5.1 Introduction

As part of the research theme of interpretation of unwritten international law, this chapter zooms in on instances of interpretation of customary international law (CIL) within an institutional context. The involvement of such a ‘context’ – here used to refer primarily to the institutional environment of an international intergovernmental organization – has different facets, which so far have not been systematically examined. The aim of this chapter is to provide an overview of the ways in which institutional context may be connected to the interpretation of custom and to offer a hypothesis on interpretative approaches that may emerge therefrom.

Interpretation in (international) law is generally taken to refer to a ‘process of assigning meaning to … statements for the purposes of establishing rights, obligations, and other consequences relevant in a legal context’.Footnote ¹ It is a commonplace that the interpretation of written international law is an elusive operation.Footnote ² This holds both for interpretation performed as an explicit act, for instance, by a court, and for interpretation performed as a non-formal and often implicit act by legal actors and stakeholders involved. The interpretation of unwritten or customary international law is still a more complex exercise, which makes it a timely topic of study.Footnote ³ International organizations then are frequently the setting for interpretation of customary international law, even when the interpretation is not conceived as a formal or even explicit act.

The picture of custom interpretation in an institutional context is multifaceted. For one, it may be at issue where international custom is applied – and perhaps has been co-created – at general international level by an international organization. It may also be found when inside an organization’s institutional order non-binding rules and norms are set (with resolutions of the UN General Assembly as a prominent example). Technically speaking, these rules may give rise to custom and ultimately become binding that way, to be subsequently interpreted when they are put to application, both by member states and by the organization and both inside and outside the organization’s institutional sphere. In some cases, the organization’s adoption of non-binding instruments such as ‘resolutions’, may as such amount to a form of interpretation, because of the resolution’s (implicit) claim to be declaratory of existing custom.Footnote ⁴

Interpretation of custom by courts and tribunals, even if these do have an institutional dimension, is in principle left out of the account in this chapter. Explicit acts of custom interpretation in a (semi-)judicial setting – eminently valuable for bringing concrete interpretative issues to a head – have already been examined comparatively extensively.Footnote ⁵ In order to capture also more implicit and fluid acts of interpretation, the present chapter focuses on (other) actors and institutional frameworks. This entails the use of a broad notion of ‘interpretation’, which essentially includes ‘application’; this in recognition of the notoriously thin line between ‘application’ and ‘interpretation’Footnote ⁶ (somewhat related to the dual meaning of ‘interpretation’ as CIL ascertainment and as CIL content determination),Footnote ⁷ as well as between ‘interpretation’ and ‘modification’ of rules.Footnote ⁸ It may be argued that such boundaries are still thinner for CIL than for written rules.

The chapter first addresses instances of organizations applying and interpreting customary international law on par with other international actors (Section 5.2), also considering the thorny subject of the contribution of organizations themselves to the formation of custom at international level (Section 5.3). Another main instance where ‘institutional context’ plays a role is when organizations or their member states apply and interpret unwritten international law within the institutional order (Section 5.4). A particular dynamic occurs when organizations produce within the institutional order acts of ‘soft law’, which plausibly in one way or another (co-)create customary international law, to be subsequently developed further through interpretation on the part of the organization and/or the member states (Section 5.5). The chapter then briefly considers the notion of ‘customary institutional law’ (Section 5.6) and proposes some considerations as to what interpretative trends may be surmised in relation to the institutional context (Section 5.7). It ends with concluding remarks (Section 5.8).

5.2 Organizations as Interpreters at International Level

One way in which an institutional context may be at play in interpretation is when international organizations as such apply and interpret general customary international law. A notable example is the domain of international human rights law (IHRL), with which the United Nations (UN) has engaged intensely over time, increasingly also with regard to its ‘own’ conduct. In the background, scholarly discussion continued to be animated by the question as to whether the UN, or any organization, could be considered bound by customary human rights law. The possibility of a customary basis for international human rights had been at issue already in the 1960s and 1970s and had culminated in an unsuccessful attempt in the context of General Comment 24 of the Human Rights CommitteeFootnote ⁹ to list human rights in the Covenant with customary status.Footnote ¹⁰ In its 2007 judgment in the Diallo case, the ICJ confirmed that international human rights have assumed customary status.Footnote ¹¹ Since the 2000s, rules of IHRL were essentially declared by the UN to be binding upon itself,Footnote ¹² and thereby also came to be interpreted by the organization. The field of international humanitarian law (IHL) shows a similar development, as evidenced by the 1999 bulletin of the UN Secretary-General setting out ‘fundamental principles and rules of international humanitarian law applicable to United Nations forces conducting operations under United Nations command and control’.Footnote ¹³

At the same time, the view that international organizations as such could not generate legally relevant practice or opinio juris was widely shared, as appears in a general sense from the travaux of the 1986 Vienna Convention dating from the same period.Footnote ¹⁴ The 2018 ILC Conclusions on the identification of customary international law, addressed below, have echoes of this outlook. They suggest that a binding effect of custom on organizations would be incidental, since the symmetry envisaged in traditional international law – legal actors can only be bound by obligations to which they have consented or by law they have co-created – would be lacking.

Meanwhile, the debate has been spurred, especially by developments in the field of human rights, and the proposition that international organizations are fully bound by relevant customary international law has not been controversial for at least two decades.Footnote ¹⁵ Still, while it is a well-received proposition, it is not always clear by what mechanism international organizations become bound by customary international law, including human rights law and humanitarian law.Footnote ¹⁶ According to one scholar ‘jus cogens norms always bind IOs and … general international law binds IOs as a default matter’.Footnote ¹⁷ Another author, after a careful examination of theoretical explanations of international organizations being bound by custom, and rejection of views that derive such bindingness in some way from the member states, opts for a constitutionalist (arguably ‘public’) view of international law, in which organizations are bound in their capacity of participants in the international order.Footnote ¹⁸

Either way, it is clear that such binding effect cannot be accounted for in the voluntarist and symmetrist reasoning of classic international law, as appears from the next section, which addresses the limitations posed to international organizations as lawmaking actors. This must mean that the proposition rests at least partly on a public law conception of international law: only then does it make sense to admit new members to a ‘legal community’ on condition they accept the legal ‘acquis’ of that community. Such a public law conception in fact points to a view in which all customary international law – including branches that do not focus on the human individual in the way of IHRL and IHL – would be binding on international organizations.

5.3 The Contribution of Organizations to International Custom

Thus, international organizations acting in accordance with customary law that is (construed as) binding upon them is one way in which ‘institutional context’ may be involved with the interpretation of custom. For a further understanding of such involvement, it is helpful also to consider the position of organizations from a reverse angle and look at the – fundamental – question of whether international organizations are able to produce custom or contribute to its formation. As mentioned above, the 2018 ILC Conclusions on the identification of customary international law suggest that contemporary international law and doctrine invariably accord a very modest role to international organizations as independent actors in the formation of customary international law.Footnote ¹⁹ This could seem remarkable, given that international organizations have an ever more prominent role in international legal life.

In the 2018 Conclusions, international organizations appear in two ways: as a platform for the (legal) acts of States and as an independent international-legal actor. Conclusion 4 (‘Requirement of practice’) para 2 is the only provision that refers to the practice of international organizations in their own right, as a possible contribution to ‘the formation, or expression, of rules of customary international law’. This is most likely to occur, according to the commentary – with a clear (and restrictive) reference to ‘regional (economic) integration organizations’ such as the EU – when States have transferred competences to an international organization or ‘conferred powers upon the international organization that are functionally equivalent to the powers exercised by States’.Footnote ²⁰ The opinio juris of organizations is not mentioned, although the commentary states that para 2 of Conclusion 10 (‘Forms of evidence of acceptance as law’) is applicable mutatis mutandis.Footnote ²¹ More generally, the ILC commentary points to a key role for states – where it should be noted that the Reports of the Special Rapporteur in respect of organizations take a more nuanced approach, referring, for example, to ‘operational activities’ of organizations that may amount to ‘relevant practice for purposes of formation and identification of customary international law’.Footnote ²²

Elsewhere I have proposed one explanatory factor for the limited role of organizations in the formation of custom. This is connected to the necessity in international law to ascribe to organizations a ‘juridical will’ – a term used as shorthand for the various subjective ‘intentional states’, such as ‘intention’, ‘opinion’, ‘acquiescence’, ‘consent’, that systems of law project onto legal participants in order to operationalize their legal agency.Footnote ²³ International law seems to have (since the nineteenth century) no problem attributing such legally relevant ‘psychological states’ to a state but traditionally shows signs of hesitation when it comes to an international organization. This in turn can be linked to a functionalist, mechanistic view of organizations’ legal personality, subservient to states as the original legal persons and prime political actors.Footnote ²⁴ It is one reason why the ascertainment of an organization’s opinio juris, or of an organization’s distinct ‘will’ for the purpose of attributing a particular practice, can pose a challenge. It could certainly also stifle the position of organizations as interpreters of CIL at global level.

5.4 Interpretation of Custom inside the Institutional Framework

Another instance of interaction between custom interpretation and institutional context is found when customary rules are interpreted within the institutional framework of an organization. One example is the strong role in (customary) lawmaking processes by the UN High Commissioner for Refugees (UNHCR). It has been argued before that the slow development of treaty-based international refugee law has created a need for more informal ‘soft law’ standards to supplement the provisions found in the 1951 Convention.Footnote ²⁵ Research shows how the UNHCR has filled that gap, interpreting and to a limited extent shaping the obligation of non-refoulement.Footnote ²⁶ This occurs especially through its Executive Committee, which annually adopts by consensus ‘Conclusions on International Protection’. The conclusions are not binding upon states, but they are conceptualized (with an implicit interpretation-claim) as ‘expressions of opinion which are broadly representative of the views of the international community’Footnote ²⁷ and exercise a steady normative influence.Footnote ²⁸ The UNHCR gives evidence of influence on refugee law in several respects, as is pointed out by Trevisanut,Footnote ²⁹ and this is not just about interpretation of written rules. Non-refoulement, which became interlinked with the law of the sea, has long since been ascribed also customary status. This is expressed, for instance, in a UNHCR amicus curiae brief, in which the Agency addresses the geographical remit of the principle of non-refoulement and specifically its application at sea. The brief explicitly draws on ‘the broader human right of refugees to seek asylum from persecution as set out in the Universal Declaration of Human Rights’.Footnote ³⁰

For one who adopts a legal lens, it is not always evident how to distinguish interpretation by the organization from that of the member states. That said, it is undisputed that inside an institutional framework both the organization and the individual member states may engage with rules of custom, sometimes simultaneously. Individual states’ voting behaviour in the UN General Assembly, or inside the institutional framework, is a familiar element in the ICJ’s reasoning on custom, as can be gleaned from the 1986 Nicaragua Judgment and the 1996 Legality Opinion.Footnote ³¹ Further deconstruction of an institutional procedure can be found in the 2011 dispute between the Former Yugoslav Republic of Macedonia (FYROM) and Greece.Footnote ³² When at the 2008 NATO summit Greece blocked FYROM’s bid to become a member of NATO, FYROM claimed that by putting in a negative vote, Greece had breached its obligations under Article 11 of the 1995 Interim Accord between Greece and FYROM. In order to examine possible legal responsibility on the part of Greece for its conduct within NATO, the International Court ‘pierced’ the institutional veil of the organization and found in favour of the claimant. Commentators spoke of ‘the first time in which the ICJ so assertively identified the individual conduct of a State in the process of institutional decision-making.’Footnote ³³

Looking at states, it can moreover be difficult to distinguish between state (interpretative) acts ‘inside’ an international organization and those ‘outside’ of it. No doubt the – porous – boundary between the institutional order of an organization and the general international legal order is ‘real’ in a legal-doctrinal sense. This is borne out by straightforward examples such as Article 5 in the 1969 Vienna Convention on the Law of TreatiesFootnote ³⁴ (i.e. on how the law of treaties applies to treaties adopted within an institutional framework but ‘without prejudice to any relevant rules of the organization’) and Article 64 of the 2011 Draft Articles on the Responsibility of International OrganizationsFootnote ³⁵ (on the ‘rules of the organization’, which as lex specialis would remain outside the scope of the Draft Articles). That said, especially with the (in the words of the ILC) ‘holistic’ exercise of interpretation, it can be unclear whether particular state conduct is part of – in legal terms – an institutional process or a global process. The distinction between the ‘internal’ institutional level and the general international level may be obfuscated all the more when these, in terms of membership, practically overlap, as in the case of an organization with universal membership such as the UN.

