Chapter 1 Introducing Environmental Science and Stability

1. Chapter 1Introducing 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 6 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. Population • Globally, 1 in 4 people lives in extreme poverty • Cannot meet basic need for food, clothing, shelter, health • Difficult to meet population needs without exploiting earth’s resources

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

7. Types of Natural Resources

8. Overpopulation • People 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

9. Ecological Footprint • The average amount of land, water and ocean required to provide that person with all the resources they consume

10. Ecological Footprint Comparison

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

12. 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

13. 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

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

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

16. Earth As a System • System • 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

17. 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

18. Scientific Method

19. Controls and Variables in Experiment • Variable • 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

20. 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 changed with new information

21. Inductive and Deductive Reasoning • 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

22. Five Stages to Addressing An Environmental Problem • Five steps are idealistic • Real life is rarely so neat • Following Slides are Case Study Using the Five Stages

23. Assessing Environmental ProblemCase 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

24. Assessing Environmental ProblemCase 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

25. Assessing Environmental ProblemCase 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)

26. Assessing Environmental ProblemCase Study: Lake Washington • Results!