4 Measuring Population Change Demographic Balancing Equation Population change = (Births -Deaths) +(Immigrants -Emigrants)Or using the common notation, it can be expressed: Pt -P0 = (B -D) + (I-E)Where: P0 is the initial population and Pt is the population after time t
5 Measuring Population Change Natural Increase In this chapter, we will just be looking at births and deaths.This is called the ‘Natural Increase’.We will bring migration into the equation in Chapter 3.
8 Natural Increase Rate (NIR) The term “natural” means that this rate does NOT include migration.Natural Increase Rate (NIR)Percentage by which a population grows in a yearOnly uses birth and death ratesImmigration and emigration are excludedDoubling timeNumber of years needed to double a population
9 Crude Birth Rate (CBR)Total number of live births per year / 1,000 people in a society
10 Crude Death Rate (CDR)Total number of deaths per year / 1,000 people in a society
11 Natural Increase Rate Percentage by which a population grows in a year NIR = (CBR – CDR) / 10
12 Components of Population Growth Natural IncreaseAbout 82 million people are added to the population of the world annually.Rate of natural increase affects the doubling time– number of years needed to double the population, assuming a constant rate of natural increase.Twenty-First Century Rate (1.2 percent): 54 yearsGlobal population in 2100 would reach 24 billion.1963 (2.2): 35 yearsGlobal population in 2010 would have been 10 billion instead of nearly 7 billion.More than 95 percent of the natural increase is clustered in developing countries.
13 Natural Increase Rate Example United States (2010): Population ≈ 308,745,538 Births ≈ 3,999,386 - CBR ≈ Deaths ≈ 2,437,163 - CDR ≈ CBR = #Births / (Total Population / 1000) CBR = 3,999,386 / (308,745,538 / 1000) CBR = 3,999,386 / 308,746 CBR = 13.0
14 Natural Increase Rate Example United States (2010): Population ≈ 308,745,538 Births ≈ 3,999,386 - CBR ≈ 13 Deaths ≈ 2,437,163 - CDR ≈ CDR = #Deaths / (Total Population / 1000) CDR = 2,437,163 / (308,745,538 / 1000) CDR = 2,437,163 / 308,746 CDR = 8
16 Doubling TimesThe doubling time is the number of years before a population will be twice as large as it is today.
17 Doubling TimesThe doubling time is the number of years before a population will be twice as large as it is today.World = 50U.S = 138MDCs = 143LDCs = 40Africa = 27 yearsLatin America = 38 yearsAsia = 46 yearsNorth America = 117 yearsEurope = decreasing!
18 Total Fertility Rate (TFR) Average number of children a woman will have throughout her childbearing years (ages 15-49)Behavior predictor
19 Palestinian Territories Total Fertility Ratethe average number of children a women will have in her childbearing years (15-49 yrs. old).This rate varies from just over 1 (Japan, Italy) to around 7 (Niger, Mali).The U.S. rate is 2.The global average is 2.52.1 is generally regarded as the replacement rate (the rate at which a population neither grows nor shrinks) in the developed world.TFR exceeds 5 in sub-Saharan Africa, while 2 or less in nearly all European countriesPalestinian TerritoriesTotalFertility Rate7.397.006.436.465.995.57U.K.TotalFertility Rate1.721.801.811.781.701.66AfricaTotalFertility Rate6.606.456.115.675.264.97
20 Infant Mortality Rate (IMR) Annual number of deaths of infants under 1 year of age, compared with total live birthsIMR is 5 in developed countries and 80 in sub-Saharan Africa
21 Life expectancyNumber of years a newborn infant can expect to live, assuming current mortality levelsHealth care access and wealth indicator
22 LDC (Least Developed Country) MDC (Most Developed Country) Compare the following demographic factors:LDC (Least Developed Country)MDC (Most Developed Country)Crude Birth Rate = highCrude Death Rate = lowInfant Mortality Rate = highTotal Fertility Rate =highLife Expectancy = lowNatural Increase Rate = highCrude Birth Rate = lowCrude Death Rate =lowInfant Mortality Rate = lowTotal Fertility Rate = lowLife Expectancy = highNatural Increase Rate = low
24 Population Pyramids = graphic device that represents a population’s age and sex composition. Pyramid describes diagram’s shape for many countries in 1800’s when was created.
25 Population Pyramid Overview The most important demographic characteristic of a population is its age-sex structure. Age-sex pyramids (also known as population pyramids) graphically display this information to improve understanding and ease comparison.Age-sex pyramids display the percentage or actual amount of a population broken down by gender and age. The five-year age increments on the y-axis allow the pyramid to vividly reflect long term trends in the birth and death rates but also reflect shorter term baby-booms, wars, and epidemics.
26 Population PyramidsThe shape of a pyramid is primarily determined by the crude death rate in the community.Dependency ratio-the number of people who are too young or too old to work, compared to the number of people in their productive years.People who are 0-14 and 65-plus normally are classified as dependents.The “graying” of a population refers to the aging of a community.Population pyramids also foretell future problems from present population policies or practices. Ex. China’s population policies skewed in favor of males.
29 Sex RatioThe number of males per hundred females in the population is the sex ratio. In Europe and North America the ratio of men to women is about 95:100In poorer countries the high mortality rate during childbirth partly explains the lower percentage of women.
31 There are three key types of population pyramids: Rapid Growth:This pyramid of the Philippines shows a triangle-shaped pyramid and reflects a high growth rate of about 2.1 percent annually.
32 There are three key types of population pyramids: Slow Growth:In the United States, the population is growing at a rate of about 1.7 percent annually. This growth rate is reflected in the more square-like structure of the pyramid. Note the lump in the pyramid between the ages of about 35 to 50.
33 In wealthy countries with very slow rate of population growth – population is nearly equally divided - so pyramids haveAlmost vertical sides.War can be reflected by showing depleted age cohorts and male – female disparities.The % of a country’s population in each age group strongly influences demand for goods and services within that national economy.Country with high % of young has high demand for educational facilities and health delivery services.
34 There are three key types of population pyramids: Negative Growth:Germany is experiencing a period of negative growth (-0.1%). As negative growth in a country continues, the population is reduced.A population can shrink due to a low birth rate and a stable death rate. Increased emigration may also be a contributor to a declining population.
35 Population Pyramids in U.S. cities : Population pyramids can vary greatly with different fertility rates (Laredo vs. Honolulu), or among military bases (Unalaska), college towns (Lawrence), Fig. 2-16and retirement communities (Nples).