This is in addition to the above-mentioned fluidity of categories within the institutional framework, where it can be unclear whether an interpretative act must be attributed to the organization or to individual member state(s). In all cases, it seems logical to start from the ‘constitutional limit’ of organizations or, to put it differently, the principle of speciality,Footnote ³⁶ to determine whether a particular organization as such is even suited to engage with a particular rule or norm. Otherwise, law and practice do not offer clear guidelines in respect of these fuzzy boundaries, which means that sometimes both the organization and the member states will be interpreting the same rule of custom. In a socio-legal vein, who can successfully claim to be the prime interpreting actor might depend on how they have negotiated authority. The shaping and solidifying of the customary ‘human right to water’, which has changed substance and scope several times over the past twenty years, may serve as an example. Apart from classic diplomatic work by states, such as by the international watergezant on behalf of the Netherlands,Footnote ³⁷ the process has involved interpretation within the UN context by institutional bodies (examples are the 2002 General Comment 15 of the ICESCR Committee,Footnote ³⁸ the 2008 Human Rights Council resolution on human rights and access to safe drinking water and sanitation,Footnote ³⁹ and the (not unanimously adopted) 2010 UN General Assembly Resolution on the human right to water and sanitation)Footnote ⁴⁰ and by states (examples are the ‘acceptance speech’ regarding the human right to water and sanitation by the Netherlands in Geneva in 2008Footnote ⁴¹ and individual abstentions by prominent states such as Canada when voting for the 2010 Resolution in the UN General Assembly).Footnote ⁴²

5.5 Normative Acts Produced within the Organization

The institutional context has an especially distinct role in case of the adoption, within an organization of a non-binding act (binding acts are left aside as they would call strictly speaking for the interpretation of written rules). Many ‘soft law’ acts will not give rise to custom, but some of them will. In the latter regard, a preliminary consideration is the classic requirement of a ‘fundamentally norm-creating character’,Footnote ⁴³ to determine whether the normative and prescriptive content of the act is of a suitably general nature. The role of UNGA Resolutions in the formation of customary international law was hotly debated already in the 1970s.Footnote ⁴⁴ The aforementioned ILC Conclusions on the identification of customary international law are a recent pronouncement in this delicate area of international law and doctrine. The Conclusions provide that ‘a resolution adopted by an international organization … may provide evidence for determining the existence and content of a rule of customary international law’.Footnote ⁴⁵

The relevance for custom interpretation is shown by certain UN General Assembly resolutions, which, as instruments, famously constitute ‘soft law’ and as normative substance are then recognized to have crystallized into customary international law. Now, how do non-binding, arguably CIL-creating resolutions of the UN General Assembly fare when it comes to interpretation – such as the 1960 Declaration on the Granting of Independence to Colonial Countries and PeoplesFootnote ⁴⁶ or the 1970 Declaration on Principles of International Law concerning Friendly Relations and Cooperation among States in accordance with the Charter of the United Nations,Footnote ⁴⁷ to name two classics? A solid answer to this question requires separate research. But there is no doubt that the resulting rules and norms are subject to some form of interpretation, be it a ‘by proxy’ textual interpretation (which is readily facilitated by the ample production of text in an institutional context – see below) or a ‘logical interpretation’.Footnote ⁴⁸ Neither is there any doubt that such interpretation can involve both organizations and states, as is apparent for instance in the Chagos Advisory Opinion when the ICJ in relation to the ‘maximalist interpretation of self-determination’Footnote ⁴⁹ based on resolution 1514 (XV) routinely refers to the considerations of both ‘the General Assembly or any other organ of the United Nations’ and of ‘States [who] have consistently emphasized … respect for the territorial integrity of a non-self-governing territory’.Footnote ⁵⁰

In relation to the interpretation of UN General Assembly resolutions, it is otherwise worthwhile to point to the powerful dynamic of contestation and confirmation, which is perhaps not found in regular international relations. This holds equally for other international organizations and their decision-making organs, especially when these are constituted by state representatives. The public records, public voting and tracing of numerical majorities and minorities make for a comparatively proceduralized and stylized process of custom formation and interpretation. This has, for instance, allowed us to follow the – in terms of normative content and customary legal status – hapless fate of the agenda of the ‘New International Economic Order’ that was importantly brought to the fore in the 1974 UNGA Resolution.Footnote ⁵¹ Also the development of the concept of Responsibility to Protect can be traced along a string of soft law instruments, from the ‘launch’ of the concept in 2001 by an external report commissioned by the UN Secretary-General (which left a small opening for the possibility of unilateral humanitarian intervention) to the 2005 UN ‘Outcome Document’ (in which the concept had been re-interpreted so as to align entirely with the collective security system of the UN).Footnote ⁵² Already in the 1940s, a seminal piece was written on the (mostly legal) statements by the UN Secretary-General and their influence on international law.Footnote ⁵³

The 2015 UNGA Resolution promulgating the Sustainable Development Goals,Footnote ⁵⁴ too, is well-placed to generate custom. The intricate process of application and interpretationFootnote ⁵⁵ of the resolution will, interestingly, differ somewhat from classic examples because the normative framework is largely operationalized at the states’ domestic level, through a complex system of indicators (themselves the subject of continuous discussion) and reporting on performance and implementation.

A final example to mention concerns the recommendations of the Universal Periodic Review organized by the Human Rights Council. Unlike the pronouncements and interpretative efforts of (semi-)judicial bodies, the Universal Periodic Review process is not based on a concrete complaint but on member states’ reciprocal recommendations, involving in turn application and interpretation of human rights. As is set out in a fine analysis by Cowell, the ‘[r]ecommendations are numerous and wide ranging but, when aggregated, can demonstrate certain trends in relation to human rights protection’.Footnote ⁵⁶

It has been pointed out that customary international law as a discourse poses a foundational(ist) problem since its grounding is ‘a past social reality’ that ‘can never be traced but can solely be presupposed’.Footnote ⁵⁷ This question emerges also when custom is considered from an immanent, positive law-perspective. Here too, in a different guise, the interpretation of unwritten law is an exercise that rests on shaky ground, because no ‘objective’ text exists but only a proposed rule that is itself an interpretation – thus posing an interpretative challenge akin to that of infinite regress. While it may be true that in one way or another ‘CIL is always shrouded in a “lexical garment”’,Footnote ⁵⁸ especially an environment which produces a considerable amount of written ‘soft law’ or ‘informal law’ – such as an international organization – may at some level bypass this infinite regress problem, as it creates text. Not only is it fair to say that some (non-binding) resolutionsFootnote ⁵⁹ are interpretations, especially where they claim to be declaratory of custom. It is also recognized that (written) re-statements of unwritten law (the Customary IHL Database of the ICRC is a prime example)Footnote ⁶⁰ have a ‘transformative’ dimension.Footnote ⁶¹

5.6 Customary Institutional Law

Focusing on substance, we see that the previous sections deal with ‘general international customary law’. Next to this, a special category of ‘institutional law’ exists within the framework of every international organization. The domain of institutional law comprises both institutional acts with ‘external’ effect (that is, directed at the member states) and institutional acts with ‘internal’ effect (that is, directed at the administration and operation of the organization as such).Footnote ⁶² In principle, ‘customary institutional law’, either within a single organization or as some scholars would have it, shared by multiple organizations (thus amounting to the elusive ‘common law of IOs’),Footnote ⁶³ can come into existence through the same process of interpretation and application.

We frequently find application and interpretation of customary institutional law in the UN context. An example is the unwritten rules – in origin related to the UN Charter – concerning the voting procedure in the UN Security Council (UNSC), which were then applied and interpreted further by the Council in the 1950s when abstention from voting by a permanent member came to be interpreted in such a way that it did not amount to a negative vote and hence would not trigger the ‘veto’.Footnote ⁶⁴ Another example is the continuously developing body of customary institutional rules and legal classifications in regard of the phenomenon of ‘peacekeeping’ that famously has no basis in the UN Charter.Footnote ⁶⁵ More recent re-interpretation of unwritten institutional rules is found with the UN General Assembly. Its practice of decision-making by consensusFootnote ⁶⁶ dates to the 1960s and was itself for a long time based on UN institutional custom, unmentioned in the Rules of Procedure.Footnote ⁶⁷ Interpretation and application of that unwritten rule then produced a new sub-category, the procedure entitled ‘adoption without a vote’. In this case, the UNGA President asks the Assembly if it wishes to adopt a draft resolution or decision. If no objection is made, the president declares ‘it is so decided.’ But this decision, unlike a ‘decision by consensus’, is not followed by a proclamation that ‘consensus has been reached’ and, importantly, (according to current practice) states do not give public explanations of their position.Footnote ⁶⁸ In recent years, this formula has come to be used for politically weighty resolutions.Footnote ⁶⁹

5.7 Interpretative Trends

Can any interpretative trends be inferred from this cursory overview? Clearly, further research is needed for substantiated findings. It is, however, fair to mention that at first blush the examples recounted in this text, especially when these relate to interpretation within the institutional framework of an organization, suggest an alignment of the interpretative exercise with the ‘objectives’ of the organization. This would match a prime characteristic of treaty interpretation in an institutional context, as has been examined notably in relation to constitutive treaties.Footnote ⁷⁰ Because of that match, and also because courts have been found to have recourse to rules of treaty interpretation when interpreting custom,Footnote ⁷¹ it is relevant briefly to consider interpretation of treaties in an institutional context.

