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The Human Population and Its Impact Chapter 6. Core Case Study: Are There Too Many of Us? (1) Estimated 2.4 billion more people by 2050 Are there too.

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Presentation on theme: "The Human Population and Its Impact Chapter 6. Core Case Study: Are There Too Many of Us? (1) Estimated 2.4 billion more people by 2050 Are there too."— Presentation transcript:

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

4 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.


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 (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?


9 Over 95% of this increase will take place in Developing Countries Population Projections


11 Current World Population Population ClockVital Events (per time unit) Population ClockVital Events (per time unit) Global population was 6,901,260,547 US population- 310,859,059 On Feb. 20 th 2011at 9:30 pm The global population grows by: Nearly 2.4 persons per second Nearly 8,607 persons per hour Over 206,563 persons per day Over 75 million persons per year

12 How Much is a Billion? 1,000 seconds = 16.7 minutes 1 million-s = 16,677 min = 11.6 days 1 billion-s = 11,574 days = 31.7 years 1,000 pennies = ~ 88 ounces = 5.5 pounds 1 million pennies = 5,500 pounds (~1-Suburban) 1 billion pennies = 2,750 tons (~2 Space Shuttles)

13 Billion Grains of Rice 200 grains of rice in a teaspoon 9,600 grains of rice in a cup (48 tsp) How many Cups are in a Gallon? 16 cups How many grains of rice are in 16 cups? 9,600 x 16 = 153,600 grains of rice How many gallons would it take to take to equal 1 million grains of rice? 1,000,000 divided by 153,600 = 6.5 Gallons = 1 million grains of rice

14 If 6.5 gallons equal 1 million how many gallons would it take to equal 1 billion? 6.5 gallons x 1000 = 6,500 gallons = 1 billion How many gallons would it take to equal 6.6 billion? 42,900 gallons of rice = 6.6 billion grains of rice.

15 Science Focus: How Long Can the Human Population Keep Growing? Thomas Malthus and population growth: 1798 Humans have altered 83% of the earths land surface Can the human population grow indefinitely?

16 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.

17 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 population Crude death rate- # deaths / 1000 population



20 Rates of Global Pop. Change Rates of Global Pop. Change use: International Data Base then Online Demographic Aggregation CBR (crude birth rate) = # births / 1000 population 1990: 24now: 20.6 CDR (crude death rate) = # deaths / 1000 population 1990: 9now: 8.8

21 Growth Rate = (b + i) – (d + e) 1990: 1.5%now: 1.19% growth rates have come down Annual rate of Natural Population change % = (BR – DR/1000) x 100 (BR-DR)/10

22 22 Rule of 70 How long does it take to double? Resource use Population size Money in a savings account Rule of divided by the percentage growth rate = doubling time in years 70 / 7% means it takes ten years to double Homework: YouTube- rule of 70- Albert Bartlett Most important video you will ever see 9 min.

23 Women Having Fewer Babies but Not Few Enough to Stabilize the Worlds Population Replacement fertility rate (RFR) The number of children a couple must have to replace their parents A RFR of 2.1 for developed countries with low infant and child mortality rates Africa RFR = 2.5 Total fertility rate (TFR) The average number of children born to a woman Average in developed countries = 1.5 Average in developing countries = 3.8 Worldwide 1990: 3.1now: 2.76


25 Year Births per woman Baby boom ( ) Total Fertility Rates for US Replacement level

26 Case Study: The U.S. Population Is Growing Rapidly Drop in TFR in U.S. Rate of population growth has slowed Population still growing and not leveling off Fourfold increase since 1900 Changes in lifestyle in the U.S. during the 20 th century

27 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

28 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

29 47 years 77 years 8% 81% 15% 83% 10% 98% 2% 99% 10% 52% $15 $ Life expectancy Married women working outside the home High school graduates Homes with flush toilets Homes with electricity Living in suburbs Hourly manufacturing job wage (adjusted for inflation) Homocides per 100,000 people

30 Several Factors Affect Death Rates Life expectancy Average # of years a newborn can expect to live Infant mortality rate (IMR) infant deaths per 1000 live births (infant < 1 yr) Why are people living longer and fewer infants dying? Increased food supply and distribution Better nutrition Medical advances Improved sanitation

31 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

32 mortality-2.htm

33 Migration Affects an Areas Population Size Economic improvement Religious freedom Political freedom Wars Environmental refugees

34 Case Study: The United States: A Nation of Immigrants Historical role of immigration in the U.S. Opportunity for the worlds poor and oppressed Since 1820, the U.S. has admitted almost twice as many immigrants and refugees as all other countries combined Legal immigration Illegal immigration Legal and illegal immigration accounts for 40% of the countrys annual population growth


36 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.

