chapter 9: the human population. demography definition: the study of populations, most often human...

Chapter 9:Chapter 9:The Human PopulationThe Human Population

DemographyDemography

Definition: the study of populations, Definition: the study of populations, most often human populationsmost often human populations

Includes study of:Includes study of:1.1. History of the populationHistory of the population2.2. Current makeup of populationCurrent makeup of population3.3. Properties that affect the population, Properties that affect the population,

such as economics and social such as economics and social structurestructure

Make predictionsMake predictions

The Human Population Over The Human Population Over TimeTime

1880

1930

1960

1974

1987

1999

2015*

Yr. each billion was reached

* projected

And the Current World And the Current World Population Is…Population Is…

Population clockPopulation clockhttp://math.berkeley.edu/~galen/http://math.berkeley.edu/~galen/

popclk.htmlpopclk.html

Population SizePopulation Size

Population size = (births + immigration) – Population size = (births + immigration) – (deaths + (deaths +

emigration)emigration)

Crude birth rate (CBR) =Crude birth rate (CBR) = number of live births per 1000 people in number of live births per 1000 people in a a population per yearpopulation per year

Crude death rate (CDR) = number of deaths per 1000 people in a Crude death rate (CDR) = number of deaths per 1000 people in a population per yearpopulation per year

Annual rate of natural population change (%) = birth rate – death Annual rate of natural population change (%) = birth rate – death rate rate divided by 1000 persons multiplied by 100divided by 1000 persons multiplied by 100

Falling growth rates do not Falling growth rates do not mean fewer peoplemean fewer people

Falling rates of growth Falling rates of growth do not mean a do not mean a decreasing population, decreasing population, but only that rates of but only that rates of increase are slowingincrease are slowing

World Population Statistics World Population Statistics

Average crude birth rate Average crude death rate

World

All developedcountries

All developingcountries

Developingcountries

(w/o China)

21

9

11

10

24

8

27

9

© 2004 Brooks/Cole – Thomson Learning

Africa

LatinAmerica

Asia

Oceania

UnitedStates

NorthAmerica

Europe

38

14

22

6

20

7

18

7

14

8

14

8

10

12

© 2

004

Bro

oks

/Co

le –

Th

om

son

Lea

rnin

g

© 2

004

Bro

oks

/Co

le –

Th

om

son

Lea

rnin

g China

India

USA

Indonesia

Brazil

Pakistan

Russia

Bangladesh

Japan

Nigeria

2004 2025

1.3 billion1.4 billion

1.1 billion1.4 billion

294 million

349 million

219 million308 million

179 million

211 million

159 million

229 million


141 million

205 million

128 million

121 million


Population sizes of most populous countries in 2004 and projected population size for 2025

Forecasting Population SizeForecasting Population Size

Population size = (births + Population size = (births + immigration) – (deaths + emigration)immigration) – (deaths + emigration)

Based on current dataBased on current data Based on general population Based on general population

propertiesproperties Not always accurate!Not always accurate!

Properties of Populations used Properties of Populations used in forecastingin forecasting

1. 1. Age StructureAge Structure – definition: the – definition: the distribution of ages in a specific distribution of ages in a specific population at a certain timepopulation at a certain time

Graphed as a Graphed as a population pyramid, , defined as a double-sided bar graph defined as a double-sided bar graph showing percent of males and showing percent of males and females in different age groupsfemales in different age groups

Generalized Population Generalized Population PyramidPyramid

Three stages of lifeThree stages of life 0-14 years: 0-14 years:

PrereproductivePrereproductive 15-44 years: 15-44 years:

ReproductiveReproductive 45+ years: 45+ years:

PostreproductivePostreproductiveThe percent of the The percent of the

population in each population in each stage indicates what stage indicates what the population will the population will probably do in the probably do in the future…future…

Why will Kenya experience rapid growth? Why is there a bulge in the middle age range for the U.S.? Do males or females generally live longer?


