Found some information of COMMOM RESOURCES(RC Common Tragedy)

rooneyfang

Examples of Common Resources

  1. Air. No one owns the air, it is available for all to use, and its unlimited use leads to air pollution.
  2. Water. Water in the seas, estuaries, and the ocean is a common resource. But, water in lakes and rivers is often owned by cities, farmers, or others, especially in the western US.
  3. Fish of the sea.
     Hardin writes that In 1625, the Dutch scholar Hugo Grotius said, "The extent of the ocean is in fact so great that it suffices for any possible use on the part of all peoples for drawing water, for fishing, for sailing." Now the once unlimited resources of marine fishes have become scarce and nations are coming to limit the freedom of their fishers in the commons. From here onward, complete freedom leads to tragedy.

rebecca_wang

感谢，正纠结这个题呢，看来结案了。谢谢~！

kazemi

所以北美上空的空气是正确答案？