ES101 Lecture Notes - Lecture 13: Aluminium Recycling, Null Hypothesis, Negative Feedback
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”
find more resources at oneclass.com
find more resources at oneclass.com
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
find more resources at oneclass.com
find more resources at oneclass.com
● 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
find more resources at oneclass.com
find more resources at oneclass.com
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.