Natural Step

System Conditions from The Natural Step, extracted from Karl Ostrom‘s Ecological Footprint PowerPoint.

1. Substances from the Earth’s crust must not systematically increase in the biosphere
   This means: fossil fuels, metals and other minerals must not be extracted at a faster rate than their redeposit and regeneration in the Earth’s crust.
   
2. Substances produced by society must not systematically increase in nature
   This means: substances must not be produced faster than they can be broken down and be reintegrated into the cycles of nature or be deposited in the Earth’s crust
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 recreated or renewed.
4. There needs to be fair and efficient use of resources with respect to meeting human needs.
   This means: basic human needs must be met with the most resource efficient methods possible, including equitable resource distribution.