Applying Population Dynamics: The Human Population and Its Impact Chapter 6

Applying Population Dynamics:Applying Population Dynamics:

The Human Population and The Human Population and Its ImpactIts Impact

Chapter 6Chapter 6

Chapter Overview QuestionsChapter Overview Questions What is the What is the historyhistory of human population of human population

growth, and how many people are likely to be growth, and how many people are likely to be here here by 2050by 2050??

How is population size affected by How is population size affected by birth, birth, death, fertility, and migration ratesdeath, fertility, and migration rates??

How is population size affected by How is population size affected by percentagespercentages of males and females at each of males and females at each age level?age level?

Chapter Overview Questions (cont’d)Chapter Overview Questions (cont’d) How can we How can we slow population growthslow population growth??

What success have What success have IndiaIndia and and ChinaChina had in had in slowing population growth?slowing population growth?

What are the What are the major impactsmajor impacts of human of human activities on the world’s activities on the world’s natural ecosystemsnatural ecosystems??

Core Case Study: Is the World Core Case Study: Is the World Overpopulated?Overpopulated?

The world’s population is projected to The world’s population is projected to increase from increase from 7 billion7 billion to about to about 9.5 billion9.5 billion between 2011 and 2050.between 2011 and 2050.

The debate over interactions among The debate over interactions among population growthpopulation growth, , economic growtheconomic growth, , politicspolitics, , and and moral beliefsmoral beliefs is one of the most is one of the most important and controversial issues in important and controversial issues in environmental science.environmental science.

Core Case Study: Is the World Overpopulated?Core Case Study: Is the World Overpopulated?

Much of the world’s population growth occurs Much of the world’s population growth occurs in developing countries like China and India.in developing countries like China and India.

China 22%India 18%

China + India = 40%

USA is #3 with 4.5%

Core Case Study: Is the World Core Case Study: Is the World Overpopulated?Overpopulated?

SomeSome argue that the planet has argue that the planet has too manytoo many people.people.

SomeSome feel that the world can support feel that the world can support billions billions of moreof more people due to technological people due to technological advances.advances.

There is a There is a constant debateconstant debate over the need to over the need to reduce population growth.reduce population growth. Must consider moral, religious, and personal Must consider moral, religious, and personal

freedom.freedom.

Two Fundamental Questions…Two Fundamental Questions…WHY are living conditionsWHY are living conditions so radically different so radically different

between developed countries and between developed countries and undeveloped countries?undeveloped countries?

WHY are population dynamicsWHY are population dynamics so different so different between developed countries and between developed countries and undeveloped countries?undeveloped countries?

“Accidents of Geography”…read Jared Diamond’s Guns, Germs, & Steel”

3 Revolutions, Expansion into new ecosystems, and The Demographic Transition

Birth rate

Death rate

Total population

Stage 1Preindustrial

Stage 2Transitional

Stage 3Industrial

Stage 4Postindustrial

Growth rate over time

Bir

th r

ate

and

dea

th r

ate

(nu

mb

er p

er 1

,00

per

yea

r)

Rel

ativ

e p

op

ula

tio

n s

ize

Low Low LowIncreasing Very high Decreasing Zero Negative

High

The Demographic TransitionMore on this later….

HUMAN POPULATION GROWTH:HUMAN POPULATION GROWTH:A BRIEF HISTORYA BRIEF HISTORY

The human population has grown rapidly The human population has grown rapidly because of because of the the expansion of agricultureexpansion of agriculture and industrial and industrial

productionproduction expansion into expansion into new ecosystemsnew ecosystems lower deathlower death rates from improvements in hygiene rates from improvements in hygiene

and medicine.and medicine.

3 Revolutions!3 Revolutions!

AgriculturalAgricultural Industrial-MedicalIndustrial-Medical Info-GlobalizationInfo-Globalization

Agricultural RevolutionAgricultural Revolution

Before…


After… (but before the “green revolution”)


After…. (and after

the “green revolution”)

Industrial-Medical RevolutionIndustrial-Medical RevolutionBefore…

Industrial-Medical RevolutionIndustrial-Medical Revolution

After.


Before…


After.