37 Population Pyramids Graphic device: bar graph shows the age and gender composition of a region horizontal axis: gender male: left-handfemale: right-hand absolute number of people or % vertical axis: age groups Pre-reproductive ages = birth –14 years of age Reproductive ages= 15 –44 years of age Post reproductive ages = 45 & up

38 Population Pyramid with young cohorts

39 Population Pyramids Population Pyramids on the Web High Growth: Afghanistan Moderate Growth: Mexico Zero Growth: U.S. Negative Growth: Austria or Italy


41 Population Pyramids Population Pyramids on the Web High Growth: Afghanistan Moderate Growth: Mexico Zero Growth: U.S. Negative Growth: Austria or Italy


43 Population Pyramids Population Pyramids on the Web High Growth: Afghanistan Moderate Growth: Mexico Zero Growth: U.S. Negative Growth: Austria or Italy


45 Population Pyramids Population Pyramids on the Web High Growth: Afghanistan Moderate Growth: Mexico Zero Growth: U.S. Negative Growth: Italy


47 We Can Use Age-Structure Information to Make Population and Economic Projections Baby boomers Job market when they retire

48 Influencing Population Size Age Structure & Population Projections Baby boomers - half of U.S. population; use most of goods and services; make political and economic decision baby-bust generation - born since 1965; may have to pay more income, health care and social security to support retired baby boomers; but face less job competition Better health may --> later retirement of baby boomers --> keep high-salary jobs

49 Tracking the baby-boom generation in the United States

50 Populations Made Up of Mostly Older People Can Decline Rapidly Slow decline Manageable Rapid decline Severe economic problems Severe social problems

51 Effects of Population Decline As percentage of 60+ aged people increases, population begins decline 60+population increase --> severe economic and social problems because 60+ consume more medical care Social Security costly public services Labor shortages require automation & immigration


53 The Graying of Japan Family-planning access, cramped housing, expensive land, late marriage, education cost --> voluntary decrease in birth rate Low immigration rate Health insurance and pension - 45% of national income; could -->low economy Illegal immigration bolsters work force

54 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

55 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.

56 As Countries Develop, Their Populations Tend to Grow More Slowly Demographic transition stages Preindustrial AKA Pre Transition Transitional AKA Early Transitional May lead to a demographic trap Industrial AKA Middle Transition Postindustrial AKA Late Transition


58 The Demographic Transition

59 Five Stages of the Demographic Transition Used to be 4, now 5 stages birth rates, death rates and growth rates systematically change through time as societies change: modernize, urbanize gain access to technology

60 Stage 1- Pre-transition or Pre-industrial stage high birth rates, high (at time erratic) death rates, low growth rates stage for much of human history, traditional societies practically no country today

61 Stage 2- Early Transition or Transitional high birth rates, declining death rates, rising growth rates improvements in sanitation (water) and medicine in Europe during Industrial Revolution in developing countries since the 50s/60s much of Africa today, some countries of Asia (Afghanistan, Nepal, etc.)

62 Stage 3- Middle Transition or Industrial stage continued decline of death rates, declining birth rates, growth rates decline from high to lower levels change in behavior: adaptation to lower death rate, in particular infant mortality rate economic change: urbanization (incentive to have fewer children) Mexico today

63 Stage 4- Late Transition or Postindustrial stage Stage 4: low birth rates, low death rates, low growth rates United States today Stage 5: low birth rates, rising death rates, declining growth rates (if birth rates drop below death rates: negative growth rates) several countries of Europe today (Austria) Stage 5-

64 64 Link to Population Pyramids?

