Apes ch 6
Key Concepts
Factors affecting human population size
Human population problems
Managing population growth
Core Case Study: Are There Too
Many of Us?
Estimated 2.4 billion more people by 2050
Are there too many people already?
Will technological advances overcome environmental resistance that populations face?
Should populations be controlled?
Core Case Study: Are There Too
Many of Us?
Will growing populations cause increased environmental stresses?
Infectious diseases
Biodiversity losses
Water shortages
Traffic congestion
Pollution of the seas
Climate change
Factors Affecting Human Population Size
Population change equation
Population change = (Births + Immigration) – (Deaths + Emigration)
Crude birth rate (BR): # live birth / 1000 / year
Crude death rate (DR) # deaths / 1000 / year
Human Population Growth Continues but It Is Unevenly Distributed
Reasons for human population increase
Movement into new habitats and climate zones
Early and modern agriculture methods
Control of infectious diseases through
Sanitation systems
Antibiotics
Vaccines
Human Population Growth Continues but It Is Unevenly Distributed
Population growth in developing countries is increasing 15 times faster than developed countries
By 2050, 97% of growth will be in developing countries
Should the optimum sustainable population be based on cultural carrying capacity?
Science Focus: How Long Can the Human Population Keep Growing?
Thomas Malthus and population growth: 1798
Humans have altered 83% of the earth’s land surface
Can the human population grow indefinitely?
World Population Growth
Overall population growth has slowed from 2.2% to 1.25%
Death rate has fallen more than birth rate
~ 219,000 new people per day
97% in developing nations
China: 1.3 billion people (20%)
India: 1.1 billion people (17%)
U.S.A.: 294 million people (4.6%)
Describing Population Changes
Doubling Times (Rule of 70): 70 / % growth rate = doubling time in years
Africa’s growth rate is 2.8%, how long will it take to double the population?
Fertility Rate
Fertility: The # of births that occur to an individual or population
Replacement-level Fertility: The number of children a couple must have to replace themselves (2.1
developed nations, 2.5 in developing nations)
Total Fertility Rate (TFR): The average # of children a woman has during her reproductive years
U.S. Population Growth
U.S. population has grown from 76 mil. In 1900 to 294 mil. in 2004
“Baby Boom”: 1946-1964 79 mil., TFR=3.7
Since 1972 growth rate is at or below replacement level but population is growing faster than any other
developed nation
Why?
Factors Affecting Birth Rates & TFR
Children in Labor Force
Cost of raising and educating children
Availability of pension systems
Urbanization
Education and employment for women
Infant mortality rate
Average marrying age
Abortion
Availability of birth control
Factors Affecting Death Rates
Life expectancy: The average number of years an infant can be expected to live
76 years in developed nations
65 years in developing nations
U.S. projection for 2050 is 82 years
Infant mortality rate (IMR): The number of children who die before their first birthday
7 per 1000 in developed nations
61 per 1000 in developing nations
Immigration
Only Canada, Australia and U.S. encourage immigration
Since 1820 the U.S. has admitted ~ twice as many immigrants as the rest of the world combined
1820-1960: Most U.S. immigrants from Europe
1960-present: Most immigrants form Latin America (51%), and Asia (30%)
~8-10 million illegal immigrants in U.S.
Populations Made Up of Mostly Older People Can Decline Rapidly
Slow decline
Manageable
Rapid decline
Severe economic problems
Severe social problems
Populations Can Decline from a Rising Death Rate: The AIDS Tragedy
25 million killed by 2008
Many young adults die: loss of most productive workers
Sharp drop in life expectancy
International community called upon to
Reduce the spread of HIV through education and health care
Financial assistance and volunteers
Demographic Transition
Demographic transition: four stage transition as nations become industrialized
Preindustrial: Little pop. change, high birth rate & high death rate
Transitional: Industrialization begins, death rate drops but birth rate remain high
Industrial: birth rate drops and eventually reaches death rate, population still grows
Postindustrial: Birth rate less than death rate and population decreases
Solutions: Influencing
Population Size
Migration
Environmental refugees
Reducing births
Family planning
Empowerment of women
Economic rewards and penalties
Case Study: Slowing Population Growth in India
Generally disappointing results:
Poor planning
Bureaucratic inefficiency
Low status of women
Extreme poverty
Lack of support
Case Study: Slowing Population Growth in China
Economic incentives
Free medical care
Preferential treatment
Locally administered
Very intrusive and coercive
Cutting Global Population Growth
Family planning
Improve health care
Elevate the status of women
Increase education
Involve men in parenting
Reduce poverty
Sustainability
Planning for Babies Works
Family Planning
Responsible for a 55% drop in TFRs
In developing countries
Expansion of program
Include teenagers, sexually active unmarried women, and men
Slow and stabilize population growth
Invest in family planning
Reduce poverty
Elevate the social and economic status of women
Empowering Women Can Slow Population Growth
Education
Paying jobs
Human rights without suppression
“For poor women the only holiday is when you are asleep”