A common access resource is one that is non-excludable but rivalrous: anyone can access it and use it but doing so reduces the benefits the resource can provide to others in society. Common examples are pastureland that is shared by cattlemen, fish in the open ocean and the atmosphere itself, which the more it is used as a sink for toxic air pollutants, the worse human health becomes.

In the American West, examples of common access resources abound, leading to several tragedies of the commons, the problems arising from individuals over-using a common resource for their own gain at the expense of others in society whose ability to benefit from the resource is diminished.

Lately farms have been popping up deep in the Arizona desert. Not because there is lots of water in the desert, which of course, there is not; rather because the water that lies under the desert floor is not managed by anyone and is a pure common access resource. Anyone is allowed to use as much of it as they want without any regulations regarding its use!

The story below from Marketplace sheds some more light on this story.

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About the author:  Jason Welker teaches International Baccalaureate and Advanced Placement Economics at Zurich International School in Switzerland. In addition to publishing various online resources for economics students and teachers, Jason developed the online version of the Economics course for the IB and is has authored two Economics textbooks: Pearson Baccalaureate’s Economics for the IB Diploma and REA’s AP Macroeconomics Crash Course. Jason is a native of the Pacific Northwest of the United States, and is a passionate adventurer, who considers himself a skier / mountain biker who teaches Economics in his free time. He and his wife keep a ski chalet in the mountains of Northern Idaho, which now that they live in the Swiss Alps gets far too little use. Read more posts by this author

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