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The triumph of the commons

Image: grfx4, Lobster Maine crustacean, Pixabay, CC0 Creative Commons
Image: grfx4, Lobster Maine crustacean, Pixabay, CC0 Creative Commons

This paper describes eight examples where open-access property regimes do not lead to the well-known “tragedy of the commons” - i.e. overexploitation of the public resource - and outlines conditions that contribute to sustainable use of common-pool resources.

The case studies are pastoralists in Cameroon, Mongolia and Turkmenistan, freshwater fishers in Brazil, shellfish gatherers in Ecuador, subsistence foragers in Australia, swidden (slash-and-burn) farmers in Belize, and commercial lobster fishers in the United States.

The eight conditions identified as contributing towards sustainable use of open-access resources identified by the researchers are:

  1. High productivity of the resource relative to the number of users, leading to low competition.
  2. Variability across space and time in resource distribution, making it less advantageous for individuals to control a single area.
  3. Low mobility costs, so that users can move to the most productive areas.
  4. A shared set of norms governing open access.
  5. Users gain knowledge of the resource, both individually and as a society.
  6. Resource use may increase the productivity of the system.
  7. Irregular disturbances to the system make it hard for users to overexploit it, e.g. snowstorms in Mongolia can reduce herds below carrying capacity every few years.
  8. Limits on the accumulation of resources by individual users, whether social , technological or economic.

The study also identified five boundary conditions (related to external drivers of the resource system) that are necessary for sustainable resource use:

  1. Low population densities.
  2. Ability of users to move beyond their resource system.
  3. Low market value of common-pool resources.
  4. Low external capital investments.
  5. Low degree of state intervention in the management of the resource system.

Lead author Mark Moritz said, “We’ve been told that if there is open access, then there must be tragedy, but that’s simply not true… We’ve been blinded by the theoretical models.”



Current theoretical models of the commons assert that common-pool resources can only be managed sustainably with clearly defined boundaries around both communities and the resources that they use. In these theoretical models, open access inevitably leads to a tragedy of the commons. However, in many open-access systems, use of common-pool resources seems to be sustainable over the long term (i.e., current resource use does not threaten use of common-pool resources for future generations). Here, we outline the conditions that support sustainable resource use in open property regimes. We use the conceptual framework of complex adaptive systems to explain how processes within and couplings between human and natural systems can lead to the emergence of efficient, equitable, and sustainable resource use. We illustrate these dynamics in eight case studies of different social–ecological systems, including mobile pastoralism, marine and freshwater fisheries, swidden agriculture, and desert foraging. Our theoretical framework identifies eight conditions that are critical for the emergence of sustainable use of common-pool resources in open property regimes. In addition, we explain how changes in boundary conditions may push open property regimes to either common property regimes or a tragedy of the commons. Our theoretical model of emergent sustainability helps us to understand the diversity and dynamics of property regimes across a wide range of social–ecological systems and explains the enigma of open access without a tragedy. We recommend that policy interventions in such self-organizing systems should focus on managing the conditions that are critical for the emergence and persistence of sustainability.



Moritz, M., Behnke, R., Beitl, C. M., Bird, R. M., Chiaravalloti, R. C., Clark, J. K., Crabtree, S. A., Downey, S. S., Hamilton, I. M., Phang, S. C., Scholte, P. and Wilson, J. A., 2018. Emergent sustainability in open property regimes. Proceedings of the National Academy of Sciences, Published ahead of print,

Read the full paper here and read the Ohio State University’s press release here. See also the Foodsource resource How far could socio-economic change reduce GHG emissions? and the article The complexity of the commons: Scientists recast social dilemmas.

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