This Article analyzes how scientific uncertainty is handled in international environmental law. It identifies ten legal techniques used for this purpose (i.e., precautionary reasoning," framework-protocol approach; advisory scientific bodies; lawmaking by treaty bodies; managerial approaches to compliance; prior informed consent; environmental impact assessment and monitoring; provisional measures; evidence; and facilitated liability) and links them to four different stages of development of environmental regimes (i.e., advocacy, design, implementation, and reparation). These techniques are illustrated by reference to some fifteen environmental treaties and other instruments as well as through a detailed case study focusing on the climate change regime.
TABLE OF CONTENTS I. INTRODUCTION II. REGIMES AND REGIME DEVELOPMENT A. The Theory of Regimes B. Regime Development III. TACKLING SCIENTIFIC UNCERTAINTY IN THEORY: LEGAL TECHNIQUES USED IN IEL A. Overview of the Techniques B. Analysis of Individual Techniques 1. Precautionary Reasoning 2. Framework-protocol Approach 3. Advisory Scientific Bodies 4. Law-making by Treaty Bodies 5. Managerial Approaches to Compliance 6. Prior Informed Consent 7. Environmental Impact Assessment and Monitoring 8. Provisional Measures 9. Evidence 10. Facilitated Liability III. TACKLING SCIENTIFIC UNCERTAINTY IN PRACTICE: THE CLIMATE CHANGE REGIME A. Introductory Observations B. Scientific Uncertainty in the Climate Change Regime 1. Advocacy 2. Design 3. Implementation 4. Reparation V. CONCLUSION I. INTRODUCTION
Since the modern inception of international environmental law (IEL) in the late 1960s, proponents of international regulation of environmental issues have struggled against scientific uncertainty and economic hostility. From a political standpoint, these two obstacles often have been closely related, as economic hostility has heavily relied upon the considerable scientific uncertainty underlying most environmental challenges at different stages of their understanding and recognition to downplay the legitimacy of environmental regulation. The historical development of the climate change regime provides perhaps the most prominent illustration of this latter point. (1)
However, even when considered objectively, scientific uncertainty remains a major obstacle to the elaboration of efficient environmental regulation. Whether it is to gain momentum for the introduction of such regulation, to design a resilient regulatory system, or to ensure its effective implementation or the reparation of breaches, scientific uncertainty raises daunting challenges. One interesting avenue to addressing these challenges has been the development of a number of legal techniques that deal with scientific uncertainty. Such legal techniques include a broad array of rules, principles, and mechanisms grounded in IEL that provide guidance on the steps to be taken at different stages of the development of an international regime facing scientific uncertainty. In order to better understand the operation of such techniques, it is important to specify further the contours of the challenges scientific uncertainty raises.
In his seminal work, published in 1921, (2) the economist Frank Knight introduced an important distinction between uncertainty and risk. Knight famously noted that
Uncertainty must be taken in a sense radically distinct from the familiar notion of Risk, from which it has never been properly separated.... The essential fact is that "risk" means in some cases a quantity susceptible of measurement, while at other times it is something distinctly not of this character; and there are far-reaching and crucial differences in the bearings of the phenomenon depending on which of the two is really present and operating.... It will appear that a measurable uncertainty, or "risk" proper, as we shall use the term, is so far different from an unmeasurable one that it is not in effect an uncertainty at all. (3) Thus, Knight uses the term "uncertainty" to refer to cases in which the probability of alternative future scenarios cannot be determined, whereas the term "risk" is left for cases where the relative probabilities of alternative future scenarios can be determined (quantified) and at least one of those scenarios is undesirable. (4) In the context of environmental regulation, the term uncertainty normally applies to (1) the initial identification of a phenomenon; (2) the increasing understanding of the processes that govern it; (3) the forecast of its likely consequences, whether positive or negative; and, as the case may be, (4) the processes that can be triggered to manage it. It is unclear at which particular point the uncertainty surrounding a given phenomenon is sufficiently dissipated for that phenomenon to become a risk. Intuitively, one may consider that the more the predictability of a given phenomenon increases and its implications are understood (i.e., once step (3) is reached), the better one can circumscribe and address the potential risk arising from that phenomenon.
To take again the example of climate change, the research on climate change was initially intended to explain prehistoric ice ages (or climate modification for military purposes) rather than future global warming, (5) and, for a long time, it was unable to determine with any accuracy the relative probability of alternative future scenarios. (6) It was only with the advent and subsequent refinement of computer models that global warming technically became a risk. (7) The policy actions accompanying the move from scientific uncertainty to the recognition of risk followed a recognizable pattern that shifted from the increasing allocation of research funds to the actual adoption of mitigation and adaptation measures. As this Article will discuss, most of the legal techniques that have been developed in IEL focus on risks (i.e., partial scientific uncertainty) rather than on uncertainty--even those that come into play at early stages of regime development.
The purpose of this Article is to survey several examples from IEL in order to map the techniques currently available, link them to each stage of regime development, and then discuss their operation in practice. After a brief discussion of the concept of international regimes and their dynamics (Part II), this Article analyzes a number of legal techniques used to deal with scientific uncertainty at different stages of development of international environmental regimes (Part III) and then explores the operation of some of the techniques surveyed in the context of the climate change regime (CCR) (Part IV).
REGIMES AND REGIME DEVELOPMENT
The Theory of Regimes
Both political scientists and international lawyers know well the theory of regimes. (8) This survey therefore is limited to only those concepts that provide the basic structure underlying the analysis conducted in the following Parts.
The context in which regime theory emerged considerably influenced its theoretical premises. In the aftermath of the Second World War, a controversy arose between international legal scholars and political scientists regarding the effectiveness and even the very existence of international law. (9) This controversy lasted three decades. (10) In this context, the theory of regimes appeared as an attempt to provide political grounding to international law or, as noted by one commentator, as an attempt to "[r]einvent international law in rational choice language." (11)
A classical work on regime theory by Stephen Krasner defines a regime as "[a set] of implicit or explicit principles, norms, rules, and decision making procedures around which actors' expectations converge in a given area of international relations." (12) This characterization certainly raises further questions about the definition of its main components. Krasner explains the meaning of those components as follows:
Principles are beliefs of fact, causation, and rectitude. Norms are standards of behavior defined in terms of rights and obligations. Rules are specific prescriptions or proscriptions for action. Decision-making procedures are prevailing practices for making and implementing collective choice. (13) A more detailed understanding of these concepts calls for some additional comments. First, "regimes must be understood as something more than temporary arrangements" or agreements that govern particular ad hoc questions based on short-term calculations of interest. (14) Regimes are only relevant if there exists "some sense of general obligation," (15) which could be compared (although not simply equated) to the legal concept of opinio juris. (16)
A second observation concerns the basic distinction between principles and norms on the one hand, and rules and procedures on the other. The normative dimension or "sense of general obligation" is found above all in principles and norms. (17) Only principles and norms provide the basic defining characteristics of a regime. Rules and procedures also enjoy some degree of normativity, but they have a hierarchically lower position in that "[t]here may be many rules and decision-making procedures that are consistent with the same principles and norms." (18) That said, it is often difficult to distinguish rules from norms, and it seems more realistic to think of a regime as a set of "injunctions of greater or lesser specificity." (19)
Third, the manner in which international regimes influence state behavior is not entirely clear. There are three basic views on the issue of regime significance. One view is that no pattern of behavior can last without generating a congruent regime. (20) Another view is that only political and economic power relations are relevant to understand international politics, so the concept of regimes is a mere facade. (21) A third (intermediate) position holds that international regimes can play a considerable role in structuring state...