Transcript Causal Loop Diagrams

Appendix 1
Water vapor feedback
In your own words describe the feedback loop a b c d e a.
In your own words describe the feedback loop a b c d e a.
Possible Answer: As Earth’s temperature increases, increased evaporation
(not shown) increases atmospheric water vapor. This increases the
atmospheric emissivity, resulting in more longwave radiation going downward
from Earth’s atmosphere to its surface. This results in increased surface
heating and subsequently a higher surface temperature than would be
expected without this positive feedback process.
What is the meaning of loop a b c f g d e a?
What is the meaning of loop a b c f g d e a ?
Possible answer: This captures the idea that as the atmosphere warms it
also radiates more energy to the surface.
i.e. The downward flux of longwave radiation from the atmosphere to Earth’s
surface is proportional to the product of atmospheric emissivity and the fourth
power of atmospheric temperature.
Loop a b c d e a captures the increase in emissivity
Loop a b c f g d e a capture the increase in atmospheric temperature.
Appendix 2
Ocean temperature CO2 uptake feedback
Two new connections
Are the connections positive or negative?
Earth’s ocean surface temperature
? CO
CO2 solubility in oceans
? Atmospheric CO
2
solubility in oceans
2
Two new connections
Are the connections positive or negative?
Earth’s surface temperature
CO2 solubility in oceans
- CO
2
solubility in oceans
- Atmospheric CO
2
Complete the causal loop diagram below. Make sure to label
all connections as + or – and also determine whether the
whole loop is a positive or negative feedback loop.
Complete the causal loop diagram below. Make sure to label
all connections as + or – and also determine whether the
whole loop is a positive or negative feedback loop.
+
+
+
-
Appendix 3
Clouds and climate
High thin cirrus clouds vs. low thick clouds
Three regions on Earth: I) clear skies II) low clouds III) high thin clouds
Red arrows represent ???? and green represent ????
High thin cirrus clouds vs. low thick clouds.
Three regions on Earth: I) clear skies II) low clouds III) high thin clouds
Red arrows represent solar radiation and green represent terrestrial
radiation.
High thin cirrus clouds vs. low thick clouds
I. Is our reference with no radiative forcing.
II. Low clouds reflect sunlight but since the clouds are low they radiate longwave
radiation nearly as well as the surface, so the radiative forcing is dominated by
the increased reflection of sunlight and is negative.
III. High thin cirrus clouds do reflect some sunlight. Since they are much colder than
the surface, their presence drastically decreases the outgoing longwave radiation
and hence the radiative forcing is positive. That is, the greenhouse effect of high
thin clouds is more important than their reflection of sunlight.
• T/F Increasing clouds in the atmosphere will
always decrease Earth’s surface temperature.
• T/F All clouds influence Earth’s climate in the
same way.
What might be the radiative effect of smog on
the Los Angeles area?
Think for a minute on your own and then share
with your neighbors.
What might be the radiative effect of smog on
the Los Angeles area?
There is no right or wrong answer to this
question as the answer would be highly
dependent upon the composition, density, and
vertical extent of the smog layer.
Appendix 4. Possible systems
diagrams for:
Select one of the ideas below as a basis to create a complete yet simple
systems diagram……. In your own words, briefly explain your causal loop
structure.
1. Dieting: emotional health, caloric food intake, person’s weight , exercise.
2. Drug addiction: Self-esteem, Risk for drug use, drug use, emotional instability
(Can you think of an outside factor may initiate the original change in self esteem).
3. Forest Fires: Forest fires, activity to stop fires, forest fire fuel.
4. Career success: Interest in career, amount of time spent working, success on
projects
5. Crying wolf: boredom relief, crying wolf, attention gained.
6. Market place: Product Inventory, product price, consumption of product
7. Or one of your own.
Appendix 3.1
Dieting: emotional health, caloric food intake, person’s weight, exercise.
Both loops are positive suggesting that either weight gain or loss can be amplified. It
is interesting to speculate about modifications to this diagram that may capture key
aspects of anorexia or bulimia disorders.
Appendix 3.2
Drug addiction: Self esteem, risk for drug use, drug use, emotional instability
(Can you think of an outside factor that may initiate
the original degradation of self esteem?).
Granted, this is an oversimplistic view of the drug addition cycle. Outside factors
could be dysfunctional relationships, outside demands for performance, or loss of
loved-one or long held job.
Appendix 3.3
Forest fires: Forest fires, activity to stop fires, forest fire fuel.
Assumptions:
1) As forest fires increase in number, the tendency to fight fire increases.
2) Fighting fires reduces then burning of underbrush and other fuels so fighting
fires increases the available forest fire fuel.
3) When there is more fuel, the chance of a forest fire start from lightning or human
activity increases.
Appendix 3.4
Career success: Interest in projects, time spent working on projects,
success on projects.
Assumptions:
1) Interest in projects inspires spending time working on projects.
2) Time spent working on projects promotes success on projects.
3) Success on projects fuels interest in projects.
Appendix 3.5
Crying wolf: boredom relief, crying wolf, attention gained
Assumptions:
1) Crying wolf works at gaining attention
2) The attention gained helps relieve boredom
3) Success at boredom relief promotes the desire to continue to cry wolf.
Karl North describes the full story and the balancing loop that dominates once the
“townspeople” lose trust in the boy. He extends this analogy in
“Folk Tales, Foreign Policy, and the Value of Systems Thinking”
Appendix 3.6
Market place: Product inventory, product price, consumption of product
The connections
1) As product inventory increases, product price decreases
2) As product price increases, consumption of product decreases
3) As consumption of product increases, product inventory decreases.
A specific example of this structure related to hogs and pork is given in
http://cabiles-cano.wikispaces.com/Case+8+-+Building+%26+Simulating+a+Model+Using+Dynamo
Appendix 5
Other examples
Chemical weathering
T/F All loops in the systems diagram above are negative
Chemical weathering
True/False All loops in the systems diagram above are negative