Why System Dynamics?

Review of prior post 

Why System Dynamics?

All systems, everywhere have levels and flows. These are the only two concepts needed to understand why systems work the way they do (Forrester, 1996).

We were taught in school to accumulate knowledge and skills in order to get a job. We define learning as the accumulation of knowledge. We test every child at every grade level to measure their accumulated knowledge. We teach people how to do things so they have a skill in order to get a job.

Public education teaches people what is important to know. Students learn skills so that they know how to do things.  Students are tested on what they know and the skills for how to use what they know. System Dynamics (SD) enables us to understand why systems work they way they do.

Public education involves a way of thinking, learning and communicating that focuses on the past up to the present. Science, math, reading and writing are all focused on knowledge (what) and skills (how) that have been codified into a curriculum. In public education students learn about the past up to the present.

Life is moving fast. We need a way to think, learn and communicate about the future.  The current public school system does not meet that need.

Sustainability education and environmental literacy are focused on students learning more and more about how to do more things.  By conforming to the way the current public education system focuses on what and how, we are asking students to accumulate more and more knowledge about the recent past.  We are asking students to accumulate more and more skills about how things were done in the recent past.

System dynamics is a tool to think, learn and communicate about the future. (Richmond 2010)  With SD, learning is about why systems work they way they do.  What is needed to model a system is accumulated just in time to use in a model.  The knowledge needed about how the parts of a system are related is accumulated just in time to use them in a model.  The understanding needed about why feedback loops in systems tell a story is accumulated just in time to use them in a model.

SD enables us to understand why systems work they way they do.  Politicians and decision makers need to know why systems work the way they do so that they can craft policies that are successful in the future. Policy makers need informed citizens who know why systems work they way they do.

Why do policymakers choose policies that fail? A policy response is rational for decision makers who fail to account for the feedback structure of a system. Only by considering the full feedback structure is the ineffectiveness of a policy revealed. By learning why feedback affects system behavior, small system dynamics models have a crucial role to play in policy making. (Ghaffarzadegan, 2012)

Policy makers fall prey to the “Pull my finger” joke.  They develop a policy that responds to correlations, trends and events believing that they understand the cause like when the finger pull and the sound are close together in space and time. The irony of public policy making is that, without understanding system feedback, what happened in the past will be made worse by a policy response.

Without SD, public education is teaching students to look to the past to make decisions about the future.  The public school system is walking backwards into the future. 

The public school system is the primary obstacle to students using SD.  The entrenched paradigms are the foundation for education institutions that teach what and how from K12 through university doctorate programs.  Educators and students are evaluated based on what they know and how to use what they know.  SD enables us to understand why systems work they way they do.

System dynamics is a tool to think, learn and communicate in a new way so that educators engage student’s mental models. When mental models rely on “Pull my finger” thinking a person is not going to understand feedback. To use SD requires a new way of thinking: Think about levels and flows connected in feedback loops within a closed boundary.

To use SD requires a new definition of learning: Learning is improving the quality of our mental models.(Richmond 2010) The current public school system does not attempt to improve the quality of student’s mental models. 

To use SD requires a new way of communicating: Communicate about why your model works using feedback loops.  This is where qualitative tools like causal loop diagrams and behavior-over-time graphs are used and useful.

Jay Forrester is the founder of System Dynamics. He has said for many years that with the right guidance “students must create their own models and learn from trial and error.” In this way dynamic modeling is learning by doing. “I believe that immersion in such active learning can change mental models.” (Forrester 2009)

Why System Dynamics? System Dynamics enables us to understand why systems work they way they do in order to prepare for the future.

Bibliography

1. Forrester, Jay W. "System Dynamics and K-12 Teachers." Creative Learning Exchange. 30 May 1996. Web. 11 Feb. 2012. <http://clexchange.org/ftp/documents/Roadmaps/RM1/D-4665-5.pdf>.
2. Ghaffarzadegan, Navid, John Lyneis, and George P. Richardson. "Why and How Small System Dynamics Models Can Help Policymakers: A Review of Two Public Policy Models." System Dynamics Society. Web. 10 Feb. 2012. <http://www.systemdynamics.org/conferences/2009/proceed/papers/P1388.pdf>.
3. Richmond, Barry. "Introduction: The Thinking in Systems Thinking- Eight Critical Skills." Ed. Joy Richmond. Tracing Connections: Voices of Systems Thinkers. Lebanon, NH: ISEE Systems, 2010. 3-21. Print.
4. Forrester, Jay W. "Learning through System Dynamics as Preparation for the 21st Century." Creative Learning Exchange. 2009. Web. 11 Feb. 2012. <http://clexchange.org/ftp/documents/whyk12sd/Y_2009-02LearningThroughSD.pdf>.

