countries):
Country Name
TFR
Niger
7.68
World’s Highest
Afghanistan
5.50
India
3.28
World Average
2.56
Mexico
2.31
United States
2.06
China
1.54
Japan
1.20
World’s Lowest

38. When Total Fertility Rate = Replacement-level Fertility
Zero population growth

39. Case Study: Fertility and Birth Rates in the United States
Nearly 2.9 million people were added to the U.S. in 2006:
59% occurred because of births outnumbering deaths.
41% came from illegal and legal immigration.

40. Case Study: Fertility and Birth Rates in the United States
In 2006, the total fertility rate in the United States was slightly > 2.0
Figure 9-5

41. Case Study: Fertility and Birth Rates in the United States
The baby bust that followed the baby boom was largely due to delayed marriage, contraception, and abortion.
Figure 9-6

42. Case Study: U.S. Immigration
Since 1820, the U.S. has admitted almost twice as many immigrants and refugees as all other countries combined.
Figure 9-8

43. Factors Affecting Birth Rates and Fertility Rates
The number of children women have is affected by:
The cost of raising and educating them.
Availability of pensions.
Urbanization.
Education and employment opportunities.
Infant deaths.
Marriage age.
Availability of contraception and abortion.

44. Factors Affecting Death Rates
Death rates have declined because of:
Increased food supplies, better nutrition.
Advances in medicine.
Improved sanitation and personal hygiene.
Safer water supplies.
U.S. infant mortality is higher than it could be (ranked 46th world-wide) due to:
Inadequate pre- and post-natal care for poor.
Drug addiction.
High teenage birth rate.

45. POPULATION AGE STRUCTURE
The number of people in each age group determines how fast populations grow or decline.
The number of people younger than age 15 is the major factor determining a country’s population growth.
Changes in the distribution of a country’s age groups have long-lasting economic and social impacts.

46. POPULATION AGE STRUCTURE
Populations with a large proportion of its people in the preproductive ages 1-14 have a large potential for rapid population growth.
Figure 9-9

47. Expansive/rapid growth
Birth rate exceeds the death rate.
Population is getting larger.
Pyramid shaped histogram with wide base.

48. Stable/Slow Growth (Zero Growth)
Birth rate almost equals death rate.
The population is not getting any larger or is growing very slowly.
Histogram shape is straighter and more box-like until old age
Mainly due to immigration

49. Declining (negative growth)
When the birth rate is smaller than the death rate.
The pyramid bulges near the top or is inverted.

50. POPULATION AGE STRUCTURE
Under 15 years old in 2006:
17% in developed countries.
32% of the people in developing countries
Figure 9-10

51. POPULATION AGE STRUCTURE
Today, baby boomers make up nearly half of all adult Americans and dominate the populations demand for goods and services.
Figure 9-11

52. POPULATION AGE STRUCTURE
Death from AIDS and war can disrupt a country’s social and economic structure by removing significant numbers of young adults.
→ leaving very old and very young

53. POPULATION AGE STRUCTURE
About 14% of the world’s population live in countries with stabilizing or declining populations.
Global aging may help promote peace.
Fewer young adults available for service
Smaller families → parents more reluctant to support military that could wipe out offspring
Smaller labor force → competition for workers between industry & military
Less taxes → decreasing government funds

54. POPULATION AGE STRUCTURE
A rapid population decline can lead to long-lasting economic and social problems.
The cost of an aging population will strain the global economy.
Figure 9-12

55. Rapid population growth or decline can lead to societal problems
Growth (Problems)
Decline (Problems)
Insufficient food
Too few workers…less tax revenue
Insufficient housing/space
Increasing medical costs for elderly
Higher crime
Fewer technological developments…less entrepreneurship, new businesses
Higher unemployment
Slower economic growth

56. SOLUTIONS: INFLUENCING POPULATION SIZE
Demographic Transition: As countries become economically developed, their birth and death rates tend to decline.
Preindustrial stage: little population growth due to high infant mortality.
Transitional stage: industrialization begins, death rates drops and birth rates remain high.
Industrial stage: birth rate drops and approaches death rate.
Postindustrial stage: birth rate drops below death rate = population is declining

57. SOLUTIONS: INFLUENCING POPULATION SIZE
Generalized model of demographic transition.
Some developing countries may have difficulty making the demographic transition.
Figure 9-14

58. Demographic stages in countries- As countries becomes industrialized their birth rates decline.

59. Pre-industrial
Harsh living conditions lead to a high birth rate and high death rate. Thus, little population growth.

