Population Theories
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Transcript Population Theories
Theories of Demographic Transition
Demographic Transition is
the phenomenon of a
country’s death and birth
rates changing over time
from high to low.
Over time, the average
family size has decreased
in every country of the
world.
In approximately 60
countries, the total
fertility rate has fallen to
less than 2.1. Canada is
one of these countries.
Stage 1: Pre-transition
Stable population
High birth rate and
death rate
Fertility rate of 8 or more
Extremely high infant
mortality rate
Many young children,
very few older people
No country in the world
is still at the pretransition stage.
Stage 2: Early Transition
Very rapid increase in
population
Death rate declines
rapidly
Fertility rate remains
high
Infant mortality rate
declines
High birth rate
Many young people
Early Transition is
marked by death control
Stage 3: Late Transition
Population growth slows
down
Birth rate declines
rapidly
Death rate declines
slowly
Fertility rate declines
Increasing number of
older people
Late Transition is
marked by birth control
Stage 4: Post-transition
Stable or slow
population increase
Low birth rate and death
rate
Fertility rate less than 2.1
Many older people which
leads to a high
dependency load
Stage 5:? (doesn’t fit the model, but is happening now!)
Declining population
Extremely low birth rate
Death rate is low
Fertility rate less than 2
A lot of older people
Is it permanent or just a
temporary trend???
Optimistic vs. Pessimistic
Optimistic Views
Historically, large families and a
growing population have been
desirable for various reasons.
1. Religious Reasons: More
Children = More Followers and
More Followers = More
Political/Social Power
2. Non-Religious Reasons: Leaders
needed larger numbers to
support their economic and
military expansionist desires.
Cornucopians
Cornucopians believe that humans have the ability to
find technological innovations that will increase the
earth’s carrying capacity.
The Agricultural and Industrial Revolutions would be
their evidence.
A cornucopian may say that the next major human
innovation will solve our energy crisis without
damaging the environment.
Bogue (1960’s)
D.J Bogue’s theory of demographic regulation
stated that over an extended period of time, a society
will naturally limit its own population in accordance to
the Earth’s ability to support it.
Bogue’s theory is supported by the demographic
transition model and in the fact that some countries
have tried to limit their population growth in recent
years.
Pessimistic Views
Critics have all made the
same basic point – Earth
is of finite size and has
an ability to support
only a certain level of
population.
Thomas Malthus
William Catton
Warned of population
Expanded on Malthus’ views
problems in his writing in
1798.
in 1980’s.
Introduced idea of Earth’s
Pop. grows in a geometric
sequence (1,2,4,8,16. . .) while
food grows arithmetically
(1,2,3,4 . . .)
carrying capacity; it can only
be exceeded at the expense of
the environment.
Suggests we’re beyond the
Only result is onset of
“misery”. (famine, disease,
war)
carrying capacity now only
because we’re using up the
world’s fixed stock of natural
resources for future
generations.