2 Core Case Study: Are There Too Many of Us? 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?Why/ why not?How?
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.
5 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
6 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?
7 Global Connections: UN World Population Projections by 2050
8 Science Focus: How Long Can the Human Population Keep Growing? Thomas Malthus and population growth: 1798Human pop = exponential, ag = linearActually, both are exponentialHumans have altered 83% of the earth’s land surfaceCan the human population grow indefinitely?
9 Natural Capital Degradation: Altering Nature to Meet Our Needs
10 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.
11 The Human Population Can Grow, Decline, or Remain Fairly Stable Population changeBirths: fertilityDeaths: mortalityMigrationPopulation change =(births + immigration) – (deaths + emigration)Crude birth rate live births /1000 ppl/yrCrude death rate deaths/1000ppl/yr
13 Women Having Fewer Babies but Not Few Enough to Stabilize the World’s Population Fertility rateReplacement-level fertility rate – 2.1/coupleWhy not 2?Total fertility rate (TFR) – ave 3 children/woman during her reproductive years
14 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
15 Several Factors Affect Birth Rates and Fertility Rates Infant mortality rateAverage age of a woman at birth of first childAvailability of reliable birth control methodsReligious beliefs, traditions, and cultural normsAvailability of legal abortionsDo we have easy access to birth control in the US?
16 Several Factors Affect Death Rates Life expectancyInfant mortality rateWhy are people living longer and fewer infants dying?Increased food supply and distributionBetter nutritionMedical advancesImproved sanitation
17 Several Factors Affect Death Rates Americans spend more on healthcare than many developed countries but has lower life expectancy than some.Many lack insuranceHigh obesity rateU.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
18 Migration Affects an Area’s Population Size Economic improvementReligious freedomPolitical freedomWarsEnvironmental refugees
19 Case Study: The U.S. - A Nation of Immigrants Historical role of immigration in the U.S.Legal immigrationIllegal immigration
20 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 190034% of growth from immigrationChanges in lifestyle in the U.S. during the 20th century
24 Legal Immigration to the U.S. b/t 1820 and 2003
25 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.
26 Populations Made Up Mostly of Young People Can Grow Rapidly Age structure categoriesPrereproductive agesReproductive agesPostreproductive ages
33 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
34 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.
35 As Countries Develop, Their Populations Tend to Grow More Slowly Demographic transition stagesPreindustrialTransitionalMay lead to a demographic trapIndustrialPostindustrial
37 Planning for Babies Works Family planning in ThailandHans Rosling on population growthFamily PlanningResponsible for a 55% drop in TFRsIn developing countriesExpansion of programSlow and stabilize population growthInvest in family planningReduce povertyElevate the social and economic status of women
38 Empowering Women Can Slow Population Growth EducationPaying jobsHuman rights without suppression
39 Case Study: Slowing Population Growth in China: the One-Child Policy Encourages fewer childrenGender imbalance-Most parents abandon girls and give them up for adoptionFast-growing economyFace serious resource and environmental problems
40 Case Study: Slowing Population Growth in India Population control: gender biasPovertyMalnutritionEnvironmental problems