1 - Introduction

Summary

Chapter 1 introduces the questions the book focuses on and explains its key contributions to literature on international adjudication. It introduces the three challenges facing international tribunals analysed throughout the book: managing change in applicable law or relevant facts, determining the appropriate standard and method of review when scrutinising State conduct for compliance with international law, and contributing to broader processes of dispute resolution. The chapter explains why the book focuses on environmental disputes, as such disputes lack a dedicated tribunal and are litigated across various regimes, and how it defines such disputes. It also justifies the choice of the four adjudication contexts focused upon (adjudication in the World Trade Organization, the UN Convention on the Law of the Sea, the International Court of Justice, and under investment treaties). The chapter also notes certain insights the book incorporates from methodological debates in comparative law, given its focus on identifying and explaining similarities and differences in how the three selected challenges are managed across the four adjudication contexts studied.

A. Focus and Contributions of the Book

At the broadest level, this book considers how international tribunals might perform their functions given the limitations of their roles and the demands they are being confronted with across several areas of international law. More specifically, the book uses the focus of environmental disputes to reflect upon three cross-cutting challenges confronting international tribunals across four key sites of contemporary international adjudication. The book analyses how tribunals across the World Trade Organization (WTO), United Nations Convention on the Law of the Sea (UNCLOS), International Court of Justice (ICJ), and investment treaty contexts manage the problems of change in relevant legal norms or facts, review of State conduct for compliance with international obligations, and dispute resolution, and why their practices differ.¹

A WTO panel or the Appellate Body decides a dispute concerning an environmental measure that restricts international trade.² A dispute concerning marine environmental harm is brought before the International Tribunal for the Law of the Sea (ITLOS) or an arbitral tribunal under UNCLOS.³ A dispute concerning environmental harm is brought before the ICJ.⁴ A State’s refusal on environmental grounds of a permit required for an investment to operate is challenged by a foreign investor before an arbitral tribunal under an investment treaty.⁵ In each case, the international tribunal is faced with adjudicating the international obligations of a State (or States) in a dispute involving an environmental component. While all the tribunals operate within distinct institutional contexts, they are likely to face, to a greater or lesser degree, several common challenges confronting international tribunals today. How do changes in international law, or changes in relevant facts, affect the tribunal’s task of interpreting and applying obligations under an applicable treaty? How much deference, if any, should the international tribunal afford to determinations made by domestic authorities who may have greater familiarity with local conditions, have applied specialist forms of non-legal expertise, or enjoy greater legitimacy? How should adjudicators scrutinise measures that further one legally protected interest under the relevant regime but undermine another? Should adjudicators apply a test for reasonableness, necessity or least restrictive means, or engage in proportionality balancing stricto sensu? Finally, should adjudicators aim to dispose completely of the parties’ dispute, or should they clarify contested issues of law and fact and hand parts of the dispute back to the parties for further negotiation or cooperation?⁶

The overall argument this book develops is that international tribunals perform several crucial roles or functions in the contemporary international legal order by incrementally adapting international norms, scrutinising State conduct for compliance with international obligations, and contributing to broader processes of dispute resolution. However, international tribunals are subject to significant constraints. These include constraints imposed by States as system designers and controllers, constraints imposed by adjudicators themselves, and other practical limitations.⁷ For example, international tribunals may lack the legitimacy or specialist knowledge needed to engage in significant law-making, weigh competing values, or resolve a dispute in its entirety.

Addressing how international tribunals might discharge their functions is important because international adjudication is at a crossroads. International adjudication has become increasingly central to some areas of international law and international relations over the past 25–30 years.⁸ International tribunals are frequently asked to determine how States’ treaty obligations are affected by changes in international law or relevant facts, or to determine the legality of domestic regulatory measures that are based on specialised forms of expertise and/or strike a contestable balance between competing values. However, substantial concerns have arisen about the desirability of ‘court-based governance of international relations’⁹ in light of its operation in recent decades. Many have raised concerns over the legitimacy of the significant power exercised by international tribunals through their development of legal principles that affect the rights and obligations of actors far beyond the disputing parties.¹⁰ For example, a tribunal’s decision may restrict the policy space of States who were not parties to a case.¹¹ Another common concern is that tribunals embedded within particular regimes – as most contemporary international tribunals are – may promote values specific to their own regime, at the cost of other concerns.¹² Others have posed the question of whether more flexible modes of dispute resolution, such as negotiation, mediation or conciliation, would be better suited to resolving some of the disputes coming before international tribunals.¹³ Far from being issues only of academic interest, these issues are central to ongoing policy debates over reform of existing adjudicatory mechanisms, particularly in relation to investor–State dispute settlement (ISDS) and WTO dispute settlement.¹⁴

International tribunals continue to be presented with a large number of disputes across a variety of institutional contexts. Contemporary adjudicators are, on the whole, acutely sensitive to the broader concerns surrounding their work and often seek to address such concerns in their decisions.¹⁵ Thus, a crucial challenge facing international adjudication is to develop legal doctrines and techniques that respond to the demands facing the contemporary legal order, including by addressing concerns and potential shortcomings that have arisen from the increased adjudicatory activity of recent decades.¹⁶

