“People are everywhere. Some people say there
are too may of us; but no one wants to leave”
What is the Earth’s carrying
capacity?
 Present population is 7 billion
 Many believe the Earth can support 4-16 billion, others
up to 50 billion
 Changes in technology, improvements in food
production and medicine plus the fact that humans
can determine the number of children they have, make
measuring the planet’s carrying capacity difficult
 For most of our history, humans were hunter-
gatherers, and these populations remained small.
 About 10,000 years ago, people began to raise animals
and grow crops. (Agricultural Revolution)
 Agriculture allowed people to produce more food than
they could gather, and to be able to store the excess.
Farming increased the earth’s carrying capacity!
 The human population then began to grow as more
was available and people had more children to help
with the farming.
The human population reached 1
billion around 1800.
Number of years to add 1 billion people
First billion
Second
Third
Fourth
Fifth
Sixth
Seventh
Eitgth
year
1800
1930
1960
1975
1987
1999
2012
2026
years to add
all of human history
130
30
15
12
12
13
14
Demography
 The study of human population patterns
 There are 3 stages of demographic transition
 Stage 1 reflects preindustrial societies in which the
population grows slowly. Both birth and death rates are
high
 Stage 2 reflects an increasing population due to
improved health care. Death rates fall and birth rates
remain high. This is seen in developing countries such
as Mexico, Bangladesh, and Ethiopia.
 Stage 3 shows a slowing of population growth as birth
rates fall. This is typical of a more developed country.
Population Pyramids (histograms) are one
way to illustrate population growth.
 Age structure categories
 Pre-reproductive ages (0-14)
 Reproductive ages (15-44)
 Post-reproductive ages (45-over)
Males vs. females
We Can Use Age-Structure Information to Make
Population and Economic Projections
 Baby boomers
 Job market when they retire-job shortage
The Fastest Growing Age Group Is…
SENIORS!
 The global populations of seniors is projected to triple
by 2050 in which 1 of every 6 people will be 65 or older.
 This graying of the population is due to declining birth
rates and longer life expectancies due to medical
advancements.
The world’s population is increasing at a growth
rate of 1.09%
So, what does a 1.09% growth rate mean?
 There were about 83 million people added to the earth
in 2010
 Which is about 227,000 people every day
 Which is 2 more people every time your heart beats
Women Having Fewer Babies but Not Few
Enough to Stabilize the World’s
Population
 Total fertility rate
(TFR)- avg. # of kids
TFR in 2010:
1.7 per woman in
developed
countries
2.7 per woman in
developing
countries
born to a woman during
reproductive years.
Where are populations growing?
 in developing countries
their population is increasing 15 times faster
than developed countries
By 2050, 97% of growth will be in developing
countries
Growth Rates and TFR
 US= 0.96%
 China= 0.49%
 Japan= -0.278%
 Mexico= 1.1%
 Ethiopia= 3.2%
 Zimbabwe = 4.31%
 Niger= 3.6%
2.0
1.5
1.2
2.3
6.0
3.6
7.6
 From 1972- 2010, TFR in
developing countries dropped
from 6.2 to 2.7 and in
developed countries, from
2.8 to 1.7
 In China, the TFR dropped
from 5.7 to 1.5 (from 19722010)
Life Expectancy
 Increased globally from 47 to 69 years from 1955-
2010. by 2050…74 years
 Japan has longest life expectancy of 83 and US is
78 (50th of all nations)
 Angola has shortest life expectancy of 39 years.
 Why are people living longer?




Increased food supply and distribution
Better nutrition
Medical advances
Improved sanitation
Why do growth rates increase?
 Immigration, decline in death rate, high TFR
 Most poor couples believe they need several children
to work and care for them in old age
 Cultural preference for male children
 Only 48% use some form of birth control
Why Do Growth Rates Decrease?
 Emigration- religious and political freedom, economic
improvement, wars
 Death and Disease- HIV/AIDS
 Higher education levels, medical care, sanitation
Problems Related To Population Growth
 1. Shortage of resources
 Water- diseases such as cholera, typhoid
and dysentery and death related to dirty
water
 Fuelwood- many foods need to be cooked
and water is sterilized by boiling
 2. Urban Crisis
 People move to cities for work and
education
 Not enough infrastructure- schools,
medicine, fire stations, roads…
• 3. Social unrest
Civil wars and disputes between nations
• 4. Environmental refugees
Environmental changes can cause people to
leave their homes
Drought, floods, earthquakes
Should population problems be solved?
 Countries with stable populations can better provide
services such as education and health care.
 Environmental damage is decreased
 Families are healthier when a mother bears children
after age 20, has no more than 3 children and they are
spaced apart
 Bangladesh- TFR dropped from 6.0 in
1960 to 2.7 in 2010.
 Family planning and economic
development are responsible for the drop.
 Thailand’s TFR dropped from 6.4 to 1.8
 The best way to slow and stabilize
population growth are through
1. promoting economic development
2. elevating the social and economic
status of women
3. Encouraging family planning
Empowering Women Can
Slow Population
 Education
 Paying jobs
Women account
for 2/3 of all
hours worked,
but only get 10%
of world's
income
 Human rights without suppression
 “For poor women, the only holiday
is when you are asleep”
Women
 Make up 70% of the world’s poor
 64% are illiterate (and 5-7 children)
 60-80% of work associated with growing
food, gathering wood and hauling wood
and water
 In most societies, they have fewer rights
and educational and economic
opportunities
 (Sharbat Gula 1985 and 2002)
 (Afghanistan refugee who crossed over
into Pakistan
What is really the problem?
 Overpopulation? This is degrading our planet. (82% of
population is in less developed nations)
 Overconsumption? Americans ecological footprints are
4.5X larger than the average Chinese and 9.5 times larger
than the average Indian
If the world had 100 people…
 http://www.100people.org/statistics_detailed_statistic
s.php?section=statistics