2 Core Case Study: Are There Too Many of Us? (1) Estimated 2.4 billion more people by 2050Are 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 diseasesBiodiversity lossesWater shortagesTraffic congestionPollution of the seasClimate 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 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 increaseMovement into new habitats and climate zonesEarly and modern agriculture methodsControl of infectious diseases throughSanitation systemsAntibioticsVaccines
7 Human Population Growth Continues but It Is Unevenly Distributed (2) Population growth in developing countries is increasing 15 times faster than developed countriesBy 2050, 97% of growth will be in developing countriesShould the optimum sustainable population be based on cultural carrying capacity?
11 Current World Population Population Clock Vital Events (per time unit)Global population was 6,901,260,547 US population- 310,859,059On Feb. 20th 2011at 9:30 pmThe global population grows by:Nearly 2.4 persons per secondNearly 8,607 persons per hourOver 206,563 persons per dayOver 75 million persons per yearUs. Population 308 million exactly 308,782,965 as of march 1st 2010
12 How Much is a Billion? 1,000 seconds = 16.7 minutes 1 million-s = 16,677 min = 11.6 days1 billion-s = 11,574 days = 31.7 years1,000 pennies = ~ 88 ounces = 5.5 pounds1 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 cupsHow many grains of rice are in 16 cups?9,600 x 16 = 153,600 grains of riceHow 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 billionHow 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: 1798Humans have altered 83% of the earth’s land surfaceCan the human population grow indefinitely?Thomas Malthus published his famous Essay on Population in 1798 predicting that humanity was doomed to poverty and famine because the human population was growing exponentially, while mankind’s ability to produce food could only increase at a linear rate.He wrote at a time when the famous curve of human population growth was way down here. The ensuing science-based increases in agricultural production supported a tripling of the human
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 changeBirths: fertilityDeaths: mortalityMigrationPopulation change =(births + immigration) – (deaths + emigration)Crude birth rate- # births / 1000 populationCrude death rate- # deaths / 1000 population
20 Rates of Global Pop. Change use: International Data Base http://www Rates of Global Pop. Change use: International Data Base then Online Demographic AggregationCBR (crude birth rate) = # births / 1000 population1990: 24 now: 20.6CDR (crude death rate) = # deaths / 1000 population1990: 9 now: 8.8
21 Growth Rate = (b + i) – (d + e) 1990: 1.5% now: 1.19%growth rates have come downAnnual rate of Natural Population change % = (BR – DR/1000) x 100(BR-DR)/10
22 Rule of 70 How long does it take to double? Rule of 70 Resource use Population sizeMoney in a savings accountRule of 7070 divided by the percentage growth rate = doubling time in years70 / 7% means it takes ten years to doubleHomework: 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 World’s Population Replacement fertility rate (RFR)The number of children a couple must have to replace their parentsA RFR of 2.1 for developed countries with low infant and child mortality ratesAfrica RFR = 2.5Total fertility rate (TFR)The average number of children born to a womanAverage in developed countries = 1.5Average in developing countries = 3.8Worldwide 1990: 3.1 now: 2.76
25 Total Fertility Rates for US 4.03.53.02.5Births per woman2.12.01.5Baby boom( )Replacementlevel1.0Baby boom started at the end of WWII0.51920193019401950196019701980199020002010Year
26 Case Study: The U.S. Population Is Growing Rapidly Drop in TFR in U.S.Rate of population growth has slowedPopulation still growing and not leveling offFourfold increase since 1900Changes in lifestyle in the U.S. during the 20th century
27 Several Factors Affect Birth Rates and Fertility Rates Children as part of the labor forceCost of raising and educating childrenAvailability of private and public pensionUrbanizationEducational and employment opportunities for women