In the 1996 WHO opinion, the International Court of Justice stated that ‘the imperatives associated with the effective performance of [the organization’s] functions as well as its own practice’ deserved ‘special attention’ in the interpretation of constitutive treaties.Footnote ⁷² How is this ‘special attention’ brought to bear? Traditionally, treaty interpretation accords considerable weight to the parties’ consent as a basis for the treaty. Articles 31 and 32 of the VCLT thus emphasize a ‘textual’ approach, whether alone or in concert with an ‘intentional’ approach. A similar method may be gleaned from the ICJ’s practice. Conversely, ‘object and purpose’ as an interpretative tool to establish the text’s meaning receives less attention.Footnote ⁷³

In contrast, the interpretation of a constitutive treaty – which embodies the institutional context in that it grounds and sets out the structure of the organization – appears to have been generally inspired by the treaty’s object and purpose or, put differently, by the principle of effectiveness in connection with the objective of the organization.Footnote ⁷⁴ When it comes to organizations’ (binding) secondary law, taken here as extended treaty law, the interpretative practice appears somewhat more restrained than the interpretation of constitutive instruments, likely due to ‘the delegated character of secondary rules’.Footnote ⁷⁵

Overall, one trend in the interpretation of constitutive treaties that stands apart from standard practice is the ‘teleological approach’ to the text, similar to traditions of statutory interpretation in a domestic, constitutional context. Here, some terminological distinction is helpful: the familiar notion ‘object and purpose’ is used in Article 31 VCLT to elucidate a textual approach for discerning the ‘ordinary meaning’ to be given to a treaty’s terms.Footnote ⁷⁶ This is not quite the same as a ‘teleological approach’, which in its classic sense is a general interpretative approach, taking the treaty’s objective as a guiding principle for an ‘effective’ interpretation of the text.Footnote ⁷⁷ Both approaches play a role in the interpretation of constitutive treaties, but the teleological approach is most prominent. It is also the most relevant for the interpretation of custom because it is the least text-bound.

Why teleological treaty interpretation shows signs of prevalence in an institutional context is not entirely clear. One plausible factor is that organizations have a vertical dynamic, as was captured early on by the notion of ‘centralization’ used by Kelsen in relation to the United Nations.Footnote ⁷⁸ Another factor may be that each organization represents a single epistemic community, or ‘interpretive community’, similar to a state domestic legal order governed by a single constitutional instrument.Footnote ⁷⁹ The existence of an interpretative community, reinforced by the ‘sectoral constitutionalization’ in an organization,Footnote ⁸⁰ is a powerful influence – even if of course it is not a simple dynamic. Similar to different branches in public law professions (the legal advisor and the judge, to name two),Footnote ⁸¹ different organs within an organization are known to form distinctive interpretative communities: think of the ‘three UNs’Footnote ⁸² or of the well-known contrast between the UN sector working on Peace and Security (‘UN New York’) and the UN sector involved in Human Rights work (‘UN Geneva’).

The hypothesis put forth in this chapter is that the institutional environment conducive to a teleological interpretation of treaty law also has this effect on the interpretation of customary international law.

5.8 Conclusions

The aim of this chapter is to provide a bird’s-eye view of the scenarios in which custom interpretation is connected with an institutional context – a frequent occurrence. Insight into the specificities and intricacies of these scenarios is therefore an essential tool for our understanding of custom interpretation.

Institutional context can play a role in custom interpretation in two main ways: an international organization may engage in custom interpretation alongside states at the general international level. Secondly, custom may be interpreted by the organization or the member states inside the institutional framework – for instance, through deliberations or decisions of an organ. A striking phenomenon is the production of what this chapter has termed ‘written custom’: non-binding acts adopted by an organization, which give rise to custom that, in turn, is applied and interpreted within (and outside) the framework of the organization.

A key proposition of this chapter is that the steady production of non-binding written instruments makes international organizations a dynamic normative environment with a thriving practice of – mostly implicit – custom interpretation. As argued, this interpretative practice is both relevant and understudied. Hence, the practice of custom interpretation in an institutional context deserves scholarly examination alongside the outstanding research that is focused on explicit efforts of custom interpretation carried out by courts, tribunals and semi-judicial bodies.

As this chapter sets out, the ‘institutional context’ has a number of complexities to be taken into account. Two may be reiterated here. First, the separate institutional sphere of an organization adds a layer of normativity and authority next to that of general international law. Therefore, it may happen that written rules created by the organization would have normative effect within the institutional framework but not per se in general international law (such as the Operational Policies and Procedures of the World Bank). Conversely, a rule of customary international law could be of uncontested validity but not automatically have normative force within the institutional framework.

Second, within the institutional framework, conduct of the organization may not be readily distinguishable from the conduct of member states. As confirmed in the ILC’s work on custom identification, in some situations the question arises as to which entity actually is performing the interpretation. The answer may have implications for the authority and the embedding of the interpretative act. That said, international (institutional) law does not for now offer clear guidelines on this point – with the arguable exception of the ‘principle of speciality’.

As for patterns of interpretation, the introductory overview in this chapter does not allow for solid conclusions. The examples do, however, suggest an orientation on the objective(s) of the organization and/or their expression in IO ‘soft law’ acts. In other words, they point to a predominantly teleological approach. This leads to another key proposition of this chapter, which is that the institutional context apparently conducive to a teleological interpretation of treaty law generally has the same effect when it comes to the interpretation of custom.

For the purpose of this chapter, ‘institutional context’ is defined as the institutional sphere of an international organization. However, we know that in relation to treaty interpretation the ‘institutional effect’ is also found in less formal and more fluid institutional arrangements, such as treaty regimes with a ‘constitutional character’ (possibly featuring a compliance mechanism or a mechanism for subsequent decisions by treaty parties).Footnote ⁸³ Insofar as these regimes engage with custom, it is a reasonable expectation that the ‘institutional effect’ would work in the same way.

The current chapter takes the technical-legal dimension of ‘institutional context’ as a starting point, from the idea that this can contribute to the analytical clarity in a legal examination of custom interpretation. But more angles are possible. With the legal landscape becoming ever more dense, a focus on the politics of interpretation appears ever more important. As illustrated by the aforementioned process of interpretation of the ‘responsibility to protect’, the multilayered and proceduralized environment of an international organization such as the UN brings out the politics of interpretation much more clearly than a classic international law environment.

6.1 Introduction

International humanitarian law (IHL) is the body of law designed to apply in the most extreme circumstances and yet it is subject to the same public international law norms as other bodies of international law: its sources are those listed in Article 38 of the ICJ Statute; it is adjudicated by international and domestic tribunals; and, importantly for the purposes of this chapter, IHL treaties are subject to the same rules of interpretation embodied in the 1969 Vienna Convention on the Law of Treaties (VCLT).Footnote ¹ This has been shown time and again by the practice of StatesFootnote ² and international bodies,Footnote ³ as well as in decisions of international tribunals.Footnote ⁴ It is also widely supported in the legal scholarship.Footnote ⁵ However, as this chapter will discuss, IHL treaties do have some specificities that affect how they are interpreted, one of which is that IHL has a ‘guardian’, the International Committee of the Red Cross (ICRC).

Before delving into how the rules of treaty interpretation apply to IHL treaties, this chapter will explore the ICRC’s role as the guardian of IHL, which gives the organization unique insights into how this body of law, and in particular its core treaties, the Geneva Conventions and their Additional Protocols,Footnote ⁶ are interpreted and applied. It will then zoom in on the ICRC’s legal Commentaries as one tool through which the organization has historically provided extensive guidance on interpreting the Geneva Conventions. Looking at the shifts in methodology behind these Commentaries over time gives important clues as to how IHL treaties have been interpreted over time. Although the Commentaries’ interpretive methodology has evolved, it has done so apace with the evolution of the rules of treaty interpretation in general public international law – culminating in the adoption of the VCLT. The chapter will close by giving examples of how the VCLT methodology is used in the current project to update the ICRC Commentaries and examining some of the particularities of IHL treaties that impact how the VCLT rules are applied.

6.2 Born on the Battlefield: IHL and Its Guardian

In the words of International Law Commission (ILC) Special Rapporteur Georg Nolte, ‘The role which ICRC assumes with regard to the Geneva Conventions for the protection of war victims and their Additional Protocols is a case apart.’Footnote ⁷ The ICRC has been involved in developing, codifying and clarifying IHL,Footnote ⁸ giving it unique insights that are invaluable in the related but distinct work of providing guidance on how to interpret those norms. The ICRC acts as the guardian of IHL in part because of their shared origins and history.Footnote ⁹ The ICRC’s special role as guardian of IHL, most clearly laid out in the Statutes of the International Red Cross and Red Crescent Movement,Footnote ¹⁰ is also partially explained by its consistent response to humanitarian needs on the battlefield, which serves as a foundation for its advocacy for better respect for legal protections and new protections where existing law is not sufficient.Footnote ¹¹

The ICRC undertakes ‘to work for the faithful application of international humanitarian law applicable in armed conflicts … [and] to work for the understanding and dissemination of knowledge of international humanitarian law applicable in armed conflicts and to prepare any development thereof’.Footnote ¹² Because of its role as guardian, the ICRC is an authority that States and scholars often turn to for guidance on how to interpret and apply IHL and an actor with which States actively engage on whether they agree or disagree with the its positions.Footnote ¹³ Indeed, the ICRC’s history is so intertwined with the history of modern IHL and especially its core treaties, the Geneva Conventions and their Additional Protocols, that one might say the organization was “born” to play this role.

The birth of modern IHL and the birth of the ICRC are both commonly traced back to the battlefield at Solferino in 1859, where Swiss businessman Henry Dunant witnessed the battle and saw the townspeople of nearby Castiglione, in particular the women, organizing to collect and care for the wounded soldiers from both sides without distinction.Footnote ¹⁴ Dunant joined in their efforts along with several other bystanders. He described the scene of the battle and the efforts to treat the wounded that followed in vivid detail in his 1862 book, A Memory of Solferino. He made two important proposals in the book: (1) that in every country societies be established – already in peacetime – for the assistance of wounded and sick soldiers (which was at the origin of the ICRC and the wider International Red Cross and Red Crescent Movement) and (2) that internationally agreed rules be laid out to protect the wounded and sick and those who cared for them (which was at the origin of the 1864 Geneva Convention, and its subsequent iterations).Footnote ¹⁵

The ICRC, established in 1863, lobbied for the 1864 Geneva Convention and was present on the battlefield to observe how the law has been interpreted by States since its first application in the 1870–71 Franco-Prussian war.Footnote ¹⁶ Over time, its role in working to ensure respect for IHL was firmly established.Footnote ¹⁷ Because of the important work of the organization, the 1949 Geneva Conventions explicitly provided a role for the ICRC as a neutral intermediary and humanitarian actor, further cementing its special relationship with IHL.Footnote ¹⁸ These Conventions and their Additional Protocols are the core IHL treaties, but other treaties also contain IHL norms, for example, treaties regulating weapons.

Separate from its work in developing the law, the ICRC is uniquely placed to provide insights into how the law has been (and should be) interpreted and applied. It is constantly engaged in interpreting IHL. Indeed, the organization cannot fulfil its humanitarian mission without interpreting IHL treaties, which is ‘at the heart of the ICRC’s daily work’.Footnote ¹⁹ One way the ICRC does this is in providing guidance on how to best interpret and apply IHL norms.

