How much should it cost?

Rank the following items in order of their
importance to you. Then, next to each item,
write down how much you would be willing to
pay for it.
Fresh, clean drinking water
 Clean air to breathe
 An endangered plant containing a substance that can
cure cancer
 Gas for your family car

What Is Environmental
Science?
What do you think this class will be
about?
What will you learn?
What do you want to learn?
Environmental Science

The study of how we and other species interact
with one another & with the nonliving
environment (matter & energy)

Includes:

Physics, chemistry, biology, ecology, geology,
meteorology, geography, resource technology,
engineering, resource conservation &
management, demography, economics, politics,
sociology, psychology, ethics
The environment is
difficult!
The environment is difficult to study
because…

A hypothesis must be testable

VARIABLES must be controlled and isolated

Too many interactions – known & unknown
More problems

Scale is often a problem
Populations over time
 Environmental factors over centuries


Measurement is difficult

Species, pollutants, tons of soil
We do our best…

At best, we provide trends & estimates
 Rely on models

Correlations

Example: BPA findings (1:34)
http://www.npr.org/templates/story/story.php?storyId=94699105
Models


A representation or simulation of a system
being studied
Can be mental, physical, graphical,
mathematical, conceptual
Correlation

Relationship between two separate events

More CO2 and higher global temperatures
Correlation DOES NOT mean
causation…

More lemons imported causes more traffic accidents?
SYSTEMS & FEEDBACK LOOPS
System Vocabulary
• INPUT
 matter, energy, information entering a system
• THROUGHPUT
 rate flow of matter, energy, or information
through a system
• OUTPUT
 matter, energy, information leaving a system
Stuff goes in
Stuff is
processed
Stuff comes
out
Input  Throughput  Output
FEEDBACK LOOPS
Change induces change
Feedback Loop
Stuff goes in
Stuff is
processed
Stuff comes
out
Negative Feedback Loops
• The change counteracts the
situation
Examples:
What happens when you’re hot?
What happens when you’re cold?
Positive feedback Loops
• The change compounds the
situation = Snowball Effect!
Example:
As long as there are more human births than
deaths, population will continue to
increase.
Pesticides:
Urban Sprawl
Positive or Negative
• 1 person in a group of 10 has cold.
• That person passed the cold to another
and soon 5 people now have the cold.
• Those 5 students then each pass the cold
to another.
Feedback Loops in Context
Global warming hypothesizes that
the average temperature of Earth
is increasing. During analysis,
scientists have identified possible
positive and negative feedback
loops to explain atmospheric
climate change.
• http://science.howstuffworks.com/global-warming.htm
Radiation and Reflection
Positive or Negative?
• The warming of the oceans causes
dissolved CO2 to bubble out into the
atmosphere. This atmospheric CO2 helps
to trap heat near the earth. This trapped
heat continues to warm the ocean.
Positive or Negative?
• Warmer water temperatures cause greater
water evaporation, which increases the
formations of clouds. A lot of water vapor
in the air also traps heat inside the
atmosphere.
Positive or Negative?
• The increased cloud cover from example 2
might also act to reflect sunlight back into
space, preventing it from entering our
atmosphere. This might cool the earth.
Positive or Negative?
• Sunlight striking the earth is absorbed by
dark colors and reflected by light colors.
The polar ice caps act like huge mirrors,
reflecting sunlight back into space.
Warmer water temperatures are melting
these ice caps and decreasing these big
“mirrors,” leaving dark water behind.
Positive or Negative?
• Warmer temperatures cause greater water
evaporation, which falls to earth as
precipitation. Therefore global warming
may cause increased snow fall in the polar
regions, leading to increased ice
formation.
How did you do?
• 1. Positive
• 2. Positive
• 3. Negative
• 4. Positive
• 5. Negative
Contemplate this…
• What would Earth look like if there weren't
any greenhouse effect at all?
• It would probably look a lot like Mars.
• Mars doesn't have a thick enough
atmosphere to reflect enough heat back to
the planet, so it gets very cold there.
Hmmmmm….
• Some scientists have suggested that we
could terraform the surface of Mars by
sending "factories" that would spew water
vapor and carbon dioxide into the air.
• If enough material could be generated, the
atmosphere might start to thicken enough
to retain more heat and allow plants to live
on the surface.
Just like early Earth…
• Once plants spread across Mars, they
would start producing oxygen.
• After a few hundred or thousand years,
Mars might actually have an environment
that humans could simply walk around in
-- all thanks to the greenhouse effect.