1. Chapter 1 Key Themes in Environmental Sciences

2. Major Themes of Environmental Science Human population growth An urbanizing world Sustainability of our population and all of nature People and nature A global perspective Science and values

3. Human Population Growth The human population grew at a rate unprecedented in history in the twentieth century. Population growth is the underlying environmental problem. Famine is one of the things that happen when a human population exceeds its environmental resources. An example is African Famine.

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5. Human Population AD1- 100 million people 1960-3 billion people Today-7 billion people 2050-9 billion people

6. An Urban World When the impact of technology is combined with the impact of population, the impact on the environment is multiplied. In an increasingly urban world, we must focus much of our attention on the environments of cities and on the effects of cities on the rest of the environment.

7. Examples Urban sprawl takes over good agricultural land. Pavement Water recreation

8. Sustainability and Carrying Capacity What is the maximum number of people the Earth can sustain? Population increases due to – education and economics Population decreases due to – war, famine, disease and weather

9. Sustainability Sustainable resource harvest –An amount of a resource that can be harvested at regular intervals indefinitely Sustainable ecosystem –An ecosystem that is subject to some human use, but at a level that leads to no loss of species or of necessary ecosystem functions

10. What does this mean ?? Insuring that future generations have equal opportunity to the resources that we currently enjoy

11. Carrying Capacity Maximum # of individuals of a species that an ecosystem can carry – without – decreasing the ability for that ecosystem to carry the same amount in the future.

12. Science and Values To make decisions about an environmental problem we: –Know what is possible based on science –Choose the best option based on our values

13. Precautionary Principle Precautionary Principle states that we should not wait for scientific proof before taking action to prevent environmental damage. Global Warming ? Water Shortage ?

14. Assignment Read Pages 13 and 15 –Justifying the value of the Environment !! –List the justification and give an example for each –Read the “Critical Thinking” on page 14 Answer the question #1 and hand in for a classwork grade.