28 Several Factors Affect Birth Rates and Fertility Rates Infant mortality rateAverage age of a woman at birth of first childAvailability of legal abortionsAvailability of reliable birth control methodsReligious beliefs, traditions, and cultural norms
29 Homes with flush toilets 98% 47 yearsLife expectancy77 yearsMarried women workingoutside the home8%81%15%High school graduates83%10%Homes with flush toilets98%2%Homes with electricity99%10%Some major changes that took place between 1900 and Data from U.S. Bureau of the Census and department of Commerce.Living in suburbs52%1900$3Hourly manufacturing jobwage (adjusted for inflation)2000$151.2Homocides per100,000 people5.8
30 Several Factors Affect Death Rates Life expectancyAverage # of years a newborncan expect to liveInfant mortality rate (IMR)infant deaths per 1000 livebirths (infant < 1 yr)Why are people living longerand fewer infants dying?Increased food supply and distributionBetter nutritionMedical advancesImproved sanitation
31 Several Factors Affect Death Rates (2) U.S. infant mortality rate high due toInadequate health care for poor women during pregnancy and their infantsDrug addiction among pregnant womenHigh birth rate among teenagers
33 Migration Affects an Area’s Population Size Economic improvementReligious freedomPolitical freedomWarsEnvironmental refugees
34 Case Study: The United States: A Nation of Immigrants Historical role of immigration in the U.S.Opportunity for the world’s poor and oppressedSince 1820, the U.S. has admitted almost twice as many immigrants and refugees as all other countries combinedLegal immigrationIllegal immigrationLegal and illegal immigration accounts for 40% of the country’s annual population growth
36 6-3 How Does a Population’s 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 regionhorizontal axis: gendermale: left-hand female: right-handabsolute number of people or %vertical axis: age groupsPre-reproductive ages = birth –14 years of ageReproductive ages= 15 –44 years of agePost reproductive ages = 45 & up
47 We Can Use Age-Structure Information to Make Population and Economic Projections Baby boomersJob 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 decisionbaby-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 competitionBetter 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 declineManageableRapid declineSevere economic problemsSevere social problems
51 Effects of Population Decline As percentage of 60+ aged people increases, population begins decline60+population increase --> severe economic and social problems because 60+ consumemore medical careSocial Securitycostly public servicesLabor shortages require automation & immigration
53 The Graying of JapanFamily-planning access, cramped housing, expensive land, late marriage, education cost --> voluntary decrease in birth rateLow immigration rateHealth insurance and pension - 45% of national income; could -->low economyIllegal immigration bolsters work force
54 Populations Can Decline from a Rising Death Rate: The AIDS Tragedy 25 million killed by 2008Many young adults die: loss of most productive workersSharp drop in life expectancyInternational community called upon toReduce the spread of HIV through education and health careFinancial 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 stagesPreindustrial AKA Pre TransitionTransitional AKA Early TransitionalMay lead to a demographic trapIndustrial AKA Middle TransitionPostindustrial AKA Late Transition
59 Five Stages of the Demographic Transition Used to be 4, now 5 stagesbirth rates, death rates and growth rates systematically change through time as societies change:modernize, urbanizegain access to technology
60 Stage 1- Pre-transition or Pre-industrial stage high birth rates, high (at time erratic) death rates, low growth ratesstage for much of human history, traditional societiespractically no country today
61 Stage 2- Early Transition or Transitional high birth rates,declining death rates,rising growth ratesimprovements insanitation (water)and medicinein Europe during Industrial Revolutionin developing countries since the 50s/60smuch of Africa today, some countries of Asia (Afghanistan, Nepal, etc.)
