human population growth, demography, carrying capacity
TRANSCRIPT
HUMAN POPULATION
Growth, Demography, Carrying Capacity
Population Growth
• Natural Rate (NR) = birth rate (br) – death rate (dr)
• PopulationChange = (br/1000 + Immigration) – (dr/1000 + emigration)
Natural rate of population change = br-dr/1000 x 100 OR br-dr/10
Crude birth rate = number of live births per 1,000 people in a population in a given year.
Crude death rate – number of deaths per 1,000 people in a population in a given year.
Average crude birth rate Average crude death rate
World
All developedcountries
All developingcountries
Developingcountries
(w/o China)
21
9
11
10
24
8
27
9
© 2004 Brooks/Cole – Thomson Learning
Africa
LatinAmerica
Asia
Oceania
UnitedStates
NorthAmerica
Europe
38
14
22
6
20
7
18
7
14
8
14
8
10
12
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Population Growth
• Total Fertility Rate (TFR) – estimate of the average number of children a female will have during reproductive years (15-45).
• Global TFR in 2004 = 2.8 children per woman.• Developing Countries TFR = 3.1, some African
countries have a TFR of 6!• Developed Nations are steady with a TFR of 1.6• Not until Developing Nations reach a TFR of 2.1
will world populations stabilize!• GOAL = Replacement Level Fertility (RLF)
Global Total Fertility Rates
World
Developedcountries
Developingcountries
Africa
LatinAmerica
Asia
Oceania
NorthAmerica
Europe
5 children per woman2.8
2.5
1.6
6.53.1
6.65.1
5.92.6
5.92.6
3.82.1
3.52.0
2.61.4
1950 2004
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Why Are TFR’s So High In Africa?
• No government supported family planning.• Low literacy rate among woman.• Few economic roles for woman.• Woman’s rights…are there any?• Poor health care for mothers/mothers-to-be.• AIDS rampant.• Need many children for labor.• High infant mortality due to poor quality of life.• Abortions, legal or safe?
Growing Cities
How Have Fertility Rates Changed in the USA?
• Population in 1900 – 76 million
• Population in 2004 = 294 million
• 1957 (peak baby boom) – TFR = 3.7
• Since 1972 – USA at or below replacement level fertility (RLF)
• USA population is growing faster than any other developed nation, why?
4.0
3.5
3.0
2.5
2.02.1
1.5
1.0
0.5
01920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Year
Bir
ths
per
wo
man
Baby boom(1946-64)
Replacement level
Baby Boom Years
Population Increase in the USA
• Br>dr because standard of living is high.• Baby-boomers now finally approaching post-
reproductive age!• Increase in unwed mothers (teenagers mostly,
many in inner-city areas).• Inadequate family planning.• Ethnic group increases from immigration from
developing nations who believe in the large family unit.
• Immigration (legal and illegal) = 71% of the population increase in the USA!
Male Female
Rapid GrowthGuatemala
NigeriaSaudi Arabia
Slow GrowthUnited States
AustraliaCanada
Male Female
Ages 0-14 Ages 15-44 Ages 45-85+
© 2004 Brooks/Cole – Thomson Learning
Pre-reproductive Reproductive Post-reproductive
Factors That Affect Birth/Fertility Rates
• Average level of education and affluence;• Importance of children in the labor force;• Cost of raising and educating children;• Education and employment opportunities for
woman;• Infant mortality rates related to access to health
care and medicine;• Availability of legal abortions.• Access to contraceptives and family planning
education.
Factors That Lower Death Rates
• Increased distribution and supply of food resources;• Higher living standards;• Better nutrition (food/vitamins);• Improvements in medical and public health technology;• Improvements in sanitation and personal hygiene;• Safer water supplies.• NOTE: Infant mortality rate (IMR) is a good indicator of
quality of life because it reflects the general level of nutrition and health care for a geographic region.
Global Infant Mortality Rates
Why Are TFR’s Higher In Developing Countries?
• Infant mortality rate is high;• Need a few children to help farm, earn an income, take
care of parents as they age;• Ignorance regarding sexual education (also accounts for
high incidence of AIDS especially in African Nations);• No access to contraceptives or other birth control;• Socially acceptable to have many children and multiple
sexual partners at an early age(12-15).• NOTE: Average age for marriage in a developing nation
is 15!• Average age for marriage in a developed country is 25!
“Young Mothers”
Survivorship Curves
• Survivorship curves indicate life expectancies for organisms. This is a way to represent the age structure of the population.
• The curve represents the number of survivors of each age group for a particular species.
Late Loss Curves
• Late loss curves are common to k-strategists. They produce few young and care for them. This reduces infant and juvenile mortality.
• Examples = humans, elephants, gorilla, etc..