GLOBAL HUMAN POPULATION GROWTHGLOBAL HUMAN POPULATION GROWTH 10,000 years ago10,000 years ago 5 5

millionmillion 18001800 1 billion1 billion 19301930 2 billion2 billion 19601960 3 billion3 billion 19741974 4 billion4 billion 19871987 5 billion5 billion 19991999 6 billion6 billion 20112011 7 billion7 billion

Currently: Still increasing, but at a decreasing rate.

(Birth rates are still higher than death rates, but by a lesser and lesser amount)

GLOBAL HUMAN POPULATION GROWTH:GLOBAL HUMAN POPULATION GROWTH:A BRIEF HISTORYA BRIEF HISTORY

In 2008:In 2008: Still growing exponentially at Still growing exponentially at 1.22%1.22% = = 82 million people added/yr =82 million people added/yr = 225,000 per day =225,000 per day = 2.4 people every time your heart 2.4 people every time your heart

beats!beats!

Where Are We Headed?Where Are We Headed?

We do not know how long we can continue We do not know how long we can continue increasing the earth’s carrying capacity for increasing the earth’s carrying capacity for humans.humans.

There are likely to be between 7.8-10.7 billion There are likely to be between 7.8-10.7 billion people on earth by 2050 (mean probability of 9.5 people on earth by 2050 (mean probability of 9.5 billion).billion).

97% 97% of growth will be inof growth will be in developing countries developing countries among people living in among people living in acute povertyacute poverty..

Which leads to the question…


What is the What is the optimumoptimum sustainable populationsustainable population of of the earth based on the the earth based on the cultural carrying cultural carrying capacitycapacity??

Thomas Malthus- 1796- Proposed that human populations will crash because agricultural production increases linearly, while population increases exponentially.

So far, Malthus was “wrong”, because he did not forsee the exponential increase in food supply due to genetic & technical advances in agriculture.


U.N. world U.N. world population projection population projection based on women based on women having an average of having an average of 2.5 (high), 2.0 2.5 (high), 2.0 (medium), or 1.5 (medium), or 1.5 (low) children.(low) children.

((Total Fertility RateTotal Fertility Rate))

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Fig. 9-2, p. 173

High10.7

Po

pu

lati

on

(b

illi

on

s)High (2.5)

Medium (2.0)

Low (1.5)

Low7.8

Medium9.3

Year

Total Fertility Rate

FACTORS AFFECTING HUMAN FACTORS AFFECTING HUMAN POPULATION SIZEPOPULATION SIZE

Population increases because of births and Population increases because of births and immigration and decreases through deaths immigration and decreases through deaths and emigration.and emigration.

Instead of using raw numbers, Instead of using raw numbers, crude birth crude birth ratesrates and and crude death ratescrude death rates are used (based are used (based on total number of births or deaths per 1,000 on total number of births or deaths per 1,000 people in a population).people in a population).

Fig. 9-3, p. 174

Average crude death rate

Average crude birth rate

World21

9

All developedcountries

11

10

All developingcountries

27

8

9

23

Developingcountries

(w/o China)

2006 data

Why?

2011?

20

8

Fig. 9-3, p. 174

14

Europe

North America

UnitedStates

Oceania

Asia

Africa

Latin andCentral America

38

15

21

6

20

7

17

7

14

8

8

11

10

2006 data

2011?

12

36

6

18

18

7

18

7

13

8

813

11

11

Declining Fertility Rates: Declining Fertility Rates: Fewer Babies per WomenFewer Babies per Women

FertilityFertility is the number of babies is the number of babies oneone woman has in woman has in her lifetime.her lifetime.


Total Fertility Rate (TFR) Total Fertility Rate (TFR) is the is the averageaverage number of number of babies born per woman, per region.babies born per woman, per region.

Declining Total Fertility Rates: Declining Total Fertility Rates: Fewer Babies per WomenFewer Babies per Women

The average number of children that a The average number of children that a woman bears has woman bears has dropped sharply.dropped sharply.

This decline is This decline is not low enough to stabilizenot low enough to stabilize the the world’s population in the near future.world’s population in the near future. Replacement-level fertility a.k.a. “ZPG”Replacement-level fertility a.k.a. “ZPG”: the : the

number of children an number of children an average coupleaverage couple must bear must bear to replace themselves.to replace themselves.