The ICRC has produced numerous interpretive guides,Footnote ²⁰ fact sheets,Footnote ²¹ articlesFootnote ²² and other materialsFootnote ²³ designed to generate understanding and respect for the law, as well as facilitate its interpretation and application. It has published textbooks,Footnote ²⁴ case books,Footnote ²⁵ and a long-running academic journal (the International Review of the Red Cross)Footnote ²⁶ and has produced online databasesFootnote ²⁷ and an application for smartphones.Footnote ²⁸ Among this wealth of IHL resources, treaty commentaries are the most exhaustive interpretive tools produced by the organization.

6.3 The ICRC Commentaries as Interpretive Tools

As IHL grew through the addition of new treaties, the ICRC produced legal commentaries explaining how each provision of those treaties should be interpreted and applied. The methodology behind these commentaries evolved apace with developments in general international law governing how treaties should be interpreted.Footnote ²⁹

6.4 Applying the VCLT to the Geneva Conventions and Their Additional Protocols

In 2011, the ICRC began its project to update its Commentaries on the 1949 Geneva Conventions and their 1977 Additional Protocols, taking into account State practice and legal developments that have taken place in the decades since the Conventions were adopted to ensure the Commentaries are fit for purpose as an interpretive tool for practitioners in contemporary armed conflicts.Footnote ⁵⁹

There is a dedicated team of ICRC lawyers undertaking this project, authoring most of the commentaries on the articles of the Conventions and ensuring the overall coherence of the Commentaries. There are also some external contributors invited to join the project,Footnote ⁶⁰ as well as around fifty external peer reviewers from all over the world for each of the Commentaries and an editorial committee to provide guidance and support to the project team, made up of internal and external legal experts representing academics, judges and military practitioners.Footnote ⁶¹ This is a long way away from the Commentaries that were the work of a single author. The current way of working represents an openness to the views of diverse legal experts and a willingness to acknowledge alternate legal interpretations where there is no consensus.

The VCLT is relied upon as the basis for the interpretations presented in the updated Commentaries despite the fact that the VCLT was adopted twenty years after the conclusion of the 1949 Geneva Conventions, as ‘an international instrument has to be interpreted and applied within the framework of the entire legal system prevailing at the time of the interpretation.’Footnote ⁶² Since the entry into force of the VCLT, the interpretive norms contained in Articles 31–33 have crystallized into customary international law.Footnote ⁶³ It is therefore appropriate to rely on Articles 31–33 of the VCLT as a reflection of customary international law that is applicable to the interpretation of IHL treaties.

The VCLT-based methodology being used to draft the ICRC’s updated Commentaries on the 1949 Geneva Conventions and their 1977 Additional Protocols reflects the fact that IHL treaties must be interpreted according to the same rules as other treaties. While there has been some criticism of how the VCLT’s treaty interpretation has been applied,Footnote ⁶⁴ importantly there has not been any criticism of the use of that methodology, and the updated Commentaries have generally been well-received by the international legal community.Footnote ⁶⁵ Although the updated Commentaries are not always explicit about each step in the interpretive process, the interpretive rules contained in the VCLT underlie the commentary on each article. The reliance on the VCLT represents a change from the methodology used in previous ICRC Commentaries, reflecting the evolution in the general international legal discourse rather than a change specific to IHL. It is also a means of establishing the reliability and authority of the interpretations contained in the Commentaries as based on an established means of treaty interpretation, rather than the personal opinions of their authors. Ultimately, the authority of these updated Commentaries stems from the diligent research on which it is based and faithful application of the rules on treaty interpretation methodology found in the VCLT applied to each individual article in the 1949 Geneva Conventions and their 1977 Additional Protocols.

6.5 An Updated Interpretive Approach for the Updated Commentaries

The standard rules of treaty interpretation apply to IHL treaties as demonstrated through the following concrete examples from the ICRC’s updated Commentaries of how IHL is interpreted today taken from the updated Commentary on the Third Geneva Convention, the most recently published in the series. This chapter will not endeavour to give an in-depth explanation of the VCLT’s interpretive rules, which have been adequately expounded on elsewhere,Footnote ⁶⁶ but rather will look at the particularities of applying these rules to IHL treaties as seen through the lens of the ICRC’s updated Commentaries on the 1949 Geneva Conventions.

6.6 Conclusion

Since the first ICRC Commentary in 1870, the ICRC’s Commentaries on the core IHL treaties are an important demonstration of how IHL treaties should be interpreted in light of the contemporary legal framework. The fact that these Commentaries have consistently been based on the interpretive methodology common to all bodies of public international law is decisive proof that IHL is subject to the same interpretive rules as other bodies of law.

As the general international law discourse on treaty interpretation has become more sophisticated, so has the methodology behind the ICRC’s legal commentaries, reflecting the organization’s understanding of how international humanitarian law treaties are interpreted. Early ICRC Commentaries were presented as the work of a single author expounding on their (actually, his) opinion on how the law should be interpreted and applied, relying on their presence during the negotiations of the treaty in question.

The weight of these Commentaries was expected to come from the reputation of the author, many of whom incorporated their personal views into the text. As time went on, presenting such personal opinions became frowned upon and starting with the 1930 Commentaries the reader gets the sense that the interpretive guidance being provided is focused on the lex lata, rather than the lex feranda in the eyes of the author.

As the international legal community began to approach treaty interpretation with more scientific rigour so did the ICRC. Beginning in the 1950s, teams of legal scholars worked together to present a view of the law informed not only by the negotiations but also the humanitarian needs caused by armed conflict driving the drafters to the negotiating table. In the 1980s even more emphasis was put on convincing readers of the soundness of the interpretations presented through logic, rather than dazzling them with the reputation of the authors.

The current project to update the ICRC Commentaries on the 1949 Geneva Conventions and their 1977 Additional Protocols is using the methodology found in the interpretive rules of the VCLT. Although there are some aspects of IHL that may affect how these rules are applied, it is nevertheless undeniable that they do apply. Furthermore, it is likely that norm-setting multilateral treaties from other bodies of international law would have similar particularities.

Today, the updated Commentaries rely on the practice implementing the 1949 Geneva Conventions and their Additional Protocols, rather than practice that occurred before their conclusion. In contrast to early Commentaries, the updated Commentaries rely on extensive research and the scientific rigour of the methodology to gain the confidence of readers.

At the same time, the updated Commentaries are open to a diversity of views, indicating where there are diverging views and where the ICRC is presenting its own position in the interest of transparency. The involvement of jurists from outside the organization in the drafting process (as authors, peer reviewers and members of the Editorial Committee overseeing the work) indicates a strong desire to produce a practical tool for interpretation of the core IHL treaties that is accepted by practitioners and academics alike.

7.1 Introduction

International human rights supervisory bodies often engage in human rights treaty interpretation when fulfilling their human rights monitoring tasks. Such tasks include considering individual and inter-State complaints, periodic State reports or adopting General Comments. When engaging in interpretation, such bodies may follow certain ‘methods’ of human rights treaty interpretation – including as (loosely) derived from Articles 31–32 of the Vienna Convention on the Law of Treaties (VCLT) or not.Footnote ¹ In nearly all cases, however, bodies will refer to previous interpretative practices generated by themselves or by other bodies and accord to such interpretative practice considerable, great or even ‘authoritative’ weight.

This chapter examines the formal legal role of different ‘interpretative monitoring practices’ of international human rights bodies within the wider ‘practice of international human rights treaty interpretation’. With ‘practice of human rights treaty interpretation’ this chapter refers to the ongoing day-to-day efforts of independent international human rights supervisory bodies to provide meaning to human rights treaties under their supervision, often in response specific questions, situations or contexts. With the ‘interpretative practices’ of supervisory bodies, this chapter refers to the sizeable and diverse body of interpretative materials that are generated by such bodies through their diverse monitoring activities, and which is often attributed some ‘interpretative value’. Key examples of such interpretative practices include the statements made by United Nations (UN) human rights treaty monitoring bodies (UNTBs) in their Views, General Comments or Concluding Observations; or the contributions made by UN Special Procedures of the Human Rights Council through their voluminous body of (thematic) reports or communications. The chapter is premised on the understanding that the different ways in which international human rights bodies are called upon to engage in the development of the content of the treaties, and the wide variety and diversity of interpretative practice that results from this, is arguably unlike any other field of law. The breadth and variety of interpretative practices is rather unique, forming an amorphous body of guidance that is collectively shaping the (evolving) content of the legal framework. This chapter posits that the unique nature of these interpretative practices, both when taken individually and together, is perhaps not fully understood yet as a matter of international law.

By narrowing in on the role(s) of these practices in treaty interpretation, this chapter specifically responds to two recent studies of the United Nations International Law Commission (ILC) that aimed to elucidate the legal value of various ‘pronouncements of (human rights) expert bodies’. First, it recently discussed the ‘interpretative practices’ of human rights bodies as a possible form of ‘subsequent practice’ for treaty interpretation in the sense of Articles 31–32 VCLT.Footnote ² Secondly, it currently considers them as ‘subsidiary means for the determination of rules of international law’ in the sense of Article 38 ICJ Statute. The chapter will incorporate and reflect on these studies and additionally considers several recent judgments of the International Court of Justice that embraced or rejected the use of interpretative practices by UNTBs and UN Special Procedures. Taking into account the ongoing debates in literature as well, it seems that scholarly and practioner’s opinions on the exact legal value or weight to be accorded to human rights bodies’ practices still differ considerably. In several respects, it even seems that they may possess some type of sui generis interpretative value, which is unique to human rights law and that is perhaps not yet well captured to date.

The main aim of this chapter then, is to analyze some of the different positions or approaches taken to date in literature (Section 7.1); by the ILC (Section 7.2); by the ICJ (Section 7.3) and to draw some conclusions as to the formal legal bases or conditions under which various practices could or should be taken into account in practices of human rights treaty interpretation. When or under which conditions may these practices be ‘thrown into the crucible’ of human rights treaty interpretation as part of a so-called single combined operation of treaty interpretation, along with other means to arrive at a ‘legally relevant’ interpretation?Footnote ³ The ‘crucible’ metaphor was notoriously introduced by the ILC in 1966 to highlight that a range of means of interpretation might be available and engaged for treaty interpretation and that the weight to be accorded to them may depend on the specific treaty (provision) and the interpreter involved.Footnote ⁴ In international human rights law, key interpretative means available will typically at least include: ‘the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose’, as well as the principle of ‘good faith’ interpretation.Footnote ⁵ However, by now, it certainly also includes the vast and ubiquitous interpretative monitoring practices of a range of monitoring bodies that together incrementally develop the content of treaty norms over time. This chapter considers specifically which formal role the interpretative practices of the UNTBs and UN Special Procedures of the Human Rights Council could play and also points out that several criteria may be emerging that can help interpreters to determine how to weigh or take into account this body of interpretative guidance as part of the ‘single combined operation’ of treaty interpretation supported by the ILC.

Finally, as noted, the chapter specifically suggests that there may be a unique and still somewhat undefined quality to this body of interpretative work, which deserves to be better fleshed out and studied. Specifically, it posits that the interpretative practice generated by UN bodies might occupy some sui generis position as a means of interpretation, either within, or beyond the context of the VCLT or ICJ Statute. The ILC seems to be trying to articulate this special position through its currently ongoing study on the ‘subsidiary means for the determination of rules of international law’, but it is too early to tell at the time of writing whether the ILC’s conclusions will indeed offer conclusive guidance. This chapter will certainly offer some opinions of its own.

