World Population

Links between population and the environment 1. Total pollution = (pollution per person x population) - pollution control - assimilation 2. Total resource use = (rate of resource use - recycling rate) x population

As population increases Pollution will increase unless pollution control improves 2. Resources will be depleted unless recycling increases and resource use becomes more efficient

Thomas Malthus ( ) 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!)

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

The Malthusian principle Time Population, food

Checks on population 1. War 2. Seasons of sickness 3. Epidemics today AIDS 4. Pestilence 5. Plague And the “ultimate” check: 6. Famine

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)

The Malthusian principle, revisited Time Food Population Food Pop

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

Frank Notestein (b. 1945) Three stages of population growth 1.High growth potential 2.Transitional growth 3.Incipient decline 1 2 3

1. High growth potential Pre-industrial Pre-industrial Birth rate high (25-40/1000) Death rate high Life expectancy short Population growth low but positive Widespread poverty and misery

2. Transitional growth Early industrial Early industrial Birth rate remains high or rises Death rate low and falling Life expectancy rises Population growth “explosive” Mortality declines before fertility due to better health, nutrition, and sanitation

3. Incipient decline Industrial Industrial Birth rate drops due to desires to limit family size Death rate low and stable Life expectancy high Population grows until birth rate = death rate Characterized by higher levels of wealth and reduced need for large families for labor or insurance.

Message: Birth rates=death rates, country has completed the demographic transition

Message: Birth rates > death rates, country is still in stage 2 of the demographic transition

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 strong: 90% of Europe, 25% of Africa) 3. Neo-Malthusian views generally correspond to concerns over environmental quality and speed of demographic transition.

Message: Fertility rates respond to increases in per capita income, speeding the demographic transition