Total fertility rate (TFR)Total fertility rate (TFR): the average number of : the average number of children a woman has during her reproductive children a woman has during her reproductive years (years (averageaverage per region per region))

What should global TFR be in order to achieve ZPG?


The The replacement levelreplacement level TFR to sustain a TFR to sustain a population (attain ZPG) is :population (attain ZPG) is : 2.12.1 children in the developed world children in the developed world 2.52.5 children in the developing world (why?) children in the developing world (why?)

In 2008, the average global Total Fertility Rate In 2008, the average global Total Fertility Rate was 2.6 children per woman.was 2.6 children per woman. 1.6 in developed countries (down from 2.5 in 1950).1.6 in developed countries (down from 2.5 in 1950). 2.8 in developing countries (down from 6.5 in 1950).2.8 in developing countries (down from 6.5 in 1950).

Case Study: Fertility and Birth Rates Case Study: Fertility and Birth Rates in the United Statesin the United States

1900 - 76 million1900 - 76 million 2011 – 312 million2011 – 312 million

Nearly 2.9 million people were added to the Nearly 2.9 million people were added to the U.S. in 2008:U.S. in 2008:

66%66% occurred because of occurred because of births outnumbering births outnumbering deaths.deaths.

34%34% came from illegal and legal came from illegal and legal immigration.immigration.


In 2008, the total fertility rate in the United In 2008, the total fertility rate in the United States was 2.1States was 2.1

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Fig. 9-5, p. 175

ReplacementLevel

Year

Bir

ths

per

wo

man

Baby boom(1946–64)

U.S. Total Fertility Rate


The The baby bustbaby bust that followed the that followed the baby boombaby boom was largely due to was largely due to delayed marriage, delayed marriage, contraception, and abortion.contraception, and abortion.

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Fig. 9-6, p. 175

Demographic transition:

Transitional Stage to Industrial Stage Depression

End of World War II

Baby boom Baby bust Echo baby boom

Bir

ths

pe

r th

ou

sa

nd

po

pu

lati

on

Year

Does this graph represent a stock concept or a flow concept?

U.S. Crude Birth Rate

1910 to 2010

The Times, They are a Changin’The Times, They are a Changin’ In 1905, in the US:In 1905, in the US:

The 3 leading causes of death were pneumonia, The 3 leading causes of death were pneumonia, tuberculosis, & diarrheatuberculosis, & diarrhea

90% of doctors had no college education90% of doctors had no college education 1/5 of adults could not read or write1/5 of adults could not read or write Average $ was 22Average $ was 22 cents / hour, $200-400 / year cents / hour, $200-400 / year A total of 9000 carsA total of 9000 cars A total of 144 miles of paved roadsA total of 144 miles of paved roads A 3 min. call from Denver to NYC cost $11A 3 min. call from Denver to NYC cost $11 The population of Las Vegas was 30 peopleThe population of Las Vegas was 30 people Most women washed their hair once a monthMost women washed their hair once a month

Fig. 9-7, p. 176

47 years

Homicides per100,000 people

Hourly manufacturing job wage (adjusted for inflation)

Living insuburbs

Homes withelectricity

Homes withflush toilets

High schoolgraduates

Married women workingoutside the home

Life expectancy

1.25.8

$15$3

52%10%

99%2%

98%10%

83%15%

81%

2000

1900

8%

77 years

Key

(USA)

Factors Affecting Birth Rates and Factors Affecting Birth Rates and Fertility RatesFertility Rates

The The number of children women havenumber of children women have is is affected by:affected by: The cost of raising and educating them.The cost of raising and educating them. Availability of pensions.Availability of pensions. Urbanization.Urbanization. Education and employment opportunities.Education and employment opportunities. Infant deaths.Infant deaths. Marriage age.Marriage age. Availability of contraception and abortion.Availability of contraception and abortion.

Direction of influence?

Factors Affecting Death RatesFactors Affecting Death Rates

Death rates have declinedDeath rates have declined because of: because of: Increased food supplies, better nutrition.Increased food supplies, better nutrition.

Improved sanitation and personal hygiene.Improved sanitation and personal hygiene.

Safer water supplies.Safer water supplies.

Advances in medicine.Advances in medicine.