2. 2. Total fertility rateTotal fertility rate (TFR)(TFR) – definition: the – definition: the average number of children born per average number of children born per woman in her lifetimewoman in her lifetime

High rates mean greater population growthHigh rates mean greater population growthReplacement levelReplacement level – number of children – number of children

needed per couple to replace them and needed per couple to replace them and maintain a stable population (in U.S., it is maintain a stable population (in U.S., it is 2.1 because not all children survive and 2.1 because not all children survive and have children themselves)have children themselves)

World

Developedcountries

Developingcountries

Africa

LatinAmerica

Asia

Oceania

NorthAmerica

Europe

5 children per woman2.8

2.5

1.6

6.53.1

6.65.1

5.92.6

5.92.6

3.82.1

3.52.0

2.61.4

1950 2004

© 2

004

Bro

oks

/Co

le –

Th

om

son

Lea

rnin

g

Fertility rates for women in different countries in 1950 and 2004

When was the “baby boom”?When was the “baby boom”? When was the “baby bust”?When was the “baby bust”? If replacement rate is 2.1, when did the If replacement rate is 2.1, when did the

fertility rate first drop below that level?fertility rate first drop below that level?

Fertility rates Fertility rates remained below remained below replacement level replacement level for most of the for most of the 1990s, but recently 1990s, but recently has been growing has been growing partly because the partly because the children of the baby children of the baby boom grew up and boom grew up and had children.had children.


3. 3. Migration patternsMigration patterns – – immigration and immigration and emigration can influence emigration can influence overall population sizeoverall population size

Most countries do not Most countries do not encourage immigration – encourage immigration – exceptions are Canada, exceptions are Canada, Australia and the U.S.Australia and the U.S.

““Since 1820 the United States Since 1820 the United States has admitted almost has admitted almost twice as many twice as many immigrants as all other immigrants as all other countries combined.”countries combined.”

4. Life Expectancy4. Life Expectancy

Definition: average number of years Definition: average number of years a person is likely to livea person is likely to live

Most influenced by infant mortality Most influenced by infant mortality (death before one year old)(death before one year old)

Humans by Era Average Lifespan at Birth Humans by Era Average Lifespan at Birth (years)(years)

Neanderthal 20Neanderthal 20 Upper Paleolithic 33Upper Paleolithic 33 Neolithic 20 Neolithic 20 Bronze Age 18 Bronze Age 18 Classical Greece 20-30Classical Greece 20-30 Classical Rome 20-30 Classical Rome 20-30 Pre-Colombian North America 25-35 Pre-Colombian North America 25-35 Medieval Britain 20-30 Medieval Britain 20-30 Early 20th Century 30-40 Early 20th Century 30-40 Current world average 67Current world average 67

Life Expectancy Around the Life Expectancy Around the WorldWorld

What conclusions can you draw?

Name a country…Name a country…

World Life Expectancy Chart World Life Expectancy Chart http://geography.about.com/library/whttp://geography.about.com/library/weekly/aa042000b.htmeekly/aa042000b.htm

Population(2004)

Populationprojected

(2025)

Infantmortality

rate

Lifeexpectancy

Fertilityrate (TFR)

%Populationunder

age 15

% Populationover

age 65

Per capitaGNI PPP


137 million


206 million

6.733

100

77 years

71 years52 years

2.02.2

5.7

21%30%

44%

12%6%

3%

$36,110$7,450

$800

United States (highly developed)

Brazil (moderately developed)

Nigeria (less developed)

© 2004 Brooks/Cole – Thomson Learning

Is this where we are Is this where we are headed?headed?

Maybe, maybe not…

Demographic Transition Model Demographic Transition Model (DTM)(DTM)

Definition: a model that describes how Definition: a model that describes how societies change from high birth and societies change from high birth and death rates, to low birth and death rates death rates, to low birth and death rates as they move toward industrializationas they move toward industrialization

Theory behind the model: industrialization Theory behind the model: industrialization causes social and economic development causes social and economic development that influences population growth ratesthat influences population growth rates

Low

High

Rel

ati

ve

po

pu

lati

on

siz

e

Bir

th r

ate

an

d d

eath

rat

e(n

um

ber

per

1,0

00 p

er

yea

r)

80

70

60

50

40

30

20

10

0

Stage 1Preindustrial

Stage 2Transitional

Stage 3Industrial

Stage 4Postindustrial

Low Increasing Very high Decreasing Low Zero Negative

Birth rate

Total population

Death rate

Growth rate over time

Stage 1: Pre-industrial stageHigh birth rate (many children needed to help family survive), high death rate (virtually no medical care, poor diet, much disease), population grows slowly or not at all

Low

High

Rel

ati

ve

po

pu

lati

on

siz

e

Bir

th r

ate

an

d d

eath

rat

e(n

um

ber

per

1,0

00 p

er

yea

r)

80

70

60

50

40

30

20

10

0


Stage 2Transitional

Stage 3Industrial



Birth rate

Total population

Death rate


Stage 2: Transitional stageDeath rate begins to fall as medical care and sanitation improve, population size increases because birth rate remains high

