HSS4331 – International Health Theory
Nov 17, 2008
Dr. Kirsten Stoebenau,
Post-Doctoral Fellow
IPH, University of Ottawa
Today….
• OVERPOPULATION
Population Dynamics- or
Demography 101
• If we lived on an island of 100 people- what
ways could the population on that island
change?
– Fertility
– Mortality
– Migration
What is overpopulation
• For an area to be considered overpopulated;
its population reaches a point where it can't
be maintained without rapidly depleting
nonrenewable resources
• In short, if its current human occupants are
clearly degrading the long-term carrying
capacity of an area, then that area is
overpopulated
– Overpopulation by Ehrlich (1990)
Why Is Overpopulation Bad?
• Ecological degradation
– Food supply
– Water supply
– Land overuse
• Diminished food supply
• Greater economic demands
• Increased population density means easier spread of
communicable disease
• Potential for mass migration -> refugees
• Potential for border insecurity
Population Density
• Of the Earth:
– pop density is 13/km2
• If you use the entire surface area of the Earth
– Pop density is 48/km2
• If you use the entire land area of the Earth
Map of World Population Density, by Country,
2006
http://www.nationmaster.com/encyclopedia/Image:World-population-densitymap.PNG
Population Density
• number of people per unit of area
Most Populous Nations
100%
19.81%
17.52%
7.39%
4.55%
3.47%
2.81%
Source: UN, 2005
Malthus
• Thomas Robert Malthus (1766-1834)
• Author of Essay on the Principle of Population
World Population Growth
Billions
Through History
12
11
2100
10
9
Old
Stone
7 Age
8
New Stone Age
Bronze
Age
Iron
Age
6
Modern
Age
Middle
Ages
2000
Future
5
4
1975
3
1950
2
1
Black Death —The Plague
1900
1800
1+ million 7000 6000 5000 4000 3000 2000 1000 A.D. A.D. A.D. A.D. A.D. A.D.
years B.C. B.C. B.C. B.C. B.C. B.C. B.C. 1 1000 2000 3000 4000 5000
Source: Population Reference Bureau; and United Nations, World Population Projections to 2100 (1998).
Malthus
• Food production accelerates in “arithmetic
progression”
– Farm twice as much land, create twice as much
food
• Population accelerates in “geometric
progression”
– Exponential growth
• Populations must always outgrow their food
supply, resulting in inevitable famine
–  leads to “Malthusian collapse” of society
Demographic Transition
• Idea developed by Warren Thompson in 1929
• A nation transitions from high birth rate and
high death rate to low birth rate and low
death rate, as it “evolves” from a preindustrial to post-industrial economy
Demographic Transition
• Defined in four stages
– 1) pre-industrial society, death rates and birth
rates are high and roughly in balance
– 2) death rates drop rapidly due to improvements
in food supply and sanitation, which increase life
spans and reduce disease
– 3) birth rates fall due to a variety of social factors
– 4) both low birth rates and low death rates
Demographic Transition
Demographic Transition
• Stage 1
– In pre-industrial society, death and birth rates are
high and fluctuate according to natural
phenomena (drought, disaster, disease)
– Population is relatively young
– Cost of a child is the cost of feeding him (low)
– Economic contribution of child is high (working on
farm, etc)
– Net economic value of child is therefore high
– Majority of deaths concentrated in 5-10 year olds
Demographic Transition
• Stage 2
– Decline in death rate, but birth rate remains high
• Increased survival of children, so age distribution shifts
younger
– In Europe, initiated by Agricultural Revolution in
18th century
– Today: sub-Saharan Africa, before AIDS epidemic
– Agricultural improvements
• Crop rotation, selective breeding
– Public health improvements
• Vaccination, clean water, sewerage, maternal care
Demographic Transition
• Stage 3
– Decline in birth rate
– Fewer children suffice to maintain family
economic unit
– Increased urbanization
– Increased female literacy and education
– Improved contraception practices
– Some countries that have experienced fertility
decline of 40% since pre-industrial levels:
• India, Jamaica, Mexico, Sri Lanka, Egypt, Panama
Demographic Transition
• Stage 4
– “post transition” stage
– Birth rates more-or-less equal death rates
– Some countries with total fertility rates <2.5:
• Canada, USA, Argentina, New Zealand, Australia, China
Total fertility rate = total number of children a
woman will give birth to in her lifetime
The Classic Stages of Demographic
Transition
Stage 1
Stage 2
Stage 3
Birth rate
Natural
increase
Death rate
Time
Note: Natural increase is produced from the excess of births over deaths.