Factors Affecting Death RatesFactors Affecting Death Rates

U.S. infant mortality is twice that of any other U.S. infant mortality is twice that of any other industialized nation (ranked 46industialized nation (ranked 46thth world-wide) world-wide) due to:due to:

Inadequate pre- and post-natal care for poor Inadequate pre- and post-natal care for poor women & childrenwomen & children

Drug addiction.Drug addiction.

High teenage birth rate.High teenage birth rate.

Case Study: U.S. ImmigrationCase Study: U.S. Immigration

Since 1820, the Since 1820, the U.S. has admitted U.S. has admitted almost twice as almost twice as many immigrants many immigrants and refugeesand refugees as as all other countries all other countries combined.combined.

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Fig. 9-8, p. 178

1907

Year

Nu

mb

er o

f le

gal

im

mig

ran

ts (

tho

usa

nd

s)

New lawsrestrictImmigration

1914

GreatDepression

POPULATION AGE STRUCTUREPOPULATION AGE STRUCTURE The number of people in The number of people in young, middle, and olderyoung, middle, and older

age groups determines how fast populations grow age groups determines how fast populations grow or decline.or decline.

POPULATION AGE STRUCTUREPOPULATION AGE STRUCTURE The number of people The number of people younger than age 15younger than age 15 is is

a major factor determining a country’s a major factor determining a country’s population growth.population growth. ““Perhaps the world’s Perhaps the world’s most importantmost important population population

statistic: statistic: 28%28% of the world’s population (in 2008) of the world’s population (in 2008) was was under 15 years oldunder 15 years old.”.”• Developed countries: 17%Developed countries: 17%• Developing countries: 30% (41% in Africa)Developing countries: 30% (41% in Africa)

1.9 billion about to enter their reproductive years!1.9 billion about to enter their reproductive years!

In parts of Asia, Africa, & South America, In parts of Asia, Africa, & South America, 20-50%20-50% of the of the 15-2415-24 age group is age group is unemployedunemployed..

What are the implications of this statistic for terrorism?

POPULATION AGE STRUCTUREPOPULATION AGE STRUCTURE

A population with a large proportion of its A population with a large proportion of its people in the preproductive ages 1-14 has a people in the preproductive ages 1-14 has a large potential for rapid population growth.large potential for rapid population growth.

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Fig. 9-9, p. 179

Expanding RapidlyGuatemala

NigeriaSaudi Arabia

Expanding SlowlyUnited States

AustraliaCanada

StableSpain

PortugalGreece

DecliningGermanyBulgaria

Italy

Prereproductive ages 0–14

Reproductive ages 15–44

Postreproductive ages 45–85+

FemaleMale Male Male Male FemaleFemaleFemale

Age Structure Diagrams

Fig. 9-11, p. 180

US Census Bureau Data

Year 2000 Census

2009 US Life Expectancy At Birth:

Male 75 yrs

Female 82 yrs

2011: 80 yrs


About 30%About 30% of the people in of the people in developing countriesdeveloping countries were were under 15 yearsunder 15 years old in 2008 old in 2008

versus only versus only 17%17% in in developed countriesdeveloped countries..

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Fig. 9-10a, p. 179

FemaleA

ge

Population (millions)

Developed Countries

Male

Fig. 9-10b, p. 179

FemaleA

ge

Population (millions)

Developing Countries

Male


Today, Today, baby boomersbaby boomers make up nearly half of make up nearly half of all adult Americans and dominate the all adult Americans and dominate the populations demand for goods and services.populations demand for goods and services.

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Fig. 9-11, p. 180

Females Males

Age

Females Males

Age

Females Males

Age

Females Males

Age

1955 1985 2015 2035

Follow the Boomers!


Changes in the distribution of a country’s age Changes in the distribution of a country’s age groups have groups have long-lasting economic and long-lasting economic and social impacts.social impacts. Baby boomers wield a lot of influence…how will Baby boomers wield a lot of influence…how will

they use this when they are all old?they use this when they are all old? Large numbers of baby boomers in upper Large numbers of baby boomers in upper

management may prevent baby busters from management may prevent baby busters from advancing in corporationsadvancing in corporations

Baby busters will not have a lot of competition Baby busters will not have a lot of competition among each other for getting jobs, and may among each other for getting jobs, and may eventually be able to command high wages.eventually be able to command high wages.• Assuming many jobs have not been exportedAssuming many jobs have not been exported

POPULATION AGE STRUCTURE: POPULATION AGE STRUCTURE: Decreasing PopulationDecreasing Population

About About 14%14% of the world’s population live in of the world’s population live in countries with countries with stabilizing or decliningstabilizing or declining populations.populations.