Low

High

Rel

ati

ve

po

pu

lati

on

siz

e

Bir

th r

ate

an

d d

eath

rat

e(n

um

ber

per

1,0

00 p

er

yea

r)

80

70

60

50

40

30

20

10

0


Stage 2Transitional

Stage 3Industrial



Birth rate

Total population

Death rate

Growth rate over timeStage 3: Industrial stageBirth rate declines as fewer children as needed for family survival, improvements in women’s education and access to birth control result in later and fewer pregnancies, death rate continues to fall as medical care, sanitation and diet improve, overall population continues to rise but more slowly

Low

High

Rel

ati

ve

po

pu

lati

on

siz

e

Bir

th r

ate

an

d d

eath

rat

e(n

um

ber

per

1,0

00 p

er

yea

r)

80

70

60

50

40

30

20

10

0


Stage 2Transitional

Stage 3Industrial



Birth rate

Total population

Death rate


Stage 4: Post-industrial stagePopulation growth stabilizes, birth and death rates are low, good health care and family planning, improving status of women

Another summary of the Demographic Another summary of the Demographic Transition ModelTransition Model

Analysis of DTMAnalysis of DTM

Is the demographic Is the demographic transition universal?transition universal?

It has occurred in Europe, U.S., Canada, It has occurred in Europe, U.S., Canada, Japan, and other nations over the past 200-Japan, and other nations over the past 200-300 years300 years

But, it may or may not apply to all But, it may or may not apply to all developing nationsdeveloping nations

The transition could fail in cultures The transition could fail in cultures That place greater value on childbirth or That place greater value on childbirth or Grant women fewer freedomsGrant women fewer freedoms

For people to attain the material standard of living of North Americans, we would need the natural resources of four and a half more Earths

Changing Population TrendsChanging Population Trends

Throughout history, and Throughout history, and currently in many currently in many parts of the world, parts of the world, populations that have populations that have high rates of growth high rates of growth create environmental create environmental problems.problems.

Impact of Human Population on Impact of Human Population on the Environmentthe Environment

I=PATI=PATI = impact on environmentI = impact on environmentP = population sizeP = population sizeA = affluence (consumption)A = affluence (consumption)T = technology (environmental impact per T = technology (environmental impact per

unit of consumption)unit of consumption)

““Formula” developed in 1970s by Paul Formula” developed in 1970s by Paul Ehrlich, Barry Commoner and John HoldrenEhrlich, Barry Commoner and John Holdren

Problems of Rapid GrowthProblems of Rapid Growth1.1. Increased depletion of natural resources - Increased depletion of natural resources - such as fuel to cook, boil water, use for such as fuel to cook, boil water, use for

transportationtransportation fertile soilfertile soil water water

Africa’s Sahel region and western China are turning to desert

Problems of Rapid GrowthProblems of Rapid Growth2.2. Increased pollution – Increased pollution – water: with too many people, local water supply water: with too many people, local water supply

may be used for drinking, washing and sewage may be used for drinking, washing and sewage disposal, leading to spread of infectious diseasedisposal, leading to spread of infectious disease

air pollution – China’s large population and air pollution – China’s large population and economic growth has resulted in severe air economic growth has resulted in severe air pollution due to the use of coal as the primary pollution due to the use of coal as the primary energy sourceenergy source

2008 Olympic games in Beijing

Problems of Rapid GrowthProblems of Rapid Growth3. Increased land 3. Increased land

useuse Growing populations Growing populations

may have a shortage of may have a shortage of arable arable (farmable) land(farmable) land

UrbanizationUrbanization – increase – increase in the ratio of people in the ratio of people living in cities vs rural living in cities vs rural areasareas

Suburban sprawlSuburban sprawl – – problems: traffic, problems: traffic, inadequate inadequate infrastructure, land used infrastructure, land used for housing instead of for housing instead of farms or wildlifefarms or wildlife

DesertificationDesertification and and erosion due to erosion due to agricultureagriculture

Urbanization closing in on a river

Wealth also produces severe Wealth also produces severe environmental impactsenvironmental impacts

The population problem does not exist The population problem does not exist only within poor countries only within poor countries

Affluent societies have enormous resource Affluent societies have enormous resource consumption and waste productionconsumption and waste production People use resources from other areas, as well People use resources from other areas, as well

as from their ownas from their own Individuals’ ecological footprints are hugeIndividuals’ ecological footprints are huge

