Environmental Science: Toward a Sustainable Future Richard T. Wright Chapter 5 The Human Population: Dimensions PPT by Clark E. Adams

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 % Survival B Birth Age Death

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

Disparities Developed countries Low-income developing 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 deforestation resource depletion loss of agricultural land biodiversity disease pest resistance population migration irrigation wetlands MORE More Population Causes LESS

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 elderly population.

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)

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