Lecture Outlines
Chapter 8
Human Population
This lecture will help you understand:
Human population growth
Different viewpoints on this growth
Population, affluence, and technology’s effects
Demography
Demographic transition
Factors affecting population growth
The HIV/AIDS epidemic
Central Case Study: China’s One-Child Policy
In 1970, China’s 790 million people were exhausting
their resources and faced starvation if growth continued
The government instituted a one-child policy
The growth rate plummeted
The policy is now less strict
The successful program has had unintended
consequences
Killing of female infants and an imbalance in male to female ratios
Our World at Seven Billion
Populations continue to rise in most countries,
particularly in poverty-stricken developing nations
Growth in poorer nations leads to stresses on
society, the environment, and people’s well-being
China’s stringent policies have greatly slowed
growth there, but other countries may wish to slow
their growth without the measures used by China
India’s growth continues and if not changed will surpass China’s population
The Population Explosion
The current world population is 7.732 Billion as of
September 25, 2019.
Each time your heart beats, three more people are
added to the world.
Each time a person dies 2.8 babies are born.
The human population is growing rapidly
Our population grows by over 70 million each year
It took until 1800 to reach 1 billion
In 1930 (130 years later) we reached 2 billion
We added the most recent billion in 12 years
Growth rates vary from country to country
Some countries are over 3%, while other country’s
populations are shrinking
The current world growth rate is 1.2%
At this rate, the human population of the planet would
Is population growth a problem?
Better technology, sanitation, medication, and
increased food supply have increased growth
Death rates drop, but not birth rates
Infant mortality rate = the death rate in children; has
dropped dramatically
Population growth was seen as good
Support for elderly, a larger labor pool
Thomas Malthus’s
An Essay on the Principles of
Population
(1798)
Humans will outstrip food supplies
Is population growth a problem?
Neo-Malthusians: population growth will increase faster than food production; cause famine and conflict
Paul Ehrlich’s Population Bomb (1968) predicted that civilization would end by the end of the 20th century
Intensified food production fed more people
Cornucopians argue that we will continue to find new resources and technology to support people
Environmental scientists argue that there are finite
resources
Land is limited, extinct species are gone forever
Quality of life will suffer with unchecked growth
Some national governments now fear falling
populations
Policymakers believe population growth increases
economic, political, and military strength
But growth is correlated with poverty, not wealth
Strong, rich nations have low growth rates Weak, poor nations have high growth rates
Some nations offer incentives for more children
Elderly need social services
66% of European governments think their birth rate
is too low
49% of non-European nations feel their birth rates are
Population is one of several factors that affect
the environment
The
IPAT model
:
I
=
P
×
A
×
T
×
S
Total impact (
I
) on the environment results from:
Population (P) = individuals need space and
resources
Affluence (A) = greater per capita resource use
Technology (T) = increased exploitation of resources,
but also pollution controls and renewable energy
Sensitivity (S) = how sensitive an area is to human
pressure (e.g., arid land vs. rainforest)
Population is one of several factors that affect
the environment
Impact equates to pollution or resource consumption
Humans use 25% of Earth’s net primary production
Technology has increased efficiency and reduced
our strain on resources, resulting in further
population growth
For example, increased agricultural production
Modern China’s increasing affluence is causing:
Increased resource consumption
Modeling Population Growth—
Modeling Population Growth—
Human Population Growth and Regulation 1
Modeling Population Growth
Modeling Population Growth
Modeling Population Growth
Demography
Demography =
the application of population ecology
to the study of change in human populations
All population principles apply to humans
Environmental factors limit population growth
There is a carrying capacity for all species, including
humans
Humans raise the environment’s carrying capacity
through technology
How many humans can the world sustain?
Demography is the study of human population
Demographers
study:
Population size
Density and distribution Age structure
Sex ratio
Birth, death, immigration, and emigration rates
Population size
Current world population is just over 7 billion
D. Changing Fertility Rates and the Demographic Transition
1. The gradual shift from the primitive to the modern condition that is correlated with development is called demographic transition.
2. Crude Birth Rate (CBR) is the number of births per 1000 individuals per year. Crude Death Rate (CDR) is the number of deaths per 1000
individuals per year. The term crude is used because there is no consideration for age or gender.
