ENVIRONMENTAL SCIENCE

13e

CHAPTER 6: The Human Population and Urbanization

Global Population

• http://www.youtube.com/watch?v=sc4 HxPxNrZ0

Core Case Study: Are There Too Many of Us? (1)

• 6.8 billion people • 83 million more each year • 2050: 9.5 billion people at current growth rates • Most growth in low-income and middle-income countries • Enough resources for growing population?

A important question

• Can we provide an adequate standard of living for a projected 2.7 billion more people by 2050 without causing widespread environmental damage?

• Overpopulation vs overconsumption

Core Case Study: Are There Too Many of Us? (2) • Negative viewpoint – 20% currently lack basic necessities – Declining conditions increase death rate – Increased resource use – Increased environmental degradation • Positive viewpoint – Technological solutions will increase carrying capacity – Growing population a valuable resource

Crowded street in China: largest population of all countries with 1.3 Billion people Together China and India are home to 1 of every 3 people on Earth

Fig. 6-1, p. 94

6-1 How Many People Can the Earth Support?

•

Concept 6-1 We do not know how long we can continue increasing the earth’s carrying capacity for humans without seriously degrading the life support system that keeps us and many other species alive.

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 decreased death rates

How Long Can the Human Population Grow?

• Rate slowing, but still exponential • Uneven global growth • No population can grow indefinitely • 2050: 9.5 billion people at current growth rates • Most growth in developing countries , least likely to cope

13

Exponential Growth: the J-shaped curve of past world population growth

12 ?

11 10 9 8 7 Industrial revolution Black Death —the Plague 6 5 4 3 2 1 0 2-5 million years 8000 Hunting and gathering 6000 4000 2000 B.C.

A.D.

Agricultural revolution 2000 2100 Industrial revolution Fig. 1-1, p. 1

12 11 10 9

UN world population projections

Medium 9.5

High 10.8

8 7 6 5 4 Low 7.8

3 2 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 Year Fig. 6-2, p. 96

Natural Capital Degradation Altering Nature to Meet Our Needs Reduction of biodiversity Increasing use of the earth's net primary productivity Increasing genetic resistance of pest species and disease causing bacteria Elimination of many natural predators Introduction of potentially harmful species into communities Using some renewable resources faster than they can be replenished Interfering with the earth's chemical cycling and energy flow processes Relying mostly on polluting and climate-changing fossil fuels Fig. 6-3, p. 97

6-2 What Factors Influence the Size of the Human Population?

•

Concept 6-2A Population size increases through births and immigration

and decreases through deaths and emigration.

•

Concept 6-2B 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

• 2009: China, 1.3 billion people India, 1.1 billion people USA, 306 million people

Number of Children

• Fertility rates affect population size and growth rate •

Total fertility rate (TFR)

• 1950-2009: Global TFR fell to: 1.6 from 2.5 in developed countries 2.8 from 6.5 in developing countries

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 • 2050 estimate: 439 million

TFR for US

4.0

3.5

3.0

2.5

2.1

2.0

1.5

1.0

0.5

0 Baby boom (1946 –64) Replacement level 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year Fig. 6-4, p. 98

Factors Affecting Birth Rates (1)

• Importance of children as part of labor force • Cost of raising and educating children • Availability of retirement systems • Urbanization • Educational and employment opportunities for women

Factors Affecting Birth Rates (2)

• Average marriage age • Availability of legal abortion and reliable birth control methods • Religious beliefs, traditions, cultural norms

Factors Affecting Death Rates

• • Population growth is also response to decline in crude death rate

Life expectancy

and

infant mortality rate

overall health important indicators of • Average life expectancy increased • Infant mortality – barometer of a society’s quality of life

Supplement 3, Fig. 8, p. S10

*6 3 How Does a Population’s Age Structure Affect Its Growth or Decline?

•

Concept 6-3

The numbers of males and females in young, middle, and older age groups determine how fast populations grow or decline.

*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. 6-6, p. 102

Fig. 6-6, p. 102

Age Structure Predicts the Future • • 36% of U.S. population baby boomers

Graying of America

• Over time: increasing percentage of older baby boomers • Changes the economy

Tracking the baby-boom generation in the United States. US population by age and sex for years indicated.

1955 1985 2015 2035 Stepped Art Fig. 6-8, p. 103

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

•

*6-4 How Can We Slow Human Population Growth?

Concept 6-4

We can slow population growth by -reducing poverty -encouraging family planning -and elevating the status of women.

*

Stages of Demographic Transition • Preindustrial • Transitional – demographic trap • Industrial • Postindustrial • Some analysts believe that most of the world’s developing countries will make a demographic transition over the next few decades, mostly because modern technology can raise per capita incomes by bringing economic development and family planning to such countries. Other analysts fear rapid pop growth, extreme poverty, and increasing environmental degradation in some low-income countries could leave them stuck in stage 2.

