Sustainability is a characteristic or condition of a process or of a system that allows its permanence, ay a certain level, for a certain period. Lately, this concept has become a principle accordingly which the use of natural resources to satisfy present needs cannot compromise the needs satisfaction of the future generations. This new principle has been extended to the quote “long-term sustainability”, a long term for an indefinite period.

Sustainability can also be defined as the human ability to interact with the world, preserving the environment so as not to compromise the natural resources of future generations. The concept of sustainability is complex as it reaches a set of interdependent variables, but we can assume that it must have the capacity to integrate social, energy, economic, and environmental issues.

• Social issue: it is necessary to respect human beings, so that they can respect nature. And form a human point of view, the human beings are the most important part of the environment.

 

• Energy issue: Without energy the economy does not develop. The population’s living conditions deteriorate.

 

• Environmental issue: with a degraded environment13, human beings shorten their life span, the economy does not develop, the future becomes unsustainable.

The principle of sustainability applies to everything, from a single undertaking, trough a small community  (such ecovillages), to the entire planet.For a human enterprise to be considered sustainable it must be:

• Ecologically correct.
• Economically viable.
• Socially fair.
• Culturally diverse.