Population, Urbanism
& the Environment
World population
 Currently
6.5
Billion
 Most of human history the
population of the entire earth was
500 Million (1/2 billion)
Demography
 The
study of human population
 Through
most of human history,
families had many children because:
Children
were needed on the farm
Birth control was not reliable
High death rates = many children did not
reach adulthood
Demographic terms
 Fertility
Amount
of childbearing in a
population
Several measurements of this
Demographic terms
(cont.)
 Crude
birth rate
Live births per 1,000 people each
year
High income nations e.g. U.S. =
lower than average crude birth rate
The lower the average income, the
higher the population increase
Demographic terms (Cont.)
 Fecundity
rate
Maximum possible childbearing
 Sex Ratio
Males for every 100 females
 Zero Population growth (ZPG)
Two
people produce two people
Maintains population at a steady state
Malthusian theory
 Food
increasing arithmetically
 Pop. Increasing geometrically
 Result : People reproducing
beyond what the planet can
support
Out-stripping
resources
Poisoning the planet
Demographic Transition Theory
 Population
patterns reflect a
society’s level of technological
development