65 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

66 What Is Family Planning What Is Family Planning? A.Definition 1.Measures enabling parents to control number of children (if they so desire) B.Goals of Family Planning 1.Not to limit births 2.For couples to have healthy children 3.For couples to be able to care for their children 4.For couples to have the number of children that they want


68 What Methods are Used to Control Births? A.Preconception Birth Control Methods 1.Barrier Methods a.Condom b.Vaginal sponge c.Diaphragm d.Spermicides 2.Hormonal Contraceptives a.Pill b.Injections and implants 3.Sterilization B.Postconception Birth Control Measures 1.Intrauterine Device 2.RU-486 Pill 3.Abortion

69 Extremely Effective Highly Effective Total abstinence Sterilization Vaginal ring IUD with slow-release hormones IUD plus spermicide Vaginal pouch (female condom) IUD Condom (good brand) plus spermicide Oral contraceptive 100% 99.6% 98-99% 98% 97% 95% 93% Typical effectiveness rates of birth control methods in the U.S.

70 Effective Cervical cap Condom (good brand) Diaphragm plus spermicide Rhythm method (Billings, Sympto-Thermal) Vaginal sponge impreg- nated with spermicide Spermicide (foam) 89% 86% 84% 83% 82% Typical effectiveness rates of birth control methods in the U.S.

71 Moderately Effective Unreliable Spermicide (creams, jellies, suppositories) Rhythm method (daily temperature readings) Withdrawal Condom (cheap brand) Douche Chance (no method) 75% 74% 70% 40% 10% Typical effectiveness rates of birth control methods in the U.S.

72 Contraceptive Use Worldwide 1. People in industrialized countries enjoy easy access to contraceptives while those in LDCs do not. 2. In the U.S., teens and poor women are least likely to use contraceptives. 3. Severe problems are associated with teen pregnancy. a. Teens dont receive the care they need. b. More adolescent girls die from pregnancy-related causes than any other cause. c. Maternal mortality is twice as high for women younger than 20, and 4 times as high for women younger than 17. d. Each year about 15 million young women ages have babies. e. Survival rate for babies born to teens is low. f. Young age of mother can cause problems with the child. g. Teen pregnancy causes greater public expenditures.

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

74 Empowering women to reduce births Women tend to have fewer, and healthier children when: they have access to education and paying jobs outside home their society doesnt suppress womens rights But women do most of the work not shown in GDP because of lower pay Women excluded from economic and political decision making

75 4:45 A.M. Wake, wash, and eat 5:00 A.M.- 5:30 A.M. Walk to fields 3:00 P.M.- 4:00 P.M. Collect firewood 4:00 P.M.- 5:30 P.M. Pound and grind corn 5:30 A.M.- 3:00 P.M. Work in fields 5:30 P.M.- 6:30 P.M. Collect water 6:30 P.M.- 8:30 P.M. Cook for family and eat 8:30 P.M.- 9:30 P.M. Wash dishes and children 9:30 P.M. Go to bed Typical workday for a women in Rural Africa

76 Case Study: Slowing Population Growth in China: the One-Child Policy Encourages fewer children Gender imbalance Fast-growing economy Face serious resource and environmental problems

77 Case Studies - China Family planning efforts began in 1970; TFR fell from 5.7 to 1.8; infant mortality and illiteracy rates 1/3 to 1/2 of Indias rates Population control program is extensive, intrusive and strict: postpone childbearing only one child/family -->benefits effect b/c China is dictatorship; limited resources would have meant disaster

78 Chinas Program 1.Nation With Best Known Population Control Program 2.Reasons Chinese Government Initiated Population Control Measures a.Freshwater and food at a premium for nations population b.Country experiencing population momentum 3.Government Perks / Coercive Measures for Citizen Compliance a.Free education and health care b.Increased personal and family incomes c.Increased legal marrying age for women d.Contraceptives, abortions, and sterilizations free of charge e.Preferential housing and retirement income

79 Case Study: Slowing Population Growth in India Population control: gender bias Poverty Malnutrition Environmental problems

80 Case Studies - India Family planning efforts began in 1952; fertility rate declined from 5.3 to 3.4 but population grow is still exponential -1.9% Disappointing results due to: poor planning bureaucratic inefficiency low status of women extreme poverty lack of administrative & financial support

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