Carrying capacity is dictated by limiting factors, which are whatever necessities are least abundantly available relative to per capita requirements. Impacts may be thought of as the net difference between the local situation with and without the project you are assessing. Thinking of it in this way recognizes that changes are going to occur in the community whether a project occurs or not. Those changes need to be projected into the future just as the situation with the development project must be projected. To simply look at the present situation and try to compare that with a future scenario that includes the development ignores the fact that some changes will inevitably take place even without the development.
Impacts can be benefits or costs.
And, this will vary in the eyes of different people or groups within a community or population. For example, some people will see newcomers from different cultures moving to the community as positive while others will see it as undesirable and likely to cause problems for their traditional life styles. Tourism expenditures do not simply increase local income by the initial amount of money visitors spend. As the figure below illustrates, the money is spent in more than one round. Tourists purchase goods and services that are only partially produced or supplied locally.