For this last discussion thread, let's explore the topic of externalities.Specifically, let's look at the issue that arises when multiple people share a common resource such as an ocean, forest or piece of land for their personal gain.The lack of clear ownership, accountability, and controls creates a conflict between normal short term self-interests and the long term needs of the group. The results can sometimes show up as overfishing, destruction of precious forests, unchecked pollution or out of control traffic congestion.