In addressing these wider issues, this book makes three more specific contributions to our understanding of the functions of contemporary international adjudication. First, this book contributes to debates concerning the role played by international tribunals in incrementally adapting treaty obligations over time, given changes in international law or relevant facts, and, in so doing, balancing the competing interests of stability and change. I explain why this is a key challenge for tribunals in the context of international law’s limited processes for law adjustment and why it plays out differently across the four contexts studied. Second, in relation to the interrelated problems of the appropriate standard and method of review, which arise when adjudicators scrutinise State conduct for compliance with applicable international obligations,¹⁷ this book adds to existing debates that largely focus on WTO dispute settlement and investment treaty arbitration by connecting them to more recent debates over these issues in the ICJ and UNCLOS contexts. This part of the analysis reveals significant opportunities for comparatively informed learning. For example, I will demonstrate that a small number of functionally similar balancing techniques are used across the four contexts studied in scrutinising State measures for compliance with international obligations and suggest that certain lessons emerge regarding how such techniques might be employed. Third, the book adds to understandings of how adjudicators might, through their decisions, contribute to broader processes of dispute resolution. It builds on literature that suggests that international tribunals may in some circumstances play a partly facilitative role by clarifying key questions of law and fact and providing the parties a framework for resolving their dispute and rebuilding their relationship.¹⁸ These three challenges have been selected because they are issues of significance in their own right but also provide a useful proxy for developing a broader comparative assessment of the functions of international adjudication.

A broader, overall contribution made by this book is to analyse how international tribunals might discharge their functions given the varied contexts and constraints within which they operate. Contemporary international tribunals have markedly different design features, reflecting strategic choices made by the States who created them.¹⁹ For example, the control mechanisms that States can exercise, such as deciding upon (re)appointments to a tribunal or agreeing upon authoritative interpretations of a treaty, differ significantly across contexts.²⁰ Our understanding of the functions of international tribunals must be sensitive to the marked variations that characterise contemporary international adjudication. In the chapters that follow, I will develop conclusions regarding how the particular context in which each of the tribunals operates shapes how the three selected challenges manifest themselves and are responded to by adjudicators. The analysis also identifies elements that are common across the contexts studied and provide broader insights into the functions performed by international adjudication.²¹

For several reasons, the category of environmental cases provides an ideal lens for the comparative study just described. Environmental disputes lack a dedicated international tribunal and are adjudicated across a variety of ‘borrowed’ fora with diverse design features and functional orientations.²² A substantial number of environmental cases have been litigated in each of the adjudication settings considered and no one institution or professional community has dominated such cases.²³ Accordingly, this category of cases is representative of the sectorial and decentralised nature of contemporary international adjudication,²⁴ and the familiarity with multiple subsystems of international law that this demands of international lawyers.²⁵ Environmental cases highlight the problem of how to respond to change because they often require adjudicators to interpret legal rules agreed at an earlier point – when environmental norms were less well developed – in new ways,²⁶ and because the application of such norms often depends on facts that are prone to change, such as scientific knowledge or technical capacity.²⁷ Additionally, because environmental norms are often vague or ‘standard-like’, environmental cases force adjudicators, in concretising the content of such principles, to walk ‘a tight-rope between application and development of the law’.²⁸ Environmental disputes also pose acutely the question of how intensely international adjudicators should scrutinise domestic-level determinations based on the application of specialised forms of non-legal expertise, an assessment of local circumstances, or the exercise of discretion. Thus, this category of cases foregrounds the problem of the appropriate standard or intensity of review. As environmental disputes typically involve competing economic and ecological interests,²⁹ they also raise the question of which legal techniques international tribunals might use to balance partially competing interests and whether adjudicators should ever themselves weigh the relative importance of competing regulatory aims. Finally, environmental cases have repeatedly raised the question of whether it is appropriate for international tribunals to decide disputes with a partly prospective focus, and, for example, order the parties to cooperate in conducting further environmental monitoring or negotiations.³⁰

Existing international law literature concerning international environmental adjudication largely focuses on the conditions under which international adjudication might act as an effective mechanism for protecting environmental interests.³¹ This book has a different focus as it uses environmental cases as a lens for reflecting back on the functions performed by international adjudication, and how those functions might be discharged, given the varied contexts in which the selected tribunals operate. In short, environmental disputes are used here as a useful terrain for studying the role of adjudication in international law; strictly this is not a book about environmental law.

The remainder of this chapter explains how the book achieves these aims. Section B situates this book in relation to existing debates concerning the functions of international adjudication and expands further on the three challenges facing tribunals that are traced throughout the book. Section C explains how this study has defined what counts as an environmental case and why the four adjudication settings focused upon have been selected. Section D explains certain basic insights the book has incorporated from methodological debates in comparative law. Section E provides an overview of the chapters to come.

B. The Varied Functions of Contemporary International Adjudication

By analysing how adjudicators address the three selected challenges across the four contexts studied, this book investigates the functions that these international tribunals perform. By ‘functions’ I mean the roles played by international tribunals in deciding cases, or what they are doing,³² and how their decisions serve particular ends or purposes,³³ as one part of the broader international legal order.³⁴ Thinking in terms of the functions of international adjudication is useful because international tribunals are designed with different purposes that must be analysed in an institution-specific manner,³⁵ and a tribunal’s specific functions, established by relevant constitutive instruments, are an important influence on how adjudicators perform their roles.³⁶ Furthermore, the decisions of international tribunals are typically multifunctional in that a single decision often has ‘a series of legal and social consequences that one can regard as functions’,³⁷ which are distinct yet overlapping and frequently in tension with each other.³⁸

