Introducing the economic concept of 'tragedy of the commons' using global warming

Laura Triplett, Gustavus Adolphus College
Gustavus Adolphus College, Geology
Author Profile
Initial Publication Date: April 7, 2016


In this 50-minute classroom activity, students begin by discussing historical environmental problems that demonstrate the economic principle of the 'tragedy of the commons'. The examples available here are sewage disposal in the Mississippi River, smog in London, and the ozone hole, but other examples could be used. Next, the instructor poses the question of whether global warming fits the tragedy of the commons model, and teaches some basic climate literacy concepts. Then, students brainstorm possible economic solutions to the global warming tragedy-of-the-commons. Instructor finishes by giving examples of economic solutions to historical environmental problems. This could easily lead into topics such as monetary and fiscal policy, economic development and globalization.

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Learning Goals

The Economics & Management professor's goals were to:
  • Introduce the diversity of topics and research in Economics (i.e., it's not just about making and managing money)
  • Introduce the concept of tragedy of the commons
  • Explore some effects of climate change on economic activities in developed and developing countries
The climate science specialist's goals were to:
  • Demonstrate that Earth's atmosphere is a "commons" that is vulnerable to impacts from human activity
  • Have students consider environmental services that provide real economic value

Students will use critical thinking to analyze examples and brainstorm possible solutions. Students learn about 'costs' of environmental problems in past, and are shown evidence of 'risk' presented by global warming.

Context for Use

This is a 50-minute class activity that can be done in a small- to very large-sized introductory lecture section. It was developed and tested in a class of ~45 students with a variety of backgrounds including first-year students, but could be done in a much larger class. The activity could be used in a variety of positions in a course, perhaps even as an early-term thought exercise. We used it midway through the course, after students have learned about supply and demand. The class period was co-taught by the host faculty member (Econ/Management) and the specialist faculty member (Geology), but the science concepts are basic and our intention was that the host faculty member would be able to teach it solo the second time around.

Preferably, students will read the very short assigned article before class, but alternatively that could be done as an in-class reading. The articles and discussion questions can be distributed to students as printed material or via online tools.

Description and Teaching Materials

Before class, students were assigned to read one of three short "popular" (non-scientific) articles about historical environmental problems that demonstrate the tragedy of the commons concept. The class began with students gathering in small same-article groups (3-4 students) to discuss and answer some questions. Then, the groups reported back to the whole class to briefly describe each situation, name the 'tragedy' and the 'commons', and describe how the problem was solved. The instructor then gave an interactive lecture for ~25 minutes about Earth's atmosphere and how we know that human activities can change its composition. Small groups brainstormed possible economic approaches to solving the global warming 'tragedy', then reported back to the class. Instructor ended with overview of solutions that have successfully solved other environmental problems.

The materials available here include:

Teaching Notes and Tips

Practical tips for conducting small group work in a large class:
  • If students read the articles before class, you will have more time for discussion. But, if you have poor compliance with that kind of assignment, these are short enough to be read in ~5 minutes during class. Even if you will allow reading time in class, we recommend that you make the articles available ahead of time in case any students have reading disabilities and need more time.
  • To form the small groups, you can either:
    • During the class period prior to the activity, divide the room roughly into thirds. Assign students in each third to read one of the three articles. The day of the activity, have them return to that seat and form groups with the 2-3 people seated nearest them (who have presumably read the same article). You may need to circulate around and make sure everyone has joined a group; some people will be too shy to do so, in which case you should casually but firmly assign them to a nearby group.
    • During the class period prior to the activity, organize students into groups and assign each group an article to read. Display the groupings on a .ppt slide for several minutes as students arrive, with one person highlighted as the "group leader". Then, call out each group leader name and have them stand so their group members can identify them and sit near them the following day. The benefit of this approach is that you break up groups of friends who normally sit together and who might, for various reasons, not learn well together. (Side note: I use this method to assign small groups for an activity early in the semester, then re-use the same groups every couple of weeks throughout. They get used to it, and can quickly find their group members. I put the students in alphabetical order so they can quickly find themselves on the slide, but I usually choose 'group leaders' who I know always come to class or are more senior students.)

Common questions:
Students may ask detailed questions about the science of climate change, which the host faculty member may not feel qualified to answer. That's okay! Our non-science faculty have had success responding to that kind of situation in these ways:
- "My specialty is Economics, so I do not know the specific answer to your question. However, I know enough about how the process of science works and how knowledge advances, that I trust the findings our scientists are communicating to us. They overwhelmingly agree that global warming is happening and is caused by humans. Therefore, I am confident that it is important for us to continue this lesson about the economics of global warming, even though I do not know the scientific details."
- "I do not know the answer to your question, but I would like to find out! I will consult with our campus climate specialist and get back to you with an answer during our next class meeting."
- "I do not know the specific answer to your question, but I have several reliable and unbiased sources of information about climate science that I will share with you. I encourage you to educate yourselves about this topic, and that means reading websites and reports published by the scientists themselves – not just what the popular media might say *about* the science and scientists! Many highly-regarded science organizations have created easy-to-read but accurate summaries of the scientific results."
- Or, you can turn this into an interesting discussion with the whole class if you have time. "My specialty is Economics and I do not know the answer to your specific science question. How do you (whole class) suggest we find the answer? Who will we trust to answer that question, and why?"


Assessment options:
  • Quality of reports-to-class about articles
  • Quality of interactive portions of lecture (e.g., economic values of atmosphere that they suggest)
  • Exam question, e.g. "In one paragraph, make an argument for why global warming is or is not an example of a tragedy of the commons. Be sure to describe the specific characteristics of this economic concept." A complete answer would at least define 'tragedy of the commons', explain that in this case the 'commons' is the atmosphere because there is no monetary value required for its use, and the 'tragedy' is that we are all going to be negatively impacted by the result of disposing of too much carbon in the atmosphere.
  • Exam question, e.g. "Earth's atmosphere is an example of a 'commons' because it: A. Is very large relative to the small effects humans have on it, B. Does not have a monetary value that must be paid for its use, C. Will affect other parts of the Earth system, like sea level, or D. All of the above." The correct answer is B. Answer A is false, and answer C is not relevant to whether something is a 'commons' or not.
  • Term paper about possible economic solutions to this tragedy of the commons, e.g. "Compare and contrast two economic approaches for solving global warming", or "Analyze the proposal to use carbon taxes to solve this tragedy of the commons. Use at least two primary sources of information about carbon taxes, and you may also choose to include historical examples of when taxes were used with or without success to solve a 'commons' problem."