ES101 Lecture Notes - Lecture 13: Aluminium Recycling, Null Hypothesis, Negative Feedback

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13 Jun 2018
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Week 3 Lecture 1: Scientific Method, Matter, Flashback to Grade 9 Science
Black Swans
Until 1790 it was a scientific fact that all swans were white
All swans previously observed by europeans were white
Then australia was “discovered” by europeans, and in australia there are black swans
Black Swans as a Metaphor
Nassim Nicholas Taleb's 2007 book The Black Swan: The Impact of the Highly
Improbable
Argues that people, including scientific experts, are easily fooled by what they observe
Systems are much more complex than we can fathom, so we must be prepared to deal
with the unpredictable
Turkey example: from the day they hatch, domesticated turkeys are raised to be killed
and eaten, we know this, turkey probably does not… from the turkeys lifelong
observations, human provide all the food, water and shelter a turkey could want, turkeys
therefore might assume that humans are friendly and nice, then thanksgiving comes and
the turkey experiences its “black swan” moment
What black swan tells us; limits to deductive reasoning, must do our best to
understand complexity of systems and way they operate, all complex systems
contain unintended and unknown behaviours and outcome… being prepared for
unknown system outcomes turns them from unwelcome shocks into something
manageable, many environmental challenges occur because we act like turkeys
Science
Attempts to understand world around us thru careful observation
Seek out patterns that indicate some order or logic to how things work
Deductive reasoning: all birds have feathers; dodos were birds; thus dodos had feathers
Inductive reasoning: the dodos closest living relatives eat crabs and shellfish, therefore
dodos likely did too
A sample scientific approach
Come up with hypothesis: wind turbines have a negative effect on the health of people
who live nearby
Now reverse it: wind turbines have no negative health effect on people who live nearby
(null hypothesis)
Then go collect data in a systematic fashion
Analyze data
Have you found any data that contradicts the null hypothesis?
If yes, you might be onto something, should pursue further research using other
methods
If not, may still be onto something, but you must say “there is no evidence for the
hypothesis that wind turbines have a negative effect on the health of people who live
nearby”
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Challenges in environmental studies
Scale of phenomena
Complexity of phenomena
Timeframes over which processes function
Bias, ignorance of people about environment (these notes are in week 1)
Systems approach
In this course, enviro problems will be treated as outcomes of complex, interconnected
human and natural systems
System: a set of things that function and interact in a regular and understandable way
Key elements are inputs, throughputs, and outputs
Systems
In you understand present behaviour of a system, can begin to predict what might
happen if changes occur in some part of it
Enviro systems always changing, as are human socio economic and cultural systems
Nitrogen cycle pics (check for clearer picture on myls)
*natural system that functioned on its own, humans came along and caused feedback effects
Common properties of complex systems
Feedback loops: altering one component of system affects other components
Positive feedback: causes system to do more of the same (air warms, snow melts,
exposed surface warms faster than before)
Negative feedback: causes system to do less of the same (aluminum recycling)
Throughput speed and response times are variable
Example: deer and roadways, human enviro systems interaction
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Some actions trigger immediate outcomes (deer on highway, deer either struck or
avoided)
Other outcomes have long lag times (after multiple deer collisions, highway managers
may post a warning sign, after a great many collisions, a wildlife underpass may be built
Possibility of synergies: when interactions lead to outcomes that are greater
than/different from the sum of the inputs
E.g. aids treatment, patients with hiv/aids often treated with cocktail of drugs that
have greater benefits taken together than when taken separately
Back to black swans
If you understand how complex systems function, you can be prepared for black swans
Avoid harmful destructive black swans (enviro impacts of DDT) and watch for beneficial
ones
Aids cocktail is beneficial black swan; that is, each individual drug when tested alone
produced disappointing results, but pleasant surprise to find particular combos worked
synergistically
Moral; understanding system complexity encourages you to be on lookout for
good synergy
Matter
Anything that has mass and takes up space
Made of atoms, molecules, and ions
Atoms like lego blocks, molecules like lego blocks together
Atoms are like lego
Can arrange them together in variety of ways
Certain ways you can fit them together, certain ways you cannot
When you disassemble something made of lego, you do not destroy the lego blocks
themselves
Not all atoms are alike
Number of protons, neutrons, electrons varies from one element or type of atom to
another
Number of protons and electrons usually same
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Document Summary

Week 3 lecture 1: scientific method, matter, flashback to grade 9 science. Until 1790 it was a scientific fact that all swans were white. All swans previously observed by europeans were white. Then australia was discovered by europeans, and in australia there are black swans. Nassim nicholas taleb"s 2007 book the black swan: the impact of the highly. Argues that people, including scientific experts, are easily fooled by what they observe. Systems are much more complex than we can fathom, so we must be prepared to deal with the unpredictable. Attempts to understand world around us thru careful observation. Seek out patterns that indicate some order or logic to how things work. Deductive reasoning: all birds have feathers; dodos were birds; thus dodos had feathers. Inductive reasoning: the dodos closest living relatives eat crabs and shellfish, therefore dodos likely did too. Come up with hypothesis: wind turbines have a negative effect on the health of people who live nearby.

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