Assignment: Modeling Complexity with Stella - Your Ecological Footprint

Due Date:

Tuesday, Feb. 26, at the beginning of class.

Purpose:

Learn to use STELLA software to think compartmentally. You and a partner will use STELLA to define the factors you would need to consider in order to calculate your Ecological Footprint. Essentially, your use of resources can be thought of in terms of a system in which resources flow from the stocks of the world at large into your personal system. Your task is to outline how you interact with those world stocks that are relevant to an Ecological Footprint.

Objectives:

• I want you to think about the consequences of your own lifestyle, such as what it takes for the grapes you buy in the store to get to your table. You should identify some item that you use in your daily life on which to focus. This might mean "paper products", it might mean "meat" or "food", or it might be more specific than that. You might think about a single "hamburger" or a "chair." The goal is to estimate the resources required to deliver that item to you (in a common denominator of the "land area" required to make the item and then to get it to you).
• I want you to learn to use STELLA as a way to organize your thinking about complex interactions of a system. Thus, you are using STELLA to describe the complex interactions between your hamburger, for example, and the world.
• I want you to relate your lifestyle (#1 above) to the concept of the Ecological Footprint. In other words, eventually your single hamburger has to be connected to all the different land types defined by the Ecological Footprint. Even though your hamburger is one tiny fraction of demand on Pasture Land, for example, it requires some portion of that land to produce. What you need to think about is web of interactions that connect your burger to that Land type. You may not connect to all Land Types. The Sea Production land type may not be applicable to your model of hamburger, though I can't be sure.
• Remember, there is no right answer here. I want to see that you have thought deeply about the interactions. I want to see that you understand how you eventually connect to the main components of the Ecological Footprint (land types). Finally, I want to see that you can use STELLA to graphically organize your thoughts about this system.

Tools:

You will use the modeling software STELLA. Stella can be found on any campus networked computer. It is found in the START MENU under Kenyon Programs/Biology/Stella 9.0.3/Stella 9.0.3.

Please note: in the Stella 8.1 directory of programs (above Stella 9.0.3) is a "pdf" document - "An Introduction to Systems Thinking." You will find this helpful in thinking about the modeling process.

You will use the web to investigate your ecological footprint. You can use any website you like, but here is what I recommend:

• Ecological Footprint FAQs - Explanation of the components of an Ecological Footprint. This website is helpful to read for this exercise.
• Footprint Calculator - A detailed spreadsheet that will let you exactly calculate your personal footprint. Use this to help you think about all the components you might need in your model. It is on the P: drive at P:/Class/Envs/ENVS112 2007/Stella/FootprintCalc.xls. Remember, you don't need to do the calculation right now, just use this to help you define your model.
• Global Footprint Network - Good background on the Ecological Footprint.
• Online Footprint Calculator - a very simple calculator that calculates your personal footprint from a few general questions about your lifestyle.
• Land Categories - general outline of Land Types used in the Footprint
• Stella Software - Link to a short tutorial on the basics of using STELLA
• Stella Hints for this Assignment - Brief outline of how to use stocks and flows for this assignment
• STELLA Website Examples - Stella models you can download and examine on the STELLA (ISEE Systems) website
• STELLA Global Warming Models - Examples from StellaChem website
• Brando - use as needed

What to do:

• Work in teams of two.
• Use your notes from class and the information described above to learn about calculating Ecological Footprints.
• Choose one aspect of your lifestyle to analyze in terms of Ecological Footprint components
  • Housing
  • Food
  • Transportation
  • Consumer Goods
• Identify stocks, flows, convertors that apply to your personal use of the world's resources.
  • These should parallel the resources identified in the Ecological Footprint web page.
  • This is the hard part. You must think carefully about the following questions:
    • What resources are being used?
    • What increases or decreases these resources?
    • What do you do in your daily life to increase or decrease these?
    • How do your actions influence the rate of increase or decrease in each of these?
• Use the STELLA software to build a simple compartmental system diagram that outlines your use of the world's resources and what you would need to know to calculate your own footprint.
• This should be a collaborative effort between you and your partner.

What you should hand in:

• Print the STELLA model you have constructed. It does not need to "work" in that you don't need any equations or numbers at this time. All I want is the model with stocks, flows, and influences that describe the factors that are considered when calculating your personal ecological footprint.
• A brief (type written) outline of all your model. Either:
  • Brief description of all your stocks and flows and influences with a sentence or two describing each of these.
  • Focus on one pathway that connects the focus of your project (i.e., a hamburger, a chair, wood products, etc.) and one of the Footprint stocks (Arable Land, Energy Land, etc.). Describe this pathway and your logic in choosing the stocks, flows, and influences in that pathway. Again, this should not exceed one page.
• Each group of two should submit a single report with both group members' names on it.