Pop. Dynamics

World World Population Population DynamicsDynamics

Population DistributionPopulation Distribution Population distribution is where people live, Population distribution is where people live, this can be on a global, regional or local scale.this can be on a global, regional or local scale.

Places with lots of people usually have Places with lots of people usually have habitable environments they either: habitable environments they either:

wealthy and industrial e.g. Europe, Japan etc.wealthy and industrial e.g. Europe, Japan etc. poor with rapidly growing populations e.g. poor with rapidly growing populations e.g.

India, Ethiopia India, Ethiopia

• Places with few people are usually hostile Places with few people are usually hostile environments, e.g. Antarctica, Sahara environments, e.g. Antarctica, Sahara Deserts, Alaska etc.Deserts, Alaska etc.

Areas of Large PopulationAreas of Large PopulationRiver Valleys.River Valleys.

e.g. Ganges valley in India, Rhine valley in e.g. Ganges valley in India, Rhine valley in Germany, Indus Valley in Pakistan.Germany, Indus Valley in Pakistan.Lowlands Plains.Lowlands Plains.

e.g. Denmark (very low lying and famous for dairy e.g. Denmark (very low lying and famous for dairy farms), East Anglia in the UK (good location for farms), East Anglia in the UK (good location for growing cereals)growing cereals)Area rich in natural resources.Area rich in natural resources.Coastal Plains.Coastal Plains.

e.g. New York in the U.S.A.e.g. New York in the U.S.A.

The Population ExplosionThe Population Explosion

Population ExplosionPopulation Explosiona recent eventa recent event

Last 200 years or less for MDCs Last 200 years or less for MDCs Industrial RevolutionIndustrial Revolution Improvement in sanitation and medicineImprovement in sanitation and medicine

Last 50 years or less for LDCsLast 50 years or less for LDCs Transfer of technology, i.e. medical, Transfer of technology, i.e. medical,

agricultural (Green Revolution)agricultural (Green Revolution)

Components Influencing Pop. Components Influencing Pop. GrowthGrowth

The Pop. of a country changes because of the The Pop. of a country changes because of the relationship between:relationship between:

the birth rate the birth rate — number of live births per — number of live births per

1000 of the population per year. 1000 of the population per year.

the death rate the death rate — number of deaths per 1000— number of deaths per 1000

of the population per year.of the population per year.

migration migration — number of people moving into — number of people moving into

or out of a country.or out of a country.

Rates of Global Pop. ChangeRates of Global Pop. Change

CBR (crude birth rate) = number of births per CBR (crude birth rate) = number of births per 1000 population1000 population 1990: 241990: 24 Today: 21.3Today: 21.3

CDR (crude death rate) = number of deaths CDR (crude death rate) = number of deaths per 1000 populationper 1000 population 1990: 91990: 9 Today: 8.93 Today: 8.93

growth rate = birth rate - death rate (often in growth rate = birth rate - death rate (often in %)%) 1990: 1.5%1990: 1.5% Today: 1.3%Today: 1.3% growth rates have come downgrowth rates have come down

Special Kinds of Fertility and Special Kinds of Fertility and Mortality RatesMortality Rates

TFR (total fertility rate) = TFR (total fertility rate) = number of children born to a woman during number of children born to a woman during

her reproductive years (or life time)her reproductive years (or life time) 1990: 3.11990: 3.1 2000: 2.82000: 2.8

IMR (infant mortality rate) = IMR (infant mortality rate) = infant deaths per 1000 live births (infant < 1 infant deaths per 1000 live births (infant < 1

yr)yr) 1990: 621990: 62 2000: 56 (1900: 200)2000: 56 (1900: 200)

Pop. Growth and ResourcesPop. Growth and Resources

The relationship b/w the population grwoth and The relationship b/w the population grwoth and the resources can be understand by the the resources can be understand by the following three key concepts:following three key concepts:

OverpopulationOverpopulation — when pop. is more than — when pop. is more than the available resources.the available resources.

Under populationUnder population — when pop. is less than — when pop. is less than the available resources.the available resources.

