Abstract :
Opschoor and Reijnders (1991) propose a simple structure for the development of physical indicators of sustainable development. It begins with the development of two types of environmental indicators: one describing the pressure being placed on the environment, and one describing the effects of this pressure. The sustainability indicator then measures the distance between current or predicted conditions, as described in these simple ‘state’ indicators, and a reference condition.
The reference condition is equated to sustainability. Specification of this reference requires the making of explicit choices as to the types of environmental change. It implies setting standards which make the criteria for sustainability explicit.
The power of this simple construct is demonstrated using three examples. The first Sustainability indicator comprises a pressure indicator describing acid deposition in the Netherlands and a reference condition based on ecosystem sensitivity to this deposition. The second comprises an effect indicator describing species composition in the Dutch North Sea and a reference condition based on past species composition before this ecosystem was adversely affected by pollution, overfishing, etc. The third indicator deals with cadmium accumulation in Dutch soil. It identifies two criteria for sustainability, one constraining additions of cadmium to soil and one specifying soil quality.