3. Subtracting the CDR from the CBR gives the increase or decrease per 1000 per year. Dividing this result by 10 then puts it in terms of per 100 or percent. We will call this number the percent
increase or decrease per year.
Calculating Fertility Rates and Doubling Times
(CBR - CDR)/10 = Rate of Increase or decrease
in population per 100 per year or growth
percentage rate
5. The Demographic transition has four phases.
a) Phase I is the primitive stability, with high
CBR’s and CDR’s.
b) Phase II is marked by a declining CDR that
results from improved infant mortality rates. There is a large population growth due to the fact that CBR’s do not go down. This phase is also know as Epidemiologic transition.
c) Phase III is a phase of declining CBR’s
resulting from a declining fertility rate. This phase is also known as Fertility transition.
d) Phase IV is reached, where modern stability
Phases of Demographic Transition
Phase I: primitive stability (CBR = CDR)
Phase II: declining CDR, CBR remains high
accelerating population growth
Phase III: declining fertility rate, but significant
population growth continues
Demographic Transition Comparisons (Figure
5-17)
Phase IV: developed countries
Population density and distribution
Population size alone does not tell whole story
People are not distributed equally over the planet
(clumped distribution)
Highest density: temperate, subtropical, tropical
biomes and close to water
Cities are local high-density areas
Lowest density: away from water, extreme
environments
Age structure
Age structure describes the relative numbers in each
age class within a population
Age structure diagrams (population pyramids) show
age structure
Wide base denotes many young
High reproduction, rapid population growth
Even age distribution: remains stable as births keep
pace with deaths
Age structure
Many populations are getting older
Median global age today is 28, but it will be 38 by
2050
The elderly will need care and financial assistance Taxes will increase for Social Security and Medicare But fewer dependent children may mean lower crime
Age structure
China’s age structure is changing
In 1970, the median age was 20; by 2050 it will be 45
By 2050, over 300 million will be over 65
Fewer people will be working to support social
Sex ratios
Unequal sex ratios can impact population growth
Human sex ratios at birth slightly favor males
For every 100 females born, 106 males are born
In China, 120 boys were reported for 100 girls
Culture values males over females
The government’s one-child policy
Females have been selectively aborted
The undesirable social consequences?
Many single Chinese men
Population change results from birth, death,
immigration, and emigration
Whether a population grows, shrinks, or remains
stable depends on rates of birth, death, and
migration
Birth and immigration add individuals
Death and emigration remove individuals
Technological advances caused decreased deaths
The increased gap between birth and death rates
Population change results from birth, death,
immigration, and emigration
Immigration/emigration have become more
important
War, civil strife, and environmental degradation cause
people to flee their homes
Each year, 25 million refugees escape poor
environmental conditions
This movement causes environmental problems
No incentives to conserve resources
Total fertility rate influences population growth
Total fertility rate
(TFR)
=
the average number of
children born to each female
Replacement fertility
=
the TFR that keeps the size
of a population stable (about 2.1)
TFR has been decreasing in many nations due to:
Industrialization
Improved women’s rights Quality health care
In Europe as a whole, TFR is now 1.6
Many nations are experiencing the
demographic transition
In countries with good sanitation, health care, and
food, people live longer
Life expectancy
=
average number of years that an
individual is likely to continue to live
Has increased with reduced rates of infant mortality
Demographic transition
=
a model of economic
and cultural change
Explains the declining death and birth rates in
industrializing nations
Many nations are experiencing the
demographic transition
Pre-industrial stage
=
in pre-industrial societies,
both birth and death rates are high
High birth rate to compensate for high infant mortality Population growth is slow
Transitional stage
=
declining death rates due to
increased food production and medical care
Birth rates remain high since people are not used to
the low infant mortality rates
Modeling Population Growth—
Human Population Growth and Regulation 4
Many nations are experiencing the
demographic transition
Industrial stage
=
birth rates fall as jobs provide
opportunities for women outside the home and
children are not needed in the workforce
Difference between birth and death rates shrinks Population growth slows
Post-industrial stage
=
birth and death rates are
low and stable
Demographic information
1. HDC, High income type country, like Canada, Western Europe, and the United States.
2. MDC, Middle income countries, like Latin America, parts of Asia, and parts of Africa. 3. LDC, Low income countries, like China,
central Africa, central Asia.