A primary function of international tribunals is to settle the disputes presented to them in accordance with the applicable law.³⁹ For example, the function of dispute settlement has an explicit basis in both the Statute of the ICJ and the WTO Dispute Settlement Understanding, and both the ICJ and WTO panels and the AB have affirmed this task in their case law.⁴⁰ A traditional view sees the dispute settlement function as limited and private, whereby the task of tribunals ‘is “to do justice” between the litigant States, and to render a judgment or award which takes account of all relevant facts, which is limited to the petitum of the dispute, and which is made with final and binding force’.⁴¹ However, in the course of deciding disputes, tribunals typically perform, even if only indirectly, a variety of other more public functions.⁴² To begin with, even the dispute settlement function is not solely of a private and bilateral nature. The peaceful settlement of disputes arguably serves a broader community interest beyond the disputing parties by preventing disputes festering and escalating into broader international tensions or even violent conflict.⁴³ In some circumstances, tribunals’ decisions might also enable future dispute settlement or ‘bargaining in the shadow’ of such decisions, including by parties who were not involved in the original case.⁴⁴

A second key function served by international tribunals is that they act as ‘agents’ in the development of international law.⁴⁵ There are important differences between other types of law-making, such as concluding treaties or agreeing on treaty amendments or authoritative interpretations, and the far more constrained law-making in which international tribunals have an opportunity to engage.⁴⁶ In particular, international tribunals are constrained by the cases that are brought before them and how those cases are argued by the disputing parties, and there is a strong expectation that tribunals’ decisions will be related to existing legal materials and make use of recognised methods of legal reasoning.⁴⁷ The influence of their decisions also depends, to a greater degree than other forms of law-making, on how they are received in subsequent legal practice.⁴⁸ International courts and tribunals also ‘lack the legitimacy, deliberative character’ and representative nature of some other law-making processes (e.g. multilateral diplomatic fora).⁴⁹ Yet, despite these qualifications, international tribunals are bodies with immense ‘semantic authority’, or ability to shape legal meanings and establish their communications as ‘authoritative reference points in legal discourse’.⁵⁰ By deciding cases, international tribunals contribute, at least incrementally, to the clarification and development of principles that prospectively shape the rights and obligations of actors well beyond the disputing parties.⁵¹ This aspect of contemporary international adjudication has given rise to major legitimacy concerns. Unlike domestic courts, whose decisions can typically be overridden by legislation, international tribunals are largely not under equivalent forms of direct political control because treaties cannot be authoritatively interpreted in the absence of consensus amongst the treaty parties, and treaty amendment procedures typically either require consensus or a specified majority.⁵²

This aspect of the adjudicatory function is broadly where the first cross-cutting challenge traced by this book arises. I argue that adjudicators, in interpreting and applying applicable legal norms, face a challenge of ensuring ‘legal certainty through predictable interpretation of the law and at the same time to make allowance for legal change, without which law cannot live’.⁵³ The challenge of responding to demands for change while providing a sufficient degree of legal certainty and stability has been recognised as one of the key problems facing international adjudication by various commentators who have reflected on the functions of international adjudication over the last century.⁵⁴ Similarly to these earlier perspectives, this book argues that balancing the competing interests of stability and legal certainty on the one hand, and change and responsiveness to new demands on the other, is a pressing problem for international adjudication. In addition to contemporary international law being expected to be responsive to an increasing range of social demands,⁵⁵ in many areas of international law there is little new treaty law being agreed,⁵⁶ compared to the large number of disputes being adjudicated,⁵⁷ meaning the burden of responding to demands for change is frequently placed on adjudicators.⁵⁸ Through their decisions, international tribunals clarify the content of abstract norms and adapt them to changed circumstances.⁵⁹ As Lowe has suggested, international litigation often operates ‘as an alternative to, or substitute for, law reform and treaty-making’.⁶⁰ For example, we will see in Chapter 2 that despite the negotiating processes within the WTO having been largely stalled since the conclusion of the Uruguay Round agreements, WTO law has continued to develop, including through adjudicators interpreting WTO agreements.⁶¹ While judges in any legal system try to avoid being seen to make law, this pressure is ‘particularly heavy’ for international adjudicators,⁶² including because their institutional position ultimately relies upon State consent.⁶³

In analysing the challenge that adjudicators face in balancing the competing interests of stability and change it is useful to distinguish between the questions of changes in legal norms themselves and changes in facts that affect the application of such norms. Where the meaning of a legal norm changes – for example if the meaning of a treaty term is tied to another legal concept that may change – we are dealing with change or evolution in the law.⁶⁴ In contrast, the broad meaning of a legal norm may remain constant but the norm may be applied to changing factual circumstances that will affect what the norm requires at any particular time.⁶⁵ As we will see, environmental cases have frequently raised both the question of potential changes in legal norms and that of changes in facts that affect the application of legal norms.

Another key function of international tribunals is scrutinising the conduct of State authorities for compliance with international law.⁶⁶ The particular manifestation of this function that has attracted substantial attention in recent years is the scenario where a State enjoys a degree of discretion under applicable international legal norms (often a treaty) and an international tribunal must determine whether the State has acted within the limits imposed on its discretion.⁶⁷ Some authors suggest that this ‘compliance monitoring’ role is more present in some contexts, such as WTO adjudication or regional human rights courts, than others, such as the ICJ and ITLOS, which are characterised as primarily concerned with dispute settlement.⁶⁸ This book demonstrates, however, that in the UNCLOS and ICJ contexts adjudicators also frequently grapple with issues that are central to the compliance-monitoring function, such as how to calibrate the appropriate standard or intensity of review and which methods of review to employ.

