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Environmental Science: Toward a Sustainable Future Richard T. Wright

Feb 15, 2016




Environmental Science: Toward a Sustainable Future Richard T. Wright. Chapter 5. The Human Population: Dimensions PPT by Clark E. Adams. Human Population Growth and the Consequences. Human population expansion and its cause Different worlds Consequences of population growth and affluence - PowerPoint PPT Presentation


Environmental Science: Toward a Sustainable Future Richard T. WrightThe Human Population: DimensionsPPT by Clark E. AdamsChapter 5Human Population Growth and the ConsequencesHuman population expansion and its causeDifferent worldsConsequences of population growth and affluenceDynamics of population growthHuman Population Expansion and Its CauseReasons for the patterns of growthBiotic potential exceeds environmental resistance: birth rates exceed death ratesThere are 6.3 billion people on EarthIf each one stood up, pronounced their name, and sat downIt would take 600 years to complete roll callBy 2025 it will take 1,000 years to complete this exercise

World Population over the Centuries9,000 human beings added to the planet every hourReasons for the Human Population ExplosionCauses of disease recognizedImprovements in nutritionDiscovery of antibioticsImprovements in medicineIncrease in number of women who actually reach child-bearing ageShort doubling times in some countriesChanging Human Survivorship Curves: Went from B to A% SurvivalAgeBirthDeathABWorld Population Growth and Absolute Growth

Population Projections Based on Different Fertility Assumptions

Average Number of Children, Grandchildren, and Great GrandchildrenAmericaWest GermanyAfrica145258Different WorldsRich nations, poor nationsPopulation growth in rich and poor nationsDifferent populations, different problems

Human Poverty Index for Developing Countries

Economic Categories Based on Per Capita Gross National Income (see Fig. 5-4)High-income, highly developed, industrialized countriesUnited States, Japan, CanadaAverage GNI per capita = $26,710Middle-income, moderately developed countriesLatin America, South Africa, ChinaAverage GNI per capita = $1,850Economic Categories Based on Per Capita Gross National Income (see Fig. 5-4)Low-income, developing countriesWestern and central Africa, India, central AsiaAverage GNI per capita = $430DisparitiesDeveloped countries16% of the worlds populationControl 81% of the worlds wealthLow-income developing countries41% of the worlds populationControl 3.4% of the worlds gross national incomeDifference in per capita income: 62 to 1!Population Increase in Developed and Developing Countries

Population Data for Selected Countries (Table 5-3)CountryTotal Fertility RateDoubling Time (Years)World2.854Developing Countries3.537Developed Countries1.5700Different Populations, Different ProblemsHuman pressure on the environment caused by three factorsPopulation sizeAffluenceTechnology Ecological Footprints by World RegionThe average American places at least 20 times the demand on Earths resources as does an average person in BangladeshFig. 5.7 here

Global Conditions for a Sustainable PopulationLower fertility rates (stabilize population)Consumption must decreaseProtect the environment (stewardly action must increase)Consequences of Population Growth and AffluenceThe developing countriesAffluenceDeveloping or Developed Nations?High fertility ratesHigh consumptive lifestyles: use 80% of worlds wealthIntense povertyEat high on the food chainDeveloping or Developed Nations?Long doubling timesHigh environmental degradationTwenty percent of the worlds population

Basic Human NeedsDrinkable WaterEdible FoodSafe HousingHealth CareAn EducationA JobThe Developing CountriesReform the system of land ownershipIntensify cultivation of existing land to increase production per unit areaOpen new land to farmMove to cities and seek employmentEngage in illicit activities for incomeMove to other countriesHow do these solutions aggravate the problems?Growing Cities

Consequences of Exploding Populations in the Developing World

Consequences of Exploding PopulationsMore PopulationCausesMORELESSdeforestationresource depletionloss of agricultural landbiodiversitydiseasepest resistancepopulation migrationirrigationwetlandsAffluence in the United StatesConsume the largest share of 11 of 20 major commoditiesEat more than three times the global average in meatLead the world in paper consumptionEnvironment improves with increasing affluenceAffluence in the United StatesEnables wealthy to clean up immediate environment by transferring waste to more distant locations.Affluent isolate themselves and unaware of the environmental stresses caused by their consumptive lifestyles.

Dynamics of Population GrowthPopulation profilesFuture populationsPopulation momentumThe demographic transitionPopulation Profiles of the United States

Population Profile for United States

Note increasing elderlypopulation.Future World Populations

Future United States Populations

Projecting Future Populations: Developed Countries

Population Projections: Developing Nations

Comparing Projected Populations (see Fig. 5-17)

Fertility Rate> 2Fertility Rate< 2Population MomentumCountries like Iraq will continue to grow for 5060 years even after the total fertility rate is reduced to replacement level.The Demographic Transition

Calculating Fertility Rates and Doubling Times(CBR CDR)/10 = Rate of increase or decrease in population per 1,000 per year70/Rate of Increase = Doubling TimeCalculating Fertility Rates and Doubling Times: Practice (see Table 5-5)

Demographic Transition Comparisons

By the Year 200065 out of 117 countries will not be able to feed their own peopleOne billion people will be living in cities that cannot support its inhabitants400 million more women will be in need of child spacing servicesBy the Year 2000 (continued)600 million new jobs will need to be created for new entrants into the workforceWe will need twice as much fresh water 300 million additional children will need teachers, books, and classroomsEnd of Chapter 5CountryCBRCDRRate of IncreaseDoubling Time





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