7.2 The Interpretative Practices of International Human Rights Bodies according to Literature

This section introduces and unpacks the different types of interpretative practices of independent UN human rights supervisory bodies, with emphasis on UNTBs and the independent UN Special Rapporteurs of the Human Rights Council. Special emphasis is placed on the ‘formal’ legal arguments that are presented by authors in relation to the legal value and weight to be attached to these practices, for example, by situating them in the context of Articles 31–32 VCLT or Article 38 ICJ Statute, or otherwise. It is noted that the interpretative value of different types of UNTBs monitoring practices has been rather well discussed in literature, although, seemingly, without any consensus on the formal role or position of these practices. Especially the formal role and place of Concluding Observations remains debated. In respect of the UN Special Procedures, it is increasingly recognized that also these bodies by now have engaged in ‘significant law-making and jurisprudential activities that are worthy of note and of systematization’.Footnote ⁶ These points will be further analyzed in this section.

7.3 Interpretative Practices of International Human Rights Bodies according to the ILC

The ILC has recently been studying the formal legal interpretative value of UN human rights bodies’ monitoring practices in two separate studies. Firstly, between 2008 and 2018 it considered the meaning of ‘subsequent agreements and practice’ under Articles 31 and 32 VCLT.Footnote ⁵⁹ Secondly, since 2022 it studies ‘subsidiary means for the determination of rules of international law’ under Article 38 of the ICJ Statute. So far, both studies focus mostly on the work of UNTBs, as State-created (independent) expert bodies especially established to monitor a treaty.Footnote ⁶⁰ The ILC seems to readily accept that Views, General Comments and Concluding Observations ‘often, explicitly or implicitly, interpret the treaty’ and therefore all deserve consideration.Footnote ⁶¹ However, its first study did not consider the work of the UN Special Procedures at all; and a preparatory memorandum for the study on Article 38 prepared by the ILC Secretariat only briefly notes that the work of UN Special Procedures is occasionally referred to by some judicial bodies, for example, when interpreting the term ‘torture’.Footnote ⁶² It is still unclear whether the study on Article 38 ICJ Statute will embrace Views, General Comments and Concluding Observations in equal measure – or perhaps focus on the former two – and will come to include the work of UN Special Procdures. This chapter argues that their work should be part of the study.

The following paragraphs show and discuss how the ILC has obviously been struggling to qualify the legal value of various interpretative monitoring practices of human rights expert bodies in the practice of human rights treaty interpretation. In part, this struggle is caused by the general unclarity on the use of their work in legal practice and literature.

7.4 Interpretative Practices of Human Rights Bodies according to the ICJ

Finally, the ICJ has perhaps struggled most with according a certain legal interpretative value to UN human rights monitoring bodies’ work and formally clarifying their legal status. A first important observation is that the ICJ actually takes various types of interpretative practices of international monitoring bodies ‘into account’ when interpreting specific human right treaties. It emphasizes General Comments and Views of UNTBs but also refers to Concluding Observations or findings of UN Special Rapporteurs. The ICJ has argued that while it is not legally obliged to follow the interpretations offered by ‘other’ supervisory bodies, it ‘must take due account’ of the legal interpretations offered by ‘independent bodies which have been specifically created’ to monitor the application of specific treaties, and ‘it should ascribe great weight’ to them.Footnote ⁹¹

Thus, in the Wall Opinion (2004), the ICJ considered the content of General Comments, Views and Concluding Observations equally, without clearly distinguishing which may be more or most important or ‘authoritative’.Footnote ⁹² In Ahmadou Diallo (2010) it noted that the Human Rights Committee ‘built up a considerable body of interpretative case law’, referring both to its Views and General Comments.Footnote ⁹³

However, the ICJ notoriously does not explicitly clarify on which legal grounds it takes into account or ascribes great weight to various interpretive practices.Footnote ⁹⁴ In Ahmadou Diallo, the ICJ has been most explicit about its reasons, notably: ‘the point’ of consulting the practice of the Human Rights Committee is to ‘achieve the necessary clarity and essential consistency of international law, as well as legal security’.Footnote ⁹⁵ It argued that both ‘individuals with guaranteed rights’ and States parties are ‘entitled’ to this.Footnote ⁹⁶ According to some, this shows support for a ‘systemic argument’ regarding the importance of promoting ‘legal certainty’ or ‘unity of law’.Footnote ⁹⁷ This point is also highlighted in ILC Rapporteur Jalloh’s latest report, addressing the role of subsidiary means in striving for unity of legal interpretations.Footnote ⁹⁸

Problematically, the weight attached to interpretations of UNTBs and Special Procedures by the ICJ differs considerably from case to case, often without much explanation.Footnote ⁹⁹ This reflects poorly on the quality and interpretative legal value of ICJ case-law in this respect. For instance, in its two Advisory Opinions on Israel (2004 and 2024), the ICJ widely refers to a range of interpretative practices of UN bodies to find violations of international human rights law; whilst in the Chagos Advisory Opinion (2019), it only tangentially cites Concluding Observations of the Human Rights Committee to the UK, that is, as part of a wider pattern of argumentation or factual context.Footnote ¹⁰⁰ In the Policies and Practices of Israel-opinion (2024), the ICJ even seems to go as far as largely substituting its own assessments of violations of treaty obligations for findings by different UNTBs. In this advisory opinion, it cites several CERD Concluding Observations to Israel to affirm that the CERD applies extraterritoriality to occupied territories, which are seen as ‘territories under jurisdiction’,Footnote ¹⁰¹ as well as several Concluding Observations of the CERD Committee and Human Rights Committee to support ‘the view that Israel’s residence permit policy is inconsistent with its obligations under CERD and the ICCPR’, resulting ‘in the differential treatment of Palestinians in relation to their right to reside in East Jerusalem’.Footnote ¹⁰² Similarly, it cites several CERD and ICESCR Concluding Observations to support that the residence permit policy violates the ‘right to family life, as guaranteed under Article 10 of the ICESCR and Article 17 of the ICCPR’.Footnote ¹⁰³

On the contrary, in two recent contentious cases on CERD, Qatar v. United Arab Emirates (2021) and Ukraine v. Russia (2022), the ICJ took rather evasive stances and deviated from interpretations of the CERD Committee without any meaningful justification or engagement with its actual pronouncement. This was heavily critiqued by several judges and in literature.Footnote ¹⁰⁴

In Qatar v. United Arab Emirates, the ICJ at least still paid lip service to the idea of ‘ascribing great weight’ to the interpretations of CERD, but it ultimately only indicated that it ‘carefully considered’ the CERD interpretations but arrived at its own interpretations.Footnote ¹⁰⁵ There was little discussion of why it dismissed them. More generally, the interpretative approach of the ICJ in this judgment is somewhat bewildering. For the ICJ seems to deliberately place its consideration of CERD practice outside the VCLT framework. The judgment is structured in such a way that the interpretation of Article 1 CERD takes place through a fairly elaborate consideration of the three elements in Article 31 VCLT (i.e. ordinary meaning, context, object and purpose), followed by a fairly reluctant recourse to the travaux preparatoires of CERD as a ‘subsidiary means of interpretation’ under Article 32 VCLT. Only then, the work of CERD is ‘considered’. According to the ICJ:

Several ICJ judges critiqued this approach. For example, Judge Robinson saw no reason ‘why the Court should not attach great weight to the recommendations of the CERD Committee (which is properly seen as the guardian of the Convention), if they are not in conflict with international human rights law or general international law’.Footnote ¹⁰⁷ Doing so would ‘promote the achievement of the clarity, consistency and legal security’ aspired to by the Court in Ahmadou Diallo.Footnote ¹⁰⁸ He regrets that the majority did not follow the CERD Committee’s recommendation, nor offer ‘any explanation for not following it’.Footnote ¹⁰⁹ Judge Bhandari similarly notes that the majority seems to break with the ICJ’s previous jurisprudence of ‘ascribing great weight’ to the interpretative practice of monitoring bodies and ‘provides no compelling reason as to why it has chosen to depart from the reasoning’ of the CERD Committee or failed to attach great weight to it.Footnote ¹¹⁰ In defence of CERD’s interpretative practice, Judge Bhandari addresses the functioning and work of the Committee in detail. This includes its ‘primary function’ of analyzing and commenting on State reports and its related practice of ‘establishing certain rules in dialogue’ with the parties, as well as its ‘judicial’ approach to matters.Footnote ¹¹¹ He also calls this committee a ‘guardian of the convention’.Footnote ¹¹²

Unfortunately, none of the judges point to a clear legal ground for ‘ascribing great weight’ to CERD practice – except for Judge Bhandari. He considers that the independent Committee Members ‘fall into the category of the “most highly qualified publicists” in this field’,Footnote ¹¹³ thus invoking the notion of ‘teachings of highly qualified publicists’ under Article 38 of the ICJ Statute.

Significantly, several judges noted that the ICJ appears to have misrepresented the legal argument that Qatar presented about (indirect) discrimination and potentially also the CERD Committee’s line of reasoning on indirect discrimination to date.Footnote ¹¹⁴ In this sense, it is vital to ensure that the ICJ, as a general court of law, has a sound understanding of the Convention that it is interpreting, including the (nuanced) interpretative practices developed by a dedicated expert body over a long period of time. The CERD Committee interprets its treaty through day-to-day practice of regularly and consistently engaging with the Convention, its States parties, beneficiaries and the various situations put before it. This seems to be the main message of Judge Bhandari too: the ICJ must tread with caution in providing (one-off) interpretations of human rights treaties, that other bodies have devoted a lifetime of practice to. There may be many interpretative nuances that are missed. Indeed, other judges called out the largely ‘theoretical’ and abstract definitional exercise of the ICJ in Qatar v. UAE.Footnote ¹¹⁵ An important question is then whether the ICJ has engaged in ‘good faith’ interpretation under Article 31 VCLT by dismissing the work of the CERD Committee as it did. At a minimum, the ICJ and the parties should have engaged with the substance of arguments or interpretations made by the committee, but they did not.

Finally, in Ukraine v. Russia (2024), similar concerns of misunderstanding of parties’ arguments played a role, with this judgment largely ignoring available interpretative guidance of UN bodies invoked by Ukraine, including from the CERD Committee.Footnote ¹¹⁶ Throughout this judgment, CERD pronouncements are mostly referred to by the ICJ in relation to issues of fact – thereby avoiding statements on their legal interpretative value. This was again critiqued by some judges and in academic debate; the outcome of this case could have been swayed in another direction had the ICJ followed the concept of (intersectional) indirect discrimination set out by CERD in its General Recommendations more closely.Footnote ¹¹⁷

Dissenting judges agreed that the General Comments of the CERD Committee – which Judge Charlesworth calls ‘the independent body established specifically to supervise the interpretation and application of CERD’ – provide relevant requirements for assessing indirect discrimination; and the same counts for the interpretative practices of other treaty bodies and courts that supervise ‘comparable’ non-discrimination provisions, for example, Human Rights Committee, the ICESCR Committee, the CEDAW Committee and European and Inter-American Court of Human Rights.Footnote ¹¹⁸ This suggests that these judges support a ‘systemic approach’ to the interpretation of similar treaty terms. Indeed, Judge Iwasawa explicitly favours an interpretation that ‘is consistent with the notion of indirect discrimination adopted by other international human rights courts and treaty bodies’.Footnote ¹¹⁹ He supports taking into account interpretative practices related to ‘analogous non-discrimination provisions’ in search of ‘similar interpretations’,Footnote ¹²⁰ rather than relying solely on the ICJ’s own judgment in the matter. Iwasawa thus favours searching for ‘unity’ in the interpretation of similar terms, even across a wider range of treaties than the one under review.