Optimum populationOptimum population — when population is — when population is a/c to the available resources.a/c to the available resources.

Factors Affecting Pop. GrowthFactors Affecting Pop. Growth

2. Leading to a high 2. Leading to a high

death ratedeath rate

Health CareHealth Care

Infant mortality rateInfant mortality rate

Better hygieneBetter hygiene

Life expectancyLife expectancy

HIV/AIDSHIV/AIDS

1. Leading to a high birth1. Leading to a high birth

raterate

Health CareHealth Care

Preference for sonsPreference for sons

Early marriagesEarly marriages

Need for human laborNeed for human labor

Lack of information on Lack of information on family planningfamily planning

3. Migration3. Migration

COUNTRIES 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990

USA

Birth rate 33 30 27 22 20 25 23 16 16 15

Death rate 17 15 13 11 11 10 10 9 9 9

CANADA

Birth rate 27 34 29 24 22 27 27 17 15 14

Death rate 16 13 13 11 10 9 8 7 7 7

MEXICO

Birth rate 34 32 31 39 44 46 45 42 34 27

Death rate 33 33 25 27 23 16 11 10 7 5

Percentage Population Change 1900-1990

Consequences of Pop. Growth

Benefits Problems

Benefits:Benefits: Problems:Problems: Competition for jobsCompetition for jobs

Competition for housingCompetition for housing

Educational opportunitiesEducational opportunities

Shortage of food supplyShortage of food supply

Sanitation and sewageSanitation and sewage

TransportationTransportation

Health careHealth care

Controls:Controls:Incentives and penaltiesIncentives and penalties

Family planningFamily planning

Population, population change, Population, population change, growth ratesgrowth rates

Population: number of personsPopulation: number of persons

Population change: increase in the Population change: increase in the number of persons (per year)number of persons (per year)

Growth rates: rate of change (per year)Growth rates: rate of change (per year)

Doubling Time Doubling Time Number of years in which a population Number of years in which a population reaches twice its sizereaches twice its sizedoubling time can be approximated using doubling time can be approximated using growth ratesgrowth ratesdoubling time = 69 : growth ratedoubling time = 69 : growth rate rate: 1.4rate: 1.4 doubling time: 49doubling time: 49 rate: 2.0rate: 2.0 doubling time: 34.5doubling time: 34.5 rate: 0.5rate: 0.5 doubling time: 138doubling time: 138 rate: -0.5rate: -0.5 doubling time: ????doubling time: ????

Population PyramidsPopulation Pyramids

Graphic device: bar graphGraphic device: bar graph

shows the age and gender composition shows the age and gender composition of a regionof a region

horizontal axis: genderhorizontal axis: gender male: left-handmale: left-hand female: right-handfemale: right-hand absolute number of people or %absolute number of people or %

vertical axis: agevertical axis: age 5-year or 10-year age groups5-year or 10-year age groups

The Demographic TransitionThe Demographic Transition

Five Stages of the Demographic Five Stages of the Demographic TransitionTransition

birth rates, death rates and growth rates birth rates, death rates and growth rates systematically change through time as systematically change through time as societies change:societies change: modernize, urbanizemodernize, urbanize gain access to technologygain access to technology

Stage 1Stage 1high birth rates, high birth rates, high (at time high (at time erratic) death rates, erratic) death rates, low growth rateslow growth rates

stage for much of stage for much of human history, human history, traditional societiestraditional societies

practically no practically no country todaycountry today

Stage 2Stage 2high birth rates, declining high birth rates, declining death rates, rising growth death rates, rising growth ratesratesimprovements in sanitation improvements in sanitation (water) and medicine(water) and medicinein Europe during Industrial in Europe during Industrial RevolutionRevolutionin developing countries in developing countries since the 50s/60ssince the 50s/60smuch of Africa today, much of Africa today, some countries of Asia some countries of Asia (Afghanistan, Nepal, etc.)(Afghanistan, Nepal, etc.)

