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
 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
Death rate declines
Fertility rate remains
Infant mortality rate
High birth rate
Many young people
Early Transition is
marked by death control
Stage 3: Late Transition
 Population growth slows
Birth rate declines
Death rate declines
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
 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 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
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
Thomas Malthus
William Catton
 Warned of population
 Expanded on Malthus’ views
problems in his writing in
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,
carrying capacity now only
because we’re using up the
world’s fixed stock of natural
resources for future