Uncertainty, Risk and the (in)Applicability of the Precautionary Principle: Reassessing the Scope of Precaution and Prevention in International Environmental Law

While the basic premise of precaution has been widely endorsed in environmental treaties since its inclusion in the Rio Declaration on Environment and Development, as a legal principle, it has been framed in such vastly dissimilar ways that it continues to generate significant disagreement over its precise nature, standing and legal effect. Despite the rich and extensive scholarship aimed at clarifying its normative content and operation, the ongoing lack of consensus on when the precautionary principle is applicable and what its application entails points to fundamental definitional challenges as well as its overall limitations as a regulatory tool. This thesis attempts to move beyond this impasse by reassessing the precautionary principle in light of the distinction traditionally made in formal scientific discourse between risk and uncertainty. While this technical distinction is fundamental to defining the proper scope of the principle’s application, the thesis finds that much of the existing legal discourse has either overlooked or marginalised the risk/uncertainty dichotomy, which in turn has blurred the distinction between the principles of precaution and prevention. The thesis sets out what is meant by these analytically distinct concepts in the legal context, focusing on their implications for the processes of legal reasoning and regulatory decision-making. Having examined the conceptual underpinnings of the precautionary principle, and of the principle of prevention, the thesis proceeds to address a central research question – if uncertainty, as opposed to risk, determines the operational scope of the precautionary principle, to what extent do the current applications of the precautionary principle actually fall within its proper domain? To answer this, the thesis embarks on a deconstruction of the precautionary principle in practice by analysing how precaution has been deployed as an operational principle in particular treaty contexts. The treaty regimes examined here include: international fisheries; persistent organic pollutants; ocean dumping; sanitary and phytosanitary threats under the WTO; and atmospheric pollution and climate change. In each case, the thesis scrutinises the extent to which assumptions, obligations and measures contained therein are consistent with the theoretical underpinnings of precaution. Despite the pervasive use of the precautionary rhetoric in treaty texts and practice, the thesis ultimately finds that, for the most part, these instruments are in fact aimed at specific, scientifically-determined risks, and thus what is often upheld in the name of precaution is actually the prevention principle. The thesis argues that it is better to frame risk regulation through prevention, and not precaution, by considering the implications of abandoning the precautionary principle in those areas where the prevention principle is clearly at play. The thesis completes the analysis by addressing what is actually left for the precautionary principle and discussing some of the distinct ways in which precaution functions within its specific, circumscribed domain.