60. Transitional As industrialization begins: food production rises
health care improves.
So…Death rates drop BUT birth rates remain high
The population grows rapidly
KEY: move countries through this phase as quickly as possible

61. Industrial better access to birth control
Industrialization is wide spread
The birth rate drops and eventually approaches the death rate.
Population growth slows
This is because of:
better access to birth control
decline in the infant mortality rate
increased job opportunities for women
the high cost of raising children who don’t enter the work force until after high school or college.
Birth rate
Death rate

62. Postindustrial
The birth rate declines even further, equaling the death rate and thus reaching zero population growth.
Then, the birth rate falls below the death rate and the total population size slowly decreases → negative growth rate.
37 countries have reached this stage. (mainly in W. Europe)
To most population experts, the challenge is to help the remaining 88% of the world to get to this stage.

63. Birth rate and death rate Relative population size
Stage 1
Preindustrial
Stage 2
Transitional
Stage 3
Industrial
Stage 4
Postindustrial
High
Birth rate
Birth rate and death rate
(number per 1,00 per year)
Relative population size
Death rate
Figure 9.14
Generalized model of the demographic transition. There is uncertainty over whether this model will apply to some of today’s developing countries. QUESTION: At what stage is the country where you live?
Total population
Low
Low
Increasing
Very high
Decreasing
Low
Zero
Negative
Growth rate over time
Fig. 9-14, p. 183

64. Developing vs. Developed
Developing (Transitional, Third World):
Higher infant mortality rate because of a shortage in prenatal and pediatric care. Thus, they have more children to ensure some survive.
Agricultural societies need children to help in the labor force.
Lower per capita income or poorer countries need children to provide an income and sometimes contraceptives are not affordable.
Women lack education and job opportunities.
Developed (Industrial, First World):
Educated and working women tend to delay childbearing.
Pension systems support people as they age.
Family planning and the ability to control fertility.
Higher cost of raising children causes people to have smaller families.
Abortion is legal.
Infant mortality higher in a country due to, for example, - contaminated drinking water - poor nutrition - poor health care- few or no educational opportunities for women.

65. Urbanization
Urbanization is the movement of people from rural areas into cities
Urban areas must import most of its food, water, energy, minerals, & other resources because of large populations
Large populations produce and consume enormous quantities of resources that can pollute the air, water & land.
Disease can easily spread in urban areas because of the high density population.
Environmental pressures of urbanization from population growth are reduced because birth rates in urban areas usually are 3-4x’s lower than in rural areas because cities provide more education and employment opportunities.

67. Factors that affect birth & fertility rates
Educational & employment opportunities
Infant mortality rate
Average age at marriage
Availability of reliable birth control
Importance of kids in labor force
Urbanization
Cost of raising & educating kids
Availability of private & public pensions
Religious beliefs, traditions & cultural norms

68. SOLUTIONS: INFLUENCING POPULATION SIZE
Family planning has been a major factor in reducing the number of births and abortions throughout most of the world.
Women tend to have fewer children if they are:
Educated.
Hold a paying job outside the home.
Do not have their human right suppressed.
Have access to contraceptives.

69. SOLUTIONS: INFLUENCING POPULATION SIZE
The best way to slow population growth is a combination of:
Elevating the status of women:
Education
Jobs
Human rights
Investing in family planning.
Reducing poverty.

71. Correlation between Education & Fertility

72. SLOWING POPULATION GROWTH IN INDIA AND CHINA
For more than five decades, India has tried to control its population growth with only modest success.
Since 1970, China has used a government-enforced program to cut its birth rate in half and sharply reduce its fertility rate.

