A steady-state economy is an economy consisting of a constant stock of physical wealth (capital) and a constant population size. In effect, such an economy does not grow. The term typically refers to the national economy of a particular country, but it is also applicable to the economic system of a city, a region, or the entire world. Early in the history of economic thought, classical economist Adam Smith of the 18th century pondered the concept of a stationary state of an economy. Smith thought that any national economy in the world would sooner or later devolve into a final state of "stationarity".
Since the 1970s, the concept of a steady-state economy has been associated mainly with the work of leading ecological economist Herman Daly. As Daly's concept of a steady-state includes the ecological analysis of natural resource flows through the economy, his concept differs from the original classical concept of a stationary state. One other difference is that Daly recommends immediate political action to establish the steady-state economy by imposing permanent government restrictions on all resource use, whereas economists of the classical period believed that the final stationary state of any economy would evolve by itself with no government intervention.
The world's mounting ecological problems have brought about a widening interest in the concept of a steady-state economy. Critics of the steady-state economy usually object to it by arguing that resource decoupling, technological development, and the unrestrained operation of market mechanisms are capable of overcoming any resource scarcity, any rampant pollution, or population overshoot. Proponents of the steady-state economy, on the other hand, maintain that these objections remain insubstantial and mistaken—and that the necessity for a steady-state economy is becoming more self-evident every day.
A steady-state economy is not to be confused with economic stagnation: Whereas a steady-state economy is established as the result of deliberate political action, economic stagnation is the unexpected and unwelcome failure of a growth economy.
An ideological contrast to the steady-state economy is formed by the concept of a post-scarcity economy.