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Chapter 2: Population
http://www.ted.com/talks/hans_rosling
_on_global_population_growth.html
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Why is Population Increasing at
Different Rates?
Demographic Transition Model
Figure 2-15
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Demographic Transition
• Countries that don’t fit the model:
negative growth (Ukraine)
• Applicability of the demographic
transition to third world populations
– Different economic situations
– No migration escape hatch for LDCs
(“massive exodus” from Europe during the
19th century)
– LDC populations are larger, denser, fastergrowing
– Hidden momentum of young age-sex
pyramids
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Demographic Momentum
(hidden momentum)
• Occurs in an age structure with a large
base and small top
• Very few elderly at the top of pyramid
are available to die
• Many children who will soon be in peak
reproductive ages (reproducing age 1949)
• Compare the large number of children
being born to the small number of
elderly dying
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Why Is Population Increasing at Different Rates?
• Demographic transition & world population
growth
– Most countries = stage 2 or stage 3 of the
Demographic Transition
• Stages 2 and 3 are characterized by significant
population growth
– No country is in stage 1 of the demographic
transition
– It is easier to cause a drop in the CDR than in
the CBR
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World Health Threats
Epidemiologic Transition
Stage 1: Pestilence and famine
–The Black Plague
–Pandemics
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• An epidemic is a rate of unexpectedly high
disease transmission--caused by something
like a new vector, mutation of the disease, or
favorable conditions for transmission or
infection. H1N1 was an epidemic because it
was fairly virulent and more people got it than
would be expected in a "normal" flu season.
• Pandemic is a big epidemic--there isn't a
strict definition of when an epidemic is big
enough to become a pandemic, but usually at
the continental scale if not world scale.
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World Health Threats
the epidemiologic transition
• Stage 2:
Receding
pandemics
Cholera and
Dr. John Snow
Figure 2-31
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World Health Threats
The epidemiologic transition
• Stage 3: Degenerative diseases
–Most significant: Heart disease
and cancer
• Stage 4: Delayed degenerative
diseases
–Medical advances prolong life
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World Health Threats
the epidemiologic transition
• A possible stage 5: Reemergence
of infectious diseases?
–Three reasons why it might be
happening:
»Evolution
»Poverty
»Improved travel
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The Most Lethal Infectious Disease: AIDS
Figure 2-33
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Overpopulation, Malthus, and
Neo- Malthusians
“The capacity of Earth to produce food
and support people is finite.”
- Anne & Paul Erlich
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Thomas Robert Malthus
• British political
economist,
demographer and
Reverend
• Wrote An Essay on
the Principle of
Population in 1798
http://www.youtube.com/watch?v=r1ywppAJ1xs&feature=player_embedded
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In response to Utopians….
• Argued that population increased
geometrically while food supply
increased arithmetically
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Thomas Robert Malthus
• Arithmetic increase:
when a series of
numbers increases
or by adding the
same number
• Geometric increase:
when a series of
numbers increases
by being multiplied
by the same factor
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Criticisms of Malthus
• Pessimistic viewpoint
• Assumes population growth causes
problems, while it can bring economic
growth and advancement
• Marxist critique – social problems result
from unjust economic structure, not
population problems
• Engels critique – Malthus’ theory was
based on capitalism, if resources were
shared equally, earth could sustain a
much larger population
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Criticisms
• Malthus did not account for
technological advancements that could
increase food output
• Malthus did not account for
cultural/economic factors that bring
countries to stages 3 and 4 of DTM
• Malthus over-predicted the population
growth
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Malthus: Theory & Reality
Figure 2-25
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Declining Birth Rates
Reasons for declining birth
rates
• Reliance on economic
development
• Distribution of
contraceptives
– Reducing birth rates
with contraception
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Family Planning
Figure 2-30
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Neo-Malthusians
• Share Malthus’ concern for population
growth
• Argue that Malthus thought only wealthy
countries would enter periods of high
population growth (Stage 2 of DTM)
• Argue world population growth is
outpacing many resources, not just food
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Began with this statement…
• The battle to feed all of humanity is
over. In the 1970s hundreds of millions
of people will starve to death in spite of
any crash programs embarked upon
now. At this late date nothing can
prevent a substantial increase in the
world death rate ...
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• humanity could not prevent severe
famines, the spread of disease, social
unrest, and other negative
consequences of overpopulation.
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The Population Bomb
• Published in 1968
• Launched worldwide debate and
spurred along environmental movement
• Was received with much skepticism
about its argument and predictions
• In 1968 world population was 3.5 billion,
40 years later it was 6.7 billion
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What it got right….
• Drew attention to the “over-consumption
problem”
• Expressed concern over the seas’
bounty
• Predicted high-yield grains were best
option for meeting the world’s hunger
• Expressed concern over the
environmental effects of the “Green
Revolution”
• Predicted threats of new epidemics
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What it got wrong…
• Did not account for the number of and
increase in greenhouse gas emissions
• Too optimistic about consumption: while
population nearly doubled, consumption
nearly tripled
• Underestimated environmental impact
of “Green Revolution”
• Incorrectly predicted that the Baby
Boomers would continue high birth rates
of their parents
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Key Issues
• Where is the world’s population
distributed?
• Where has the world’s population
increased?
• Why is population increasing at different
rates in different countries?
• Why might the world face an
overpopulation problem?
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• “As U.S. birth rate drops, concern for
the future mounts”
– U.S. fertility rate fell below replacement
level (1.9)
• Deep recession and slower immigration
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• “The Islamic World’s Quiet Revolution”
• “The Fertility Implosion”
– “Over the past three decades the Arab
world has undergone a little noticed
demographic implosion. Arab adults are
having fewer kids.”
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