Population and the Environment

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World Population 1750-2100
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Links between population andthe environment
1. Total pollution (pollution per person
x population)
- pollution control
- assimilation
2. Total resource use (rate of resource use
- recycling
rate) x population
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As population increases...
1. Pollution will increase unless pollution
control improves
2. Resources will be depleted unless recycling
increases and resource use becomes more
efficient
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Thomas Malthus (1766-1834)
English demographer and economist Graduated
from Cambridge in 1788 (age 22) Friend of Hume
and Rousseau Major work (published
anonymously in 1798) An essay on the
principal of population as it affects the future
improvement of society NOT a short essay (600
pages long!)
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Malthusian argument

1. Reproductive capacity of humans puts continual
   pressure on the means of subsistence
2. Human numbers increase by geometric progression.
3. Subsistence resources increase arithmetically.
4. Land, unlike people, cannot breed.

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The Malthusian principle
Population,food
Time
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Checks on population
1. War
2. Seasons of sickness
3. Epidemics today AIDS
4. Pestilence
5. Plague
And the ultimate check6. Famine
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What Malthus missed
1. Birth control and voluntary limits on
population growth (i.e. population growth
less than geometric)
2. Agricultural productivity (i.e. growth in
food production greater than arithmetic)
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The Malthusian principle, revisited
Food
Pop
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Demographic transition

• A pattern of steadily increasing population
  growth, followed by aperiod of slowing
  population growth(as experienced by
  industrialized countries).Generally indicated
  as an S-shaped curve for population through time.

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Frank Notestein (b. 1945)
Three stages of population growth 1. High growth
potential 2. Transitional growth 3. Incipient
decline
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1
2
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1. High growth potential
Pre-industrialBirth rate high
(25-40/1000)Death rate highLife expectancy
shortPopulation growth low but
positiveWidespread poverty and misery
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2. Transitional growth
Early industrialBirth rate remains high or
risesDeath rate low and fallingLife
expectancy risesPopulation growth
explosiveMortality declines before fertility
dueto better health, nutrition, and sanitation
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3. Incipient decline
IndustrialBirth rate drops due to desires to
limit family sizeDeath rate low and
stableLife expectancy highPopulation grows
until birth rate death rateCharacterized by
higher levels of wealth and reduced need for
large families for labor or insurance.
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Message Birth ratesdeath rates, country has
completed the demographic transition
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Message Birth rates gt death rates, country is
still in stage 2 of the demographic transition
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Key Points
1. Malthusian view of population growing faster
than food supply has not come to pass. 2.
Evidence in support of demographic transition
is strong90 of Europe, 25 of Africa) 3.
Neo-Malthusian views generally correspond
to concerns over environmental quality
and speed of demographic transition.
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Message Fertility rates respond to increases in
per capita income, speeding the demographic
transition