Systems and Climate Change

All systems, everywhere, have levels and flows.  A system has at least one feedback loop.  

An example of a system is a bathtub.  The faucet is an inflow, the tub is an accumulation with a level of water, and the drain is the outflow.  The rate of outflow depends on the level of water in the tub. Based on Bernoulli's equation & Torricelli's Law, the rate of flow is proportional to the height of the water column over the drain hole.

Symbols

Cloud defines system boundary

Pipe contains flow of material

Arrow head shows direction of flow

Accumulation contains material with level

Single line with arrow head moves information to control flow rate

Examples

Inflow	Level	Outflow
Water thru faucet	Bathtub	Drain
Intravenous Drug	Human body	Elimination
Affirmations	Self-Esteem	Self-Talk

Climate Change

Sunlight reaches the surfaces of the earth and warms the land and oceans.  Some light is reflected back into space and some reflected light warms the atmosphere.  The land and oceans radiate energy back into the atmosphere, also called heat.  The radiant energy is absorbed in the atmosphere by heat trapping gases such as aerosols, methane (CH4), and carbon dioxide (CO2).  This is called the greenhouse effect that increases the average temperature of the atmosphere.

As the inflow of CO2 to the atmosphere has continued for decades and increased over time, the radiant energy trapped in the atmosphere has increased.  We measure the result as the average global temperature of the atmosphere over time.

As the temperature of the lower level of the atmosphere increases, the radiant energy dissipates into the upper layers of the atmosphere and eventually out into space.  As the inflow of CO2 increases, the outflow rate increases to the upper levels of the atmosphere and into space.  However, over time the increased greenhouse gases in the atmosphere trap more radiant energy and the average global temperature continues to increase over time.

Equations

Based on the Stephan-Boltzmann equation the rate of outflow in the energy from the atmosphere is proportional to the temperature of the atmosphere.  The equation ( j = ⍺ * T^4) means the energy in joules equals a constant times the temperature to the fourth power.

Now we can link the parts together, add the many converters and constants needed for the exact calculations, and we have a complex system with multiple feedback loops.

Imagine a molecule of CO2 released in China on January 1, 2018.  In 2028, that molecule will finally reach an equilibrium temperature after absorbing radiant energy for years.  This means that the consequences of greenhouse gases are distant in time and space from the emissions.

Extending the Model

Two extensions of the model are critical to discuss.  One is adding layers to the atmosphere instead of only one atmosphere as shown in the model above.  Second, adding the oceans to the model, so we can calculate the change in atmospheric temperature over time as the oceans absorb radiant energy from the atmosphere.

Scientists have calculated that the oceans are acting as a buffer by absorbing 80 to 90 percent of the increase in radiant energy added to the atmosphere.  Water has a higher heat capacity than air so the oceans can absorb up to 1,000 times more energy than the atmosphere.

Scientists have calculated that the oceans are acting as a buffer by absorbing CO and CO2 gases.  The chemical changes in the ocean then lead to changes in the acidity of the water.  The life in the oceans can not evolve fast enough to keep up with the changes in the acidity.

These two changes in the oceans, increased heat and acidity, are slowly killing life in the oceans.

Conclusion

Causality means connecting the root cause with the eventual consequences over time and space.  The discussion above shows how each molecule of CO2 that enters the atmosphere, increases the global average temperature and kills life in the oceans.  The increases in atmospheric temperature are not evenly distributed and the consequences for humans are not evenly distributed.

The Consequences of Climate Change

As we continue in 2013 to postpone, like we have for decades, the policies that could bring about a sustainable world, the population grows too large, pollution builds too high, resources are drained too much, and a collapse is no longer avoidable.

Sustainability

As corporations continue to focus on keeping profits flowing and accumulating wealth, they will attempt to continue to privatize land and water resources. Without government intervention, the Corporations are designed to privatize all resources and dispose of all wastes in the commons.