Self-sustainability and self-sufficiency are overlapping states of being in which an entity requires little or no reliance on external sources. Self-sufficiency entails the self being enough in fulfilling one's own needs, and a self-sustaining entity can maintain self-sufficiency indefinitely. These states represent types of personal or collective autonomy. A self-sufficient economy, also called an autarky, is one that requires little or no trade with the outside world.
Self-sustainability is a type of sustainable living in which nothing is consumed other than what is produced by the self-sufficient organizations or individuals. Examples of attempts at self-sufficiency in North America include simple living, food storage, homesteading, off-the-grid, survivalism, DIY ethic and the back-to-the-land movement.
Practices that enable or aid self-sustainability include autonomous building, permaculture, sustainable agriculture, and renewable energy. The term is also applied to limited forms of self-sustainability, such as growing one's own food or becoming economically independent of state subsidies. The self-sustainability of an electrical installation measures its degree of grid independence, and is defined as the ratio between the amount of locally produced energy that is locally consumed--either directly or after storage--and the total consumption.
A system is self-sustaining (or self-sufficient) if it can maintain itself by independent effort. The system self-sustainability is:
Self-sustainability is considered one of the "ilities" and is closely related to sustainability and availability. In the economics literature, a system that has the quality of being self-sustaining is also referred to as an autarky.
Autarky exists whenever an entity can survive or continue its activities without external assistance. Autarky is not necessarily economic. For example, a military autarky would be a state that could defend itself without help from another country.
According to the Department of Labor of the state of Idaho, an employed adult shall be considered self-sufficient if the family income exceeds 200% of the Office of Management and Budget poverty income level guidelines.
Whereas self-sustainability is a quality of one's independence, survivability applies to the future maintainability of one's self-sustainability and indeed one's existence. Many believe that more self-sustainability guarantees a higher degree of survivability, although just as many oppose this, arguing that it is not self-sustainability that is essential for survivability, but on the contrary specialization and thus dependence.
As examples to this argument, commercial treats among countries are often just as important as self-sustainability, and autarkies, such as North Korea or Japan during the Edo period, often suffer from lesser ranges of products and services and a lower standard of living. Among people, social ties have also been shown to be correlated with happiness and success.
Five acres and independence.