Tragedy of the Commons
Brook Milligan
Department of Biology
New Mexico State University
Las Cruces, New Mexico 88003
[email protected]
Fall 2009
Brook Milligan
Tragedy of the Commons
The Tragedy of the Commons
Hardin, G. 1968. The tragedy of the commons. Science,
162:1243–1248.
Classic paper
Unifies fundamental issues into a common framework
Applicable to conservation biology, economics, politics, . . .
Brook Milligan
Tragedy of the Commons
Nature of a commons
A resource owned jointly
Benefits to use of resource acrued individually
Cost of resource use born jointly; therefore, individual
component of cost of resource use reduced
Imbalance in cost/benefit make increasing exploitation the
rational strategy for all individuals
Necessary outcome: overexploitation
Brook Milligan
Tragedy of the Commons
Examples of commons
pasture, grazing land
Brook Milligan
Tragedy of the Commons
Examples of commons
pasture, grazing land
A resource owned jointly
the land itself shared among users of the pasture
Benefits to use of resource acrued individually:
benefits of selling meat, dairy products, animals acrue to each
individual owner of animal(s)
Cost of resource use born jointly; therefore, individual
component of cost of resource use reduced
reduction of forage resource causing slower growth rate/lower
milk production shared among all users of the pasture
Imbalance in cost/benefit make increasing exploitation the
rational strategy for all individuals
benefitial to any individual to add one more head to the herd,
because the increased benefit of selling more milk/meat/. . .
outweighs the reduction in growth due to extra grazing
Necessary outcome: overexploitation
overgrazing
Brook Milligan
Tragedy of the Commons
Examples of commons
pasture, grazing land
reproduction
national parks
parking spaces
fisheries resources
extractive industries: mining, petroleum
atmospheric and water pollution
visual and auditory pollution
financial institutions: emerge from a common pool of money
(e.g., within a family or coop)
health care
welfare
insurance
Brook Milligan
Tragedy of the Commons
Possible means of managing commons
Convert commons into private property
Allocate right to use a commons
Coercion
Brook Milligan
Tragedy of the Commons
Possible means of managing commons
Convert commons into private property
financial pools: family pool, banks
insurance industry
ownership rights to fisheries, emissions
Allocate right to use a commons
Coercion
Brook Milligan
Tragedy of the Commons
Possible means of managing commons
Convert commons into private property
financial pools: family pool, banks
insurance industry
ownership rights to fisheries, emissions
Allocate right to use a commons based upon:
wealth, e.g., via an auction
merit based upon agreed upon criteria
lottery
first-come, first-served with queues
Coercion
Brook Milligan
Tragedy of the Commons
Possible means of managing commons
Convert commons into private property
financial pools: family pool, banks
insurance industry
ownership rights to fisheries, emissions
Allocate right to use a commons based upon:
wealth, e.g., via an auction
merit based upon agreed upon criteria
lottery
first-come, first-served with queues
Coercion
But, who watches the watchers to make sure the commons
are not degraded?
Brook Milligan
Tragedy of the Commons
Coercion as a method of managing commons
Definition of coerce: American Heritage Dictionary
to force to act or think in a given manner by pressure, threats,
or intimidation; compel
to dominate, restrain, or control forcibly
to bring about by force
Brook Milligan
Tragedy of the Commons
Coercion as a method of managing commons
Definition of coerce: American Heritage Dictionary
to force to act or think in a given manner by pressure, threats,
or intimidation; compel
to dominate, restrain, or control forcibly
to bring about by force
Elements of coercion
restriction of rights
biased sets of options
e.g., not prohibition but increasingly expensive to continue
agreed upon by majority
creates new freedoms
Brook Milligan
Tragedy of the Commons
Coercion as a method of managing commons
Definition of coerce: American Heritage Dictionary
to force to act or think in a given manner by pressure, threats,
or intimidation; compel
to dominate, restrain, or control forcibly
to bring about by force
Elements of coercion
restriction of rights
biased sets of options
e.g., not prohibition but increasingly expensive to continue
agreed upon by majority
creates new freedoms
Questions
is the dictionary defintion what Hardin means by coerce?
how can restricting rights create freedoms?
how can coercions be adopted?
Brook Milligan
Tragedy of the Commons
No technical solution problems
What are “no technical solution problems”?
Brook Milligan
Tragedy of the Commons
No technical solution problems
What are “no technical solution problems”?
technical solution: one relying solely on science and
technology, without requiring changes in “human values or
ideas of morality”
some problems cannot be solved only with technical solutions
some problems must be solved with changes in values or
morality
Brook Milligan
Tragedy of the Commons
No technical solution problems
What are “no technical solution problems”?
technical solution: one relying solely on science and
technology, without requiring changes in “human values or
ideas of morality”
some problems cannot be solved only with technical solutions
some problems must be solved with changes in values or
morality
Why does Hardin claim that the tragedy of the commons is
such a problem?
Brook Milligan
Tragedy of the Commons
No technical solution problems
What are “no technical solution problems”?
technical solution: one relying solely on science and
technology, without requiring changes in “human values or
ideas of morality”
some problems cannot be solved only with technical solutions
some problems must be solved with changes in values or
morality
Why does Hardin claim that the tragedy of the commons is
such a problem?
Rational participants will continually exploit the commons
Therefore, the “rules” must be changed so that strategy is no
longer the rational one; i.e., changes in values are required
Brook Milligan
Tragedy of the Commons
Tragedy of the commons and conservation biology
How do the points raised by Hardin relate to issues of
importance to conservation biologists?
Brook Milligan
Tragedy of the Commons
Tragedy of the commons and US politics
How do the points raised by Hardin relate to the general
approaches to government espoused by the major US political
parties?
What are some current political issues that relate to the
tragedy of the commons?
Brook Milligan
Tragedy of the Commons