Teaching the Tragedy of the Commons: Natural Resource Depletion

One of the most fascinating parts of environmental science is the interaction between ecology and sociology. Ecologists study the parts of an ecosystem and how organisms interact with each other. Sociologists study how humans interact with one another in societies. Our environmental problems and concerns stem from the collision of these two realms. The many facets of every problem in environmental science mean that there are usually no black and white answers, only many shades of gray. That is why this subject is great for class discussions and critical thinking exercises.

An initial subject of study for my environmental science students is the tragedy of the commons. Garrett Hardin first coined this phrase in 1968 to describe the abuse and mismanagement of a common resource by individuals for their own gain. He used the example of a grazing pasture in which individuals continually added more of their own livestock. Because of this abuse, the pasture is overgrazed and the once-renewable resource is lost. Many students mistake a renewable resource for an unlimited one. However, many renewable resources are not unlimited and must be carefully used to prevent their depletion.

To illustrate this for my students, I put them in groups and place a brown paper bag with candies in front of them. Before class, I put four candies for each student in the bag. I do not tell the students how many candies there are in the bag. I do not give them any rules for taking the candies, other than they may not communicate with each other and may not look inside the bags. They may take as many as they would like using plastic spoons to scoop them out. Once the bags are passed around the group once, I circulate around the room and fill the bags again. For every candy in the bag, I add another. At this point, students begin to realize that they may want to scale back on what they take. We continue this for a few more rounds. Once a group is out of candy, no more is added to their bag. Before the final round, I warn the class that any candy left in the bags will be taken away.

After the activity, students are allowed to eat their candy and we discuss what happened. I tell them how many candies were in the bag initially and challenge them to determine the ideal rate of resource extraction. Most students quickly realize that they could have taken two candies each during each round without running out. We also address the snatch-and-grab phenomenon that occurred at the end of the activity or as the resource ran out. Our discussion revolves around social behavior at first, but then we discuss the ecology of the resource. We do this by relating the renewal of the resource to fishing and hunting limits.

To extend this activity even further into the realm of real world experience, students determine and research a problem or solution that relates to the tragedy of the commons. Examples include hunting or forestry management, declining fish populations, and endangered species comeback stories. This lesson always helps my students remember that resource management and natural resource depletion are complex subjects. The natural resources lesson plans below can also help your students understand the tragedy of the commons.

The Tragedy of the Commons:

Case Study-Tragedy of the Commons 

In this activity, half of the class takes on the role of fisherman, and the other half observes. The class discusses how the way the fishermen acted relates to the tragedy of the commons, and then tries to think up ways the fishermen could have made the situation better. 

Fishing for the Future 

Students use M&Ms to study and recreate the concept of the tragedy of the commons in the fishing industry. They consider the social, environmental, and economic impacts overfishing might have on a community or across the world.

Go Fish! Exploring the Tragedy of the Commons

Students delve further into the concept of the tragedy of the commons by coming up with strategies to combat the problem; namely, a sustainable harvest.