Rapid population declineRapid population decline can lead to long- can lead to long-lasting lasting economic and social problemseconomic and social problems..

Fig. 9-13, p. 182

• Can threaten economic growth

• Less government revenues with fewer workers

• Less entrepreneurship and new business formation

• Less likelihood for new technology development

• Increasing public deficits to fund higher pension and healthcare costs

Aging populations…


Death from AIDSDeath from AIDS can disrupt a country’s social can disrupt a country’s social and economic structure by removing and economic structure by removing significant numbers of young adults.significant numbers of young adults. Doctors? Nurses? Teachers? Physical Labor?Doctors? Nurses? Teachers? Physical Labor?

Global agingGlobal aging may help promote peace may help promote peace Fewer young people for military serviceFewer young people for military service Parents w/ 1 to 2 kids less likely to support warParents w/ 1 to 2 kids less likely to support war Less govt. funds available for military due to rising Less govt. funds available for military due to rising

health care and pension costshealth care and pension costs

POPULATION AGE STRUCTUREPOPULATION AGE STRUCTURE Global age structure Global age structure

predictions based on predictions based on a a medium fertility medium fertility projection.projection.

The cost of an aging The cost of an aging population will strain population will strain the global economy.the global economy. What changes will What changes will

this precipitate?this precipitate?NextNext

Fig. 9-12, p. 181

Year

Under age 15 Age 60 or over Age 80 or over

Ag

e D

istr

ibu

tio

n (

%)

SOLUTIONS: INFLUENCING SOLUTIONS: INFLUENCING POPULATION SIZEPOPULATION SIZE

Demographic TransitionDemographic Transition: As countries : As countries become economically developed, their birth become economically developed, their birth and death rates tend to decline.and death rates tend to decline. Preindustrial stagePreindustrial stage: little population growth due : little population growth due

to high infant mortality & crude death rate.to high infant mortality & crude death rate. Transitional stageTransitional stage: industrialization begins, : industrialization begins,

death rates drops and birth rates remain high.death rates drops and birth rates remain high. Industrial stageIndustrial stage: birth rate drops and : birth rate drops and

approaches death rate.approaches death rate. Postindustrial stagePostindustrial stage : birth & death- low & equal : birth & death- low & equal


Generalized model of demographic transition.Generalized model of demographic transition. Some developing countries may have difficulty Some developing countries may have difficulty

making the demographic transition.making the demographic transition.Figure 9-14Figure 9-14

Fig. 9-14, p. 183

Birth rate

Death rate

Total population

Stage 1Preindustrial

Stage 2Transitional

Stage 3Industrial

Stage 4Postindustrial

Growth rate over time

Bir

th r

ate

and

dea

th r

ate

(nu

mb

er p

er 1

,000

per

yea

r)

Rel

ativ

e p

op

ula

tio

n s

ize

Low LowLow

Increasing Very high Decreasing Zero Negative

High

The Demographic Transition


Family planningFamily planning has has been a major factor in been a major factor in reducing the number of reducing the number of births and abortions births and abortions throughout most of the throughout most of the world.world.


Women tend to have Women tend to have fewer childrenfewer children if they are: if they are: Educated.Educated. Hold a paying job outside the home.Hold a paying job outside the home. Do not have their human right suppressed.Do not have their human right suppressed.


The best way to slow population growth is a The best way to slow population growth is a combination of:combination of: Investing in Investing in family planningfamily planning.. Reducing povertyReducing poverty.. Elevating the Elevating the status of womenstatus of women..

(Globally, women own (Globally, women own less than 2% less than 2% of the land)of the land)

MicrofinanceMicrofinance has become a leading tool in has become a leading tool in these efforts world-wide.these efforts world-wide.