It is important to emphasise that while throughout this book I refer to a ‘review’ function or similar, whereby international tribunals scrutinise State conduct for compliance with international norms, I do not assume that this can be equated with judicial review as occurs in certain domestic systems of public law. Rather, while an analogy with domestic judicial review has animated much of the international law literature concerning the standard or intensity of review, this analogy does not necessarily hold in all respects.⁶⁹ As Shirlow and Foster have both observed, the analogy with domestic judicial review relies upon a conferred or delegated powers model of sovereignty, whereby a State’s powers are limited rather than plenary, and a tribunal’s task is to determine whether the terms of the delegation have been respected.⁷⁰ Whether this view of sovereignty can be transposed to the international plane is debatable. Relatedly, Fahner has developed an important claim that due to the limited purposes of international courts and tribunals, and their limited powers to directly affect domestic legal systems (e.g. by annulling domestic legal acts), international adjudication, with the exception of regional human rights courts, is not comparable to judicial review in the domestic context.⁷¹ In Fahner’s account, whereas judicial review in domestic systems serves the purpose of ‘legitimising the exercise of public power in a constitutional sense by providing checks on political institutions’, most international courts and tribunals serve the limited purpose of settling disputes in accordance with the norms established by particular sectorial regimes.⁷²

The function of international tribunals of scrutinising State conduct for compliance with applicable international norms is where the second problem traced by this book arises, which is twofold. Specifically, across the four contexts considered I analyse tribunals’ approaches to the interrelated issues of the standard or intensity of review and the methods of review employed.⁷³ The standard of review refers to the intensity of the scrutiny applied by international adjudicators to prior determinations made by another decision-maker, typically an organ of the State whose conduct is being scrutinised for compliance with international obligations.⁷⁴ The standard or intensity of review applied can fall on a variety of points ‘on a continuum bounded by total deference to justifications provided or analysis performed by a primary decision-maker at one end, and substitutionary (de novo) review of the relevant measure and its justification at the other’.⁷⁵ In this book I use the term standard of review, however there are other concepts that are largely synonymous, which also arise in some of the case law analysed, most obviously the ‘margin of appreciation’ doctrine as developed in the jurisprudence of the European Court of Human Rights. These terms are manifestations of the broader concept of ‘deference’, which, as Shirlow puts it, encompasses a wide range of ‘techniques used by international adjudicators to recognise a domestic actor’s superior “authority” to decide issues relevant to the settlement of the dispute brought before the international adjudicator’.⁷⁶

The question of the standard or intensity of review is of central importance for the role played by international adjudication because it directly affects the division of decision-making power between the international and national levels.⁷⁷ Furthermore, the applicable standard or intensity of review is at most partly resolved by applicable treaties and is to a significant degree determined by international adjudicators themselves.⁷⁸ As we will see, the prospect of international tribunals scrutinising, and potentially second-guessing, sensitive domestic determinations, such as determinations concerning environmental risks and how to respond to such risks, raises acute concerns regarding the relative expertise and legitimacy of adjudicators.

The problem of the applicable standard or intensity of review is persistent in the context of the adjudication of a complex and ‘inward-looking’ international law of cooperation, where international law increasingly regulates issues that are the subject of domestic decision-making processes.⁷⁹ Determining whether States have complied with their international obligations frequently requires tribunals to consider contested questions based on specialised forms of expertise, often of a scientific or technical character, which adjudicators are not well placed to answer themselves.⁸⁰ Other actors, including national-level decision-makers who are not courts, and thus not constrained by the inherent limitations of an adjudicatory process, may possess greater subject-specific expertise for answering such questions.⁸¹ Compared to international tribunals, domestic decision-makers also enjoy proximity to local conditions, which can be relevant to applying international norms, particularly in the context of open-ended or standard-type norms the application of which is inherently context specific.⁸² Finally, it is widely recognised that compared to international adjudicators, domestic decision-makers may enjoy greater legitimacy to make certain kinds of determinations, for example discretionary, value-laden determinations such as determining what is in the domestic public interest.⁸³

The issue of the standard of review is already the subject of a substantial literature, particularly in the trade and investment contexts.⁸⁴ The essential move made by this book is to demonstrate that the same basic dilemmas concerning the division of decision-making power between international tribunals and States, and the relative knowledge and legitimacy of international adjudicators, also arise in ‘fact-intensive’ environmental disputes in the UNCLOS and ICJ contexts.⁸⁵ This aspect of the book explains how contextual differences across the four settings studied shape how the problem of the standard of review arises in each context and reveals significant opportunities for comparatively informed learning.