Escobar has recently suggested that the ICJ’s dismissal of UNTBs interpretations could stem from the (occasional) criticism that expert bodies’ interpretations may be too bold or lack ‘rigorous legal and methodological’ analysis or justifications.Footnote ¹²¹ Yet, omitting any meaningful engagement with the pronouncements of UNTBs, either by dismissing them without reason or, instead, referring to them plainly as evidence of certain violations, will not help to move such critiques forward. It only aggravates them. In addition, it is worthwhile to note that ICJ judgments may base its interpretation of a specific provision only on the arguments of a small number of concerned parties; UN expert bodies typically arrive at their interpretations through much more extensive and prolonged engagement or ‘dialogue’ with a range of different parties, including those benefitting from treaty norms. This author argues that deriving from the rather unique nature of the monitoring work of UN expert bodies, also a more nuanced sui generis position could be carved out for them. This argument is further elaborated below.

7.5 ‘Thrown for a Loop’ or ‘Thrown into the Crucible? Reflections on the Legal Value of Various Interpretative Practices

The preceding analysis clearly shows a rather mixed assessment of the ‘formal’ legal value or weight to be accorded to the interpretative practices of UN human rights monitoring bodies in international law. Whilst there seems to be a broad agreement that ‘specially mandated’ expert bodies play an important role in treaty interpretation, the exact legal ground(s) for ‘taking into account’, ‘ascribing great weight’ or using them otherwise (‘in good faith’) still remains somewhat shrouded in legal mystery.

The growth and ubiquity of these interpretative practices after the adoption of the VCLT (1969) and ICJ Statute (1948) means that it has become imperative to consider on which basis, or under which conditions, such interpretations should or must play any authoritative, supplementary, subsidiary, auxiliary or other type of role in providing interpretations of treaties. How might they assist with determining the (ordinary) meaning of treaty terms ‘in their context and in light of the object and purpose of the treaty’, over time?Footnote ¹²² In the words of ILC Rapporteur Jalloh, the question whether the various practices serve a role as ‘subsidiary means’ in the sense of Article 38 ICJ Statute is ‘ripe for discussion’.Footnote ¹²³

As evident from the analysis above, the monitoring practices of different bodies have been variously framed as potentially entering into play under Articles 31 and 32 VCLT (e.g. good faith interpretation, supplementary means or for even systemic interpretation by referring to practices of other bodies interpreting similar norms) or Article 38 ICJ Statute (judicial decisions, teachings or other). They have also been used or ignored without much clarification at all by the ICJ, and there are some indications that they occupy some special sui generis position, either outside the VCLT or within Article 38 ICJ Statute, which is not yet fully articulated to date. Of importance in this respect could be the special way in which interpretative practices of UN human rights bodies come about ‘in dialogue with the parties’ and other beneficiaries over a long period of time and through a variety of monitoring activities.Footnote ¹²⁴

This chapter has not analyzed how international and/or regional human rights bodies themselves have engaged with their own and others’ interpretative practices in any detail. However, it is doubtful that an unambiguous picture would emerge from such study.Footnote ¹²⁵ At present, the ILC seems to be the body mostly clearly and structurally considering their legal value/status/weight. Yet the ILC also admits it has been somewhat limited by the specific topics through which these practices are studied so far. This author is of the opinion that, ultimately, the exact legal status or place of these interpretative practices within the VCLT, Article 38 ICJ Statute or otherwise, may not be the most vital legal question. Instead, this author wants to draw attention to a somewhat more pragmatic line of reasoning that may help to decide which and how certain practices might be ‘thrown into the crucible’ of treaty interpretation, as well as weighted as part of a larger ‘single combined operation’ of treaty interpretation. For, even if it were possible to establish exactly which interpretative practices may or must be taken into account, there may still be additional questions about the overall or specific usefulness of any specific set of Views, General Comments, Concluding Observations, reports etc. In particular, it has been suggested that the interpretative value of specific interpretative statements by UNTBs and Special Procedures may depend on a number of additional factors, which have also been recognized by the ILC and may need to be considered on a case-by-case basis.Footnote ¹²⁶

The ILC recently has begun to formulate several criteria that interpreters may use to pick, weigh and/or emphasize different available means of interpretation. Specifically, it affirmed that the ‘means of interpretation’ listed in Articles 31 and 32 VCLT may be differently emphasized by interpreters ‘depending on the treaty or treaty provisions concerned’, including the ‘character of the treaty or provision’.Footnote ¹²⁷ The weight to be accorded to different available means of interpretation under Article 31 and 32 VCLT collectively, may depend, inter alia, on the clarity and specificity of a practice (e.g. ‘sufficiently concrete’) or on ‘whether and how it is repeated’ (unmindful, with intention, frequency, uniformity).Footnote ¹²⁸ These criteria are not intended to be exhaustive,Footnote ¹²⁹ and the ILC previously mentioned cogency and consistency amongst means found their direct relevance to the treaty term or the number of parties involved in the evolution of particular means.Footnote ¹³⁰

Recently, the ILC’s study on Article 38 ICJ Statute similarly suggested in Draft Conclusion 3 that:

The present author recently proposed a range of possible criteria relevant to human rights supervisory bodies’ practice specifically based on an extensive analysis of positions in human rights literature, practice and in ILC studies, to date.Footnote ¹³² Those criteria include, inter alia:

• a human rights expert body’s use of specific, obligatory, recommendatory, urgent, strong/weak, precise/vague language in its Views, General Comments, Concluding Observations, Reports, Communications etc (e.g. shall, should, may, must; articulating clear courses of action, violations or prohibitions);

• the proximity of a specific statement to an actual piece of treaty text (e.g. does the interpretation intend to offer a clear interpretation of a specific term, e.g. the meaning of torture);

• has the interpretation been (meaningfully) repeated over time (e.g. by the same or by different bodies; has it become a settled interpretation? have any States opposed or supported it; if so, how many and which, on which grounds?);

• what is the procedural quality of the adoption of the statement, e.g. has a certain interpretation been adopted after considerable deliberation, dialogue or consultation, amongst variety or number of different actors and/or after hearing and entertaining different possible legal interpretations, with reference to any specific method of interpretation supported by the VCLT or otherwise?Footnote ¹³³

All of these criteria may need to be fleshed out further over time, but it is argued here that such criteria might ultimately be more ‘legally relevant’ to efforts of treaty interpretation than any ‘formal’ legal placing within the context of the VCLT, ICJ Statute or otherwise.Footnote ¹³⁴ Especially when it comes to the diverse body of interpretative practices of UNTBs and UN Special Procedures, with its variegated qualities, functions and characteristics, such more refined criteria may be of considerable use.

Finally, the analysis presented in this chapter expressly leaves open the possibility that the interpretative practices of UN human rights expert bodies – as day-to-day ‘guardians’ of major multilateral human rights treaties regulating relations between many States and many individuals – indeed occupy somewhat of a sui generis position in international law. For, although human rights monitoring bodies are occasionally admonished for not following any clear methods of interpretation or for not closely adhering to the VCLT, there may in fact be something unique about the (incremental) modes of monitoring and interpretation of these treaties through a wide variety of monitoring activity. As stated several times, human rights treaty interpretation takes place across a wide range of bodies, typically through sustained dialogues with States parties, NGO and victims. Moreover, not yet discussed, human rights treaty interpretation also typically involves capturing the ever-evolving societal notions regarding human rights protection (i.e. the methods of ‘evolutive’ or ‘systemic’ interpretation in human rights practice, their places within the VCLT and the ways in which different practices could enter into play there as well, which were not even properly discussed in the chapter so far).Footnote ¹³⁵

All in all, it may be argued that at present, there is no comparably complex, expansive, diverse and intertwined system of expert-based monitoring available in any other field of public international law; vice-versa, the international human rights law system does not benefit from any systems of State-led development of treaty interpretations, for example, through regular meetings of and decisions by Conferences of Parties.

The efforts of the ILC to uncover the special legal value of the interpretative monitoring practices of UN bodies should therefore be applauded. More generally, the efforts of the ICJ and other bodies to meaningfully and in good faith engage in interpretations of human rights treaties through the VCLT, with ‘great’ or ‘careful’ attention to the various available expert pronouncements, can be improved.

7.6 Conclusion

Rather than remaining ‘thrown for a loop’ about the potential legal value(s) of interpretative monitoring practices of different UN human rights bodies in the practice of human rights treaty interpretation, this chapter suggests leaving some of the formalistic discussions behind somewhat and taking a ‘leap of (good) faith’. It is vital to acknowledge the unique and large volumes of interpretative practices generated by UNTBs and UN Special Procedures. As attested by many, these contributions deserve to be seriously ‘taken into account’, ‘carefully considered’, ‘ascribed great weight’ or appraised ‘in good faith’ when trying to understand the meaning of any specific human rights treaty norm. The basis for doing so may ultimately not (only) be found in a formal interpretation of Articles 31–32 VCLT, Article 38 ICJ Statute or even, strictly speaking, the mandates of specific bodies. This chapter has shown that there could be many different reasons to take practices into account, as well as possibly reasons to take them into account less so.

The International Law Commission is currently firmly taking the lead on studying the legal value(s) to be accorded to a range of legal practices and materials in international law. Amongst them are the various interpretative practices of UN human rights expert bodies, with a focus on the UNTBs. The lack of attention to the work of UN Special Procedures of the Human Rights Council, as another type of State-appointed independent expert, is a major omission.