Stage 4
Demographic Transition
CBR = crude birth rate
CDR = crude death rate
Demographic Transition
Criticisms of the model/theory
– Does not apply to current South, since model is
based and validated on the experiences of Europe
and North America, where data has been available
longest
– The model paints an overly optimistic view of the
future of developing nations
– Does not account for unforeseen huge events, like
AIDS, which disproportionately affects the South
AIDS’ Toll on Population Structure, South Africa
Population Structure in 2020
Millions
Age
80+
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Females
Males
3
2
1
0
With AIDS
1
2
3
Without AIDS
Source: United Nations, World Population Prospects: The 2006 Revision (CD-ROM Edition—Extended Dataset), 2007.
Demographic Transition
Criticisms of the model/theory
– Peruvian economist Hernando de Soto:
subsistence farmers cannot transition into
industrial economies because of political barriers,
i.e. they do not own their land
– With globalization, the extreme gap between rich
nations and poor nations creates external
pressure to keep birth rates high to maintain
economic output
– Not enough consideration of social changes on
reproduction practices (religion, social roles of
women, etc)
Demographic Transition
• Stage 5?
– Some people think a stage 5 is needed to describe
countries that have transitioned from
manufacture-based economies to informationbased
– Also called “de-industrialization”
– Fertility rates are below replacement rate
– Examples:
• Japan, Greece, Germany, Italy, Spain… pretty much all
the wealthy nations of the world
Replacement rate = national birth rate needed to
maintain the total population
For More Info
• Here’s a nice article on a socio-political take
on the Demographic Transition:
• http://www.globalchange.umich.edu/globalch
ange2/current/lectures/pop_socio/pop_socio.
html
Malthusian redux
1960s-1980s Population and Development Policy
• Concerns with rapid population growth in many parts of
the world (not seeing reduction in fertility following
reduction in mortality, but rather continued rapid
population growth)
– Concerns about the environment, depletion of resources
– Belief development could not take place within context of
high fertility rates
• Answer: Lower fertility rates, development will follow
Strategies for Reducing Population Growth
The Nation of Deonandia…
Residents are in perfect reproductive health, in their early 20s and horny as heck
100
women
100
men
9 months later:
100 babies
The Nation of Deonandia…
100
women
99
men
9 months later:
100 babies
The Nation of Deonandia…
100
women
98
men
9 months later:
100 babies
The Nation of Deonandia…
100
women
1
tired
man
9 months later:
100 babies
The Nation of Deonandia…
99
women
100
men
9 months later:
99 babies
The Nation of Deonandia…
98
women
100
men
9 months later:
98 babies
The Nation of Deonandia…
1
tired
woman
100
men
9 months later:
1 baby
The Lesson?
• Population fertility is determined mostly by
female fertility
• To address population fertility, one must
address female fertility
(Problems With That Analysis)
•
•
•
•
Not everyone has 100% fertility
Does not consider contraception
Does not consider abortion/miscarriage
Does not consider abstinence or other nonreproductive behaviours
• Does not consider twins, triplets, etc
• Does not consider social factors (monogamy,
religion, etc) that dictate reproduction
*Cairo 1994 - Female Reproductive
Rights
• The right to reproduce
• The right to contraception
– Including abortion
• The right to education about reproductive health
– STIs, contraception, etc
• Protection from reproductive alteration
– Genital mutilation
– Forced sterilization
*United Nations International Conference on Population and Development, Cairo
1994
*Beijing, 1995: Focus on Women
• “The World Bank has recognized that there is
no investment more effective for achieving
development goals than educating girls.”