4. The disparity in distribution of wealth among
countries of the world is large. HDC’s have 18.8% of
the population and 80% of the world’s wealth. The
MDC’s and LDC’s combined have 81.2% of the world’s
Average Number of Children, Grandchildren,
and Great Grandchildren
America
West Germany
Africa
14
5
Major Economic Divisions of the World
Is the demographic transition a universal
process?
It has occurred in Europe, the U.S., Canada, Japan,
and other nations over the past 200–300 years
But it may or may not apply to developing nations
The transition could fail in cultures that:
Place greater value on childbirth Grant women fewer freedoms
For people to attain the material standard of living of North Americans, we would need the natural
Population and Society
Many factors affect fertility in a given society:
Access to family planning Rates of infant mortality Levels of women’s rights Level of affluence
Importance of child labor
Family planning is a key approach for
controlling growth
Family planning
=
efforts to control the number and
spacing of children; the greatest single factor
slowing population growth
Clinics offer advice, information, and contraceptives
Birth control
=
effort to control the number of
children born by reducing the frequency of
pregnancy
Contraception = deliberate prevention of pregnancy
through a variety of methods
Family planning is a key approach for
controlling growth
Low use of family planning may have different
causes
Rural areas may have limited availability
Religious doctrines or cultural influences may reject
family planning
Family planning gives women control over their
reproductive window
=
time frame where a woman
can become pregnant
Potential to produce 25 children during the window Family planning may delay first reproduction, space
Family-planning programs are working around
the world
Funding and policies that encourage family planning
lower population growth rates in all nations,
regardless of level of industrialization
Thailand’s educational-based approach to family
planning reduced its growth rate from 2.3% to 0.5%
Brazil, Mexico, Iran, Cuba, and other developing
countries have active programs
These entail setting targets and providing incentives,
Empowering women reduces fertility rates
Where women are freer to decide whether and when
to have children, fertility rates fall, and children are
better cared for, healthier, and better educated.
Fertility rates drop most noticeably when women
gain access to contraceptives and family-planning
programs
As women receive educational opportunities, fertility
rates decline
Two-thirds of the world’s illiterate are women
Education leads to delayed childbirth as women
Increasing affluence lowers fertility
Poorer societies have higher population growth rates
Consistent with the demographic transition theory High fertility to ensure some children would survive
and be able to contribute to farm labor
More affluent societies can provide:
Better medical care, reducing infant mortality
Education for children (removing them from the
workforce and making them an economic liability)
Social security for the elderly
Increasing affluence lowers fertility
Poverty exacerbates population growth; population
growth exacerbates poverty
In 1960, 70% of all people lived in developing
nations
As of 2010, 82% live in these nations
99% of the next billion will be born in these nations
Population growth in poor nations increases
environmental degradation
Farming degrades soil in arid areas (Africa, China)
Poor people cut forests, deplete biodiversity, and hunt
Expanding wealth can increase the
environmental impact per person
Affluent societies have enormous resource
consumption and waste production
People use resources from other areas, as well as
from their own
Ecological footprints are huge
People in affluent societies have larger ecological
footprints
One American has as much environmental impact as
3.8 Chinese or 8 Indians or 14 Afghans
Expanding wealth can increase the
environmental impact per person
Biocapacity
=
the amount of biologically productive
land and sea available to us
Ecological deficit = ecological footprint > biocapacity Ecological reserve = ecological footprint < biocapacity
We are running a global ecological deficit
Humanity’s global ecological footprint exceeds
biocapacity by 50%
HIV/AIDS is exerting major impacts on African
populations
The AIDS epidemic is having the greatest impact
since the Black Death in the 14th century
Of 34 million infected, two-thirds live in sub-Saharan
Africa; 3800 die/day
Low rates of contraceptive use spread the disease
Infant mortality is 14 times that of the developed world Life expectancy has dropped from 60 years in the
1990s to 40–50 years today
Demographic change has social and economic
repercussions
AIDS undermines the ability of poor nations to
develop
Removes productive members of society Cost of medical treatment is a huge burden
Demographic change has social and economic
repercussions
Demographic fatigue
=
occurs when governments
face overwhelming challenges related to population
growth
With the added stress of HIV/AIDS, governments are
stretched beyond their capabilities
Problems grow worse and citizens lose faith
Population goals support sustainable
development
1994 UN conference on population and development
Rejected top-down, command-and-control approaches
that pushed contraceptives and preset targets
Urged education and health care
Urged addressing social needs (like poverty, sexism) from the bottom up
To generate a high quality of life for all people,
developing nations must slow population growth
Factors Influencing Family Size
• Old age security
• Infant and childhood mortality rates
• Children: an economic asset or liability
• Importance of education
• Status of women
I Reassessing the Demographic Transition A. Factors Influencing Family Size
1. Security in one’s old age: In many LDC’s the only way that the old are taken care of is by
their families. In the HDC’s we have nursing homes and Social Security. This is one of the reasons they have many children, so
2. Infant and Childhood Mortality: The common and often personal experience of children dying leads people to desire additional children as an “insurance policy” for security in
their old age.
