Applying Population Ecology: The
Human Population
Chapter 5
Applying the principles of population dynamics and
sustainability to the growth of the human population
Current Population Trends
•
•
•
•
•
World population = 6.4 billion (6,400,000) in 2004
Doubled since 1963 = 3.2 billion
In 2050 could be 7.2 – 10.6 billion
Amplifies all environmental problems
Largest increase expected in developing countries
(approximately 97%)
• Decreasing in some developed countries
• Rate actually decreased between 1963-2004, but the
population has still doubled from 3.2 –6.4 billion
Rate = 80 million new people/year
+ New York City every month
+ Germany every year
+ United States every 3.7 years
Washington State Population
8000000
7000000
6000000
5000000
4000000
3000000
2000000
1000000
18
60
19
20
19
53
19
73
20
00
20
20
20
40
20
60
0
Population projections
For the next 20 years
Factors Affecting Human Population Size
Population change equation
Population change = (Births + Immigration) –
(Deaths + Emigration)
Crude birth rate = births per 1000 people in
population per year
Crude death rate = deaths per 1000 people in
population per year
• Total Fertility Rate (TFR) - Number of children
a woman has during her lifetime, averaged
for population.
• same as biotic potential (r)
• Replacement Level Fertility - Number of
children needed to replace everyone in the
population.
• Varies between regions
• 2.1 with low infant mortality
• 2.5 with high infant mortality
• Zero Population Growth - Birth rate equals
death rate.
Sex Ratio - Age Distribution
• Sex Ratio- Relative number of males and
females in a population
• Age Distribution - Number of individuals of
each age in a population
• Together they tell how a population will grow
Population Age Structure
Developing Countries Developed
Countries
Growth is determined by teenagers – the population wave of
the future. 30% of pop’n <15 years = 1.9 billion more into
reproductive years.
Population Trend Comparisons
Developed Countries
•
•
•
•
•
•
Low infant mortality rate
Life expectancy 77 years
Total fertility rate = 2.0
21% population <15
12% population >65
Per capita GDP = $36,110
Developing Countries
•
•
•
•
•
•
High infant mortality rate
Life expectancy 52 years
Total fertility rate = 5.7
44% population <15
3% population >65
Per capita GDP = $800
Human Population Issue
• Several factors determine the impact of a society
on natural resources.
• Population size
• Population density
• Degree of technological development
• Demography - Study of populations and their
characteristics.
• Larger ecological footprint in U.S. than in
developing countries. Why?
Environmental Impact
The fertility rates
have significantly
fallen since 1950.
Factors Affecting Birth Rates and Total Fertility
Rates
•
•
•
•
•
•
•
•
•
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
Major social factor determining family size is
the role of women in society.
• Early marriages foster high fertility rates.
• Lack of education opportunities for women
reduces their options.
• When level of education increases, fertility
rates fall.
• The most important factor is the ability of
women to control the size of their family.
• Access to birth control is key.
United States Population Picture
• US population has a post-war baby boom
period, significantly affecting pop. trends.
• 20 yr period following WWII
• By 2030, 20% of US pop will be over
65
U.S. Birth Rates: 1910-2004
US Immigration rates
Immigration accounts for 41% of pop’n growth in the U.S.
Should we have tougher immigration laws to help preserve our
natural resources?
Demographic Transition
As countries become industrialized, death rates, then birth
rates decline.
Case Study: Slowing Population Growth
in India
• Generally disappointing results
• 1952 – 400 million
• 2004 – 1.2 billion
•
•
•
•
•
•
Poor planning
Bureaucratic inefficiency
Low status of women
Extreme poverty
Lack of support
Culture – Indian women believe you need children
to work, care for when they are old.
Case Study: Slowing Population Growth
in China
• Economic incentives (food, large pensions, better
housing, salary bonuses, free schooling)
• Free medical care
• Free sterilization
• Locally administered
• Very intrusive and coercive
• Problem with parents selecting for males
• Fertility rate decreased from 5.7 in 1972 to 1.7 in
2004.
Cutting Global Population Growth
•
•
•
•
•
•
•
Family planning
Improve health care
Elevate the status of women
Increase education
Involve men in parenting
Reduce poverty
Sustainability
Global Megacities
Number of large cities growing. World’s urban population will
increase from 3.1 billion to 5 billion from 2004-2030.
US metropolitan areas
Undesirable Impacts of Urban Sprawl
Loss of crop land, forest
land, and wetlands
Fragmenting fish and wildlife habitats
Increased impervious surfaces means more flooding
And soil erosion
And a larger ecological footprint
Beneficial is all a matter of one’s
perspective…..
Urban Land-Use Planning and Control
•
•
•
•
•
•
Land-use planning
Property taxes
Zoning
Smart growth
Urban growth boundary
Greenbelts
Growth Management Act
1990
• The GMA requires state and local governments to
manage Washington’s growth by identifying and
protecting critical areas and natural resource lands,
designating urban growth areas, preparing
comprehensive plans and implementing them through
capital investments and development regulations.
• GMA is passed to help protect areas critical for natural
resources by concentrating growth in urban areas
Public voices concerns at GMA hearing Sounding off: Land division and road upgrades
among issues addressed at four-hour hearing
Transportation
• Mass transit vs. automobile
• What makes one or the other feasible?
• Why is most of the US developed around
cars? When did it happen?
• Where does mass transit work?
• What are the pros and cons to each?