In analysing how adjudicators scrutinise State conduct for compliance with international norms across the four contexts studied, I also trace the related issue of the methods of review, or legal tests, employed by tribunals when faced with balancing two competing legally protected interests.⁸⁶ To varying degrees, across all the adjudication settings studied, there are debates, fuelled by developments in case law, concerning the appropriateness of a limited number of methods of review or legal tests that can be used by adjudicators to strike a balance between two (or more) competing interests both protected by a legal regime. Typically, such tests only have a limited basis in any applicable treaty and are ‘read into the law’ by tribunals.⁸⁷ For example, Foster speaks of ‘regulatory standards’ that are elaborated by international tribunals in successive disputes to give greater determinacy to open-ended international obligations and to provide a formula ‘establishing how competing legal rights and interests are to be balanced under the applicable international legal provisions and rules’.⁸⁸ Examples of such methods of review developed by international tribunals include reasonableness-based tests, requirements for a rational relationship between a measure and a permissible aim, necessity or least restrictive means testing, and proportionality balancing stricto sensu.⁸⁹ What is common to these methods of review is that they require a State’s measures to bear a particular relationship to a permissible policy objective.⁹⁰ Additionally, as Foster suggests, such methods of review (or in her terminology ‘regulatory standards’) may be understood as requiring States to engage in ‘internal balancing processes’ and to give some degree of consideration to ‘the legal rights and interests of other States and their populations’.⁹¹ While the latter point is particularly clear in relation to requirements of ‘due regard’, a concept that has been developed by some of the UNCLOS jurisprudence considered in Chapter 3, other methods of review, such as proportionality analysis or reasonableness tests, also implicitly require a State to balance its own interests with other legally protected rights and interests.⁹²

The basic reason why the problem of the appropriate method of review arises across the legal regimes studied is that all the regimes protect a variety of competing interests, often expressed through treaty provisions drafted at a high level of generality and which use inherently context-specific terms such as ‘reasonable’ or ‘necessary’.⁹³ The effect of such design features is that for those disputes where they have jurisdiction, tribunals determine where the precise balance between the competing interests protected by the relevant provisions lies.⁹⁴ The degree of discretion conferred upon adjudicators by some of these methods of review is highly controversial.⁹⁵ For example, what is widely known as proportionality balancing stricto sensu is the last stage of a structured three (or four)-stage proportionality analysis and asks whether the costs imposed by a measure are disproportionate to its benefits, having regard to the relative importance of the legally protected interest that the measure restricts and the permissible aim that is furthered by the measure.⁹⁶ The prospect of international tribunals engaging in proportionality balancing stricto sensu is highly controversial as it effectively involves them second-guessing the regulating State’s choice of how to prioritise the competing values.⁹⁷

In relation to the methods of review used by tribunals, this book suggests that there are underappreciated possibilities for comparative learning between the trade and investment contexts, where this debate is well established, and UNCLOS and ICJ adjudication, where this issue has only received scholarly attention more recently,⁹⁸ despite comparable problems and adjudicatory responses repeatedly arising in recent case law. Again, however, it will be demonstrated that differences in context remain important and shape how the issue of the method of review arises in different settings. Analysing this issue in wider comparative perspective is important because, across diverse settings, international tribunals are increasingly faced with balancing partially competing interests⁹⁹ and there is a need for legal techniques that can meet this challenge.¹⁰⁰

The third challenge facing contemporary international tribunals analysed by this book concerns whether adjudicators, through their decisions, seek to contribute to broader processes of dispute resolution. Specifically, this part of the analysis considers whether adjudication is largely retrospective and seeks to dispose of a dispute, or whether adjudication also has a partly prospective focus and aims to provide the disputing parties guidance for their future interactions. This aspect of the book builds on various strands of existing literature. As others have highlighted, in some circumstances international adjudication may be most effective in terms of dispute resolution where it clarifies key contested issues of law and fact and provides a framework in which the parties can resolve their dispute, for example through subsequent negotiation.¹⁰¹ This aspect of the analysis is relevant to the role of tribunals in scrutinising State conduct for compliance with international norms, with many suggesting that adjudicators are, given their legal training, better equipped to judge the decision-making procedure a State has followed, such as which interests it has taken into account, rather than second-guessing the merits of an underlying decision.¹⁰² Facilitative approaches to adjudication that involve a tribunal referring certain issues back to the parties are obviously more deferential than an approach in which the tribunal would itself decide the relevant issues.¹⁰³ Scholars focusing on particular regimes have also praised facilitative and procedurally focused forms of adjudicatory scrutiny in existing jurisprudence. For example, many have argued that certain early WTO Appellate Body decisions offer a desirable example of international adjudication imposing procedural guidelines on the disputing parties’ interactions, such as requiring regulating States to consider affected foreign interests, but leaving the parties scope to resolve the underlying dispute themselves.¹⁰⁴ Law of the sea commentators have also praised the ‘predominantly facilitative’¹⁰⁵ or ‘conflict management role’¹⁰⁶ sometimes performed by ITLOS, whereby the Tribunal has clarified the relevant legal framework and ordered the disputing parties to engage in further cooperation or environmental monitoring.

However, facilitative forms of adjudication have also been subject to significant criticisms. As we will see, an entirely substance-neutral form of adjudicatory scrutiny is an illusion, and even under more procedural forms of review adjudicators must make important normative choices, such as how far States must go in considering foreign interests or pursuing cooperative solutions.¹⁰⁷ The tendency of some tribunals to proceduralise disputes has also been criticised as undermining the aims of the substantive obligations in question, and thus, for example, not producing any improvement in environmental outcomes.¹⁰⁸

The contribution of international tribunals as ‘dispute resolvers’¹⁰⁹ is heavily influenced by their institutional architecture. For example, the prospective nature of WTO remedies, and the fact that findings of non-compliance by WTO adjudicators are typically followed by a process of diplomatic bargaining, means it makes particular sense to view adjudication in that regime as contributing to a broader process of dispute resolution. In contrast, we rarely see investment treaty arbitrators attempting to contribute to a broader process of dispute resolution, as opposed to tribunals aiming to dispose of the parties’ dispute. This is due to several factors including that compensation is the dominant remedy used in investment treaty arbitration, and tribunals are constituted ad hoc and are not well placed to supervise post-adjudication cooperation between the parties. The commercial rather than diplomatic backgrounds of many participants in investment treaty arbitration, and the fact that in many instances the disputing parties will no longer have an ongoing relationship by the time of an award, further explain why we generally do not see investment treaty tribunals performing a partly facilitative, forward-looking role.

