Explaining the Tragedy of the Commons

Tom Witherow offers this super explanation of the Tragedy of the Commons and some contemporary applications:

This was a title of an article by Garrett Hardin in 1968, however, now the phrase is more commonly used to name the effect which it describes. It explains what can happen when a number of people or players share a common resource. This could be the fish in the sea, common grazing land or the atmosphere. Each player is presumed to act rationally and in his own interest.

Let’s take the example of the common grazing land. If there are ten different farmers on this land then there is an incentive to add one more cow to your herd as you gain all of the benefit of this extra cow and you only have to suffer 1/10 of the cost resulting from the increased degradation of the land. Thus although it is in each individual’s self interest to increase the size of your herd, in the long run the land is exhausted.

This concept can be transferred to the other examples. With CO2 emission, it is in each countries own interest to emit more as growth will be increased, as shown by Japan. However, in the future growth will be damaged as drought and disease spread to higher latitudes and all the other consequences of global warming take effect.

Fish stocks, most notably the North Sea in recent years, have declined. Without government intervention, there is an incentive for individual fishermen to catch as much as possible. Now we are seeing the consequences in the declining stocks. In this case, the tragedy could easily have been stopped as factors such as fish net size and amount caught and brought back can be monitored effectively, and thus regulated via taxes and laws. However, there are more difficulties with the punishment and monitoring of emissions due to the atmosphere being a global resource – unlike the common land and indeed the fish stocks which will be found in the waters of no more than, say, five countries.

Charcoal harvesting killing off Ivory Coast’s rainforests (July 2012)