http://www.peterrussell.com/Odds/WorldClock.php
http://opr.princeton.edu/popclock/
http://www.pbs.org/wgbh/nova/worldbalance//
Chapter 5
Chapter 6
•World Population Trends
•Fertility Rates
•Calculations
•World Bank
•1994 UN Conference in
•Developed vs.
Developing Countries
Cairo- Program of Action
•Age Structure Diagrams
•Demographic Transition
(In 2000) 11.5 billion & 2065(?)
OLD NEW
(In 2008) 10 billion & 2200
2046 2200
2033 2047
2020 2024
2009 2012
1999 1999
1987 1987
1975 1975
1960 1960
1930 1930
1830 1830
Disparities
• Developed countries
– 15% of the world’s population
– Control 80% of the world’s wealth
• Low-income developing countries
– 37% of the world’s population
– Control 3.0% of the world’s gross national
income
• Difference in per capita income: 63 to 1!
Different Populations, Different
Problems
• IPAT Formula: calculates human pressure
on the environment (I = P x A x T)
– I = environmental impact
– P = population
– A = affluence and consumptive patterns
– T = level of technology in the society
Or should it be I = PxAxT/S
(S = Stewardly Concern/Practice)
Different Populations, Different
Problems
• Environmental impact of developing
countries due to “P.”
• Environmental impact of developed
countries due to “A” and “T.”
– Both have some measure of “I” for different
reasons.
– Average American places at least 20 times
the demand on Earth’s resources compared
to a person in Bangladesh.
(b) crude birth rate= number birth per 1000 individuals
(d) crude death rate= number death per 1000 individuals
(r) growth rate = natural increase in population expressed as percent
per years (If this number is negative, the population is shrinking.)
equation:
r=b–d
But other factors affect population growth in a certain area…
Rates cont’
increase population
births

immigration 
decrease population
 deaths
 emigration (exit)
r = (birth - death)+ (immigration-emigration)
immigration = migration of individuals into a population
from another area or country
emigration = migration of individuals from a population
bound for another country
r = (b - d)+ (i - e)
example: population of 10,000 has
100 births (10 per 1000)
50 deaths (5 per 1000)
10 immigration (1 per 1000)
100 emigration (10 per 1000)
You try.
B
D
I
E
r=( 10/1000) – (5/1000) + (1/1000) – (10/1000)
r=(0.01-0.005) + (0.001 – 0.01)
r = 0.005 – 0.009 = -0.004 or –0.4% per year
Growing Cities
Doubling time = 70 / % growth rate
Use this equation to answer this
question:
How long will it take for a population
to reach a certain size?
If the growth rate is 1% and the population size is
10,000, how many years will it take to get to a
population of 40,000?
Population doubling: 70/rate =70/1% =70 years to double
In 70 years the population will be 20,000
1 D.T.  20,000
2 D.T.  40,000
(70 years)(2) =140 years
In 140 years, the population will be 40,000 people.
In the year 2000 there are 100,000 people living in Paradise.
Every year, 10 people emigrate from paradise and
10,000 people immigrate to paradise. 100 people are
born each year and 100 people die each year.
a) Calculate the doubling time for the population of
Paradise.
b) How many years will it take for Paradise to have
400,000 people?
c) If you were the President of Paradise what would be
your policy for population control. (major problem in
Paradise)
And Pg. 141 Thinking Environmentally #3
The transition from a primitive or developing society to a
“modern” or developed society
Phase 1 = deaths and births are high
(epidemiological) Phase 2 = death rate begins to decrease
(fertility) Phase 3 = birth rate drops and death rate flattens
out
Phase 4 = modern stability
There is little population growth in phase 1 but in phase 4
people live longer and have fewer children and the
population grows.
Bottom Line= as countries develop, first their death rate
drops and then their birth rate drops
Reasons for the phases:
Phase II:

medical care
 nutrition
Phase III:

technology

birth control
(births still high)
 education (of women)

lower mortality rate of infants

less child labor
Developed Countries
 Canada, U.S., Australia, Denmark
Developing Countries
 Brazil, China, Kenya
 1/5 of the world’s population lives in absolute poverty
(which means they are: illiterate, lack clean H2O and
don’t have enough food to survive)
 80% of world’s population lives in developing
countries and this number is growing . . .
• Total fertility = avg. # of children born per
woman
• Fertility of 2.0 = replacement level (theoretical)
– About 2.1 in reality
– Under 2.0 = shrinking population
– Over 2.0 = growing pop.
Population Data for Selected
Countries (Table 5-2)
Country
World
Developing
Countries
Developed
Countries
Total Fertility
Rate
2.7
Doubling Times
(Years)
58
2.9
47
1.6
700
• Special agency of the United Nations
• Receives $$ from developed co. and loans
$$ to developing co.
– Sometimes this backfires by increasing debt
• Oversees all types of issues, not just
environmental issues
– Ex. electricity, roads, new modern technology
Reached consensus on:
• Empowerment of women
• Improving reproductive health
• Increasing basic education
• Enhancing family income
• No changes to the World Bank