40 30 20 10 0 Stage 1 Preindustrial 80 70 Population grows very slowly because of a high birth rate (to compensate for high infant mortality) and a high death rate 60 50 Low Stage 2 Transitional Population grows rapidly because birth rates are high and death rates drop because of improved food production and health Birth rate Increasing Total population Very high Death rate Decreasing Growth rate over time Stage 3 Industrial Stage 4 Postindustrial Population growth slows as both birth and death rates drop because of improved food production, health, and education Population growth levels off and then declines as birth rates equal and then fall below death rates Low Zero Negative Stepped Art Fig. 6-10, p. 105

Think about it

• Stage 1: birth rate, death rate, population • Stage 3: birth rate, death rate, population • Stage 2: birth rate, death rate, population • Stage 4: birth rate, death rate, population

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 – Often lack access to family planning

Family Planning (2)

• Invest in family planning • Reduce poverty • Elevate the social and economic status of women

Empowering Women Can Slow Population Growth (1) • Women tend to have fewer children if they: – are educated – control their own fertility – have a paying job outside the home – do not have their rights suppressed

*

Empowering Women Can Slow Population Growth (2) • Women do almost all domestic housework and childcare • Women do 60-80% of agriculture, wood gathering, water hauling • Globally, women do 2/3 of all work for 10% of income

Empowering Women Can Slow Population Growth (3)

• 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)

• One-child families • Halved birth rate and drastically reduce TFR • Improved quality of life • Strict family planning • Sons still preferred – gender imbalance

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

Case Study: Slowing Population Growth in India

• Tried to slow population growth for five decades • Most populous country in 2015 • Problems increase with growing population – Poverty – Malnutrition – Environmental degradation – Growing middle class – resource consumption

Assignment

• Read Handout: “What do you think? Cultural Choices and the Rate of Population Growth” that discusses the approach to population control taken by two Indian states, Kerala and Andra Pradesh • Answer the question Which method of population control (that used by Kerala or Andra Pradesh) offers better insights and models for other countries? What are the benefits and limitations of each approach?

• What do you think of the approach taken in Thailand? Why might this approach not work everywhere?

6-5 What Are the Major Urban Resource Environmental Problems?

•

Concept 6-5

Most cities are unsustainable because of high levels of resource use, waste, pollution, and poverty.

Urban Living

• Half the world lives in urban areas • 79% of Americans live in cities • 50% of world population lives 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

Shows populations of 18 megacities ( each with 10 million or more people ) in 2009 and their projected populations in 2015 . All but 3 are located in developing countries.

Los Angeles 13.3 million 19.0 million Mexico City 18.3 million 20.4 million New York 16.8 million 17.9 million Sao Paulo 18.3 million 21.2 million Key 2004 (estimated) 2015 (projected) Buenos Aires 12.1 million 13.2 million Cairo 10.5 million 11.5 million Lagos 12.2 million 24.4 million Karachi 10.4 million 16.2 million Dhaka 13.2 million 22.8 million Beijing 10.8 million 11.7 million Mumbai (Bombay) 16.5 million 22.6 million Delhi 13.0 million 20.9 million Calcutta 13.3 million 16.7 million Jakarta 11.4 million 17.3 million Tokyo 26.5 million 27.2 million Osaka 11.0 million 11.0 million Manila 10.1 million 11.5 million Shanghai 12.8 million 13.6 million Fig. 6-11, p. 108

Case Study: Urbanization in the United States (1) • 1800–2009: urban population increased from 5% to 79% • Migration patterns – Rural areas to large cities – Large cities to suburbs and smaller cities – Cities and suburbs to rural areas – North and East to South and West

Almost 8 of every 10 Americans live in urban areas . Areas with names in white Are fastest growing metropolitan areas.

48% of all Americans live in cities of 1 million or more

Fig. 6-12, p. 109

Urban Sprawl is a product of

• Prosperity • Ample and affordable land • Automobiles • • Cheap gasoline

Poor urban planning

• Urban sprawl=growth of low density development on the edges of cities and towns

Urban Sprawl Problems

• Increased automobile use • Decreased energy efficiency • Destruction of cropland, forests, wetlands • Economic deaths of some cities

Natural Capital Degradation Urban Sprawl Land and Biodiversity Loss of cropland Loss of forests and grasslands Loss of wetlands Loss and fragmentation of wildlife habitats Water Increased use of surface water and groundwater Energy, Air, and Climate Increased energy use and waste Increased runoff and flooding Increased surface water and groundwater pollution Decreased natural sewage treatment Increased air pollution Increased greenhouse gas emissions Can enhance climate change Economic Effects Decline of downtown business districts Increased unemployment in central city Loss of tax base in central city Fig. 6-14, p. 110

Advantages of Urbanization (1)

• Economic development • Innovation • Education and jobs • Technological advances • Longer life spans

Advantages of Urbanization (2)

• Better social and medical services • Recycling more feasible • Biodiversity increased • Increased energy efficiency

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

Natural capital degradation : urban areas rarely are sustainable systems. Typical city Depends on large non-urban areas for huge inputs of matter and energy resources and for large outputs of waste matter and heat.

