Tragedy of the commons

The tragedy of the commons is a phenomenon described in economics and ecology in which common resources, to which access is not regulated by formal rules or fees/taxes levied based on individual use, tend to become depleted.[1][2] If users of such resources act to maximise their self-interest and do not coordinate with others to maximise the overall common good, exhaustion and even permanent destruction of the resource may result, if the number of the users and the amount they demand exceeds what is available.[3]

The concept of unrestricted-access resources becoming spent, where personal use does not incur personal expense, has been discussed for millennia. Aristotle wrote that "That which is common to the greatest number gets the least amount of care. Men pay most attention to what is their own: they care less for what is common."[4] The foundation for scholarly discussion of the topic however came in an 1833 essay by British economist William Forster Lloyd.[5] Lloyd supposed that, should common land parcels shared between cattle herders in Great Britain and Ireland (known as "the commons" in Anglo-Saxon Law) come to ruin, this should be attributed to those herders that allowed more than their allocated quota of cattle to graze on them.[6][7] While it may appear economically rational to an individual to over-consume in this context as doing so bears no immediate personal cost, such common land became barren and even permanently ruined where sufficient numbers of herders engaged in such activity.[6] Although provided as a hypothetical example, according to critical scholars the commons’ destruction came about from landholders of the commons who claimed and enclosed these lands, preventing common use.[8]

In 1968 ecologist Garrett Hardin published in Science the essay "tragedy of the commons", in which he stated that commonly used land is destined for ruin unless its capacity is well above its number of users. [9] Whilst cited extensively, the paper also continues to attract criticism from anthropologists and historians. [10]  Elinor Ostrom (2009 Nobel Prize in Economics Science winner) shared examples of small communities coordinating to share common resources without expending them without falling back on the rule of law to enforce these arrangements,[11][12] while economist and academic Dieter Helm commented that these examples were unrepresentative of broader societal tendencies, stating that if such covenants were typical, "[widespread] destruction of nature would have not occurred".[13] In response to such discussions, Hardin revised his thesis in 1991 to the "tragedy of the (unmanaged) commons".[10][14]

In modern contexts such as economics, evolutionary psychology, anthropology, game theory, politics, taxation and sociology, "commons" are considered any common-access resource to which access is unregulated, such as natural assets or property shared by a group/organisation.[15] Specifically in Anglo-Saxon legal contexts, it refers to assets that are jointly held and access to which is regulated by formal rules or social structures. [7] From an ecological point of view, the tragedy of the commons is typically applied to discussions of sustainable economic development that preserves and protects the environment.[16]