1. Chapter 1 Introducing Environmental Science and Stability

2. Overview of Chapter 1 Human Impacts on The Environment
Population, Resources and the Environment
Environmental Sustainability
Environmental Science
Assessing Environmental Problems

3. The Environment (Earth)
Life has existed on earth for 3.8 billion years
Earth well suited for life
Water covers ¾ of planet
Habitable temperature
Moderate sunlight
Atmosphere provides oxygen and carbon dioxide
Soil provides essential minerals for plants
But humans are altering the planet; not always in positive ways

4. Human Impacts on Environment- Population
Earth’s Human Population is over 7 billion
Growing exponentially
Expected to add several billion more people in 21st century
Increase will adversely affect living conditions in many areas of the world

5. What does this say about the growth rate?
Where does the population growth start to stabilize?

6. Population Globally, 1 in 5 people lives in extreme poverty
Cannot meet basic need for food, clothing, shelter, health
Difficult to meet population needs without exploiting earth’s resources
$2/day

7. Gap Between Rich and Poor
Highly Developed Countries (HDC)
Complex industrialized bases, low population growth, high per capita incomes
Ex: US, Canada, Japan, England
Less Developed Countries (LDC)
Low level of industrialization, very high fertility rate, high infant mortality rate, low per capita income
Ex: Bangladesh, Mali, Ethiopia

9. Types of Natural Resources

10. Overpopulation People overpopulation Consumption overpopulation
Too many people in a given
geographic area
Problem in many developing
nations
Consumption overpopulation
Each individual in a population consumes too large a share of the resources
Problem in many highly developed nations

11. Ecological Footprint Mathis Wackernagel
The average amount of land, water and ocean required to provide that person with all the resources they consume
Earth’s Productive Land and Water
11.4 billion hectares
Amount Each Person is Allotted (divide Productive Land and Water by Human Population)
1.6 hectares
Current Global Ecological Footprint of each person
2.3 hectares

12. Ecological Footprint Comparison

13. Environmental effect of technologies
IPAT Model
Measures 3 factors that affect environmental impact (I)
I = P A T
Environmental Impact
Number of people
Affluence per person
Environmental effect of technologies

14. Environmental Sustainability
The ability to meet current human need for natural resources without compromising the needs of future generations
Requires understanding:
The effects of our actions on the earth
That earth’s resources are not infinite

15. Tragedy of the Commons Garrett Hardin (1915-2003)
Solving Environmental Problems is result of struggle between:
Short term welfare
Long term environmental stability and societal welfare
Garrett used Common Pastureland in medieval Europe to illustrate the struggle

16. Sustainable Development
Economic development that meets the needs of the present generation without compromising future generations

17. Environmental Science
An interdisciplinary study of human relationship with other organisms and the earth
Biology
Ecology
Geography
Chemistry
Geology
Physics
Economics
Sociology
Demography
politics

18. Earth As a System System Global Earth Systems Ecosystem
A set of components that interact and function as a whole
Global Earth Systems
Climate, atmosphere, land, coastal zones, ocean
Ecosystem
A natural system consisting of a community of organisms and its physical environment
System approach to environmental science
Helps us understand how human activities effect global environmental parameters

19. Earth Systems
Most of earth’s systems are in dynamic equilibrium or steady state
Rate of change in one direction equals that in the other
Feedback
Change in 1 part of system leads to change in another
Negative feedback- change triggers a response that counteracts the changed condition
Positive feedback- change triggers a response that intensifies the changing condition

20. Scientific Method

21. Controls and Variables in Experiment
A factor that influences a process
The variable may be altered in an experiment to see its effect on the outcome
Control
The variable is not altered
Allows for comparison between the altered variable test and the unaltered variable test

22. Inductive and Deductive Reasoning
Inductive Reasoning
Used to discover general principles
Seeks a unifying explanation for all the data available
Ex:
FACT: Gold is a metal heavier than water
FACT: Iron is metal heavier than water
FACT: Silver is a metal heavier than water
CONCLUSION (based on inductive reasoning): All metals are heavier than water
Conclusions reached with inductive reasoning may change with new information

23. Inductive and Deductive Reasoning
Proceeds from generalities to specifics
Adds nothing new to knowledge, but makes relationships among data more apparent
Ex:
GENERAL RULE: All birds have wings
SPECIFIC EXAMPLE: Robins are birds
CONCLUSION (based on deductive reasoning): All Robins have wings

24. Five Stages to Addressing An Environmental Problem
Five steps are idealistic
Real life is rarely so neat
The following slides illustrate a Case Study using the Five Stages

26. Assessing Environmental Problem Case Study: Lake Washington
Large, freshwater pond
Suburban sprawl in 1940’s
10 new sewage treatment plants dumped effluent into lake
Effect = excessive cyanobacteria growth that killed off fish and aquatic life

27. Assessing Environmental Problem Case Study: Lake Washington
Scientific Assessment
Aquatic wildlife assessment done in 1933 was compared to the 1950 assessment
Hypothesized treated sewage was introducing high nutrients causing growth of cyanobacteria
Risk Analysis
After analyzing many choices, chose new location (freshwater) and greater treatment for sewage to decrease nutrients in effluent

28. Assessing Environmental Problem Case Study: Lake Washington
Public Education/Involvement
Educated public on why changes were necessary
Political Action
Difficult to organize sewage disposal in so many municipalities
Changes were not made until 1963!
Evaluation
Cyanobacteria slowly decreased until 1975 (gone)

29. Assessing Environmental Problem Case Study: Lake Washington
Results!