Making environmental policy is essentially an act of balancing the short-term economic interests of present generations and the long-term environmental benefits of posterity. Such balancing ultimately rests on a value judgment, which is formed on the basis of economic, ethical, and scientific considerations of stakeholders. This chapter focuses on the latter aspect of environmental policy-making, namely, the problems that arise in taking into due account the scientific facts in such balancing. It will explore the reasons why scientific warnings on environmental degradation or the risk thereof are often incapable of driving policy decisions, and it will discuss how invoking trust obligations of States may promote a balance that is more sensitive to scientists’ inputs.

This chapter introduces the main concepts, context, focus, and framework of the book. The centre of analysis concerns the scientific engagement techniques of judges, which refers to a host of practices with which international courts and tribunals assess and interact with the scientific dimensions of environmental disputes. Judicial engagement with science will be evaluated with respect to four distinctive stages of the adjudicatory process, notably, the framing of disputes, the process of scientific fact-finding, causal inquiry, and the standard of review. The scope of this study extends to environmental disputes, broadly understood, which appear in the case law of the International Court of Justice, international arbitral tribunals, regional human rights courts, investment arbitral tribunals, the World Trade Organization dispute settlement bodies, and the International Tribunal for the Law of the Sea. The focus of this book is on the reasoning techniques with which international judges can legitimately justify their choices regarding competing science-based claims.

This chapter analyses the environmental case practice of ad hoc inter-state tribunals and arbitral panels established under the aegis of the Permanent Court of Arbitration. Judicial techniques to reflect on the scientific profile of cases are analysed in light of the Bering Sea Fur Seals, Trail Smelter, Lake Lanoux, MOX Plant, MOX Plant OSPAR, Iron Rhine, Southern Bluefin Tuna, Kishenganga, and South China Sea Arbitrations. The chapter examines how adjudicators frame the legally relevant aspects of science-intensive disputes, and the varied avenues tribunals utilize for gathering expert advice. It discusses the significance of appointing independent experts. The chapter also examines the science-based causal inquiries and causal tests from the practice of arbitral tribunals.

This chapter maps the reasons why scientific arguments do not lend themselves to straightforward judicial appraisal. The study identifies epistemic, doctrinal, and legitimacy challenges, which generate difficulties in using science in an adjudicatory setting. Epistemic challenges stem from the fact that science and law are both capable of lending cognitive authority to knowledge claims, and these authorities may be in conflict with each other. Doctrinal challenges emerge from the fundamental differences in the ways in which law and science conceive basic concepts and their different levels of tolerance towards probabilistic evidence and uncertainty. Legitimacy challenges entail difficulties for judges to preserve their monopoly over the resolution of disputes and to select the appropriate rationality to justify their reasoning. This chapter also introduces the analytic framework of the book, which is designed to evaluate the varied judicial reactions given to the intrusion of science into the adjudicatory process. It therefore introduces and discusses the framing of disputes, the scientific fact-finding process, the causal inquiry, and the standard of review.

This chapter identifies an evolving trend in the ICJ’s engagement with science, which has started with the marginalization of scientific evidence, continued with making superficial evidentiary assessments, but ultimately demonstrated an increasing willingness to engage with science. As to framing techniques, mandating the parties’ negotiations in science-intensive questions, the prevalence of finding procedural breaches as well as decoupling the notion of ’risk’ from substantive, scientific criteria will be discussed. In terms of fact-finding, the chapter addresses evolving procedures for taking expert evidence, and applicable standards of proof. The causal analysis evidences the Court’s struggle with establishing the requisite proof in cases of uncertain causation. As to the standard and extent of review, the study examines the reasonableness test, and defends the majority's solution in the Whaling in the Antarctic case based on insights from Science and Technology Studies.

This chapter surveys several entry points through which science becomes legally relevant in WTO law and in trade disputes. It reviews the elaborate techniques of WTO panels and the Appellate Body to engage with scientific evidence in cases involving environmental and health risks. The chapter addresses the WTO’s expert consultation system and discusses the changing canons of deference afforded to WTO members in adopting science-based SPS measures. It extensively analyses the epistemic nature and significance of the two-stage standard of review, under which WTO dispute settlement bodies scrutinize the coherence of the reasoning provided by the risk assessor. The chapter concludes with identifying argumentative techniques in the WTO jurisprudence justifying adjudicatory conclusions concerning scientific evidence and arguments. It distinguishes reasoning methods built on scientific, intuitive, and legal rationality. The chapter also identifies an additional particular reasoning style, which utilizes concepts that are labelled as 'hybrid' benchmarks.

This chapter argues that downplaying science in the judicial inquiry has a fundamental impact on the ways in which legitimate and persuasive reasoning can be crafted. More particularly, not respecting the cognitive authority of science undermines the epistemic legitimacy of decisions. The central yardstick in this respect is not that using more science would necessarily result in better-reasoned judgments; rather, the legitimacy of judgments hinges on how adjudicators reflect on the scientific aspects of disputes in the reasoning. The chapter identifies four types of epistemic yardsticks with which international fora justify the acceptance or rejection of a particular science-based claim. The chapter differentiates between legal, scientific, hybrid, and intuitive reasoning styles, and discusses the benefits and trade-offs of each of them in terms of factual accuracy, epistemic non-arbitrariness, practical feasibility, and preserving the judicial monopoly over adjudication. The chapter also offers solutions for remedying applicable shortcomings, and offers recommendations for selecting a sound approach to scientific knowledge in the judicial reasoning under particular circumstances.

This chapter first identifies the numerous ways in which scientific knowledge may gain legal significance in environmental disputes brought before ITLOS. It then discusses the framing techniques with which ITLOS adjusts the science-intensity of its legal inquiry. In particular, deeming science-intensive disputes justiciable, crafting precautionary justifications, mandating the parties’ expert-led co-operation in scientific issues, and utilizing scientific progress for setting a high bar for states’ due diligence obligations will be discussed. As to fact-finding, the chapter discusses the variety of evidentiary powers granted to the tribunal, and shows that it primarily relies on party-adduced evidence, while leaves its novel fact-finding avenues underutilized. The chapter concludes with discussing the causal tests announced by the tribunal on the rare occasions it has laid out a causal inquiry.