1. Environmental Science
Richard T. Wright
Environmental
Science
Tenth Edition
Chapter 5
The Human Population
Copyright © 2008 Pearson Prentice Hall, Inc.

2. 10/27—10/28 10/27 Report to the library: finish poster,
Start photo essay
Start Barrier Island lesson
10/ ½ Day alternative const. video
Please retrive any data needed from class laptops.

3. Current world Population
Current US population

4. Human Population Growth and the Consequences
Human population expansion and its cause
Different worlds
Consequences of population growth and affluence
Dynamics of population growth

5. Human Population Expansion and Its Cause
Reasons for the patterns of growth
Biotic potential exceeds environmental resistance: birth rates exceed death rates
There are 6.3 billion people on Earth
If each one stood up, pronounced their name and sat down
It would take 600 years to complete roll call
By 2025 it will take 1,000 years to complete this exercise

6. World Population Over the Centuries
9,000 human beings added to the
planet every hour

7. Modeling Population Growth
Human Population Growth and Regulation

8. Modeling Population Growth
Human Population Growth and Regulation

9. Modeling Population Growth
Human Population Growth and Regulation

10. Modeling Population Growth
Human Population Growth and Regulation

11. Reasons for the Human Population Explosion
Causes of disease recognized
Improvements in nutrition
Discovery of antibiotics
Improvements in medicine
Increase in number of women who actually reach child-bearing age
Short doubling times in some countries

12. Modeling Population Growth
Human Population Growth and Regulation

13. Changing Human Survivorship Curves: Went from B to A
% Survival B
Birth
Age
Death

14. World Population Growth and Absolute Growth

16. Population Projections Based on Different Fertility Assumptions
Maintain fertility rate
of 2.6 children/woman
Gradual decline in fertility in developing countries.
2.02 children/woman
½ child lower than medium projection
½ child higher than medium projection

17. Average Number of Children, Grandchildren, and Great Grandchildren
America
West Germany
Africa 14 5
258

18. Different Worlds Rich nations, poor nations
Population growth in rich and poor nations
Different populations, different problems

19. Major Economic Divisions of the World
Gross national income/capita

20. High-income, highly developed, industrialized countries
Economic Categories Based on Per Capita Gross National Income (see Fig. 5-4)
High-income, highly developed, industrialized countries
United States, Japan, Canada
Average GNI per capita = $26,710
Middle-income, moderately developed countries
Latin America, South Africa, China
Average GNI per capita = $1,850

21. Low-income, developing countries
Economic Categories Based on Per Capita Gross National Income (see Fig. 5-4)
Low-income, developing countries
Western and central Africa, India, central Asia
Average GNI per capita = $430

22. Disparities Developed countries Low-income developing countries
15% of the world’s population
Control 80% of the world’s wealth
Low-income developing countries
37% of the world’s population
Control 3.0% of the world’s gross national income
Difference in per capita income: 63 to 1!

23. Dimensions of the Human Poverty Index

24. Different Populations, Different Problems
IPAT Formula: calculates human pressure on the environment (I = P x A x T)
I = environmental impact
P = population
A = affluence and consumptive patterns
T = level of technology in the society

25. Different Populations, Different Problems
Environmental impact of developing countries due to “P.”
Environmental impact of developed countries due to “A” and “T.”
Both have some measure of “I” for different reasons.
Average American places at least 20 times the demand on Earth’s resources compared to a person in Bangladesh.

26. Different Populations, Different Problems
How does stewardship (S) affect the IPAT formula?
S = wildlife conservation, pollution control, energy conservation, and recycling
I = P x A x T S

27. Population Increase in Developed and Developing Countries

28. Population Data for Selected Countries (Table 5-2)
Country
Total Fertility Rate
Doubling Times (Years)
World
2.7 58
Developing Countries
2.9 47
Developed Countries
1.6
700

29. Different Populations, Different Problems
Human pressure on the environment caused by three factors
Expanding Population size
Increasing Affluence
Technology

30. Global Conditions for a Sustainable Population
Lower fertility rates (stabilize population)
Consumption must decrease
Protect the environment (stewardly action must increase

31. The Developing Countries
Pre Industrial Revolution:
Lived on the land, raised livestock, produced food for personal use and a little for barter
Small sustainable populations sustained for 1000+years
After WWII
Modern medicine (vaccines)
Death rates plummeted/ Large population growth

32. Consequences of Population Growth
Today 70% of the world’s poor live in rural areas and engage in small-scale agriculture
Farming a few acres of land

33. Options in the Developing Countries
Reform the system of land ownership
Intensify cultivation of existing land to increase production per unit area
Open new land to farm
Move to cities and seek employment
Engage in illicit activities for income
Move to other countries
How do these “solutions” aggravate the problems?

34. Options for 70% of the Worlds Poor
6 scenarios being played out today
Increasing pressure for Land ownership reform
Removal of collectivization
Privatization of state-owned land
Especially in formally communist and socialist countries
1978, China abandoned collectivism and assigned small plots to individual farmers farm output grew by more than 6% a year for each of the next 15 years!
More than doubling their production rates began their economic boom!