One American has as much environmental impact as 6 Chinese or 12 Indians or Ethiopians

The wealth gap and The wealth gap and population growth cause population growth cause

conflictconflict The stark contrast between affluent and poor societies The stark contrast between affluent and poor societies causes social and environmental stresscauses social and environmental stress

The richest 20% use 86% of the world’s resourcesThe richest 20% use 86% of the world’s resources Leaves 14% of the resources for 80% of the world’s Leaves 14% of the resources for 80% of the world’s

people to sharepeople to share Tensions between “haves” and “have-not’s” are Tensions between “haves” and “have-not’s” are

increasingincreasing

Managing Development and Managing Development and Population GrowthPopulation Growth

Today, less developed countries Today, less developed countries face the likelihood that continued face the likelihood that continued population growth will prevent population growth will prevent them from imitating the them from imitating the development of the worlddevelopment of the world ’’s s economic leaders.economic leaders.

Countries such as China, Countries such as China, Thailand, and India have created Thailand, and India have created campaigns to reduce the fertility campaigns to reduce the fertility rates of their citizens through rates of their citizens through public advertising, family public advertising, family planning programs, economic planning programs, economic incentives, or legal punishment.incentives, or legal punishment.

Successful programs: Successful programs: China (reduced TFR from 5.7 to 1.7 China (reduced TFR from 5.7 to 1.7

in 30 years) in 30 years) Thailand (reduced growth rate from Thailand (reduced growth rate from

3% to 1.1% in 30 years)3% to 1.1% in 30 years)

Managing Development and Managing Development and Population GrowthPopulation Growth

In 1994, the United Nations held the In 1994, the United Nations held the International International Conference on Population and Development Conference on Population and Development (ICPD),(ICPD),

It involved debates about the relationships It involved debates about the relationships between population, development, and the between population, development, and the environment.environment.

Many countries favor stabilizing population Many countries favor stabilizing population growth through investments in development, growth through investments in development, especially through improvements in womenespecially through improvements in women’’s s status.status.

4:45 A.M.Wake,wash, andeat

5:00 A.M.-5:30 A.M.Walk tofields

3:00 P.M.-4:00 P.M.Collectfirewood

4:00 P.M.-5:30 P.M.Pound andgrind corn

5:30 A.M.-3:00 P.M.Work infields

5:30 P.M.-6:30 P.M.Collectwater

6:30 P.M.-8:30 P.M.Cook forfamily andeat

8:30 P.M.-9:30 P.M.Washdishesand children

9:30 P.M.Go to bed

Work day for a woman in Work day for a woman in developing countrydeveloping country

Empowering women reduces Empowering women reduces growth ratesgrowth rates

Fertility rates drop when women gain access to contraceptives, Fertility rates drop when women gain access to contraceptives, family planning programs and better educational opportunitiesfamily planning programs and better educational opportunities

In 2007, 54% of married women worldwide used contraception; In 2007, 54% of married women worldwide used contraception; China = 86%; the U.S. = 68%; 20 African nations < 10%China = 86%; the U.S. = 68%; 20 African nations < 10%

Women with little power have unintended pregnancies

With these goals, worldwide fertility With these goals, worldwide fertility rates are dropping as shown below.rates are dropping as shown below.

Looking at the graph below, most Looking at the graph below, most demographers predict the medium growth demographers predict the medium growth rate, and a world population of 9 billion in rate, and a world population of 9 billion in 2050.2050.

Conclusion: Withgott and Conclusion: Withgott and BrennanBrennan

The human population is larger than at any time in the pastThe human population is larger than at any time in the past Populations are still rising, even with decreasing growth Populations are still rising, even with decreasing growth

rates rates Most developed nations have passed through the Most developed nations have passed through the

demographic transitiondemographic transition Expanding rights for women slows population growthExpanding rights for women slows population growth Will the population stop rising through the demographic Will the population stop rising through the demographic

transition, restrictive governmental intervention, or disease transition, restrictive governmental intervention, or disease and social conflict caused by overcrowding and and social conflict caused by overcrowding and competition?competition?

Sustainability requires a stabilized population in time to Sustainability requires a stabilized population in time to avoid destroying natural systemsavoid destroying natural systems

chapter 9: the human population. demography definition: the study of populations, most often human...

Documents

specific population

decreasing population

stable population

projected population

birth rate death rate

replacement rate

average number of children

number of deaths