Interestingly, even since 1966, the ILC has been suggesting that interpretation is to some extent ‘an art, not an exact science’.Footnote ¹³⁶ In particular, there may be various factors or criteria that could be relevant to determining which elements/means can or must be ‘thrown into the crucible’ of treaty interpretation and how they may interact or be weighted as part of a ‘single combined operation’ to find the ‘legally relevant’ interpretation. There is no doubt that the interpretative practices of UN monitoring bodies bear legal relevance to the practice of human rights treaty interpretation. However, whether and how specific interpretative practices might be engaged in any specific act of interpretation, or ‘thrown into any specific crucible’, will depend on the specific treaty (provision) concerned; the breadth, depth and quality of interpretative practice available; and perhaps even on the interpreter.Footnote ¹³⁷

The ILC so far suggests that a range of criteria could be relevant to engaging and/or weighing certain available means of interpretation.Footnote ¹³⁸ Such criteria might include the extent to which certain interpretations came about through a specific formal method or means of interpretation, for example, under the VCLT or ICJ Statute, but more likely, also how well a certain interpretative practice reflects a specific consensus on a certain interpretation by States and others, for example, including beneficiaries of human rights treaties, other supervisory bodies working with similar norms or highly qualified publicists, etc; The author recently proposed a range of criteria that may be relevant to the human rights context specifically (see Section 7.5).Footnote ¹³⁹

This chapter suggests that leaving some of the more formalistic approaches under Articles 31–32 VCLT or Article 38 ICJ Statute behind us, in favour of a set of substantive and procedural criteria for engaging and weighting different interpretative means available, could offer a (more) meaningful way forward for human rights interpretation. In the end, the form of the interpretative practices by expert bodies (General Comments, Views, Concluding Observations, communications, Thematic Reports) may only be a starting point; the quality and usefulness of the interpretative practice in a given setting may still need to be assessed on a case-by-case basis.Footnote ¹⁴⁰ In this sense, the interpretative practices of UN human rights bodies might even occupy some sui generis nature in public international law compared to other regimes: international human rights law uniquely takes shape through, and might be best interpretated based on, the large and amorphous body of continuous and simultaneously occurring (incremental) interpretative practice(s) generated by a variety of repeated supervisory activities of expert bodies, with the inputs from a large range of relevant interpretative actors. The full breadth of this practice may then, in theory, be ‘thrown into the crucible’, but an interpreter should (be able to) justify in good faith with which interpretative means it has (not) engaged, why and how. Section 7.5 proposed a number of criteria to guide this justificatory process. Additional guidance on weighting various means of interpretation, amongst a larger set of means, may become available from the ILC over the next few years through its study on Article 38, but arguably such guidance has to be made practicable for the unique context of human rights law specifically. Ideally the ILC incorporates the work of UN Special Procedures into its consideration of human rights expert bodies’ contributions as well.

8.1 Introduction

This is a self-reflective essay that aims to discuss the contributions of non-judicial actors,Footnote ¹ ranging from United Nations’ (UN) bodies to academic researchers in legal, natural and social sciences, as well as non-governmental organizations (NGOs) and human rights holders, to treaty interpretation as a matter of research design of an inter- and transdisciplinary project – the One Ocean Hub,Footnote ² which the author led. The reflection allows to shed light on the role of diverse actors and experts to co-develop a mutually supportive interpretation of international environmental law, the law of the sea and international human rights law that contributes to enhance, and potentially transform, the protection of the marine environment and of the human rights dependent on a healthy ocean.

As discussed in other chapters of this edited volume, ‘the law and practice in specific fields of international law has reached an unprecedented level of sophistication’,Footnote ³ and this in itself has been a barrier to connecting efforts to address the intertwined challenges of the protection of the marine environment and the protection of human rights.Footnote ⁴ The inter-linkages among these challenges have become increasingly clear in non-legal research, notably in marine and social sciences research,Footnote ⁵ as well as in the actions of researcher-activists working in solidarity with human rights holders.Footnote ⁶ As part of a broader effort of mapping out the current trends in the study of the process of interpretation in international law, this chapter therefore reflects on the increasing need to interpret in an evolutive and mutually supportive manner the rules of international environmental law, the law of the sea and international human rights law. Such evolutive and mutually supportive interpretation is based on new knowledge integrating local experiences of lack of sustainability and other injustices, interdisciplinary scientific evidence and Indigenous and local knowledge systems shedding light on the interdependence of diverse international treaty objectives. This appears necessary with a view to enhancing equity and effectiveness in the realization of the objectives of relevant treatiesFootnote ⁷ and potentially contribute to transforming current governance into more inclusive, sustainable and fair practices at different levels.

To that end, the chapter reflects on the efforts of different UN and other international bodies that provide advisory services to States on how to implement international law,Footnote ⁸ researcher-activists that seek to respond to pressing socio-cultural and environmental injustices at the local and national levels by relying on international law, as well as civil society and human rights holders working with them. The chapter focuses in particular on how these actors are increasingly working together to co-develop mutually supportive interpretations based on local-level experiences of lack of sustainability and of intergenerational injustices, interdisciplinary scientific evidence and Indigenous and local knowledge systems, in order to influence public authorities towards transforming environmental governance into more inclusive, sustainable and fair approaches. The chapter will take as a specific case study for analyzing this trend the One Ocean Hub research programme, which involved all the above-mentioned actors in activities related to the growing international recognition of human rights dependent on a healthy oceanFootnote ⁹ on the basis of mutually supportive interpretations of the international law on the marine environment, international biodiversity law, international climate change law and international human rights law. The chapter will first introduce the concepts of mutual supportiveness under the international law of treaty interpretation, together with the need for self-reflection by international law scholars and the role of collective approaches to interpretation as co-development. The One Ocean Hub will then be introduced as a case study of an inter- and transdisciplinary research programme that was designed on the basis of a mutually supportive interpretation, and the role of international law research as part of inter- and trans-disciplinarity. The chapter will then reflect on the distinctive role of a variety of non-judicial actors in co-developing mutually supportive interpretations of international law on the protection of the marine environment and human rights. Attention will focus on specific examples related to the recognition of ‘ocean defenders’ as environmental human rights defenders. The chapter will conclude with a reflection on how co-development of mutually supportive interpretations can also be institutionalized under treaty law, as a participatory monitoring, evaluation and learning approach embedded in treaty bodies devoted to the review of implementation and/or to technical and scientific advice.

8.2 Mutually Supportive Interpretations of International Law and the Need for Collective Approaches to Self-reflection

Mutual supportiveness is an emerging principle of international lawFootnote ¹⁰ that builds upon the customary rule of treaty interpretation of systemic integration, as enshrined in the Vienna Convention on the Law of Treaties – the need to take into account, ‘any relevant rules of international law applicable in the relationships between the parties’.Footnote ¹¹ Both mutual supportiveness and systemtic integration seek to find a reasonable way to apply different international instruments with minimal disturbance to the operation of the whole international legal system,Footnote ¹² with a view to preserving the unity of the international legal order.Footnote ¹³ In this sense, both also support the principle of good faith, which in its own right supports ‘cross-fertilization and coherence of international legal system’Footnote ¹⁴ through treaty interpretation.Footnote ¹⁵

Systemic integration, however, strictly speaking, applies only to treaties and other binding sources of international law, and there have been debates about whether it only applies to treaties among the same parties.Footnote ¹⁶ Due to these uncertainties, international law scholars have turned their attention to mutual supportiveness, which privileges an interpretative solution that also draws on decisions of treaty bodiesFootnote ¹⁷ and other forms of normative interactions among different international regimes.Footnote ¹⁸ Drawing on such multitude of international legal materials, mutual supportiveness requires, at the interpretative level, that states disqualify solutions to tensions between competing regimes involving the subordination of one regime to the other.Footnote ¹⁹ Mutual supportiveness is enshrined in specific multilateral environmental treatiesFootnote ²⁰ and is understood as a corollary of the principle sustainable development,Footnote ²¹ which is often part of the object and purpose of international environmental law treaties.Footnote ²²

In particular, mutual supportiveness contributes to clarify the legal content of fairness and equity, which are seen as a reflection of both sustainable development and of the general principle of good faith.Footnote ²³ Fairness is usually contained in open-ended treaty provisions in international environmental law and the law of the sea, so these provisions can be filled with content by establishing a linkage with different international legal sub-systems through mutual supportiveness.Footnote ²⁴ As I have argued in earlier work, in the specific case of human rights and the environment, these developments can be understood as evolutive interpretation of the object and purpose of relevant treaties (sustainable development, equity) in the light of emerging (natural and social) scientific evidence that human rights are dependent on healthy ecosystems.Footnote ²⁵ This interpretation in turn contributes to teleological clarity and effectivenessFootnote ²⁶ based on the realization that the respective objectives of different treaties are interdependent for their realizationFootnote ²⁷ and therefore increased cooperation is needed across these regimes to that end.Footnote ²⁸ Such interpretative directions have been adopted explicitly by a variety of global and regional human rights courtsFootnote ²⁹ and non-judicial bodiesFootnote ³⁰ in light of human rights and environmental treaties, such as the Convention on Biological Diversity (CBD), as well as in the light of decisions adopted under the CBD.Footnote ³¹

As I came to realize in my individual and collective international law research aimed at developing mutually supportive interpretations,Footnote ³² however, self-reflexivity needs to be a part of a heightened awareness with regard to unconscious and conscious power and influenceFootnote ³³ on international lawFootnote ³⁴ and national, ideological and structural biasesFootnote ³⁵ and blind spots.Footnote ³⁶ International law scholarship had already underscored that scholars do not explicitly interrogate whether their interpretative efforts are inclusive or exclusive of marginalized voices.Footnote ³⁷ As a result, I have been increasingly interested in the concept explored in the social sciences of self-reflexivity, which includes ‘the explicit articulation of values, assumptions and normative orientations; and renewed attention to asymmetries in power’Footnote ³⁸ in considering how we see our ‘scientific practice, our engagement with other agents within the process of research, how values are reflected in the work we do, and how we sense that research leads to social and political change and transformation’.Footnote ³⁹

In this reflection, I have developed a proposition that a self-reflective interpretative approach to mutual supportive interpretations requires a collective effort among legal scholarsFootnote ⁴⁰ to help one other to identify respective blind spots and biases.Footnote ⁴¹ Based on a distinction proposed by Neil Walker, I have argued that ‘pragmatist’, ‘idealist’ and ‘radically critical’ legal scholarsFootnote ⁴² should work together and constructively challenge one another with their respective insights on other scholars’ limitations. Critical legal scholars can support other lawyers with their ‘systematic attempt to include both the dimension of power and a theory of domination, and the relentless questioning of the “dark sides” of apparently emancipatory and progressive agendas’ in law.Footnote ⁴³ In turn, pragmatic lawyers can support critical lawyers in fully taking into account the actual nuances in the law and support idealist lawyers in anchoring their arguments in existing details of the law or actual workings of it. For their part, idealist lawyers can support both critical and pragmatic legal scholars to move beyond a negative critique or technicist analysis of the law, towards the development of a constructive proposition that can systematically consider the dark sides of law and accurately assess opportunities and constraints in its detailed workings.

What I explored more in my current collaborative research is the contribution of an even broader conversation with other epistemic communities, such as environmental justice scholarsFootnote ⁴⁴ and transdisciplinary researchers exploring the points of contact between different knowledge systems, including natural and social sciences, Indigenous and local knowledge systems and other forms of knowing. Such conversation can feed into the co-developing of mutually supportive interpretations of international law that respond to the needs, insights and life experiences of those most vulnerable to environmental degradation, while taking into account historic, systemic and cross-scalar injustices and carefully surfacing blind spots among all co-researchers, as discussed below.

8.3 The One Ocean Hub as an Example of Research Design Inspired by Mutually Supportive Interpretation

The One Ocean Hub (2019–25) was an inter- and transdisciplinary ocean research collaboration aiming to support fair and inclusive decision-making for a healthy ocean whereby people and the planet flourish. The Hub sought, from the outset, to integrate marine and social sciences, and the arts, as well as Indigenous and local knowledge systems and other forms of knowing, by relying on mutually supportive interpretations of international law on human rights and the marine environment. Such mutually supportive interpretation acted as a connecting frame across academic disciplines and diverse knowledge systems and as a platform for influencing ocean governance across temporal and geographical scales. The attention to different scales implies attention both to historical and current sources of injustices, including intergenerational trauma and colonial legacies, as well as to influences across different geographical scales, including local-to-global or global-to-local dynamics and Global North/South dynamics.

