population theories
Post on 24-Feb-2016
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Population TheoriesTheories 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-transitionStable populationHigh birth rate and
death rateFertility rate of 8 or
moreExtremely high infant
mortality rateMany young children,
very few older peopleNo country in the
world is still at the pre-transition stage.
Stage 2: Early TransitionVery rapid increase in
populationDeath rate declines
rapidlyFertility rate remains
highInfant mortality rate
declinesHigh birth rateMany young peopleEarly Transition is
marked by death control
Stage 3: Late TransitionPopulation growth
slows downBirth rate declines
rapidlyDeath rate declines
slowlyFertility rate
declinesIncreasing number
of older peopleLate Transition is
marked by birth control
Stage 4: Post-transitionStable or slow
population increaseLow birth rate and
death rateFertility rate less
than 2.1Many older people
which leads to a high dependency load
Stage 5:? (doesn’t fit the model, but is happening now!)Declining populationExtremely low birth
rateDeath rate is lowFertility rate less
than 2A lot of older people
Is it permanent or just a temporary trend???
Differing Ideas About Population GrowthOptimistic vs. Pessimistic
Optimistic ViewsHistorically, 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.
CornucopiansCornucopians 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 ViewsCritics 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 CattonWarned of population
problems in his writing in 1798.
Pop. grows in a geometric sequence (1,2,4,8,16. . .) while food grows arithmetically (1,2,3,4 . . .)
Only result is onset of “misery”. (famine, disease, war)
Expanded on Malthus’ views in 1980’s.
Introduced idea of Earth’s carrying capacity; it can only be exceeded at the expense of the environment.
Suggests we’re beyond the carrying capacity now only because we’re using up the world’s fixed stock of natural resources for future generations.
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