common access resources and the tragedy of the commons

Question 1

what are common access resources and examples and why they happen

Answer 1

-natural resources over which no private ownership has been established

examples: forests(timber, pulp), sea (seafood, minerals), air (O2)

-it is not cost efficient to establish private ownership

Question 2

the tragedy of the commons and graph

Answer 2

-when private producers act in their own self-interest and unsustainably keep exploiting common access resources until there are none left
-negative externality in production graph