Sustainability

The Tragedy of the Commons

What is it?

Imagine you're in class and your teacher brought in a pizza for everyone. There are more than enough slices for everyone to take one, but no set rule on how many you're allowed to take. I'm sure it wouldn't come as a surprise to you, but some people are most likely going to take more than one slice. Maybe they're concerned that if they don't take two now, there won't be leftovers for them later. Maybe it's because they don't personally face the downside of taking extra as it's not their pizza. Either way, some people take more than their fair share because it's in their own self-interest. That's essentially what's known as the tragedy of the commons.

The tragedy of the commons is what happens when individuals use shared, public resources selfishly, resulting in them being overused or degraded. If the resource is public and unregulated, it is in everyone's self-interest to take extra for themselves. Likewise, it doesn't fall on anyone to manage the resource and no one has a strong incentive to spend time, effort, or money doing so as it isn't actually owned by them as they don't directly suffer the consequences of overuse until it's too late. Eventually, the tragedy of the commons can result in the overuse and collapse of a resource. This can lead to issues such as overfishing, overgrazing, and deforestation which can have lasting and devastating effects if the resource is depleted too much.

What can be done?

When the tragedy of the commons is occurring, it harms everyone. As such, it is in society's best interest to do something about it and try to preserve the resource. There are a variety of methods that can be done, all of which have the goal of using the resource sustainably or using less than is produced so that the resource is not depleted.

One method involves transfering the public resource to private ownership. The logic behind this is that the individuals will have an incentive to maintain the resource if they own it; people tend to take better care of things they own or that they have invested in. Unfortunately, this method doesn't always work for two reasons:

  1. People aren't always willing to protect their investment, particularly if overusing it leads to large short-term profits.

  2. Certain resources, such as the atmosphere and the oceans, would be nearly impossible to split up and privatize.

Likewise, for relatively small, local resources, people can choose to work together and volunteer to sustain it. However, this is not practical nor does it work well beyond a small, local community. Things like protecting the atmosphere from the release of greenhouse gases, or the oceans from pollution, unfortunately, cannot be accomplished by individuals volunteering alone and need the aid of policy and intervention.

The main method used is the management and regulation of the resource by the government. Governments can limit the use of resources, impart fees or taxes for their use, and implement policies such as fines for those who are contributing to the degradation of a resource.

Ecological Footprint

How many resources are we using?

The ecological footprint is a form of measurement to quantify the environmental impact of resources being consumed. It measures the amount of biologically productive land and water that is needed to produce all of the resources used within a year. One could look at the ecological footprint for an individual, a country, the entire world, or anything in between. It considers both direct and indirect impacts.

Essentially, it's how much land is required to dispose of waste, produce food, provide housing, produce raw materials such as lumber, produce energy, etc. It is usually measured using global hectares (gha). Global hectares specifically focus on biologically productive land. While on average a global hectare can be produced in a standard hectare, it can vary. A hectare of a tropical rainforest will have greater global hectares than a hectare of a desert would.

You've probably heard of a carbon footprint, and the two are fairly similar. The carbon footprint, rather than quantifying the amount of land used by all of these, measures the amount of carbon dioxide released by all the resources used by and activities of an individual or population. This is typically measured in tonnes of CO2 produced per year.

There are a variety of factors that can affect the footprint of a population. In general, more affluent countries tend to have higher footprints. This is because richer countries have more material goods (which require more resources), bigger homes (which take up more space and also require more resources and energy), and travel more (which requires more energy). Other things that increase footprint are increased meat consumption (as producing meat requires more land, water, and food for the animals, along with increased energy uses) and increased energy use (for things such as heating, traveling, producing electricity, and the production of material goods). Things that can decrease the footprint are more renewable energy, increased public transport, plant-based diets, and living more simply and with fewer material goods.


If you were to look at our current global ecological footprint, we use more resources than the earth produces in one year. If the entire world lived exactly as your average American does, then we would be using more resources than the earth would produce in five years. Simply put, we are not living sustainably and are depleting our resources.

Principles of Sustainability

What does it mean to live sustainably?

Living sustainably means to live while using resources in a way or amount so that they don't deplete and run out in future generations. This relies on limiting the amount of a resource that is consumed or space that is used to prevent degradation.

One way that this can be done is through something known as the max sustainable yield. This is the maximum amount of a renewable resource that can be used without running the risk of depletion as it does not reduce the available supply. Oftentimes - but not always - it is roughly half of the carrying capacity of the population.

Environmental Indicators of Sustainability

There are environmental indicators that can help guide us toward sustainability. By monitoring these conditions, we can determine whether or not we are being sustainable.

  1. Biodiversity - As the biodiversity of an ecosystem decreases, so too does the ecosystem health and resilience. The lower it is, the greater the risk of extinction. By monitoring the extinction rate, we can monitor whether we are living sustainably or not. Currently, we are in a mass extinction event due to human activities. Things such as habitat destruction, pollution, poaching, overhunting/fishing, and worsening climate change all decrease biodiversity and lead to this increased extinction rate.

  2. Food Production - If we do not farm sustainably, our ability to produce food may deplete. The soil can be degraded and groundwater can be used up, which threatens the ability of an environment to continue producing food. As we produce more and more meat, we have less water and land available for other crops. All of this, coupled with climate change, can threaten global food supplies, and is something to be monitored to see whether we are using sustainable agricultural practices.

  3. Climate Change - Life on Earth requires a very specific temperature range. As we continue to produce CO2 into the atmosphere through deforestation and fossil fuel combustion, global surface temperatures increase. This can lead to destroyed habitats, threatened species, more intense storms, and dried-out soils and unusable farmland. In order to limit the damage caused by this, we need to begin living more sustainably.

  4. Population Size and Resource Use - As the human population continues to grow, we naturally need more resources to support ourselves. This leads to an increase in resource depletion. If we overharvest and take resources unsustainably, it can lead to deforestation, soil erosion, groundwater depletion, pollution, habitat destruction, climate change, and biodiversity loss.