MicrofinanceMicrofinance Invented by Invented by

Dr. Muhammad YunusDr. Muhammad Yunus Born in BangladeshBorn in Bangladesh 1971: PhD in 1971: PhD in

economics from economics from Vanderbilt UniversityVanderbilt University

1976- Loaned $27 to 1976- Loaned $27 to 42 women, who turned 42 women, who turned a profit, then founded a profit, then founded Grameen BankGrameen Bank

2006: Nobel Peace 2006: Nobel Peace PrizePrize

According to the journal MicroBanking Bulletin, at the end of 2006 it was tracking 704 MFIs that were serving 52 million borrowers ($23.3 billion in outstanding loans) and 56 million savers ($15.4 billion in deposits). Av. loan = $450

Of these clients, 70% were in Asia, 20% in Latin America and the balance in the rest of the world.[21]

http://en.wikipedia.org/wiki/Microfinance#cite_note-20

Because many women from one village borrow individual loans at the same time, they encourage each other to keep going when challenges arise.

The repayment % rate for most MFIs is in the high nineties, exceeding that of any large bank in the world.

SLOWING POPULATION GROWTH SLOWING POPULATION GROWTH IN INDIA AND CHINAIN INDIA AND CHINA

For more than For more than five decades, Indiafive decades, India has tried to has tried to control its population growth with only control its population growth with only modest modest successsuccess..

Since 1970Since 1970, , ChinaChina has used a government- has used a government-enforced program to cut its crude birth rate in enforced program to cut its crude birth rate in half and sharply reduce its fertility rate.half and sharply reduce its fertility rate.

India’s Failed India’s Failed Family Planning ProgramFamily Planning Program

Well intentioned, but very idealisticWell intentioned, but very idealistic Poor planning.Poor planning. Bureaucratic inefficiency.Bureaucratic inefficiency. Low status of women.Low status of women. Extreme poverty.Extreme poverty. Lack of administrative financial support.Lack of administrative financial support. Disagreement over the best ways to slow Disagreement over the best ways to slow

population growth.population growth. Recent economic development may finally Recent economic development may finally

make it possible for India to begin to reduce it’s make it possible for India to begin to reduce it’s TFRTFR

China’s Family Planning ProgramChina’s Family Planning Program Currently, China’s TFR is 1.6 children per Currently, China’s TFR is 1.6 children per

women.women. Encouraging later marriagesEncouraging later marriages Urging families to only have one childUrging families to only have one child Health, pension, & employment benefits for 1-Health, pension, & employment benefits for 1-

child familieschild families Encouraging contraception & family planningEncouraging contraception & family planning Providing free birth control & abortionsProviding free birth control & abortions

China’s Family Planning ProgramChina’s Family Planning Program China has moved 300 million people out of China has moved 300 million people out of

poverty.poverty.

Problems:Problems: Strong male baby preference leads to gender Strong male baby preference leads to gender

imbalance.imbalance. Average population age is increasing.Average population age is increasing. Still not enough resources to support China’s Still not enough resources to support China’s

huge population. huge population.

HUMAN ASPECTS ON HUMAN ASPECTS ON NATURAL SYSTEMSNATURAL SYSTEMS

Excluding Excluding Antarctica, Antarctica, human human activities have activities have affected about affected about 83%83% of the of the earths land earths land surface.surface.

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Fig. 9-16, p. 188

Biologically simplified

Mostly nonrenewable fossil fuel energy

High

Often lost or wasted

Majority used, destroyed, or degraded to support human activities

Property

Complexity

Energy source

Waste production

Nutrients

Net primary productivity

NaturalSystems

Biologically diverse

Renewable solar energy

Little, if any

Recycled

Shared among many species

Human-Dominated Systems

HUMAN ASPECTS ON HUMAN ASPECTS ON NATURAL SYSTEMSNATURAL SYSTEMS

We have used technology We have used technology to alter much of the rest of to alter much of the rest of nature in ways that threaten nature in ways that threaten the survival of many other the survival of many other species and could reduce species and could reduce the quality of life for our the quality of life for our own species.own species.

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Fig. 9-17, p. 188

Reduction of biodiversity

Increasing use of the earth's net primary productivity

Increasing genetic resistance of pest species and disease-causing bacteria

Elimination of many natural predators

Deliberate or accidental introduction of potentially harmful species into communities

Using some renewable resources faster than they can be replenished

Interfering with the earth's chemical cycling and energy flow processes

Relying mostly on non-renewable, polluting fossil fuels

Natural Capital Degradation

Altering Nature to Meet Our Needs

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Applying Population Dynamics: The Human Population and Its Impact Chapter 6