1. The Human Population
Chapter 7

2. Earth’s Carrying Capacity
Every 5 days the global human population increases by roughly 1 million lives:
1.8 million infants born ,000 people die
What factors influence Earth’s carrying capacity for humans?
Food, water, timber, fuel, disease
Advances in technology
Will humans exceed Earth’s carrying capacity?
How do we know if we have?
What should we do about it?
What are the moral, religious, and personal freedom implications?

3. Where are we headed?
U.N. world population projection: based on women having an average of 2.5 (high), 2.0 (medium), or 1.5 (low) children

4. Factors that Drive Human population growth
Demography – the study of human population trends (demographer – scientists in this field)
Crude birth rate = number per 1,000 per year
Crude death rate = number per 1,000 per year
I = immigration (movement in)
E = emigration (movement out)
Global pop growth rate = CBR – CDR 10
Nation pop growth rate = [CBR + I] – [CDR + E]

5. Some comparisons
Average crude death (blue) and birth (yellow) rates for various groupings of countries in 2006

6. Doubling time The number of years it takes for a population to double
Assumes that the growth rate is constant
Formula called the rule of 70
Doubling time (in years) =
growth rate
Example:
Population growth rate of 2% will double in 35 years:
70/2 = 35

7. fertility Total fertility rate Replacement-level fertility
Estimate of the average number of children for each woman during her childbearing years
Not measured per 1,000 – is a measure per woman
In 2008 in the, U.S. TFR = 2.1
Replacement-level fertility
The TFR needed to offset the average number of deaths in a population so that the current population size remains stable
This number is typically just over 2
This also depends on rates of pre-reproductive mortality – death before a person has children – this depends on a country’s economic status

8. United states
birth rates in the u.s

9. Factors affecting birth rates
The cost of raising and educating children
Availability of pensions
Urbanization
Education and employment opportunities
Infant deaths
Marriage age
Availability of contraception and abortion
Religious beliefs, traditions, and cultural norms

10. Factors affecting death rates
Death rates have declined due to:
Increased food supplies and better nutrition
Advances in medicine
Improved sanitation and personal hygiene
Safer water supplies
U.S. infant mortality is higher than it could be (ranked 46th world-wide) due to:
Inadequate pre- and post-natal care for poor
Drug addiction
High teenage birth rate

11. Developed vs. developing countries
Developed countries – those with relatively high levels of industrialization and income
Example: U.S.
Typically have replacement-level fertility of 2.1
TFR = 2.1  population is stable
TFR < 2.1  population likely to decrease
TFR > 2.1  population likely to increase
Developing countries – those with relatively low levels of industrialization and incomes of < $3 per person per day
Example: India, China

12. Developing countries
China is the largest country – has taken drastic population control measures
By 2050 India is predicted to pass China. Pakistan is projected to become 3rd, with Iran and Ethiopia following
Russia is losing 600,000 people/year after being the 4th largest country in 1950 – due to environmental pollution, hyperinflation, crime, corruption, disease, despair

13. Efforts to slow population growth
Governments may try these tactics:
Raising taxes
Charging other fees
Eliminating income tax deductions for a couple’s third child
Loss of health-care benefits, food allotments, job options
In China, couples who pledge to have no more than one child receive:
Extra food
Larger pensions
Better housing
Free medical care
Salary bonuses
Free school tuition for their one child
Preferential treatment in employment when their child enters the job market

14. china Currently TFR = 1.6 Has moved 300 million people out of poverty
Problems:
Strong male preference has lead to gender imbalance
Average population age is increasing
Not enough resources to support current population

15. India Family planning program has basically failed due to:
Poor planning
Bureaucratic inefficiency
Low status of women
Extreme poverty
Lack of administrative financial support
Disagreement over the best ways to slow population growth

16. The best way to slow population growth
A combination approach works best:
Investing in family planning
Reducing poverty
Elevating the status of women – especially educational opportunities

17. Life expectancy
The average number of years an infant born in a particular year in a particular country can be expected to live – influenced by availability of health care, access to good nutrition, exposure to pollutants
Usually expressed in 3 ways:
Overall ( U.S. 78)
Men (2008 – U.S. 75)
Women (2008 – U.S. 81)
Men usually have higher death rates:
Biological factors, greater workplace dangers, more hazardous lifestyle choices, more likely to die in wars

18. Infant and child mortality
Infant – deaths under age 1 per 1,000 live births
Child – deaths under age 5 per 1,000 live births
Sometimes the overall rates for a country vary widely from those for a segment of the population:
Infant mortality in U.S. = 6.6
U.S. African Americans = 13.6
U.S. Native Americans = 8.1
Related to socioeconomic status and varying access to adequate nutrition and health care
An issue of environmental justice (Ch. 20)

19. Aging and disease
Disease is an important regulator of human population
Infectious disease are the 2nd biggest killer worldwide after heart disease
Tuberculosis and malaria have been biggest portion of this in the past
Today, HIV is #1
HIV disproportionately infects people age and so has a very disruptive impact on society

20. Age structure Visual representation of ages within a population
Males on one side, females on the other
Each bar = 5 year age group
Three categories:
Pyramid – larger younger group; population will continue to grow due to population momentum; typical of developing countries; Venezuela, India
Column – little differences in age groups; slow or no growth rate; U.S., Australia
Inverted pyramid – larger older group; population is actually in decline; Italy, Germany, Russia

21. Examples

22. Demographic transition
Four-phase process of population and economic development as a country moves from subsistence economy to industrialization
Phase 1 – pre-modernization; slow population growth rate
High death rates offset high birth rates
Phase 2 – beginning modernization; rapid population growth rate
Death rates decline due to better sanitation and health care but birth rate remains high
Phase 3 – stable population growth
Birth rate slows
Phase 4 – declining population
More elderly than young people

23. Population size and consumption
Ecological footprint – the amount of resources a person uses by eating, drinking, generating waste, and consuming products
1/5th of the human population lives in developed countries but they consume more than ½ of the world’s energy and resources
The U.S. has the largest ecological footprint of any country
IPAT equation – an estimate of impact of humans
Impact = population x affluence x technology

24. Comparison of footprints

25. What goes into this?

26. sustainability
Meeting the essential needs of people in the present without compromising the ability of future generations to meet their needs
Strives to improve standards of living without causing additional environmental harm
How? Some ideas:
Slower human population growth
Understanding of the connections between economic growth and environmental challenges
This is a very important APES concept! Make sure you ‘get’ it!