applying population ecology: human population and urbanization chapter 7
TRANSCRIPT
Applying Population Ecology: Human Population and
Urbanization
Chapter 7
Core Case Study: Ecocity in Brazil (1)
Curitiba – “ecological capital” of Brazil
Inexpensive, efficient mass transit
High-rise apartments near bus routes, mixed-use structures
Bike and pedestrian paths
Fig. 7-26, p. 152WorkersInterdistrict Direct FeederExpress
City center
Bus System of Curitiba, Brazil
City center
Core Case Study: Ecocity in Brazil (2)
1.5 million trees planted
Recycling
Build-it-yourself system for poor
Emphasis on ecological awareness, health, literacy
7-1 How Many People Can the Earth Support?
Concept 7-1 We do not know how long we can continue increasing the earth’s carrying capacity for humans without seriously degrading the life-support systems for us and many other species.
Human Population Explosion
Exponential growth (J-curve) in past 200 years
Three major reasons
• Ability to expand into diverse habitats
• Emergence of agriculture
• Sanitation systems and control of infectious diseases
Last 60 years have seen emergence of antibiotics and use of chemical pesticides (DDT) and fertilizers
Source: United Nations Population Division. World Population Prospects: The 2006 Revision Data Online.In the right hand graph, S.S.Africa stands for sub–Saharan Africa Population Database
Population growth, Regions and countries
Fig. 1-1, p. 1
Hunting andgathering
Agricultural revolution Industrialrevolution
Black Death—the Plague
World Population
?
Time
Billio
ns o
f pe
op
le
How Long Can the Human Population Grow ?
Rate slowing, but still exponential
Uneven global growth (greater in developing countries)
No population can grow indefinitely
2050 global estimates: 7.2–10.6 billion people
97% growth in developing countries, least likely to cope
World Population Projections
Fig. 7-3, p. 131
Case Study: Are There Too Many of Us? (1)
Resources for growing population?
Positive viewpoint• Technological solutions (Technological fix)
• Growing population a value resource
Negative viewpoint• 20% currently lack necessities
• Declining conditions increase death rate
• Resource use already degrade environment
Case Study: Are There Too Manyof Us? (2)
Optimum sustainable population
Cultural carrying capacity
7-2 What Factors Influence Population Size?
Concept 7-2A Population size increases because of births and immigration and decreases through deaths and emigration.
Concept 7-2B The average number of children born to women in a population (total fertility rate) is the key factor that determines the population size.
Population Change
Population change =
(births + immigration) - (deaths + emigration)
Demographers look at birth rates and death rates
Fig. 7-2, p. 130
Average Crude Birth and Death Rates
Average crude birth rate Average crude death rate
Africa
LatinAmerica
Asia
Oceania
UnitedStates
NorthAmerica
Europe
3814
22
6
20
7
18
7
14
8
148
10
12
Fig. 7-2b, p. 130
Average Crude Birth and Death Rates
Fig. 7-2a, p. 130
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
Average Crude Birth and Death Rates
Number of Children
Fertility rates affect population size and growth rate
Replacement-level fertility rate
Total fertility rate (TFR)
Fig. 7-4, p. 131
US Fertility Rates (1917-2005)
Case Study: The U.S. Population Is Growing Rapidly
Quadrupled in 100 years, despite oscillations in TFR
Baby boom: High TFR
Current births outnumbering deaths and legal immigration
Growing faster than other developed countries
Factors Affecting Birth Rates (1) Children as part of the labor force
http://www.gdsnet.org/classes/ChildLaborPart1.pdf
Cost of raising and educating children
http://moneycentral.msn.com/articles/family/kids/tlkidscost.asp http://www.voanews.com/english/archive/2009-08/2009-08-05-voa3.cfm?mo
ddate=2009-08-05
Availability of retirement systems
Urbanization - definition varies by country; in U.S. it revolves around 50K
Educational and employment opportunities for women
Factors Affecting Birth Rates (2)
Infant mortality rate
Average marriage age http://en.wikipedia.org/wiki/Age_at_first_marriage
Availability of legal abortion and reliable birth control methods
Religious beliefs, traditions, cultural norms
Factors Affecting Death Rates
Population growth also response to decline in crude death rate
Life expectancy and infant mortality rate important indicators of overall health
Average life expectancy increased
Infant mortality – barometer of a society’s quality of life
Migration
Migration driven by economic desires
Other reasons• Religious persecution
• Political oppression
• Ethnic conflicts
• Wars
• Environmental degradation
Case Study: The United States (1)
Nation of immigrants
1820–1960: Most immigrants European
Since 1960• Latin America – 53%
• Asia – 25%
• Europe – 14%
Case Study: The United States (2)
Opponents of immigration• Stabilize population sooner
• Reduce growing environmental impact
• 60% of population favor reducing immigration
Proponents of immigration• Important historical role
• Do menial jobs and pay taxes
• Add cultural vitality
• Replace retiring baby boomers
7-3 How Does a Population’s Age Structure Affect Its Growth or Decline?
Concept 7-3 The numbers of males and females in young, middle, and older age groups determine how fast populations grow or decline.
