Warm Up• Which of the following are global

environmental problems Why?

• A. The growth of the human population

• B. The furbish lousewort, a small flowering plant found in the state of Maine

• C. The blue whale, listed as endangered by the US Marine Protection Act

• D. A car that has air conditioning.

Chapter 1

Key Themes in Environmental Sciences

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

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 takes place when a human population exceeds its environmental resources. An example is African Famine.

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© 2008 John Wiley and Sons Publishers

What inferences can be made from this graph?

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Population Explosion

The population bomb starts with “little sparks”. This shows 4 generations of the John Eli Miller family. He was an ordinary

American except that when he died he was head of the largest family in the U.S.

African Famine

• Drought in the 1970’s caused ~500,000 Africans to starve to death

• What are some causes for famine in Africa?

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An Urban World

• When the impact of technology is combined with the impact of population, the impact on the environment is multiplied.

What does this mean?

What can we do to manage our environmental impact?

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Some Thoughts

• 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.

WHY??????

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Sustainability and Carrying Capacity

• What is the maximum number of people the Earth can sustain?– Carrying Capacity: the max. number of

individuals of a species that can be sustained by the environment

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What does this graph tell us?

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Can you determine a “sustainable catch”

based on the information in this graph?

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

• What is needed to achieve this?

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Gaia Hypothesis

Initiated by Lovelock & Margulis

• Considers that the environment, at a global level, has been seriously changed by life over the history of the Earth & that these changes will most likely improve the chances for continued life.

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Science and Values

• To make decisions about an environmental problem we:

1. Know what is possible based on science

2. Choose the best option based on our values

How Do You Plan to Get Involved in Your Community?

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Precautionary Principle

• Precautionary Principle states that we should not wait for scientific proof before taking action to prevent environmental damage.

• Ex. San Francisco– “Megacities”

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What’s the VALUE of our environment?

• Utilitarian Justification – benefits individuals economically

• Ecological Justification – ecosystem is necessary for the survival of a species that interests us

• Aesthetic Justification – beauty of nature

• Moral Justification – aspects of environment have “right” to exist

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Any Questions?