The Precautionary Principle

When we decide to avoid the use of certain chemicals, materials, or building techniques because they may harm our health or cause serious environmental damage, we are employing the precautionary principle. This principle says that we should avoid potentially harmful actions even if we are not scientifically certain of the extent of the potential damage.

The precautionary principle came to prominence in the 1990s, after participants in the United Nations’ Earth Summit of 1992 declared, “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.” Policymakers have debated finer points on whether the principle should come into play only in the case of “serious or irreversible” damage and whether only “cost-effective” measures should be considered, but either way, the principle (or sometimes, “precautionary approach”) has caught on.