"The precautionary approach contained in Principle 15 of the Rio Declaration on Environment and Development is an approach to uncertainty, and provides for action to avoid serious or irreversible environmental harm in advance of scientific certainty of such harm."
CBD Technical Series No. 66
Geoengineering in Relation to the
Convention on Biological Diversity:
Technical and Regulatory Matters
Part I.
Impacts of Climate-Related
Geoengineering on Biological Diversity
September 2012
https://www.cbd.int/doc/publications/cbd-ts-66-en.pdf page 18