If you do not find the term you are looking for on this page, try the complete glossary . A condition when there is not enough of a resource in existence to satisfy demand for it. The mental process of making sense of the world that each of us inhabits. A philosophical position regarding the relation between humans and nature. A way of looking at the world or any part of it as an interacting set of parts.
Solar energy is an example.
A portion of the natural or human environment that is not today considered of value, but that one day may gain value as a result of technological, cognitive, or economic developments. A resource that can be depleted but will be replenished by natural processes. Forests and fisheries are examples. An entity consisting of a set of parts that work together to form a whole. The human body, a transportation network, and the earth are all systems.