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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What inferences can be made
from this graph?
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© 2008 John Wiley and Sons Publishers
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?
Can you determine a
“sustainable catch”
based on the information
in this graph?
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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?