Precautionary Principle

"The precautionary principle provides justification for public policy and other actions in situations of scientific complexity, uncertainty and ignorance, where there may be a need to act in order to avoid, or reduce, potentially serious or irreversible threats to health and/or the environment, using an appropriate strength of scientific evidence, and taking into account the pros and cons of action and inaction and their distribution."
(European Environment Agency (2013) "Late lessons from early warnings: science, precaution, innovation", EEA Report No 1/2013, p.649, https://www.eea.europa.eu/publications/late-lessons-2/late-lessons-2-full-report/late-lessons-from-early-warnings/view)