Per
cen
tag
e su
rviv
ing
(lo
g s
cale
)
100
10
1
0
Age
Figure 9-11Page 171
Early loss
Constant loss
Late loss
Early Loss Curve
• Early loss curves are common to r-strategists. They produce many young who receive no parental care. This allows compensates for high infant/juvenile mortality.
• Once the young reach a critical age, there is high survivorship.
• Examples = annual plants, bony fish, amphibians, etc…
Per
cen
tag
e su
rviv
ing
(lo
g s
cale
)
100
10
1
0
Age
Figure 9-11Page 171
Early loss
Constant loss
Late loss
Constant Loss Curve
• An intermediate number of young with limited parental care are common to constant loss curves.
• They experience a fairly constant rate of mortality in ALL age classes, so there is a steady decline in survivors.
• Examples = lizards, songbirds, and small mammals.
Per
cen
tag
e su
rviv
ing
(lo
g s
cale
)
100
10
1
0
Age
Figure 9-11Page 171
Early loss
Constant loss
Late loss
Age Structure Diagrams
Rapid GrowthGuatemalaNigeriaSaudi Arabia
Slow GrowthUnited StatesAustraliaCanada
Ages 0-14 Ages 15-44 Ages 45-85+
Zero GrowthSpainAustriaGreece
Negative GrowthGermanyBulgariaSweden
Male Female Male Female
Ages 0-14 Ages 15-44 Ages 45-85+
© 2004 Brooks/Cole – Thomson Learning
Population(2004)
Populationprojected
(2025)
Infantmortality
rate
Lifeexpectancy
Fertilityrate (TFR)
%Populationunder
age 15
% Populationover
age 65
Per capitaGNI PPP
294 million179 million
137 million
349 million211 million
206 million
6.733
100
77 years
71 years52 years
2.02.2
5.7
21%30%
44%
12%6%
3%
$36,110$7,450
$800
United States (highly developed)
Brazil (moderately developed)
Nigeria (less developed)
© 2004 Brooks/Cole – Thomson Learning
POPULATION MOMENTUM
Is greatest in developing nations because the pre-reproductive and reproductive population make up the largest portion of the total population = POPULATION GROWTH
Population Momentum is dictated by quality of life indicators and Per capita income.
Percentageof world
population
Population
Population (2025)(estimated)
Illiteracy (%of adults)
Population under age 15(%)
Population growth rate (%)
Total fertility rate
Infant mortality rate
Life expectancy
GDP PPP per capita
17%20%
1.1 billion1.3 billion
1.4 billion
1.4 billion
47%17%
36%
22%
1.7%0.6%
3.1 children per woman (down from 5.3 in 1970)1.7 children per woman (down from 5.7 in 1972)
6432
62 years
71 years
$2,650
$4,520
IndiaChina
Thailand
• 1971 – Thailand adopted a National Policy to reduce its population growth.
• The population was growing at a rate of 3.2%/year.
• TFR was 6.4• 1986 – population decreased to 1.6%• 1988 – population decreased to 1.1%• 2000 – population decreased to 1%
(TFR = 1.9)
Population Growth Rate
• If Thailand’s population growth rate is was 1% in 2000, when will it’s population double?
• Use the “Rule of 70”
• 70/growth rate = doubling time• 70/1.0 = 70 years• Therefore, Thailand’s population is expected to
double in the year 2070.
How Did Thailand Accomplish Such a Dramatic Decrease in Population Growth
Rate?• 1. Government –supported family planning program• Mechai Viravidaiya created the Population and Community
Development Association in 1974. It’s goal was to make family planning a national goal.
• PCDA Workers:
a. Handed out condoms at festivals, movie theaters, traffic jams.b. Wrote humorous songs about condom use and why you shouldn’t
have more than 2 children (Replacement Fertility)c. Traffic police handed out condoms on New Year’s Eve, now
known as “Cops & Rubbers Day!”d. Carts to dispense birth control pills and spermicidal foams at bus
stations and public events.e. Open vasectomy clinics (sterilization is the #1 form of birth control
in Thailand)f. On the King’s Birthday, PCDA offers free vasectomies!
Thailand’s Decrease in Population Rate
• 2. High literacy rate among woman (90%)• 3. Economic roles for woman • 4. Advances in woman’s rights• 5. Better health care for mothers and children• 6. Openness of Thailander’s to new ideas• 7. Support of family planning by religious leaders (95%
Budhist)• 8. Government financial support – economic incentives
– family planners can apply for low interest loans to install toilets, drinking water systems, and farmers can install irrigation systems.
Problems Still Facing Thailander’s
• Pollution (increase in resource use per capita) Bangkok is one of the most polluted and congested cities in the world.
• High levels of traffic congestions (NOx = photochemical smog & acid deposition), CO2 & H2O (greenhouse gases)
• Increased environmental degradation.• Public Health (respiratory problems on the rise,
AIDS and other sexually transmitted diseases are rampant (prostitution is legal).
