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
