1. Key Themes in Environmental Sciences
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.
What are some examples of how a growing human population affects the environment?

4. Population change since 1950 projected to the year 2150 for major areas of the world, medium fertility scenario. The population of Africa will nearly quadruple. The only major area whose population is projected to drop over time is Europe – from 728 million to 595 million, a decline of 18% over 155 years.
© 2008 John Wiley and Sons Publishers

5. Human Population AD1 - 100 million people 1960 - 3 billion people
Today - 7 billion people
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 Sustainable ecosystem
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.