C. Issues of Case Selection

1. What Constitutes an Environmental Case?

This book uses the focus of environmental disputes to reflect on the functions of international adjudication and an important question is therefore how to define an environmental case. This book builds on the approach of existing international law contributions that have suggested it is preferable to focus on those disputes that have ‘an environmental or natural resources component’,¹¹⁰ rather than focusing on the apparently environmental characteristics of the applicable law or institutional context.¹¹¹ As we will see throughout this book, disputes with an environmental component routinely arise under treaties and in institutions that might not be characterised as environmental and require one to understand a wide range of other international legal issues.¹¹² Specifically, this book focuses on cases involving adjudication of the obligations of States in disputes that include an environmental component, that is, cases where at least one of the issues at stake is a question of environmental protection or management.¹¹³

This, of course, still raises the question of what counts as an environmental issue or component within a case and generally international lawyers have not spent much time debating definitions of the environment.¹¹⁴ At one level, the question might be answered intuitively based on experience in this area of law. For example, the Iron Rhine Tribunal noted that across international environmental law ‘“environment” is broadly referred to as including air, water, land, flora and fauna, natural ecosystems and sites, human health and safety, and climate’.¹¹⁵ Similarly, Boyle and Harrison note that: ‘Most of what we generally regard as “environmental” concerns pollution of air, freshwater and oceans; climate change; unsustainable use of natural resources; loss of biodiversity, ecosystems and habitat; and conservation of endangered species and natural heritage.’¹¹⁶

Understandings of the environment have ‘expanded rapidly over the past several decades’, shifting from compartmentalised to holistic approaches and increasingly incorporating social, cultural and economic factors.¹¹⁷ Contemporary ecology suggests that the historically influential ‘distinction between “nature” and “human” is untenable’ because ‘[h]uman systems, such as economies, cultures, and polities, are subsystems nested within larger ecological and biogeochemical systems’.¹¹⁸ Above all, the concept of the Anthropocene, developed in the natural sciences and employed in recent years in law and many other disciplines, suggests that the Earth has entered a new geological epoch ‘in which humanity has become the dominant force of global environmental change’ and ‘human and natural forces are intermixed and inseparable’.¹¹⁹ In this perspective, the ultimate unit of analysis is ‘the planet as an interdependent integrated social-ecological system’.¹²⁰

This expansion in understandings of the environment means that more cases will potentially qualify as having an environmental component, and it is appropriate to reject certain definitions that have previously been advanced. For example, writing in 1975, Bilder defined international environmental disputes as disagreements ‘relating to the alteration, through human intervention, of natural environmental systems’, seeking to focus on the natural rather than social environment.¹²¹ Today it is far less certain that the sharp distinction between humans and nature within this definition can hold, given the developments just outlined.

Writing twenty-five years after Bilder, Romano defined an international environmental dispute as ‘[a] conflict of views or of interest between two or more States … relating to an anthropogenic alteration of an ecosystem, having detrimental effect on human society and leading to environmental scarcity of natural resources.’¹²² Part of Romano’s definition, specifically the focus on potential or realised detrimental effects of human-induced alterations of ecosystems, captures much of what is at stake in international disputes with an environmental component. Yet today the inter-State limitation is not appropriate, for example given the massive number of investor–state arbitrations in recent years with an environmental or natural resources component,¹²³ and the substantial jurisprudence developed by regional human rights courts concerning the environment.¹²⁴ Romano’s other restrictions – that the dispute concerns environmental scarcity as opposed to other types of scarcity, for example physical or socio-economic scarcity,¹²⁵ and that renewable, rather than non-renewable, resources are involved¹²⁶ – are also questionable. For example, a large number of investment treaty arbitrations in recent years have concerned non-renewable resources and questions around the host State’s right to allocate the right to exploit such resources and liability for resulting environmental damage.¹²⁷

In selecting the case law to be covered, this book has sought to avoid overly restrictive definitions. This reflects that environmental cases were selected as a focus precisely because they are representative of the highly varied nature of contemporary international adjudication and the professional versatility this demands of international lawyers. Nevertheless, certain restrictions have been imposed. For example, in recent years numerous disputes have arisen in WTO dispute settlement and investment treaty arbitration concerning State measures to incentivise renewable energy sources.¹²⁸ In the WTO context, such disputes have focused on the legality of subsidies and domestic content requirements.¹²⁹ In the investment treaty context, such disputes have focused on State liability for altering the incentives that apply to investments in the renewable energy sector, that is, obligations of regulatory stability and respecting the legitimate expectations of investors under the fair and equitable treatment standard.¹³⁰ Overall, such renewable energy disputes, as they have arisen to date, have only incidentally raised environmental considerations, which, for example, have explained the rationale behind measures to incentivise particular types of energy supply.¹³¹ This book does not place a primary focus on disputes concerning renewable energy incentives; however, such cases are discussed where they are particularly relevant to the themes analysed.