Fig. 7-8, p. 135
Population Age Structures
Age Structure
Distribution of population• Prereproductive
• Reproductive
• Postreproductive
Country with many young people grows rapidly
Country with many older people will decline
Developing countries >30% under 15 years old
Fig. 7-8b, p. 135
Expanding RapidlyGuatamala
NigeriaSaudi Arabia
Male Female
Prereproductive ages 0-14 Reproductive ages 15-44 Postreproductive ages 45-85+
© 2004 Brooks/Cole – Thomson Learning
Population Age Structures Male Female Male Female Male Female
Expanding SlowlyUnited States
AustraliaCanada
StableSpain
AustriaGreece
DecliningGermanyBulgariaSweden
Age Structure Predicts the Future
50% of U.S. population baby boomers
Graying of America
2043 – 25% of population over 65
Changes the economy
Declines Occur in Aging Populations
“Baby bust” or “birth dearth” – TFR below 1.5 children per couple
Labor shortages
Strain on governments for public services
Fewer taxpayers
Fig. 7-10, p. 136
Tracking the US Baby Boom Generation
Rising Death Rate: The AIDS Tragedy
Disrupts social, economic structure
Removes productive young adults
Next 50 years, 278 million will die (mostly African)
Eight African countries 16–39% infected adults
Life expectancy 30–40 years
7-4 How Can We Slow Population Growth?
Concept 7-4 Experience indicates that the most effective ways to slow population growth are to invest in family planning, to reduce poverty, and to elevate the status of women.
Stages of Demographic Transition
Preindustrial
Transitional – demographic trap
Industrial
Postindustrial
Fig. 7-11, p. 137
Stage 1Preindustrial
Stage 2Transitional
Stage 3Industrial
Stage 4Postindustrial
Low Increasing Very high Decreasing Low Zero Negative
Birth rate
Total population
Death rate
Growth rate over time
Demographic Transition
Low
High
Rel
ati
ve
po
pu
lati
on
siz
e
Bir
th r
ate
an
d d
eath
rat
e(n
um
ber
per
1,0
00 p
er
yea
r)
0
10
20
30
40
50
60
70
80
Family Planning (1)
Birth spacing, birth control, health care
Increased availability of contraception
55% drop in TFR of developing countries
Developing countries• Almost half pregnancies unplanned
• Lack access to family planning
Family Planning (2)
Replacement-level fertility achievable within decades
Invest in family planning
Reduce poverty
Elevate the social and economic status of women
Empowering Women Can Slow Population Growth
Educated women have fewer children
Illiterate woman 64% of world’s population, 70% of the poor
When daughters considered less valuable, not sent to school
Poor conditions for women leads to environmental degradation
Case Study: Slowing Population Growth in China (1)
Half birth rate and drastically reduce TFR Currently 1.79 (2009) CIA Factbook
Improved quality of life
Strict family planning (see next slide)
Sons still preferred – gender imbalance Approximately 1.1/1.0 male/female for all age groups
Family PlanningCurrently used by about 35% of country
Key Aspects of Program
Strongly encourage couples to marry later
Expand educational opportunities for men and women
Provide married couples easy access to free sterilization, contraceptives and abortion.
Provide couples who sign the pledge to have no more than 1 childsalary bonusesextra foodlarger pensionsbetter housingfree medical care and school tuition for their childpreferential treatment in employment when child grows up
Family Planning(continued)
Requiring those who break the pledge to return all benefits
Exerting pressure on women pregnant with a 3rd child to have an abortion
Requiring one of the parents in a 2-child family to be sterilized
Using mobile units and paramedics to bring sterilization, family planning, health care, and education to rural areas
Train local people to carry on the family planning program
Expect all leaders to set examples with their own family size
Current population growth rate 0.655% CIA Factbook70/0.655 = 107 years to double population at this rate
Still have high infant mortality rate 20.25 deaths / 1000 live births CIA
Case Study: Slowing Population Growth in China (2)
Population rapidly aging
Rapidly growing economy
Larger middle class increases resource consumption and waste
Sustainable economic plan needed to avoid environmental degradation
Fig. 7-12, p. 139
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 billion1.63 billion
47%17%
36%22%
1.6%0.6%
2.72 children per woman (down from 5.3 in 1970)1.7 children per woman (down from 5.7 in 1972)
30.15
20.25
67 years male/72 females
71 years males/ 75 females
$2,880 $4,980
Demographic Data on India and China
8147
Percent living below $2 per day
Case Study: Slowing Population Growth in India
Tried to slow population growth for five decades
High illiteracy rate of about 71%, 80-90% are rural women
Initially provided information about advantages of small families
1976 government started mass sterilization program, mainly for those with 2 or more children; supposedly voluntary with financial incentives to volunteers; coercion used in rural areas
1978 government raised the legal minimum are for marriage from 18 to 21 for men and from 15 to 18 for women
No change in population growth rate between 1971-1981
Current population growth rate 1.548 (2009)
70/1.548 = doubling time of 45 years
Most populous country in 2015
Problems increase with growing population
PovertyMalnutritionEnvironmental degradationGrowing middle class – resource consumption
7-5 What Are the Major Population and Environmental Problems of Urban Areas?
