The precautionary principle states that if a project has great environmental
uncertainties, then, given the complexity of eco-systems, the project should be
postponed and only implemented if and when we possess sufficient knowledge
of the eco-system to act with reasonable certainty that the environmental risk is
acceptable. The precautionary principle is very risk averse, being concerned that
unforeseen spread effects may cause disastrous damage. Recognizing that
eco-systems are complex, the precautionary principle states that, if the
environmental uncertainties are great, then a project should be postponed. As a
corollary to the precautionary principle, a project can go ahead if and only if we
possess sufficient knowledge of the eco-system to be reasonably certain that the
project will not create unacceptable environmental damage. Social cost–benefit
analysts may be in the front line of identifying the need to exercise the precautionary principle, because they must identify risks and uncertainties as part
of the social cost–benefit analysis procedure.