Thinking in Systems: A Primer

by Donella H. Meadows

Whether a real renewable resource system can survive overharvest depends on what happens to it during the time when the resource is severely depleted. A very small fish population may become especially vulnerable to pollution or storms or lack of genetic diversity. If this is a forest or grassland resource, the exposed soils may be vulnerable to erosion. Or the nearly empty ecological niche may be filled in by a competitor. Or perhaps the depleted resource can survive and rebuild itself again. I’ve shown three sets of possible behaviors of this renewable resource system here: overshoot and adjustment to a sustainable equilibrium, overshoot beyond that equilibrium followed by oscillation around it, and overshoot followed by collapse of the resource and the industry dependent on the resource.