Concept 7-5 Cities can improve individual lives, but most cities are unsustainable because of high levels of resource use, waste, pollution, and poverty.
ArgentinaPopulated centers with 2,000 or more
Canada Places of 1,000 or more*
China
Cities designated by the State Council and other places with density of 1,500 or more per sq. km.*
India
Specified towns with governments and places with 5,000 or more and at least three-fourths of the male labor force not in agriculture*
JapanCities (shi) with 50,000 or more*
Maldives Male, the capitalMexico Localities of 2,500 or more
New ZealandCities, towns, etc. with 1,000 or more
NigerCapital city and department and district capitals
Norway Localities of 200 or more
PeruPopulated centers with 100 or more dwellings
SenegalAgglomerations of 10,000 or more
United StatesPlaces of 2,500 or more, urbanized areas of 50,000 or more*
Country Urban Definition
Urban Living
Half the world lives in urban areas
80% of Americans in cities
Urban areas continue to grow• Natural increase
• Immigration
Major Trends in Urban Growth
Proportion of urban global population growing
Number and sizes of urban areas mushrooming
Rapid increase in urban populations in developing countries
Urban growth slower in developed nations
Poverty increasing
Case Study: Urbanization in the United States
1800–2007, increased population 5–80% in urban areas
Migration patterns
Better working and housing conditions compared to the past
Problems in urban areas
Urban Sprawl
Gobbling up countryside
Causes• Prosperity
• Ample and affordable land
• Automobiles
• Cheap gasoline
• Poor urban planning
Consequences of Urban Sprawl
Inadequate mass transportation
Need to drive everywhere
Decreased energy efficiency
Traffic congestion
Destruction of prime cropland, forests, wetlands
Advantages of Urbanization
Economic development
Innovation
Education and jobs
Technological advances
Recycling more economically feasible
Longer life spans
Disadvantages of Urbanization (1)
Unsustainable systems
Lack of vegetation
Water problems
Pollution and health problems
Disadvantages of Urbanization (2)
Noise pollution
Climate and artificial light
Urban heat islands
Light pollution
© 2006 Brooks/Cole - Thomson
Fig. 7-19, p. 146
Noise Levels (in dbA)
Permanent damagebegins after 8-hour
exposure
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
85
Normalbreathing
Whisper
Quietrural area
Quietroom
Rainfall
Normalconversation
Vacuumcleaner
Averagefactory
Lawnmower
Chainsaw
Rock music
Thunderclap(nearby)
Earphonesat loud level
Air raidsiren
Boomcars
Militaryrifle
Urban Poor in Developing Countries
Slums
Shantytowns and squatter settlements
Lack of basic services
Millions
Source: United Nations, World Urbanization Prospects: The 2003 Revision (medium scenario), 2004.
1950 2000 2015
Largest Cities, Worldwide
811 12
17 18
34
2123
36
London Tokyo New York
Sao Paulo
MexicoCity
Tokyo Delhi Mumbai(Bombay)
Tokyo
© 2006 Population Reference Bureau
• The largest cities in the world are growing rapidly, and they are shifting from the more developed regions to the less developed regions. In 1950 the three largest cities were in more developed countries; by 2000, only Tokyo remained in the top three. • In 1950, New York was the largest city in the world, with a population of about 12 million. By 2015, the largest city worldwide is projected to be Tokyo, with triple this population size: 36 million.
s on Largest Cities, Worldwide
Case Study: Mexico City (1)
Large population
Severe noise, water, and air pollution
50% unemployment
>33% live in barrios
100,000 premature deaths per year
Case Study: Mexico City (2)
3 million without sewer
Fecal snow
Geography contributes to air pollution
Progress – tree planting and lower air pollution
7-6 How Does Transportation Affect Urban Development?
Concept 7-6 A combination of plentiful land, inexpensive fuel, and an expanding network of highways results in dispersed cities that depend on motor vehicles for most transportation.
Cities Can Grow Outward or Upward
Compact cities• Transportation by walking, biking, or mass transit
• Hong Kong, Tokyo
Dispersed cities• Transportation by automobile
• Most American cities
Automobiles in the United States
<10% of world’s population own 1/3 of cars
Gas guzzlers
40,000 people per year die from auto accidents
Largest source of air pollution
Lead to urban sprawl and congestion
Reduce Automobile Use
User-pays system
Full-cost pricing
Tax revenues to finance mass transit, bike paths, sidewalks
High gasoline tax unlikely
Need to discourage automobile use
Alternatives to Cars
Bicycles
Mass transit systems in urban areas
Bus systems
Rapid rail
7-7 How Can Cities Become More Sustainable and Livable?
Concept 7-7 An ecocity allows people to: choose walking, biking, or mass transit for most transportation needs; recycle or reuse most of their waste; grow much of their food; and protect biodiversity by preserving surrounding land.
Environmentally Sustainable Cities
Smart growth
Ecocities• Build and design people-oriented cities
• Use energy and matter efficiently
• Prevent pollution and reduce waste
• Recycle, reuse, and compost
• Protect and encourage biodiversity