35. Options for 70% of the Worlds Poor
Intensify cultivation to improve production
Introduce more productive varieties of grain
Work the land harder
Continuous production / no fallow time
Deteriorates the soil, causes erosion , reduces production
Graze more animals in less space
Over grazing causes desertification
Land deterioration
Food production per capita, in Africa, is in decline

36. Options for 70% of the Worlds Poor
3. Open up new land to farm
Converting natural ecosystems to farms- loss of ecosystem contribution
Often not land well suited to farming and requires irrigation
Expensive and damages waterways
Tropical deforestation
Poor quality soil

37. Options for 70% of the Worlds Poor
4. Engage in illicit activities for $
Desperate people without food will do whatever they must to get it.
Need vs Greed
Poaching Wildlife
Drug-related crops

38. Options for 70% of the Worlds Poor
5. Emigrate to other countries, illegally or legally
Gap between high- and low-income countries
People believe that they can better their life
Aging wealthy countries attract young families
Called Replacement Migration
175 million people live outside of their native countries!
Problems
Prejudice: western Europe takes only 50% of the immigrants compared to USA
Refugee immigration: to escape war,
Diseases, hunger and enslavement

39. Options for 70% of the Worlds Poor
6. Move to the cities for jobs
Hundreds of millions of people
2000, 292 “million-plus” cities in Dev. Countries!
Mega cities- 10 million plus
By 2020 the urban population in these countries is expected to double to close to 4 billion people
Problems
Pop. Growth faster than economic growth(no Jobs)
Challenge providing basic services
Terrible streets, poor sanitation and drinking water, erratic power and phone and rapidly rising crime!
Shanty towns on the rise
Increasing disease (malnutrition, malaria, HIV/AIDS)

40. Consequences of Population Growth
Dilute the value of labor
Workers can not earn enough to provide food
< $1 or $2 a Day!
Extreme poverty and jobless
Environmental decline

41. Developing or Developed Nations?
High fertility rates
High consumptive lifestyles: use 80% of world’s wealth
Intense poverty
Eat high on the food chain

42. Developing or Developed Nations?
Long doubling times
High environmental degradation
Twenty percent of the world’s population

43. Basic Human Needs Drinkable water Edible food Safe housing Health care
An education
A job

44. Growing Cities

45. Consequences of Exploding Populations in the Developing World

46. Consequences of Exploding Populations
deforestation
resource depletion
loss of agricultural land
biodiversity
disease
pest resistance
population migration
irrigation
wetlands
MORE
More Population
Causes
LESS

47. Consequences of Affluence
High resource consumption
Largest consumer of these major commodities: Aluminum, coffee, corn, copper, lead, oil, oilseed, natural gas, rubber, tin and zinc
Lead consumption in meat
3-4X global consumption
Most paper consumed: 725lb/person/year
Unusually high environmental impact per person!

48. Consequences of Affluence
Positive effect on environment
Safe drinking water
Sanitary sewage treatment
Good waste collection and disposal
Pollution is held in check
Not destroying forests
Can afford conservation and management,
Have better agricultural practices
Environment improves with increasing affluence

49. The Dark Side of Affluence in the United States and Other Wealthy Countries
Lead in production of many pollutants
CO2, 24% of worlds production (5% pop.)
Huge consumption places stress on environment
86% of consumption and 80% of trade
Exploitation of fisheries and cut of old growth forest
Oil spills, exotic wood harvests, mining, oil extraction

50. The Dark Side of Affluence in the United States and Other Wealthy Countries
Enables wealthy to clean up immediate environment by transferring waste to more distant locations
Use resources of other countries
Affluent isolate themselves and unaware of the environmental stresses caused by their consumptive lifestyles

51. Affluence
Provides people with opportunity, choices, and the ability to preserve and
protect!

52. Dynamics of Population Growth
Population profiles: shows number or proportion of people at each age in a given population
Collected via census
Future populations
Population momentum
The demographic transition

53. Population Profile United States

54. Population Profile United States

55. Population Profile United States

57. This rate now hovers about the replacement rate!
US Fertility Rate
This rate now hovers about the replacement rate!

58. Population Profile of Italy

59. Population Profile Italy

60. Very low birth rates!

61. Population Projections United States
Increased fertility rate
of 2.0 and current
migration
Fertility rate of 1.8

62. Population Profile Developing Country

63. Population Profile Developing Country Based on assumption of fertility rate reduction from 4.8 to 2.7 by 2025

64. Population Momentum
Effect of current age structures on future population growth
Determined by percent of population in younger versus older age cohorts

65. Population Momentum
It will take countries with a large base of younger population a long time to achieve stability.
Countries like Iraq will continue to grow for years even after the total fertility rate is reduced to replacement level.

68. Calculating Fertility Rates and Doubling Times Crude Birth Rates (CBR) Crude Death Rate (CDR)
(CBR - CDR)/10 = Rate of Increase or decrease
in population per 1000 per year
70/ Rate of Increase = Doubling Time

71. Phases of Demographic Transition
Phase I: primitive stability (CBR = CDR)
Phase II: declining CDR, CBR remains high accelerating population growth
Phase III: declining (CBR) fertility rate, but significant population growth continues
Phase IV: modern stability with low CBR and CDR

72. Demographic Transition Comparisons (Figure 5-17) Pg 138
Phase IV: developed countries
Phases II and III: developing countries

73. In the Year 2000
65 out of 117 countries will not be able to feed their own people
One billion people will be living in cities that cannot support their inhabitants
400 million more women will be in need of child spacing services

74. In the Year 2000 (continued)
600 million new jobs will need to be created for new entrants into the workforce
We will need twice as much fresh water
300 million additional children will need teachers, books, and classrooms
nature's way.wmv