Overview%20of%20355%20Themes%20and%20Concepts

1
Overview of 355 Themes and Concepts

• Environmental Problems are generally characterize
  by noisy and ambiguous data.
• Understanding errors and data reliability/bias is
  key to implementing good policy
• Making a model of the data is an advanced
  technique that is sorely needed in this field

2
Goals of this Course

• To gain practice in how to frame a problem
• To practice making toy models of various data
  waveforms
• To understand the purpose of making a model
• To understand the limitations of modeling and
  that models differ mostly in the precision of
  predictions made
• Provide you with a mini tool kit for analysis

3
Sequence for Environmental Data Analysis

• Conceptualization of the problem ? which data is
  most important to obtain how to obtain a
  random/representative data set?
• Methods and limitations of data collection ? know
  your biases (e.g. Sunshine Moonbeam)
• Presentation of Results gt data organization and
  reduction data visualization statistical
  analysis
• Compare different models

4
Statistical Distributions

• Why are they useful?
• How to construct a frequency distribution and/or
  a histogram of events.
• Frequencies are probabilities
• How the law of large numbers manifests itself ?
  central limit theorem random walk expectation
  values

5
Statistical Distributions
Mapping dispersion units into probabilities of an
event occurring
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Some Tools

• Linear Regression ? predictive power lies in
  scatter the r value is unimportant for
  scientific analysis
• Slope errors (cell C18 in Excel) are important
  and must be factored in to determine the total
  uncertainty of your prediction
• Identify anomalous points by sigma clipping (/-
  1.8 s (1-cycle)

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More Tools

• Chi square test measures goodness of fit
• Understand how to determine your expected
  frequencies
• Chi square minimization used to find best fitting
  model
• Chi square statistic used to accept or reject the
  null hypothesis (that the data is consistent with
  the model plus random fluctuations)

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More Tools

• Moving average technique applied to noisy data
• Z-test determine significance between two mean
  values for two distributions

9
KS Test

• Most powerful for comparing two distributions
• Statistic is the maximum difference between 2
  cumulative frequency distributions
• Data does not need to be normally distributed
• Best means to compare data distribution against a
  model
• Cant be used for sample sizes less than 10

10
Arrival Statistics (Poisson)

• Events have to be discrete
• A good measure of the average event rate allows
  the probability that N events will occur over
  some time period to be determined
• Large values of l produces a distribution that is
  normal.

11
Green House Effect
Long wavelength absorption properties of our
atmosphere increase the surface temperature-
Water vapor is the dominant effect, followed by
CO2
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Methane

• Potential role of methane is larger than CO2
• GWP 21
• Scales with population growth
• Released from permafrost
• Released from hydrate deposits
• Emissions now rising again due to global wetlands
  returning from prolonged drought

13
Difficulty of Climate Change Detection

• Data is noisy
• Temporal baseline of data is not long enough
• Multi decadal climate cycles seem to be very
  important
• Oceans act as a buffer that delays the overall
  effect

14
Predator Prey Relations

• Non linear in nature ? small changes in one part
  of the system can produce rapid population
  crashes
• Density dependent time lags are important (what
  causes them?)
• Equilibrium is intrinsically unstable
• Logistic growth curve makes use of carrying
  capacity concept, K
• Negative feedback occurs as you approach K
• R selected vs. K selected mammals

15
P vs H

• Understand why graphical representations look
  like this
• What drives the lag time?

16
Human Population Projections

• What assumptions are used?
• Does human population growth respond to the
  carrying capacity concept?
• World population growth rate is in continuous
  decline (but still positive) ? will this continue
  indefinitely?
• Oscillatory model may be most realistic
• What role does increased life expectancy have? ?

17
Estimation Techniques

• Extremely useful skill ? makes you valuable
• Devise an estimation plan ? what factors do you
  need to estimate
• Scale from familiar examples when possible
• Perform a reality check on your estimate

18
Applied Ecology

• Know what the terms mean and understand what an
  iterative solution is

19
Applied Ecology II

• Understand from the point of view of the
  framework (e.g. the equations) why stability is
  very hard to achieve
• What role does finite reproductive age play?
• What makes human growth special within this
  framework.
• Understand concepts of equilibrium occupancy and
  demographic potential
• Why is error assessment so important here?

