3. Question 1, with your pet
buddy:
Hypothesize as to WHY
our population growth
continues to be so high
4. Why?
3 main reasons
We’ve gotten better at living in more places
Agriculture meant we could feed more
people
Better sanitation, medicines, and vaccines
keeps disease under control
5. The results of all this
Death rate drops significantly
Birthrate has actually slowed - but it is
not enough to counter the death rate
6.
7.
8. Some numbers
The global population is growing
at ~ 1.2%/year
82 million people added to the
population in 2008
Every second 5 people are born,
2 people die - a net gain of 3
people
That’s over 260,000 people per
day
9. Where are all these
people?
We are not evenly spread out
Of the 82 million added in 2008
1.2 million added in the developed nations
80.8 million added in the developing nations
12. Developing nations
97% of the population growth from now
to 2050 will occur in these countries
More than 1/2 the people in the world
live in extreme poverty (less than
$2/day; 17% of those on less than
$1/day)
13. So how big are we going
to get?
?
Projections are 8-11 billion by 2050
14. Question 2 with your holiday
buddy: Vote!
Should the United States adopt a population
control policy? Defend your position.
15.
16. How many people can the
Earth support?
Low estimates - 2
billion
High estimates -
30 billion
Is this even the
right question to
ask?
17. Another way of looking at
it
Many analysts think we should be
asking:
What is the optimum sustainable
population based on a cultural carrying
capacity
The optimum level at which most people
can live in comfort and freedom without
sacrificing that for future generations
18. Some basics
High births -- low
deaths = high
growth
Low births -- high
deaths = decline
Equal births and
deaths = stable
population
19. 3 rates control human
population size
Birth rate
Death rate
Migration rate
We calculate the population change by
subtracting those who leave (death,
emigrants) from those who arrive
(births, immigrants)
20. Rates
We don’t use raw
numbers usually, we use
RATES
Birth rate - the number of
births per 1000 per year
Death rate - the number
of death per 1000 per
year
21. Who has the most
people?Number 1: China at 1.5 billion
Number 2: India at 1.1 billion
Number 3: USA at 300 million
Number 4: Indonesia at 240
million
Number 5: Pakistan at 173
million
Together
they have
36% of the
people
22. Women are having fewer
babies
Fertility rate - the
number of children
born to a woman
during her lifetime
23. 2 types
1. Replacement level fertility rate - the
number of children a couple must
have to replace themselves
1. 2.1 in developed nations
2. 2.5 in developing
24. 2 types
2. Total fertility rate - the average number of
children born to women in a population during
their reproductive years
This has been going down
Developed nations
1950 - 2.5
2008 - 1.6
Developing nations
1950 - 6.5
2008 - 2.8
26. 10 Factors that affect the birth
rate
1. Children in the
work force
1. Developing
nations tend to
have more
children in the
work force
More or less kids?More or less kids?
27. 10 Factors that affect the birth
rate
2. The cost of raising and
educating children
- birth rate lower in
developed countries
where it is much more
expensive to raise kids
(they don’t work for the
family usually)
- costs about
$290,000 to raise a kid
to 18 years old
More or less kids?More or less kids?
28. 10 Factors that affect the birth
rate
3. Private and public
pension systems (or
lack thereof)
Pensions reduce the
need for children to
care for adults in their
old age
More or less kids?More or less kids?
29. 10 Factors that affect the birth
rate
4. Urbanization -
urban areas have
more family
planning clinics -->
less kids
rural families need
kids to help raise
crops/livestock
More or less kids?More or less kids?
30. 10 Factors that affect the birth
rate
5. Education for
women
fertility rate lower
when women are
educated
marriage is
delayed also
More or less kids?More or less kids?
31. 10 Factors that affect the birth
rate
6. Infant Mortality Rate
- the number of children per 1000 births who
die before age 1
More or less kids?More or less kids?
32. 10 Factors that affect the birth
rate
7. Age at marriage
More or less kids?More or less kids?
33. 10 Factors that affect the birth
rate
8. Ability to have abortions
each year ~ 190 million pregnancies
~ 46 million abortions
(about half illegal) More or less kids?More or less kids?
34. 10 Factors that affect the birth
rate
9. Availability of birth
control methods
More or less kids?More or less kids?
35. 10 Factors that affect the birth
rate
10. Religious beliefs,
traditions, culture More or less kids?More or less kids?
36. Question 4
Is it rational for a poor couple
in a developing country such
as India to have 4 or 5
children?
Explain your thinking.
37. Put this number next to your
name
Jot down the number of people in the
world now
How many people were added during our
lesson?