2. The Adjudicatory Bodies Covered

The adjudication settings covered by this book – adjudication in the WTO and under UNCLOS, ICJ litigation, and investment treaty arbitration – were selected because they are the key fora of global reach where environmental cases have been repeatedly litigated.¹³² Compared to existing studies of international environmental adjudication, a key contribution of this book is to provide a state of the art treatment of treaty-based investor–State arbitration, which is analysed in a comparative manner alongside the key sites of inter-State adjudication that regularly hear environmental disputes.¹³³ A question that runs throughout this book is the extent to which treaty-based investor–State arbitration is comparable to the three inter-State adjudication settings studied.

The key international tribunals that regularly hear environmental cases and are not considered by this book are regional human rights courts¹³⁴ and regional courts of economic integration.¹³⁵ This approach was adopted because such bodies are heavily tied to the specific regional human rights or regional integration contexts in which they operate and accordingly raise difficulties for comparative analysis that seeks to draw more general conclusions regarding the functions of international adjudication.¹³⁶ Where a tribunal is embedded within a strong regional integration or regional human rights project, this can provide a basis for adjudicators engaging in certain tasks, such as invalidating national-level measures, or weighing the importance of competing regulatory aims, which are much more controversial in regimes of global reach that do not enjoy any strong value-based consensus.¹³⁷

This book also does not cover quasi-adjudicatory bodies that hear disputes with an environmental component. For example, it does not cover the large number of conferences of the parties and their non-compliance mechanisms developed under multilateral environmental agreements,¹³⁸ human rights treaty bodies and their individual complaint mechanisms,¹³⁹ or the inspection procedures established within multilateral development banks to enable review of projects.¹⁴⁰ As these bodies do not issue binding decisions, they do not meet a key criterion for being included within any definition of international tribunals and the related concept of international adjudication.¹⁴¹ Furthermore, these bodies are sometimes designed to operate in a manner that is markedly different from adjudication, as in the context of many environmental non-compliance mechanisms.¹⁴²

D. Methodological Insights from Comparative Law

This book seeks to identify and explain similarities and differences in how the three selected challenges are managed by adjudicators across the four contexts studied. These are, in short, the traditional aims of comparative law,¹⁴³ and it is instructive to consider methodological debates in comparative law insofar as they may offer insights into the challenges of comparing different sites of international adjudication.¹⁴⁴ Historically, the dominant approach to comparative law has been functionalism, which focuses on functionally equivalent problems and legal solutions developed across different contexts.¹⁴⁵ According to functionalist approaches, the legal doctrines and institutions of different societies can be compared where they fulfil similar functions, and every legal system ‘faces essentially the same problems, and solves these problems by quite different means though very often with similar results’.¹⁴⁶ Functionalism is the subject of substantial debate within comparative law scholarship, and key criticisms include that it ‘exaggerates the extent to which different societies face similar problems’, underemphasises the ‘cultural, economic, political and social context within which legal rules exist’, and cannot provide a basis for evaluating different legal solutions.¹⁴⁷ The major alternative to functionalism that exists in comparative law literature is cultural approaches, which emphasise that legal rules are heavily intertwined with their broader social, economic, and cultural context, and at their strongest suggest that different legal systems are not comparable.¹⁴⁸

The perspective of this book is towards the functionalist end of the methodological spectrum,¹⁴⁹ as the common yardsticks that structure my comparison are three challenges facing international tribunals, namely managing change in applicable legal norms or relevant facts, scrutinising State conduct for compliance with international obligations, and contributing to broader processes of dispute resolution.¹⁵⁰ Much of my analysis focuses on the extent to which the problems faced, legal techniques used in response, and functions performed by tribunals are comparable across the contexts studied.¹⁵¹ This book shares the implicitly functionalist view that comparative inquiry can make one aware of comparable challenges faced, and potentially useful legal techniques developed, in other contexts.¹⁵² However, it is crucial to remember that even where international tribunals appear to face similar problems or develop similar solutions, differences persist reflecting the varied contexts in which tribunals operate and the numerous interrelated factors which shape their work. The challenge is partly one of managing ‘scale change’¹⁵³ and differentiating between levels of analysis because legal regimes often appear similar at one level of analysis and different at another level of analysis.¹⁵⁴

In order to address potential shortcomings of a functional approach, this book analyses in significant detail contextual factors relevant to understanding each of the adjudication settings studied.¹⁵⁵ Each chapter begins with an analysis of such factors, which include whether adjudication occurs within a wider regime with particular goals, the activity of other law-making processes within the regime, whether compulsory jurisdiction exists and which actors can access adjudication, the appointment arrangements for adjudicators, and the types of remedies typically utilised.¹⁵⁶ Attention to such contextual factors is in fact required by a functional approach as the functions of a court or tribunal may be unstated and implicit¹⁵⁷ and become clear through analysis of considerations such as the structure and procedure of a tribunal.¹⁵⁸ I attempt to explain my findings of similarity or difference regarding the case law analysed in light of such contextual considerations.

