Presentation on theme: "Where has the world’s population increased?"— Presentation transcript:
1 Where has the world’s population increased? Key Issue 2Where has the world’s population increased?
2 Population ChangeGeographers measure population change in a country or the world as a whole through three measures:Crude Birth RateCrude Death RateNatural Increase Rate (NIR or NRI)WHY ARE THESE IMPORTANT?What do they tell us about the world?Increase in populationPredict how quicklyPopulation trends
3 Crude Birth/Death Rate Crude means the world as a wholeCBR Definition:Total # of live births in a year for every 1,000 peopleExample:CBR of 20 =20 births per 1,000 in a 1 year periodCDR Definition:Total # of deaths in a year for every 1,000 people
4 Natural Increase NIR definition: % by which a population grows each yearFormula:CBR- CDR = NIR20 – 5 = 15=1.5% NIRNatural increase means migration is excludedWorld NIREarly 21st century = 1.2%All time peak in 1963 with 2.2%80 million people added annuallyEven though NIR is slowing, population base is large
5 Doubling Time Rate of NIR effects doubling time Definition: # of years needed to double a populationExampleNIR of 1.2 = 54 years to doubleIf world NIR remains steady through 21st century world population will be 24 billion by 2100More than 95% of NIR is clustered in LDCsExceeds 2.0 in sub-saharan Africa and Middle East
6 Population ExplosionThe population continues to “explode” as the doubling time decreases.Example:8 A.D. – 250 million1650 A.D million1820 A.D.- 1 billion1930 A.D.- 2 billion1975 A.D.- 4 billion
7 Fertility Total Fertility Rate World TFR = 2.6 Measures the # of births in societyAverage # of children a woman will have during childbearing years (15-49 years)CBR provides picture of society for given yearTFR attempts to predict future behavior of individual womenWorld TFR = 2.6Sub-saharan Africa =6Western Europe= .09
8 Mortality IMR rates highest in poorer countries U.S. special example Sub-Saharan Africa100 means 10% of all babiesOften reflect’s countries healthcare systemU.S. special examplehigh MRI for a MDCWhy?Minorities, poor population access to healthcareTwo useful measuresCDRInfant mortality rateDefinition:# of deaths of infants under 1 year of age per year
9 Death RateDeath rate is not a good statistic to use in determining quality of life.Why?Not all countries are at same stage….Example: US is wealthy MDC but may have more deaths because of an older population than Ethiopia.
10 Life Expectancy Definition: Average # of years a newborn infant can expect to live at current mortality levelsLike all mortality/fertility rates higher in core/MDC nationsWestern Europe = 80 yearsSub-Saharan Africa= 50 yearsAll become repetitious because all follow similar patterns
11 Population Growth Curves S Curve – historical growthJ Curve – exponential growth (fixed percentage)