20
Skewed Distributions
This is a probability distribution function and
one can still use the area under the curve or
area between x values to determine probabilities
via numerical integration
21
Time Series Analysis

• Much of environmental data analysis or modeling
  represents the time evolution of some observed
  quantity.
• Long term trends with cyclical oscillations
  and/or short term regular deviations plus random
  variations

22
Value of time Series Analysis
Gas Prices The long term trend is steep and
rises above the fluctuations Climate The long
term trend is overwhelmed by the fluctuations

• You want to uncover the long term trend that may
  be buried under the fluctuations
• Determining the amplitude of the fluctuations
  helps to determine if any recent events are
  aberrant
• Two cases Gas prices Climate Cycles

23
Multiple Sine Wave Fits

• Can often reproduce the behavior seen in complex
  time series

24
The Data Rules

• Always, always ALWAYS plot your data
• Never, never NEVER put data through some blackbox
  reduction routine without examining the data
  themselves
• The average of some distribution is not very
  meaningful unless you also know the dispersion.
  Always calculate the dispersion and then know how
  to use it!

The Average value for this data set is totally
meaningless
25
More Data Rules

• Always compute the level of significance when
  comparing two distributions
• Always know your measuring errors. If you don't
  them you are not doing science.
• Always calculate the dispersion in any
  correlative analysis. Remember that a correlation
  is only as good as the dispersion of points
  around the fitted line.

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The Biggest Rules

• Always require someone to back up their "belief
  statements" with credible data.
• Change the world. Stop being a passive absorber
  of some one else's belief system.
• Frame all environmental problems objectively and
  seek reliable data to resolve conflicts and make
  policy

27
And Now For Something Completely Different

• Global climate change, species extinction, oil
  depletion, world food crises, global inequity,
  environmental justice, depletion of mineral
  resources, blogs, sustainability, alternative
  energy solutions, alternative fuels, more blogs,
  Obama, Hillary, McCain, whatever
• WTF? How did all of this happen?

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Your World Upon Graduation

• The Fossil Fuel Legacy

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Engineering the Planet

• What Compels us to do so?

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Consumption Pros and Cons

• This depends on how you want to index consumption
  personal consumption/affluence is different
  than production/consumption that indirectly leads
  to better society infrastructure and services.
• What matters is the rate of consumption relative
  to the resource base. Main problem is that
  short term market growth, which we value, wants
  high rates.
• Sustainability demands lower rates ? this is the
  clash of values.

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Key Historical Moments

• We are special (different than other animals)
• We are uniquely positioned at the center of the
  Universe (reflects our special-ness)
• The Universe is ordered, logical and rational
  Age of Reason ?humankind is unbounded
• The Newtonian world shows us the machine and it
  is precise (we can now engineer the planet)
• The notion of uncertainty, as a valid and
  integral scientific concept, arises too late in
  this process ? we already have truth pathways
  established

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Essence of Science

• Knowledge based on measurement means that
  knowledge is both uncertain and subject to change
  when new and better measurements are made there
  is no room for absolute truth in this methodology
• Problems can then only be solved by objective
  means that rely on real data and not bias or
  wishful thinking.

33
Choice Pathways

• Which world does humanity want to live in?
• One that is based on a belief system that is then
  projected on to the natural world to support that
  belief (this is the BIAS)
• One where scientific methodology and thinking is
  used to enable, on a planet wide scale, the
  enlightenment motto that all men are created equal

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Relationship with the Land is key

• Three possibilities
• The Land is Sacred ? Indigienous Model your
  ancestors are buried in it
• The Land is shared ? European Model ? lots of
  people, not much land
• The Land is Owned ? American Model ? lots of
  land, I can piss on it if I want, afterall, its
  mine.

35
Continued Economic Development Requires high
Energy Use

• 1900 ? 100 Million Capitalists to build markets
• 2003 ? 2.5 Billion new capitalists
• Energy is the core of the environmental
  problem Environment is the core of the energy
  problem
• The energy-environment intersection is the core
  of the sustainable-prosperity problem

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Resolution?

• We need to stop be driven by market economics and
  start to recognize that energy and environment is
  a shared resource.
• 20 Million college students should march on
  Washington demanding this