62 Stage 3- Middle Transition or Industrial stage continued decline of deathrates, declining birth rates,growth rates decline fromhigh to lower levelschange in behavior: adaptation to lower death rate, in particular infant mortality rateeconomic 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, lowgrowth ratesUnited States todayStage 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-
65 Planning for Babies Works Family PlanningResponsible for a 55% drop in TFRsIn developing countriesExpansion of programInclude teenagers, sexually active unmarried women, and menSlow and stabilize population growthInvest in family planningReduce povertyElevate the social and economic status of women
66 What Is Family Planning? DefinitionMeasures enabling parents to control number of children (if they so desire)Goals of Family PlanningNot to limit birthsFor couples to have healthy childrenFor couples to be able to care for their childrenFor couples to have the number of children that they want
68 What Methods are Used to Control Births? Preconception Birth Control MethodsBarrier MethodsCondomVaginal spongeDiaphragmSpermicidesHormonal ContraceptivesPillInjections and implantsSterilizationPostconception Birth Control MeasuresIntrauterine DeviceRU-486 PillAbortion
69 Typical effectiveness rates of birth control methods in the U.S. Extremely EffectiveTotal abstinence100%Sterilization99.6%Vaginal ring98-99%Highly EffectiveIUD with slow-releasehormones98%IUD plus spermicide98%Vaginal pouch(“female condom”)97%IUD95%Condom (good brand)plus spermicide95%Oral contraceptive93%
70 Typical effectiveness rates of birth control methods in the U.S. Cervical cap89%Condom (good brand)86%Diaphragm plusspermicide84%Rhythm method (Billings,Sympto-Thermal)84%Vaginal sponge impreg-nated with spermicide83%Spermicide (foam)82%
71 Typical effectiveness rates of birth control methods in the U.S. Moderately EffectiveSpermicide (creams,jellies, suppositories)Rhythm method (dailytemperature readings)75%74%Withdrawal74%Condom (cheap brand)70%UnreliableDouche40%Chance (no method)10%
72 Contraceptive Use Worldwide People in industrialized countries enjoy easy access to contraceptives while those in LDCs do not.In the U.S., teens and poor women are least likely to use contraceptives.Severe problems are associated with teen pregnancy.Teens don’t receive the care they need.More adolescent girls die from pregnancy-related causes than any other cause.Maternal mortality is twice as high for women younger than 20, and 4 times as high for women younger than 17.Each year about 15 million young women ages have babies.Survival rate for babies born to teens is low.Young age of mother can cause problems with the child.Teen pregnancy causes greater public expenditures.
73 Empowering Women Can Slow Population Growth EducationPaying jobsHuman 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 hometheir society doesn’t suppress women’s rightsBut women do most of the worknot shown in GDP because of lower payWomen excluded from economic and political decision making
75 Typical workday for a women in Rural Africa 4:45 A.M.Wake,wash, andeat5:00 A.M.-5:30 A.M.Walk tofields5:30 A.M.-3:00 P.M.Work infields3:00 P.M.-4:00 P.M.Collectfirewood4:00 P.M.-5:30 P.M.Pound andgrind corn5:30 P.M.-6:30 P.M.Collectwater6:30 P.M.-8:30 P.M.Cook forfamily andeat8:30 P.M.-9:30 P.M.Washdishesand children9:30 P.M.Go to bed
76 Case Study: Slowing Population Growth in China: the One-Child Policy Encourages fewer childrenGender imbalanceFast-growing economyFace serious resource and environmental problems
77 Case Studies - ChinaFamily planning efforts began in 1970; TFR fell from 5.7 to 1.8; infant mortality and illiteracy rates 1/3 to 1/2 of India’s ratesPopulation control program is extensive, intrusive and strict:postpone childbearingonly one child/family -->benefitseffect b/c China is dictatorship; limited resources would have meant disaster
78 China’s ProgramNation With Best Known Population Control ProgramReasons Chinese Government Initiated Population Control MeasuresFreshwater and food at a premium for nation’s populationCountry experiencing population momentumGovernment Perks / Coercive Measures for Citizen ComplianceFree education and health careIncreased personal and family incomesIncreased legal marrying age for womenContraceptives, abortions, and sterilizations free of chargePreferential housing and retirement income
79 Case Study: Slowing Population Growth in India Population control: gender biasPovertyMalnutritionEnvironmental problems
80 Case Studies - IndiaFamily 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 planningbureaucratic inefficiencylow status of womenextreme povertylack of administrative & financial support