Clearly, focusing on other aspects of international adjudication may have produced different findings.¹⁵⁹ However, as justified above, the three challenges focused on in this book were selected because they capture key contemporary challenges facing international tribunals, and also serve as a useful proxy for developing a broader, comparative assessment of the functions of international adjudication. Functionalism is a constructive approach to law in that it involves developing hypotheses about the problems faced by legal systems and how they are responded to by legal institutions and doctrines. Accordingly, functional approaches, such as this study, should be judged according to their contribution to our understanding of the legal systems compared.¹⁶⁰

E. An Overview of the Chapters to Come

Chapter 2 analyses the three selected challenges confronting international tribunals – change, review of State conduct, and dispute resolution – in WTO dispute settlement. It demonstrates that within the WTO’s environmental case law, adjudicators have grappled with the question of potential change in applicable international legal norms, and, even more frequently, changes in relevant facts that affect what an applicable legal norm requires at a particular point in time. In the context of disputes under the Agreement on the Application of Sanitary and Phytosanitary Measures, WTO adjudicators have developed a highly structured approach to the issue of the standard of review that may foreseeably be drawn upon by adjudicators in other contexts also faced with ‘fact-intensive environmental disputes’.¹⁶¹ While this approach avoids WTO adjudicators themselves deciding on the correctness of contested scientific claims that are often raised by environmental disputes, it requires adjudicators to determine what counts as an adequate risk assessment process. The chapter analyses the elaborate form of necessity testing that has been developed by WTO adjudicators as a method of review, or balancing test, when scrutinising measures that pursue a permissible regulatory aim but also restrict a competing treaty-protected interest in trade liberalisation.¹⁶² It argues that the WTO’s necessity jurisprudence contains important lessons for other international tribunals. Finally, the chapter considers the contribution of certain early trade and environment disputes to the so-called ‘chapeau jurisprudence’ concerning the general exceptions contained in WTO covered agreements. As noted above, this case law has been interpreted by many commentators as a desirable example of a procedurally focused form of international adjudicatory scrutiny that pushes States to consider affected foreign interests.¹⁶³ In short, although the chapeau jurisprudence does not impose a free-standing obligation to cooperate, these cases highlight that WTO adjudication often contributes to a broader process of dispute settlement, including because of the system’s prospectively focused system of remedies and strong diplomatic ethos.

Chapter 3 analyses the three selected challenges in UNCLOS adjudication, undertaken by ITLOS and arbitral tribunals. The chapter analyses significant examples of UNCLOS adjudicators incrementally adapting the Convention, given changes in wider international law, reflecting, inter alia, that the Convention includes various generic terms, obligations to protect the marine environment framed in general terms, and instructs adjudicators to apply other relevant international law. The standard of review is shown to be a key problem in the context of ITLOS’ prompt release jurisdiction, which raises questions also seen in the other adjudication contexts studied, for example given the greater proximity of domestic authorities to local conditions. The chapter also demonstrates that UNCLOS adjudicators have increasingly employed balancing tests, such as necessity testing, that raise equivalent questions to such methods of review as seen in the other contexts considered, with some UNCLOS adjudicators even noting the parallel to WTO necessity testing. Finally, UNCLOS environmental adjudication provides repeated examples of tribunals attempting to contribute to broader processes of dispute resolution, for example by ordering the disputing parties to engage in further cooperation.

Chapter 4 turns to environmental litigation before the ICJ. The ICJ’s responses to the three selected challenges are shaped by the Court’s general and consent-dependent jurisdiction, which means that it adjudicates across highly varied legal contexts and is particularly sensitive to consent-based concerns. There are repeated examples of the ICJ incrementally updating aging treaties in light of wider developments in international law. In its environmental case law, the ICJ has often faced the question of how to balance two partially competing interests, both protected by the relevant legal regime, and how intensely to scrutinise domestic-level determinations that may have involved the application of specialist forms of non-legal expertise or an assessment of local circumstances. While the Court’s approach to such questions is shaped by the particular context in which it adjudicates, the legal techniques used in scrutinising State conduct for compliance with international law display important functional similarities with those seen in the other contexts studied. The ICJ has often adjudicated with a partly prospective focus, seeking to facilitate future cooperation between the disputing parties.

Chapter 5 addresses investment treaty arbitration. Investment treaty tribunals, like the other international tribunals considered in this book, are often faced with determining whether applicable international legal norms have evolved. However, differently from the other contexts studied, investment treaty tribunals, by applying investment treaty norms in particular disputes, also play a crucial role in determining the permissible degree of change in host State regulation. In scrutinising State conduct for compliance with investment treaty obligations, arbitrators have endorsed many of the reasons for a limited degree of deference to domestic authorities also seen in the other contexts studied. Investment treaty tribunals have also employed methods of review encountered in the other contexts studied, with a growing number of tribunals engaging in the controversial step of proportionality balancing stricto sensu. In contrast to the other adjudication settings studied in this book, there are few examples of investment treaty tribunals performing a forward-looking, facilitative role and contributing to broader processes of dispute resolution. This reflects inter alia that in this context the disputing parties frequently do not have an ongoing relationship by the time of a final award and adjudication is widely understood as a retrospectively focused compensation mechanism, in contrast to the more diplomatic ethos of the inter-State adjudication mechanisms studied.

Chapter 6, which concludes the study, draws together and extends the insights gained from the comparative analysis undertaken. It analyses convergences and divergences in how the three selected challenges are managed across the four adjudication contexts studied and advances explanations for the trends identified. The chapter also reflects on the wider implications emerging from this book for our understanding of the functions of international adjudication in contemporary international law.