Inputs Outputs Energy Food Water Raw materials Manufactured goods Money Information Solid wastes Waste heat Air pollutants Water pollutants Greenhouse gases Manufactured goods Noise Wealth Ideas Fig. 6-15, p. 111

Urban Poor in Developing Countries • Slums • Shantytowns and squatter settlements • Lack of basic services

Slums Mexico City

Case Study: Mexico City (1)

• Large population • Severe noise, water, and air pollution • 50% unemployment • 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

6-6 How Does Transportation Affect Urban Environmental Impacts?

•

Concept 6-6 In some countries, most people live in dispersed urban areas and depend mostly on motor vehicles for their 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

• Gas guzzlers • 40,000 people per year die from auto accidents in the United States • World’s 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

Advantages Are quiet and non-polluting Trade-Offs Bicycles Disadvantages Provide little protection in an accident Take few resources to make Burn no fossil fuels Require little parking space Provide no protection from bad weather Are impractical for long trips Secure bike parking not yet widespread Fig. 6-18, p. 115

Trade-Offs Advantages Uses less energy and produces less air pollution than cars do Reduced need for more roads and parking areas Mass Transit Rail Disadvantages Is expensive to build and maintain Is cost-effective only in densely populated areas Causes fewer injuries and deaths than cars do Reduces car congestion in cities Commits riders to transportation schedules Can cause noise and vibration for nearby residents Fig. 6-19, p. 116

Advantages Can greatly reduce car use and air pollution

Trade-Offs

Buses Disadvantages Can lose money because they require affordable fares Can be rerouted as needed Cost less to develop and maintain than heavy-rail system Can get caught in traffic and add to noise and pollution Commit riders to transportation schedules Fig. 6-20, p. 116

Advantages Is much more energy efficient per rider than cars and planes are Produces less pollution than do cars and planes Can reduce need for more air travel, cars, roads, and parking areas

Trade-Offs

Rapid Rail Disadvantages Is costly to run and maintain Causes noise and vibration for nearby residents Has some risk of collision at car crossings Fig. 6-21, p. 116

*

6-7 How Can Cities Become More Sustainable and Livable?

•

Concept 6-7

An

ecocity

allows people to choose walking, biking, or mass transit for most transportation needs; recycle or reuse most of their wastes; grow much of their food; and protect biodiversity by preserving surrounding land.

• What is an Ecocity? What is an example of an ecocity?

Environmentally Sustainable Cities • •

Smart growth Ecocities

– Use renewable energy as much as possible – Build and design people-oriented cities – Use energy and matter efficiently – Prevent pollution and reduce waste – Recycle, reuse, and compost – Protect and encourage biodiversity – Promote urban gardens and farmers markets – Zone for environmentally stable population levels

Homework Assignment

• Go on an ecocity scavenger hunt ! Find at least 3 things in Athens or on campus that could be found in an ecocity. • Take pictures and email them with a description of why you think you would find it in an ecocity  • You may work in pairs or groups of 3 if you wish

Solutions Smart Growth Tools Limits and Regulations Limit building permits Urban growth boundaries Greenbelts around cities Protection Preserve existing open space Buy new open space Buy development rights that prohibit certain types of development on land parcels Public review of new development Zoning Encourage mixed use of housing and small businesses Concentrate development along mass transportation routes Promote high-density cluster housing developments Planning Ecological land-use planning Environmental impact analysis Integrated regional planning State and national planning Taxes Tax land, not buildings Tax land on value of actual use (such as forest and agriculture) instead of on highest value as developed land Tax Breaks For owners agreeing not to allow certain types of development (conservation easements) For cleaning up and developing abandoned urban sites (brownfields) Revitalization and New Growth Revitalize existing towns and cities Build well-planned new towns and villages within cities Fig. 6-22, p. 117

*Case Study: Curitiba, 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

Case Study: Curitiba, Ecocity in Brazil (2)

• 1.5 million trees planted • Recycling • Many services for the poor • Emphasis on ecological awareness, health, literacy

Curitiba Video

• http://www.youtube.com/watch?v=hR D3l3rlMpo&feature=fvw

Bus rapid transit system in Curitiba, Brazil. Boarding is speeded up by the use of Extra-wide doors and boarding platforms sheltered by large glass tubes where passengers can pay before getting on the bus.

Fig. 6-23, p. 118

Each of the 5 major spokes has 2 express lanes used only by buses.

City center Route Express Interdistrict Direct Feeder Workers Fig. 6-23, p. 118

Three Big Ideas from This Chapter - #1

The human population is increasing rapidly and may soon bump up against environmental limits.

Three Big Ideas from This Chapter - #2

We can slow human population growth by reducing poverty, encouraging family planning, and elevating the status of women.

Three Big Ideas from This Chapter - #3

Most urban areas, home to half of the world’s people, are unsustainable, but they can be made more sustainable and livable within your lifetime.

Review Growth Curves

Exponential Growth Logistic Growth Carrying capacity= capacity of a given habitat to support a given species, stated in terms of the maximum population of the species that the habitat can support over a given period

*What will happen to the population size in the future in each of the age structure diagrams?

*What will happen here?

Fig. 6-6, p. 102