3. Helping hands : In the agriculture setting children can do work at a young age and will help
support
the family. In an industrial setting, the children
are more of a luxury, in that they cost more money than they bring in.
4. Importance of Education: When people go
through more education they will put off having children and thus they will have less reproductive
years. In addition, when children go to school they can not do the amount of work they
5. Status of Women: opportunities for women’s education and careers. : In
the LDC’s most women are thought of as only important for the number of children they can have. It is shown that the women
that have an eighth grade education have half the number of children as their
counterparts. 6. Availability of Contraceptives-
Contraceptives are available in the
industrialized world and not very available in the LDC’s. More than any other single
factor, lower fertility rates are correlated with the percent of the population using
TFR vs GNI PPP per capita,2004
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Conclusion
The human population is larger than at any other time Rates are decreasing but populations are still rising Most developed nations have passed through the
demographic transition
Expanding women’s rights slows population growth How will the population stop rising?
The demographic transition, governmental intervention, or disease and social conflict?
Sustainability requires a stabilized population to avoid
QUESTION: Review
What has accounted for most of the world’s population
growth in recent years?
a) Women are having more babies.
b) Technology, medicine, and food have decreased death rates.
c) Fewer women are using contraceptives.
QUESTION: Review
According to the
I
=
P
A
T
S
formula, what would
happen if China’s 1 billion people had a lifestyle like
that of Americans?
a) Their population would automatically drop.
QUESTION: Review
Where is the highest
density
of people found?
a) In the colder climates (e.g., Siberia)b) In temperate or tropical biomes c) In rural areas
QUESTION: Review
An age structure diagram shaped like a pyramid with a
wide base shows a/an ________ population.
a) increasing b) decreasing c) stable
QUESTION: Review
Describe the relationship between population growth
rates
and population
size
.
a) Falling growth rates automatically mean a smaller population.
b) Falling growth rates automatically mean a larger population.
c) Falling growth rates mean we no longer have a population problem.
d) Falling growth rates do not mean a smaller
QUESTION: Review
Pre-industrial societies tend to have higher growth
rates because
a) good medical care prevents infant mortality. b) there is little opportunity for women to get an
education or employment.
c) governments provide social support networks for the elderly.
QUESTION: Weighing the Issues
Should the United States fund international family-
planning efforts?
a) Yes, absolutely.
b) Yes, but only in nations that follow U.S.-approved programs.
c) Only if it can influence the nations’ policies.
QUESTION: Weighing the Issues
Would you rather live in a country with a larger
population or smaller population?
a) Small population, so there will be more resources for me
b) Small population, so there will be more resources for others, including wildlife
c) Large population, so I can find a date
QUESTION: Interpreting Graphs and Data
What happens during the “transitional” stage of the
demographic transition?
a) High birth and death rates rise—population increases
b) High birth and death rates—population is stable c) High birth rates with
low death rates—
population increases d) Low birth and death
rates cause—
QUESTION: Interpreting Graphs and Data
According to this age pyramid, Nigeria’s future
population will be
a) balanced. b) larger.
c) much larger. d) smaller.
QUESTION: Interpreting Graphs and Data
According to these graphs, which countries had
access to family planning?
a) Iraq and Pakistan c) Malawi and
Kenya
b) Malawi and Haiti d) Kenya and