Stage 3Stage 3continued decline of death continued decline of death rates, declining birth rates, rates, declining birth rates, growth rates decline from growth rates decline from high to lower levelshigh to lower levelschange in behavior: change in behavior: adaptation to lower death adaptation to lower death rate, in particular infant rate, in particular infant mortality ratemortality rateeconomic change: economic change: urbanization (incentive to urbanization (incentive to have fewer children)have fewer children)E.g. Mexico, ChinaE.g. Mexico, China

Stage 4 & 5Stage 4 & 5Stage 4: low birth Stage 4: low birth rates, low death rates, rates, low death rates, low growth rateslow growth rates United States todayUnited States today

Stage 5: low birth Stage 5: low birth rates, rising death rates, rising death rates, declining growth rates, declining growth rates (if birth rates drop rates (if birth rates drop below death rates: below death rates: negative growth rates)negative growth rates) Western Europe, JapanWestern Europe, Japan

-500 -400 -300 -200 -100 0 100 200 300 400 500

0-4

5-9

10-14

15-19

20-24

25-29

30-34

35-39

40-44

45-49

50-54

55-59

60-64

65-69

70-74

75-79

80-84

85 OR

female

male

Population Pyramid with Population Pyramid with young cohortsyoung cohorts

Population Pyramids and Population Pyramids and Demographic StagesDemographic Stages

characteristics shapes of ‘pyramids’characteristics shapes of ‘pyramids’ wide base (true pyramid)wide base (true pyramid) wide middle (bulge), somewhat wider basewide middle (bulge), somewhat wider base urn- or bottle-shapedurn- or bottle-shaped reversed pyramidreversed pyramid

different shapes--different dynamicsdifferent shapes--different dynamics

Population Pyramid and Population Pyramid and Demographic TransitionDemographic Transition

Stage 2: wide baseStage 2: wide base


stage 3: wide middlestage 3: wide middle


stage 4: slenderstage 4: slender


stage 5: narrow basestage 5: narrow base

Population Dependency in Population Dependency in LEDCs & MEDCsLEDCs & MEDCs

Population dependency is a ratio comparing the Population dependency is a ratio comparing the number of working age (16-64)* with the number of working age (16-64)* with the number of dependents (0-15 and over 65)*.number of dependents (0-15 and over 65)*.

It’s normally written as a single number which is It’s normally written as a single number which is the number of dependents for every one the number of dependents for every one hundred people of working age. hundred people of working age.

* The range of these age group can be vary.* The range of these age group can be vary.

Dependency Ratio Dependency Ratio == no. of children(0-15) + old people(65+)x100no. of children(0-15) + old people(65+)x100 no. of people of working age (16-64) no. of people of working age (16-64)

Example: Example:

The dependency ratio for the UK (1995)The dependency ratio for the UK (1995)

in millions == in millions == 11,360 + 9,02911,360 + 9,029 x100 == 53.84 x100 == 53.84

37,86737,867

This means that This means that for every 100 economically activefor every 100 economically active

peoplepeople , there are , there are nearly 54 peoplenearly 54 people are dependent. are dependent.

Note that:Note that: D.R. D.R. 50-60 50-60 MEDCs MEDCs

D.R. D.R. 60-100 60-100 LEDCs LEDCs

use: International Data Base use: International Data Base http://http://www.census.gov/ipc/www/idbnew.htmlwww.census.gov/ipc/www/idbnew.html, , then Online Demographic Aggregationthen Online Demographic Aggregation

Frequency of Vital Events: Frequency of Vital Events: The Population ClockThe Population Clock

Population ClockPopulation Clockhttp://www.census.gov/main/www/popclock.htmlhttp://www.census.gov/main/www/popclock.htmlVital Events (per time unit)Vital Events (per time unit)http://www.census.gov/cgi-bin/ipc/pcwehttp://www.census.gov/cgi-bin/ipc/pcwe

The global population reached 6 billion in fall of The global population reached 6 billion in fall of 19991999

Population PyramidsPopulation Pyramids

Population Pyramids on the WebPopulation Pyramids on the Webhttp://www.census.gov/ipc/www/idbpyr.htmlhttp://www.census.gov/ipc/www/idbpyr.html