• Relates to MDG #3 and #5:
– #3: promote gender equality and empower
women
– #5: improve maternal health
*Fourth World Conference on Women (also UN affiliated), Beijing China 1995
Why Is Female Education Important?
• Reducing women’s fertility rates. Women with formal
education are much more likely to use reliable family planning
methods, delay marriage and childbearing, and have fewer
and healthier babies than women with no formal education
– one year of female schooling reduces fertility by 10 percent.
(www.worldbank.org)
• Lowering infant and child mortality rates. Women with some
formal education are more likely to seek medical care, ensure
their children are immunized, be better informed about their
children's nutritional requirements, and adopt improved
sanitation practices
Why Is Female Education Important?
• Lowering maternal mortality rates. Women with formal
education tend to have better knowledge about health care
practices, are less likely to become pregnant at a very young
age, tend to have fewer, better-spaced pregnancies, and seek
pre- and post-natal care.
– one year of schooling for 1000 women prevents 2 maternal deaths.
(www.worldbank.org)
• Protecting against HIV/AIDS infection. Girls’ education ranks
among the most powerful tools for reducing girls’
vulnerability. It slows and reduces the spread of HIV/AIDS by
contributing to female economic independence, delayed
marriage, family planning, and work outside the home, as well
as conveying greater information about the disease and how
to prevent it.
Why Is Female Education Important?
• Increasing women’s labor force participation rates and
earnings. Education has been proven to increase income for
wage earners and increase productivity for employers,
yielding benefits for the community and society.
• Creating intergenerational education benefits. Mothers’
education leads to child education. A mother with a few years
of formal education is considerably more likely to send her
children to school.
– Each year of maternal education means an additional 1/3 to ½ year of
child education (www.worldbank.org)
OVERPOPULATION?
• Overpopulation = population demands > carrying
capacity
– Population density
– Population growth (high fertility, low mortality)
– Resource allocation and consumption
• How to measure overpopulation on a global scale?
– Bangladesh, Madagascar (Does high pop density or rapid
pop growth in these countries pose a threat to global
health?)
• Overpopulation should be considered alongside overconsumption
– U.S., China
• Remainder of slides were not included in
Kirsten Stoebenau’s lecture, but were among
slides provided by Ray Deonandan from his
2007 presentation on the topic
Other Measures of Population Density
• Arithmetic density: The total number of people / area of land
measured in km² or mi².
• Physiological density: The total population / the amount of
arable land.
• Agricultural density: The total rural population / amount of
agricultural land.
• Residential density : The number of people living in an urban
area / the area of residential land.
• Urban density: The number of people inhabiting an urban
area / the total area of urban land
• Ecological optimum: The density of population which can be
supported by the area's natural resources.
Nations With Highest Pop. Density
Source: UN, 2005
Where Do Some Of The Poorer Countries Rank?
Source: UN, 2005
Malthus
• Criticisms of Malthus
Malthus
• Criticisms of Malthus
– William Godwin (1820):
• There’s plenty of land to farm
• Reproductive rates will not necessarily be constant
• Due to attrition, population growth is not geometric
(Not an economist, but a journalist and philosopher)
Malthus
• Criticisms of Malthus
– Marx (1867): rising population is actually a
measure of wealth
Demographic Transition
• “Demographic Trap”
– During stage 3 –high birth rates, low death rates
– Failure to progress to stage 4
• Birth rates remain high, resulting in rapidly growing
population
– Country’s economic growth is used up to support
the exploding population, and not on promoting
economic and social development
• E.g. Yemen
Demographic Trap
– Fear that exploding population will lead to
ecological collapse
– Fear that this will lead to mass migration of
people
• Border insecurity
• Food depletion
• Population density leads to easier epidemics
http://www.enotes.com/public-health-encyclopedia/demographic-trap
Demographic Trap
• Dissenting voice:
– Demographic Trap mostly seen as a path to famine
– Nobel Prize-winning economist Amartya Sen
argues that most large famines are a result of lack
of access to food, rather than a lack of actual food
• therefore it’s a political issue, not necessarily a
scientific one