Precautionary Principle

The precautionary principle, which has become a general principle of international law, says that if the environmental consequences of human action may be serious and irreversible, efforts should be made to avoid or lessen them. It is based on the classical virtue of “prudence” and embraces the folk wisdom of “better safe than sorry” and “look before you leap.”

Although uncertainties about the consequences of human behavior have always existed, they have become more significant in recent times because of the growing scope, complexity, and hazard of human activities. This means it is becoming more vital to be able to prevent the harm these activities might do, even without being sure what that is.

Environmental regulations generally aim to prevent known risks rather than anticipate and prevent uncertain potential harm. It is when the risk is uncertain because either the probability of damage is uncertain and/or the extent of damage is uncertain that the precautionary principle applies. When the risk is unknown, then risk assessment is not an appropriate tool to use because the probability of harm cannot be quantified. The precautionary principle fills the gap.

United Nations Educational, Scientific and Cultural Organization's (UNESCO) World Commission on the Ethics of Scientific Knowledge and Technology defines the precautionary principle as follows: “When human activities may lead to morally unacceptable harm that is scientifically plausible but uncertain, actions shall be taken to avoid or diminish that harm.”

“Morally unacceptable harm” refers to harm to humans or the environment that is

• threatening to human life or health, or
• serious and effectively irreversible, or
• inequitable to present or future generations, or
• imposed without adequate consideration of the human rights of those affected.

The judgment of “plausible” should be grounded in scientific analysis. Analysis should be ongoing so that chosen actions are subject to review. “Uncertain” may apply to, but need not be limited to, causality or the bounds of the possible harm. “Actions” are interventions [Page 341]that are undertaken before harm occurs that seek to avoid or diminish the harm. Actions should be chosen that are proportional to the seriousness of the potential harm, with consideration of their positive and negative consequences, and with an assessment of the moral implications of both action and inaction. The choice of action should be the result of a participatory process.

In the past, many products and processes have been marketed without prior approval or any requirement that the manufacturer show evidence that they will not harm human health or the environment. Similarly, many activities and developments have been undertaken without the need for developers to show they will not have an adverse environmental impact. Traditionally, it has been up to consumers, environmentalists, or government authorities to make a convincing scientific case that such activities or products were harmful before they could be regulated. The thinking was that regulations constrained economic activity and should only be justified if there was scientific proof that such activity would cause harm. This is a “wait and see” approach, in which the burden of proof is on those asserting that damage is being or will be done.

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