The Natural Step: The Four System Conditions
System Condition no.1:
Substances from the Earth's crust must not systematically increase in nature.
This means: fossil fuels, metals, and other minerals must not be extracted at a faster pace than their slow redeposit in the earth's crust.
Because: otherwise quality will be lost due to the inevitable spread of wastes and their accumulation toward often unknown limits beyond which irreversible changes occur.
In practical terms this means: radically decreasing mining and use of fossil fuels.
System Condition no. 2
Substances produced by society must not systematically increase in nature.
This means: substances must not be produced at a faster pace than they can be broken down in nature or deposited into the earth's crust.
Because: otherwise quality will be lost due to the inevitable spread of substances and their accumulation toward often unknown limits beyond which irreversible changes occur.
In practical terms this means: decreased production of natural substances that are accumulating, and a phase out of all persistent and unnatural substances.
System Condition no. 3
The physical basis for the productivity and diversity of nature must not be systematically deteriorated.
This means: the productive surfaces of nature must not be diminished in quality or quantity, and we must not harvest more from nature than can be re-created.
Because: our health and prosperity depend on the capacity of nature to reconcentrate and restructure wastes into resources.
In practical terms this means:sweeping changes of our use of surfaces in, for instance, agriculture, forestry, fishing, and planning of society.
System Condition no. 4
Just and efficient use of energy and other resources.
This means: basic human needs must be met with the most resource-efficient methods possible, incuding a just resource distribution..
Because: humanity must prosper with a resource metabolism meeting system conditions 1-3. This is necessary to get the social stability and cooperation for making the changes in due time.
In practical terms this means:an increased technical and organizational efficiency in the whole world, including a more resource-economical lifestyle in the rich part.