Part III Conceptual Pillars, Ch.18 Precaution

Abstract

This chapter describes the concept of precaution in international environmental law, which concerns anticipatory action in response to scientifically uncertain threats of environmental harm. Its most frequently referenced formulation can be found in Principle 15 of the Rio Declaration on Environment and Development. The Rio Declaration's endorsement of precaution in Principle 15 introduced to international environmental law a new discourse over the appropriate evidentiary foundations of global environmental regulation. The chapter then focuses on four key questions (and attendant debates) regarding precaution that have been critical in understanding its role in international environmental law. These questions concern the meaning of precaution as a conceptual pillar of international environmental law; the legal status of precaution as a principle of international environmental law; the formulation and understanding of precaution evident from international environmental treaties and case law; and the consequences of applying precaution in decision-making concerning threats of environmental damage.