73. Illiteracy (% of adults) 47% 17% 36% Population under age 15 (%) 20%
Percentage
of world
population
17%
India
20%
China
1.1 billion
Population
1.3 billion
Population (2050)
(estimated)
1.4 billion
1.6 billion
Illiteracy (% of adults)
47%
17%
36%
Population under age 15 (%)
20%
1.6%
Population growth rate (%)
0.6%
2.9 children per women (down from 5.3 in 1970)
Total fertility rate
1.6 children per women (down from 5.7 in 1972) 58
Infant mortality rate 27
Figure 9.15
Global connection: basic demographic data for India and China in (Data from United Nations and Population Reference Bureau)
62 years
Life expectancy
70 years
Percentage living
below $2 per day 80 47
$3,120
GDP PPP per capita
$5,890
Fig. 9-15, p. 186

74. India’s Failed Family Planning Program
Poor planning.
Bureaucratic inefficiency.
Low status of women.
Extreme poverty.
Lack of administrative financial support.
Disagreement over the best ways to slow population growth.

75. China’s Family Planning Program
Currently, China’s TFR is 1.6 children per women.
China has moved 300 million people out of poverty.
Problems:
Strong male preference leads to gender imbalance.
Average population age is increasing.
Not enough resource to support population.

76. Some countries, including China, penalize couples who have more than one or two children by:
Raising their taxes
Charging other fees
Eliminating income tax deductions for a couple’s third child
Loss of health-care benefits, food allotments and job options
Forced abortions

77. In China couples who pledge to have no more than one child receive
Extra food
Larger pensions
Better housing
Free medical care
Salary bonuses
Free school tuition for their one child
Preferential treatment in employment when their child enters the job market.

78. Because of one-child policies and cultural issues, in some countries, there is a strong preference for male children.
Girls are aborted at a higher rate than boys
Some infant girls are killed
Male children receive more education & sometimes are even fed better than female children.
Result: Rapidly growing gender imbalance or “bride shortage” → resort to kidnapping brides

79. Environmental Impact
Our big footprints

80. Affluence - having a lot of wealth such as money, goods, or property.
Ecological
Footprints

81. HUMAN ASPECTS ON NATURAL SYSTEMS
Excluding Antarctica, human activities have affect about 83% of the earths land surface.
Figure 9-16

82. HUMAN ASPECTS ON NATURAL SYSTEMS
We have used technology to alter much of the rest of nature in ways that threaten the survival of many other species and could reduce the quality of life for our own species.
Figure 9-17

83. 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
Deliberate or accidental 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 fossil fuels
Figure 9.17
Natural capital degradation: major ways humans have altered the rest of nature to meet our growing population, needs, and wants. QUESTIONS: Which three of these items do you believe have been the most harmful? How does your lifestyle contribute directly or indirectly to each of these items?
Fig. 9-17, p. 188

84. Environmental Impact Equation
Population X affluence X technology

85. The IPAT Equation: to estimate impact of human lifestyles on Earth
Impact = Population x Affluence x Technology

86. Thailand

87. Japan

88. The IPAT Equation: to estimate impact of human lifestyles on Earth
Intensifies
Can mitigate
Intensifies
Impact = Population x Affluence x Technology
Deveoped lower higher higher
Countries:
Developing higher lower lower
Countries :

89. The Impact of Affluence
Gross domestic product (GDP)- the value of all products and services produced in a year in that country.
GDP is made up of consumer spending, investments, government spending, and exports minus imports.
A countries GDP often correlates with its pollution levels.

90. High rates of resource use
Developed Countries
High rates of resource use
Result in high levels of pollution and environmental degradation per person
These are believed to be the key factors determining overall environmental impact.

91. It is estimated that a US citizen consumes 35 X’s as much as the average citizen of India and 100 X’s as much as the average person in the world’s poorest countries.
Thus, poor parents in a developing country would need kids to have the same lifetime environmental impact as 2 typical US kids.

92. 1994 Global Summit on Population & Development
Cairo, Egypt – 20 years ago
Encouraged action to stabilized the world’s population at 7.8 billion by 2050, instead of the projected billion.

93. The major goals are to:
Provide universal access to family-planning services.
Improve the health care of infants, children & pregnant women
Encourage development of national population policies
Improving the status of women by expanding education & job opportunities

94. Major goals continued:
Increase access to education for girls
Increase men’s involvement in child-rearing responsibility & family planning
Take steps to eradicate poverty
Reduce & eliminate unsustainable patterns of production & consumption.

95. 2005 Millennium Ecosystem Assessement
United Nations project
Goal: Sustainable Development
Conclusions:
Ecosystem threatened if current resource consumption patterns continue
Human actions are depleting resources – Earth’s ability to sustain future generations can no longer be taken for granted.
Action required – understand connection betw natural & human systems – reduce impact