King: PHUMIPHON Adunyadet
Japan
• 1949-1956 (Post - WWII) – cut birth rate, TFR & population growth rates by 50%!
• TFR in 1949 was 4.5, in 1998 was 1.8 and it is on the decline still.
• How? Family Planning Services and Stressed Resources (Japan has no natural resources, they import all necessary raw materials and process it in Japan).
• Zero immigration rate = “pure population of Japanese” Population = 99% Japanese!
• Economic burden of caring for elderly.• Declining workforce = lead the world in automated
technology.• Japan has reached Zero Population Increase…now the
world watches to see how they handle these issues in the future.
40
35
30
25
20
15
10
5
01950 1970 1990 2010 2030 2050 2070 2090 2110 2130 2150
Year
Ag
e D
istr
ibu
tio
n (
%)
Under age 15 Age 60 or over Age 80 or over
Access to Family Planning Education and Contraception
• Family Planning – Rhythm Method
Extremely Effective
Highly Effective
Total abstinence
Sterilization
Vaginal ring
IUD with slow-releasehormones
IUD plus spermicide
Vaginal pouch(“female condom”)
IUD
Condom (good brand)plus spermicide
Oral contraceptive
100%
99.6%
98-99%
98%
98%
97%
95%
95%
93%
CONTRACEPTIVE METHODS
Effective
Cervical cap
Condom (good brand)
Diaphragm plusspermicide
Rhythm method (Billings,Sympto-Thermal)
Vaginal sponge impreg-nated with spermicide
Spermicide (foam)
89%
86%
84%
84%
83%
82%
LESS EFFECTIVE CONTRACEPTIVE METHODS
Moderately Effective
Unreliable
Spermicide (creams,jellies, suppositories) Rhythm method (dailytemperature readings)
Withdrawal
Condom (cheap brand)
Douche
Chance (no method)
75%
74%
74%
70%
40%
10%
Contraception in the USA
• 60 million US woman are in the reproductive age range(15-44).
• 9/10 are practicing contraception.• There are 3 million unintended pregnancies
each year resulting from incorrect or inconsistent use of contraceptives.
• Most unintended pregnancies occur in teens!• Is abortion being used in the USA as a form of
contraception by teens?
Life Tables
• Life tables show projected life expectancy and probability of death for individuals at each age.
• Insurance companies use these tables to determine policy costs for their customers.
• Woman in the USA survive on average 7 years longer than men.
• Therefore, a 65 year old male will pay more $ for life insurance than a 65 year old woman.
How Does Population Relate to the Economics of a Country?
• Demographic Transition – A hypothesis of population change that states as countries become industrialized, first their death rates decrease followed by declines in birth rates.
• There are four stages: Pre-industrial, Transitional, Industrial, Post-industrial.
Pre-Industrial Stage (Stage 1)
• Harsh living conditions lead to a high birth rate (to compensate for high infant mortality rate) and a high death rate .
African Nations
Transitional Stage (Stage 2)• Industrialization
begins which leads to an increase in food production and better access to health care and nutrition.
India, China, South & Central America, Middle East, Thailand
Industrial Stage (Stage 3)• Industrialization is
widespread and birth rate begins to drop. Eventually birth rate will approach death rate. There is better access to birth control and family planning, decreased infant mortality, increase in jobs, and increased opportunities for woman. Most Developed Countries
Post-Industrial Stage (Stage 4)• Birth rate decreases even
further and equals death rate = ZERO POPULATION GROWTH (ZPG).
• THEN… birth rate drops below death rate and population begins to decline slowly.
• *** Shift from unsustainable to sustainable forms of economics!!!
• 37 Western European Countries and Japan have reached this stage (12% world population).
Conclusion
• Over the next several decades, Developing countries now in the Transitional Stage can make the jump to the Industrialized Stage. As they make this jump, their quality of life improves…so does their per capita resource consumption. What happens next? Keep a close watch on China!
• Demographic Trap – A poor country with a population growth of 2.5%/year needs an economic growth rate of 5% per year to make the transition. (Unlikely).
Rapid Population Growth Leads to…
Rapid and wasteful use of resources with too little emphasis on pollution prevention and waste reduction.
Degradation to Earth’s life-support systems. Poverty which can drive poor people to use potentially
renewable resources unsustainably for short-term survival.
Failure of economic and political systems to encourage sustainable economic development.
Our urge to dominate and manage nature for our use with far too little knowledge about how nature works.
Major Connection: Population x Affluence x Technology = Environmental Degradation
P x A x T = E D
How Do We Slow Population Growth?
• Promote Family Planning Education• Reduce Poverty• Empower Woman• Improve health care for infants, children, and pregnant
woman.• Increase access to education especially for girls.• Increase the involvement of men in child rearing
responsibilities.• Reduce and eliminate unsustainable patterns of
economic production and consumption.• Promote free trade, private investment, and assitance to
countries that need help.
