1/9/2016
Human population change
Chapter 8b
Raven and berg
O'Connell: Human Population 8b 1

[Earth,] A tiny raft in the enormous, empty night.
- Archibald
MacLeish (1970)
Finite space
1/9/2016 O'Connell: Human Population 8b 2

The Human Population
Current world population as of Jan. 9, 2016 is:
7,297,700,000
(per Population Connection)
Demography: science of human population structure and growth.
http://www.prb.org/pdf15/2015-world-population-datasheet_eng.pdf
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Data Sites
• http://www.prb.org
• http://www.prb.org/pdf15/2015-worldpopulation-data-sheet_eng.pdf
• http://www.populationconnection.org/
• http://www.census.gov
• https://www.cia.gov/library/publications/theworld-factbook/
• http://data.worldbank.org/indicator/SP.POP.G
ROW
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Where the growth comes from
Current Population Numbers
Rapid growth primarily due to drop in death rates
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Thomas Malthus
• British economist (1766-
1834)
• Populations were increasing faster than food production
• Could not be sustained
• Didn’t foresee the advent
(arrival) of the Industrial
Revolution
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Population growth
• 1 billion – about the year 1800
• 2 billion – 1930
• 3 billion – 1960
• 4 billion – 1975
• 5 billion – 1987
• 6 billion – 1999
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World Population Growth, in Billions
Number of years to add each billion (year)
First Billion All of Human History
Second
Third
Fourth
Fifth
30 years (1960)
15 years (1975)
Sixth
Seventh
Eighth
Ninth
12 years (1987)
12 years (1999)
12 years (2011}
14 years (2027)
130 years
(1930)
(1800)
Agricultural Revolution: 10,000
BC
Industrial Revolution: 1800 AD
Baby Boom: 1946 - 1964
21 years
(2048)
Sources: First and second billion: Population Reference Bureau. Third through ninth billion: United Nations, World
Population Prospects: The 2004 Revision (medium scenario), 2005.

How Much is a Billion?
• 1,000 seconds = 16.7 minutes
• 1 million-s = 16,677 min = 11.6 days
• 1 billion-s = 11,574 days = 31.7 years
_________________________________________
• 1,000 pennies = ~ 88 ounces = 5.5 pounds
• 1 million pennies = 5,500 pounds (~1-Suburban)
• 1 billion pennies = 2,750 tons (~2 Space Shuttles)
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World Population Growth Through
History
12
Billions
11
10
9
8
7
Old
Stone
Age
6
New Stone Age
Bronze
Age
Iron
Age
2100
Modern
Age
Middle
Ages
2000 Future
5
4
3
2
1
Black Death —The Plague
1975
1950
1900
1800
1+ million 7000 years B.C.
6000
B.C.
5000
B.C.
4000
B.C.
3000
B.C.
2000
B.C.
1000
B.C.
A.D.
1
A.D.
1000
A.D.
2000
A.D.
3000
A.D.
4000
A.D.
5000
Source: Population Reference Bureau; and United Nations, World Population Projections to 2100 (1998).

Total Fertility Rate
• The average number of children a woman can have in her lifetime
• 2.1 replacement rate
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Top 10 Most Populous countries
1. China 1,367,485,388 6. Pakistan 199,085,847
2. India
3. United States
1,251,695,584 7. Nigeria
321,368,864 8. Bangladesh
4. Indonesia
5. Brazil
1/9/2016
255,993,674 9. Russia
204,259,812 10. Japan
O'Connell: Human Population 8b
181,562,056
168,957,745
142,423,773
126,919,659
12

density of Countries
1/9/2016 O'Connell: Human Population 8b 13

Decreasing growth rate
• From a peak of 2.2% (1964 – end of the Baby
Boom) to 1.13% per year in 2016
• Mexico example
– r = 26/1000 – 5/1000 = 0.026 – 0.005 = 0.021/100 =
2.1% per year
• Absolute numbers are increasing due to sheer volume of people of reproductive age
– Baby Boom echo
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Projected growth
• Population rate was 1.13% per year in 2015
• Population will top out at 9 billion in the year
2050
• Zero population growth
– When the birth rate equals the death rate
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Zero population growth
• Projecting Future
Population Numbers
– When will zero population
growth occur?
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World Population Growth rate and
Absolute Growth
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Doubling time
• The amount of time it would take for a population to double in size (t
• t d
= 70%/r
– Called the Rule of 70 d
)
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Doubling time example
• How many years would it take for the population of Guatemala to double in size at the 2007 growth rate?
– Needed information:
• Current population: 13.4 million (13,400,000)
• Birth rate (b): 34 (per 1000 people)
• Death rate (d): 6 (per 1000 people)
• Growth rate (r): r = b – d (natural increase)
• t d
= 70%/r
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Doubling time example
 Calculations:
 Growth rate (r) = 34/1000 – 6/1000 or 34 - 6
1000
= 0.034 – 0.006
= 0.028 (x 100 = 2.8%)
• t d
= 70%/r
= 0.7/0.028
= 25 years
– At the current growth rate of 2.8% it will take the population of Guatemala 25 years to double in size.
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Developed vs. Developing countries
(table 8.2)
2004 Population Data
Fertility rate
Projected population change
2004-2050*
Infant mortality rate
United States
(Highly
Developed)
2.0
+43%
6.7 per 1000
Brazil
(Moderately Dev.)
2.2
+24%
33 per 1000
Ethiopia
(Less Developed)
5.9
+139%
105 per 1000
Life expectancy at birth 77 years 71 years 46 years
Per capita GNI PPP**
Women using modern contraception
$36,110
72%
$7,450
70%
$780
6%
*Includes fertility, mortality, and migration estimates
**GNI PPP = gross national income in purchasing power parity (at
O'Connell: Human Population 8b 21

08_15.JPG

Demographic Stages
 Pre-industrial Stage
 Birth and death rates high, modest population growth
 Transitional Stage
 Lowered death rate, rapid population growth
 Industrial Stage
 Birth rate decline, population growth slow
 Post Industrial Stage
 Low birth and death rates, population growth very slow
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Demographic Transition Comparisons
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Age structure pyramids
• Each row covers 5 years (e.g. 10 year olds – 14 year olds)
• Males are on one side and females on the other
• Percent or numbers of population on the bottom
• 3 basic types of pyramids
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Age Structure Diagrams
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Demographic example
• Nigeria
– What affect will this have on Nigeria’s future?
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Demographic example
• United States
– What affect will this have on the United States’ future?
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Tracking the baby-boom generation in the United States
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Demographic example
• Germany
– What affect will this have on
Germany’s future?
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Age structure pyramid of
Germany
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Population Under Age 15
30% of the human population is under age 15
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Aging population
• Strain on retirement programs (e.g. pensions)
• Health problems
• Less workforce
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• A country is OVERPOPULATED if:
– If the population cannot be sustainably supported
• People overpopulation
– environment is harmed because of too many people
• Consumption overpopulation
– environment is harmed from too much consumption

I. Population and the environment
A. IPAT model- measures humans ’ total impact
(I) on the environment
I = P x A x T
P = population
A = affluence
T = technology
1. Increase in any factor increases the environmental impacts.
2. Impacts to env. are generally pollution and resource consumption.

Environmental Impact
4/16/2020
Fig. 1-11 p. 13
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