Bài giảng Environmental Sciences - Chapters 5 & 6 The Human Population/ Population & Development

Main PointsChapter 5World Population TrendsCalculations Developed vs. Developing CountriesAge Structure Diagrams Demographic TransitionChapter 6Fertility RatesWorld Bank1994 UN Conference in Cairo- Program of ActionHuman Population Growth Rate (2000)Human Population Growth Rate (2008)(In 2000) 11.5 billion & 2065(?)Human Population Growth Rate (00/08 Composite) (In 2008) 10 billion & 2200OLD NEW2046 22002033 20472020 20242009 20121999 19991987 19871975 19751960 19601930 19301830 1830DisparitiesDeveloped countries15% of the world’s populationControl 80% of the world’s wealthLow-income developing countries37% of the world’s populationControl 3.0% of the world’s gross national incomeDifference in per capita income: 63 to 1!Different Populations, Different ProblemsIPAT Formula: calculates human pressure on the environment (I = P x A x T)I = environmental impactP = populationA = affluence and consumptive patternsT = level of technology in the societyOr should it be I = PxAxT/S (S = Stewardly Concern/Practice)Different Populations, Different ProblemsEnvironmental 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.(b) crude birth rate= number birth per 1000 individuals(d) crude death rate= number death per 1000 individuals(r) growth rate = natural increase in population expressed as percent per years (If this number is negative, the population is shrinking.) equation: r = b – d But other factors affect population growth in a certain areaPopulation Growth RatesRates cont’ increase population decrease population births   deaths immigration   emigration (exit) r = (birth - death)+ (immigration-emigration) immigration = migration of individuals into a population from another area or country emigration = migration of individuals from a population bound for another countryr = (b - d)+ (i - e) B D I E r=( 10/1000) – (5/1000) + (1/1000) – (10/1000) r=(0.01-0.005) + (0.001 – 0.01)r = 0.005 – 0.009 = -0.004 or –0.4% per yearexample: population of 10,000 has 100 births (10 per 1000) 50 deaths (5 per 1000)10 immigration (1 per 1000)100 emigration (10 per 1000)You try.Growth Rate ExampleGrowing CitiesDoubling TimeDoubling time = 70 / % growth rate  Use this equation to answer this question:How long will it take for a population to reach a certain size?If the growth rate is 1% and the population size is 10,000, how many years will it take to get to a population of 40,000?Population doubling:Double Time ExampleIn 140 years, the population will be 40,000 people.(70 years)(2) =140 years 2 D.T.  40,0001 D.T.  20,000In 70 years the population will be 20,00070/rate =70/1% =70 years to doubleIn the year 2000 there are 100,000 people living in Paradise. Every year, 10 people emigrate from paradise and 10,000 people immigrate to paradise. 100 people are born each year and 100 people die each year. a) Calculate the doubling time for the population of Paradise. b) How many years will it take for Paradise to have 400,000 people? c) If you were the President of Paradise what would be your policy for population control. (major problem in Paradise)  And Pg. 141 Thinking Environmentally #3HomeworkDemographic TransitionThe transition from a primitive or developing society to a “modern” or developed society  Phase 1 = deaths and births are high (epidemiological) Phase 2 = death rate begins to decrease(fertility) Phase 3 = birth rate drops and death rate flattens outPhase 4 = modern stabilityThere is little population growth in phase 1 but in phase 4 people live longer and have fewer children and the population grows. Demographic TransitionBottom Line= as countries develop, first their death rate drops and then their birth rate dropsReasons for the phases:Phase II:  medical care  nutrition (births still high)  technologyPhase III:  birth control  education (of women)  lower mortality rate of infants  less child laborDemographic TransitionDeveloped CountriesCanada, U.S., Australia, DenmarkDeveloping CountriesBrazil, China, Kenya1/5 of the world’s population lives in absolute poverty (which means they are: illiterate, lack clean H2O and don’t have enough food to survive)80% of world’s population lives in developing countries and this number is growing . . .Developed vs. Developing Total fertility = avg. # of children born per womanFertility of 2.0 = replacement level (theoretical)About 2.1 in realityUnder 2.0 = shrinking populationOver 2.0 = growing pop.Fertility RatesPopulation Data for Selected Countries (Table 5-2)CountryTotal Fertility RateDoubling Times (Years)World2.758Developing Countries2.947Developed Countries1.6700Special agency of the United NationsReceives $$ from developed co. and loans $$ to developing co. Sometimes this backfires by increasing debtOversees all types of issues, not just environmental issuesEx. electricity, roads, new modern technologyWorld BankReached consensus on:Empowerment of womenImproving reproductive healthIncreasing basic educationEnhancing family incomeNo changes to the World BankU.N. Conference (1994) on world population