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EESA01H3 Study Guide - Soil Retrogression And Degradation, Aeration, Particulates


Department
Environmental Science
Course Code
EESA01H3
Professor
Carl Mitchell

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EESA01 Lecture 1 Chapter 1 (both text books)10/26/2012
1:56:00 PM
An Introduction to Environmental Science
Our Environment is more than just our surroundings
Environment : sum total of our surroundings all biotic and abiotic components with which we interact
Environmental Science study of how our natural world works, how our environment affects us and how we affect
the environment
Natural resources are vital to our survival
Natural resources: various substances and energy sources we need to survive
Renewable: natural resources which are replenishable over time sunlight, wind, wave energy
Some resources such as agricultural crops, fresh water, forest products and soils are renewable if used
properly if over-used then they become nonrenewable resources
Resource management: planning on how to use a resource in such a way that we are still protecting and
preserving it
Stock is the harvestable portion of the resource if resources are being withdrawn from the stock at
higher rates than it is being replenished, then the stock will eventually be depleted
Non-renewable : in finite supply and are depleatable fossil fuels, mineral deposits, natural gas etc.
They are deplated because they are formed much more slowly than we use them 100 million years for
natural geological processes to form an ore deposit or a petroleum deposit
Tragedy of Commons and Carrying Capacity
Earth’s carrying capacity is between 10 million and 33 billion
Carrying capacity: the ability of a system to support life number of individuals of a certain species that
can be sustained by biological productivity of a certain area of land
When carrying capacity of the system is exceeded either population will decline or collapse or the system
itself will be altered, damaged or depleted
Once carrying capacity is reached, the amount of births = amount of death that occur per year
Tragedy of the commons concept proposed by Garret Hardin in 1968
Unregulated exploitation leads to resource depletion
Resource users are tempted to increase use (people use the resources as much and as quickly as they
can) until the resource is gone
Is this still the basis for ongoing environmental issues?

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Can we do anything about it?
In some countries like China, private land ownerships has been introduced people tend to take more
care of their land when it is theirs, so they will make better decisions when it comes to using its resources
In other cases people who share a part of land get together to enforce its responsible use
In other cases government regulation may be required
Each approach has its own strengths and weaknesses
Ecological Footprint
Ecological footpring is a tool that can be used to express the environmental impact of an individual or the
population
Calculated in terms of land and water needed to provide the raw materials that the person or population
consumes and to absorb or recycle the wastes produced
Essentially the inverse of carrying capacity
Some nations have smaller ecological footprints than other
Canada’s ecological footprint is of 7.6 ha which is lower than the US (9.6ha) but a lot higher than India
(0.8ha)
Biocapacity: capacity of a system to be biologically productive and to absorb waste (especially CO2)
Our species is not using 39% more resources than are available using resources 39% faster than they
are replenished
Right now we would need 1.4 worlds to sustain all people we are already over
If everyone lived like Canadians, we would need 4 planets to survive
Rapa Nui (Easter Island)
Discovered by Europeans in 1722 had population of less than 2000 that basically lived in caves
The presence of intricate and huge statues suggested that a sophisticated civillzation once lived there
The island was once lushly forested supporting 6000-30000 individuals
Civilaztion over-used the resources of the islands and cut down all the trees
This caused starvation and conflict which eventually destroyed the once flourishing population
21 species of plants (including trees) which were once common on the island are now extinct
with the trees gone, soil eroded away which degraded agricultural lands less crops = less food =
starvation for the people
and faster runoff of water meant less available freshwater for drinking
6 species of land birds and 25 species of seabirds were eaten by the people today no native land birds
are left and only 1 species of sea birds
with the trees gone they could not build canoes to fish, so they could not get food that way and feed on
seafood
without any resources left, the islandars fell to war with each other and killed each other for what was left
of any resources population eventually died off

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Environmental Science is an interdisciplinary pursuit
Environmental science is an interdisciplinary field employs concepts and techniques from numerous
disciplines and brings research results from these disciplines together into a broad synthesis
The Base Cause of Environmental Degradation
His opinion: the environmental issues that we face today are due to a combination of world population
growth and consumption (energy) far above what can easily be replaced or supported and a general
ignorance to recognize this for what it’s true value is i.e there are too many of us, and we use too much
but we are ignorant of the fact
Environmental Scientist vs. Environmentalist
a scientist is not necessarily and environmentalist (who has a biased view about the environment) AND an
environmentalist does not need to be an environmental scientist
Environmentalism: social movement dedicated to protecting the natural world from undesirable changes
brought about by human choices
The Nature of Science
Science is the systematic process for learning about the world and testing our understanding of it
How does Science work?
Science is curiosity focused towards a question that scientific method can help to inform
The scientific method is a set of rules which prescribe how to derive knowledge of a particular kind
certified, validatable knowledge
Using the scientific method one cannot show that a theory is right, only that it is not wrong
Any notion of the world (theory) is only not wrong until scrutiny reveals it to be incomplete any theory
is good until the first piece of info is gained which the theory cannot accommodate (example: evolution,
sun at the center of the Earth etc.)
Our science based understanding of the universe is always changing because of doubt, scrutiny and the
acquisition of new information doubt and questioning lead to better understanding
There is no absolute truth in science, but we do have laws a natural phenomenon that has been proven
to occur invariably whenever certain conditions are met
Scientific Method
Observations question hypothesis predictions test results
If results reject the hypothesis (hypothesis is wrong), then you must go back and make new hypothesis
and re-do everything again
An experiment involves manipulating variables scientist manipulates the independent variable while
keeping the dependant variable constant
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