Environmental Science: Toward a Sustainable Future Richard T. Wright

Environmental Science: Toward a Sustainable Future Richard T. Wright

The Human Population: DimensionsPPT by Clark E. Adams

Chapter 5

Human Population Growth and the Consequences Human population expansion and its cause Different worlds Consequences of population growth and

affluence Dynamics of population growth

Human Population Expansion and Its Cause

Reasons for the patterns of growth Biotic potential exceeds environmental

resistance: birth rates exceed death rates There are 6.3 billion people on Earth If each one stood up, pronounced their

name, and sat down It would take 600 years to complete roll call By 2025 it will take 1,000 years to complete

this exercise

World Population over the Centuries

9,000 human beings added to the planet every hour

Reasons for the Human Population Explosion Causes of disease recognized Improvements in nutrition Discovery of antibiotics Improvements in medicine Increase in number of women who actually

reach child-bearing age Short doubling times in some countries

Changing Human Survivorship Curves: Went from B to A

% S

urv i

val

AgeBirth Death

A

B

World Population Growth and Absolute Growth

Population Projections Based on Different Fertility Assumptions

Average Number of Children, Grandchildren, and Great Grandchildren

America West Germany Africa

14 5 258

Different Worlds

Rich nations, poor nations Population growth in rich and poor nations Different populations, different problems

Human Poverty Index for Developing Countries

Economic Categories Based on Per Capita Gross National Income (see Fig. 5-4)

High-income, highly developed, industrialized countries United States, Japan, Canada Average GNI per capita = $26,710

Middle-income, moderately developed countries Latin America, South Africa, China Average GNI per capita = $1,850

Economic Categories Based on Per Capita Gross National Income (see Fig. 5-4)

Low-income, developing countries Western and central Africa, India, central Asia Average GNI per capita = $430

Disparities

Developed countries 16% of the world’s population Control 81% of the world’s wealth

Low-income developing countries 41% of the world’s population Control 3.4% of the world’s gross national

income Difference in per capita income: 62 to 1!

Population Increase in Developed and Developing Countries

Population Data for Selected Countries (Table 5-3)

Country Total Fertility Rate

Doubling Time (Years)

World 2.8 54

Developing Countries

3.5 37

Developed Countries

1.5 700

Different Populations, Different Problems

Human pressure on the environment caused by three factors Population size Affluence Technology

Ecological Footprints by World Region The average American places at least 20 times

the demand on Earth’s resources as does an average person in Bangladesh

Fig. 5.7 here

Global Conditions for a Sustainable Population Lower fertility rates (stabilize population) Consumption must decrease Protect the environment (stewardly action

must increase)

Consequences of Population Growth and Affluence

The developing countries Affluence

Developing or Developed Nations?

High fertility rates High consumptive lifestyles: use 80% of

world’s wealth Intense poverty Eat high on the food chain

Developing or Developed Nations?

Long doubling times High environmental degradation Twenty percent of the world’s population

Basic Human Needs

Drinkable Water Edible Food Safe Housing Health Care An Education A Job

The Developing Countries

Reform the system of land ownership Intensify cultivation of existing land to

increase production per unit area Open new land to farm Move to cities and seek employment Engage in illicit activities for income Move to other countries

How do these “solutions” aggravate the problems?

Growing Cities

Consequences of Exploding Populations in the Developing World

Consequences of Exploding Populations

More PopulationCauses

MORE

LESS

deforestationresource depletionloss of agricultural landbiodiversitydiseasepest resistancepopulation migrationirrigationwetlands

Affluence in the United States

Consume the largest share of 11 of 20 major commodities

Eat more than three times the global average in meat

Lead the world in paper consumption Environment improves with increasing

affluence

Affluence in the United States

Enables wealthy to clean up immediate environment by transferring waste to more distant locations.

Affluent isolate themselves and unaware of the environmental stresses caused by their consumptive lifestyles.

Dynamics of Population Growth

Population profiles Future populations Population momentum The demographic transition

Population Profiles of the United States

Population Profile for United States

Note increasing elderlypopulation.

Future World Populations

Future United States Populations

Projecting Future Populations: Developed Countries

Population Projections: Developing Nations

Comparing Projected Populations (see Fig. 5-17)

Fertility Rate> 2

Fertility Rate< 2

Population Momentum

Countries like Iraq will continue to grow for 50–60 years even after the total fertility rate is reduced to replacement level.

The Demographic Transition

Calculating Fertility Rates and Doubling Times

(CBR – CDR)/10 = Rate of increase or decrease in population per 1,000 per year

70/Rate of Increase = Doubling Time

Calculating Fertility Rates and Doubling Times: Practice (see Table 5-5)

Country CBR CDR Rate of Increase

Doubling Time

Kenya 33 13 2.0 35

Mexico 27 5 2.2 32

USA 15 9 0.6 116

Denmark 13 11 0.2 431

Demographic Transition Comparisons

By the Year 2000

65 out of 117 countries will not be able to feed their own people

One billion people will be living in cities that cannot support its inhabitants

400 million more women will be in need of child spacing services

By the Year 2000 (continued)

600 million new jobs will need to be created for new entrants into the workforce

We will need twice as much fresh water 300 million additional children will need

teachers, books, and classrooms

End of Chapter 5