Precautionary principle

The precautionary principle

 is the concept that establishes it is better to avoid or mitigate an action or policy that has the plausible potential, based on scientific analysis, to result in major or irreversible negative consequences to the environment or public even if the consequences of that activity are not conclusively known, with the burden of proof that it is not harmful falling on those proposing the action. It is a major principle of international environmental law and is extended to other areas and jurisdictions as well.
This principle is important in that it allows one to anticipate harm and take appropriate precautions even in the absence of scientific consensus that the action or policy is harmful and what might be the level of harm. As a result, policy makers are able to make discretionary decisions to delay such an action until scientific findings emerge that provide sound evidence that no harm will result. It is analogous to such commonplace aphorisms as “an ounce of prevention is worth a pound of cure," “better safe than sorry," “look before you leap," and the ancient medical principle associated with Hippocrates of "First, do no harm."
In some legal systems, as in the law of the European Union, the application of the precautionary principle has been made a statutory requirement. However, a rigid application of this principle also has drawbacks, such as ignoring possible risks associated with not doing the proposed activity or policy, perhaps resulting in banning a technology that brings advantages out of concern for potential negative impacts. Under such a scenario, the cellular phone might not have been permitted until it could be proved not to be a carcinogen. In the case of the pesticide DDT, if the precautionary principle were to be applied universally and narrowly, it would mean that DDT could not even be introduced into regions heavily infected by malaria because of the deleterious potential impacts of DDT on the fauna.
The precautionary principle recognizes a social responsibility to protect the public from exposure to harm, when scientific investigation has found a plausible risk. Its development as part of international law reflects a growing international recognition of the human responsibility to care for the environment and others and to find legal avenues to prevent actions that might cause severe or irreversible consequences to either.

Basic components

Many definitions of the precautionary principle exist, with precaution itself defined as “caution in advance,” “caution practiced in the context of uncertainty," or “informed prudence.” All definitions of the precautionary principle have three major components:

1. Anticipate harm and take action to minimize potential harm. This is an expression of a need by decision-makers to anticipate harm before it occurs and an obligation, if the level of harm may be high, for action to prevent or minimize such harm.
2. Onus of proof on proponent. Under the precautionary principle, it is the responsibility of an activity proponent to establish that the proposed activity will not (or is very unlikely to) result in significant harm. This is an implicit reversal of the typical onus of proof, whereby harm needs to be demonstrated.
3. Absence of scientific certainty not an obstacle. The precautionary principle is activated even when the absence of scientific certainty makes it difficult to predict the likelihood of harm occurring, or the level of harm should it occur. There is an obligation, if the level of harm may be high, for action to prevent or minimize such harm, with the control measures increasing with both the level of possible harm and the degree of uncertainty.

It is important to note that, although this principle operates in the context of scientific uncertainty, it generally is considered by its proponents to be applicable only when, on the basis of the best scientific advice available, there is good reason to believe that harmful effects might occur.

Diverse formulations of the precautionary principle

Rio Declaration.; One of the primary foundations of the precautionary principle, and globally accepted definitions, results from the work of the Rio Conference, or "Earth Summit" in 1992. Principle #15 of the Rio Declaration notes (UNEP 1992):

"In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation."

This definition is important for several reasons. First, it explains the idea that scientific uncertainty should not preclude preventative measures to protect the environment. Second, the use of "cost-effective" measures indicates that costs can be considered. This is different from a "no-regrets" approach, which ignores the costs of preventative action.
Note that this definition uses the term “precautionary approach” rather than “precautionary principle,” a not unimportant distinction given the power of law that the term "principle" is sometimes held to convey. (See "Principle" vs. "approach”.)