The Nature of Environmental Science

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The Nature of Environmental Science

• How we learn about our world and understand the
  effects that we have on it

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What is The Environment The sum total of our
surroundings, biotic and abioticfor example

• Abiotic Physical
• heat
• light
• gravity

• Biotic
• plants
• animals
• bacteria
• fungi

• Abiotic Chemical
• oxygen
• water
• nutrients

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How do we use our environment?Extractive Uses

• Renewable
• Food
• Water
• Forest products
• Renewable energy
• Solar
• Wind
• Hydro

• Non-Renewable
• Fossil fuels
• Minerals

Whether a resource is sustainable or not is a
matter of how fast it is used and how fast it is
renewed.
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Renewable or non-renewable?
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Renewable or non-renewable?
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World population growth
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Impact of Population

• The other half of the equation is the standard
  of living.
• Energy use per capita
• Land use per capita

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Resource Management
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The Tragedy of the Commons
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The Tragedy of the Commons

• A cautionary tale.
• Need for controls.
• Shows how public resources can be misused.
• An example of problem solving involving resource
  use.
• How do you prevent overuse?
• Private ownership?
• Central control?
• Collective decision-making?
• New technology?

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Case Study Easter Island

• Mystery of the Sentinels of Rapa Nui
• Discovered by Europeans in 1722
• Small population, about 2000
•  Isolated island / now seaworthy craft
•  Low technology
•  No trees
•  Evidence of a larger complex society
• Large Moai all tipped over

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Small island in the Southeast Pacific
ocean About 3000 km from the Coast of
Chile
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Case Study Easter Island

• We know the island was first inhabited from
  Polynesia sometime between 400 to 900 AD
• What was the island like before people appeared?

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How do they know what the island was like in 400
AD?

• Each year, pollen from all the plants on the
  island falls into the 3 lakes on the island

Pollen will sink and become trapped in the mud
at the bottom of the lake
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Mud from the bottom of the lake can be removed in
chronological order.
It is possible to determine the age of each layer
of mud
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Pollen grains from different plants are different
shapes
Can be used to reconstruct past plant communities
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What was the environment like on Easter island
before humans arrived?
Abiotic factors Temperate climate (not
tropical, at times cool, dry, windy) Fairly
fertile volcanic soil, though with a lot of
rocks modest rainfall, but subject to
droughts Freshwater available (springs, hard to
access lakes, rain, intermittent streams) Cool
ocean with high cliffs, no coral reefs Biotic
factors Widespread pine and palm forests No
land mammals modest sea bird populations Ocean
relatively poor in fish due to lack of reefs or
other nurseries for spawn
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By the time the Europeans arrived, the island
had changed
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The island was barren of trees Due to Harvesting
for human uses Fuel, boats, moai work, etc And
rats eating the seeds, preventing reproduction
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The effect of deforestation

• Soils were washed away
• Surface water streams dried up
• Wood was no longer available for human use

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The trees were gone by the 15th century, so it
was then more difficult to grow
crops impossible to build canoes for
fishing, And as a result, the carrying capacity
of the island to support humans
decreased Intense clan warfare, cannibalism
became common Size of human population falls to
2,000 by 1722, collapse of their civilization