As an inter- and transdisciplinary ocean researchFootnote ⁴⁵ collaboration that was specifically mandated by its funder to achieve long-lasting, sustainable development impacts,Footnote ⁴⁶ the One Ocean Hub had the ambition to serve as a prototype for transformative ocean governance at different scales. Interdisciplinarity refers to efforts to integrate research efforts across different academic disciplines: the intention and challenge here is to move beyond multi-disciplinarity, where different academic disciplines proceed in parallel, and their separate findings are then brought together (juxtaposed) at the end. Instead, interdisciplinarity entails that the basic assumptions, key concepts and prior findings of various disciplines interrogate and challenge one another at the outset of the project, with a view to identifying respective blind spots and biases, eventually leading to the co-identification of research questions, which will then be pursued by various constellations of mixed approaches and findings from different disciplines. At that point, it is still possible and helpful to undertake also disciplinary research (including intra-disciplinary research, such as across different areas of legal scholarship) as long as the research questions are clearly anchored in and informed by the overall interdisciplinary research approach of the project and there are iterative ways to keep interrogating disciplinary research from the perspective of the other disciplines. In addition, transdisciplinarity refers to the effort to co-develop research across academic disciplines and diverse knowledge systems, such as Indigenous science and local knowledge, and the lived experiences and distinctive insights of other human rights holders, such as women and children.

The Hub brought together ocean-dependent people, decision-makers, and civil society in Ghana, Namibia and South Africa, and academic researchers from these countries, the UK and the two regional universities in the Caribbean and South Pacific. In addition, the Hub included legal officers from UN bodies: the UN Environment Programme, the UN Division on Ocean Affairs and the Law of the Sea, the UN Development Programme, the Food and Agriculture Organization of the UN and the Convention on Biological Diversity.Footnote ⁴⁷ Over time, the One Ocean Hub also worked closely with the Office of the High Commissioner for Human Rights and several UN Special Rapporteurs, particularly on Environment and Human Rights, Climate Change and the Right to Food. The Hub, therefore, was conceived as an ambitious attempt to co-develop knowledge across disciplines in different sectors and at different scales (global-local) to address multiple challenges to ocean health that undermine multiple Sustainable Development Goals (SDGs), while developing capacities and approaches to value, and learn from, different knowledge systems and voices at different scales. This was considered necessary to respond more holistically to the cumulative challenges facing marine ecosystems and undermining their multiple contributions to sustainable development.

The Hub research design, and model for research partnerships with all these diverse actors, was framed by international law scholarship and included explicit commitments to contribute to the mutually supportive and evolutive interpretation of international environmental law, the law of the sea and international human rights law in the light of co-produced knowledge on local experiences of lack of sustainability and injustices, interdisciplinary scientific evidence and Indigenous science and local knowledge systems. Specifically, the Hub aimed to develop a mutually supportive interpretation of the ecosystem-based approach under international environmental law and the human rights–based approaches for enhancing the effectiveness and fairness of the implementation of the law of the sea. This was with a view to supporting the implementation of the law of the sea to address multiple and cumulative threats: ocean plastics; ownership, tenure, stewardship and benefit-sharing of ocean space and resources; sustainable renewables and tourism development; climate change responses and disaster risk reduction. To that end, the One Ocean Hub was conceived as the first attempt to test the potential of the Framework Principles on Human Rights and the Environment developed by the UN Special Rapporteur on Human Rights and the Environment, John Knox,Footnote ⁴⁸ to guide the development of coherent, pro-poor, gender-sensitive, climate-proofed and transparent frameworks for ocean management across these sectors.

The Hub took as interdisciplinary research questions to what extent international law on the marine environment is a governance problem, why this is the case and who (among humans and across the marine environment) is most affected by it.Footnote ⁴⁹ Those interdisciplinary research questions were, in turn, meant to allow the Hub to test the extent to which international law can overcome its perceived limits to address intractable challenges through creative reading of existing legal instruments and legal forecasting,Footnote ⁵⁰ based on the understanding arising from the social and marine sciences research, as well as diverse knowledge systems. For instance, what is the potential of legal processes on public consultations, from the local to the international level, to truly take into account the lived experiences, needs, aspirations, distinct knowledge systems and human rights of Indigenous peoples and other ocean-dependent communities, as well as rural women and children, as they are developed and run in ways that are inherently limiting and disempowering.Footnote ⁵¹

The underlying intuition was that the way science and evidence are produced to support future decision-making on the ocean (but also other areas of the global and national sustainable development agendas) is where one needs to ensure genuine co-development by different knowledge holders. Without a co-developed integrated evidence base, it is much harder for ocean decision-makers to consider and understand the perspectives of those that are usually not represented in scientific knowledge production, and therefore to give due consideration to their insights on ocean health and human well-being. In other words, without the inclusion of human rights holders and diverse knowledge holders in the production of evidence base, the opportunities to protect their human rights in decision-making are drastically reduced. On the other hand, relying on the recognition in international law of the interdependence of a healthy environment (including a healthy ocean) and basic human needs (protected as human rights)Footnote ⁵² – as a matter of international law interpretation and research design – served to underscore the need for researchers to engage in inter- and transdisciplinary practices. In turn, integrated evidence from inter- and transdisciplinary research supports decision-makers to prioritize and take action on, as a matter of international law, key findings from the marine and social sciences that aligned in showing how to protect the marine environment with clear benefits for the protection of basic human needs. As part of this process, international law scholarship, particularly focused on treaty interpretation, contributed to build the capacity of different sectors of society (small-scale fishers, Indigenous Peoples, rural women, children, and researchers themselves) to demand legal protection for the ocean and their ocean-dependent human rights and to clarify the corresponding duties of public authorities.Footnote ⁵³

The ultimate assumption of the One Ocean Hub was that the interpretation of international law, in a dialogue with marine and social sciences research co-developed with diverse knowledge holders and human rights holders, could contribute to transformationFootnote ⁵⁴ – the shift away ‘from the technocratic and regulatory fix of environmental problems to more fundamental and transformative changes in social-political processes and economic relations’Footnote ⁵⁵ – in ocean governance at different scales.Footnote ⁵⁶ Here the overarching research question was how to interpret – to the full extent of their potential – provisions in international environmental law, the law of the sea and international human rights lawFootnote ⁵⁷ to identify ‘solutions that also have sustainable impacts at other scales and in other sectors’ and ‘empower those whose interests are currently not being met and represent transformative sustainability values’.Footnote ⁵⁸

To close the circle, transformation is understood to require transdisciplinary governance – the recognition of different knowledge systems and the inclusion of underrepresented types of knowledge in decision-making processes.Footnote ⁵⁹ International environmental law, to some extent, and international human rights law already recognize the need to recognize and integrate Indigenous and local knowledge,Footnote ⁶⁰ but much remains to be clarified about how to genuinely and respectfully do so, while preventing a shifting of the burden of response onto the vulnerable and addressing issues of power and legitimacy.Footnote ⁶¹ These were further research questions that shaped the design and practices of the One Ocean Hub and shed light on the topicality of interpretation across international environmental law, the law of the sea and international human rights law to support transdisciplinarity as an essential precondition for transformation. Transdisciplinarity, as mentioned above, requires engaging with and recognizing the value of non-academic experts, and from an interpretation perspective, this specifically requires engaging with understandings of the law and its underpinnings from legal professionals outside academia (such as UN officers, or lawyers working in NGOs) as well as with Indigenous peoples and local community representatives or children. These were the non-judicial actors that, together with legal scholars, contributed to the co-development of mutually supportive interpretations under the One Ocean Hub.

8.4 The Role of Non-judicial Actors

There is already a significant body of literature on the practices and importance of interpretation ‘from below’ in international human rights law,Footnote ⁶² in particular with a view to overcoming colonial legacies and preventing cultural impositions. These interpretative debates, however, remain limited in international environmental law and even more so in the law of the sea. It has thus been the area of cross-fertilization between international environmental law and international human rights law that initially created a space for shared scholarship on the importance of interpretation from below, notably with a focus on Indigenous Peoples’ human rights.Footnote ⁶³

On the one hand, these mutually supportive interpretation efforts serve to identify and address blind spots and limitations in the State-centric international environmental law, notably with regard to indeterminate environmental obligations with a very wide margin of discretion and an apparent lack of procedural guarantees.Footnote ⁶⁴ A paradigmatic example is that of obligations to carry out environmental impact assessments, which can be found in general international law,Footnote ⁶⁵ as well as international biodiversity lawFootnote ⁶⁶ and the law of the sea.Footnote ⁶⁷ These obligations have been considered so general by the International Court of Justice that the precise content and process of an environmental impact assessment (EIA) was considered a matter left to the State’s discretion.Footnote ⁶⁸ The ICJ, however, in reaching this conclusion, did not consider that the 196 CBD Parties had already clarified, by consensus, the content and process of an EIA to a significant degree.Footnote ⁶⁹ In addition, in a separate decision, the International Court of Justice (ICJ) had interpreted the wording of the applicable CBD provision on EIA as not even giving rise to a legally binding obligation, because of the vagueness of its formulation.Footnote ⁷⁰ Instead, in my previous legal research, I had contended that the CBD wordingFootnote ⁷¹ only opens up a margin of discretion for different parties to decide how (not whether) to implement such duty.Footnote ⁷² This margin of discretion is further limited by the joint reading of States’ obligations to prevent negative impacts on the marine environment under their jurisdiction, pursuant to the law of the seaFootnote ⁷³ and on human rights arising from biodiversity degradation under international biodiversity law and international human rights law.Footnote ⁷⁴ Hub research expanded this argument, by showing how diffuse environmental harm and degradation of nature’s benefits to human well-being (which could be considered foreseeable negative impacts on human rights), as well as historical evidence on marginalization from decision-making and current disregard for cultural rights linked to the effective protection of the marine environment, were routinely left out of EIAs.Footnote ⁷⁵ A mutually supportive interpretation of international biodiversity law, the law of the sea and international human rights law, therefore, served to identify some minimum content for the EIA obligation, which allowed to take into account the findings from the marine sciences about environmental blind spots in current EIA practices, as well as social sciences findings about negative impacts on human rights.Footnote ⁷⁶ This interpretation finds resonance in the 2023 Agreement on the Conservation and Sustainable Use of Marine Biological Diversity of Areas beyond National Jurisdiction, which requires States to carry out EIAsFootnote ⁷⁷ in order to duly consider ‘consequences of climate change, ocean acidification and related impacts’,Footnote ⁷⁸ as well as ‘economic, social, cultural and human health impacts’.Footnote ⁷⁹ This is therefore an example in which mutually supportive interpretations contribute to the evolutive and effective interpretation of the law of the sea, by providing more normative detail to generic terms, with a view to better achieving interdependent treaty objectives in the light of new (natural and social) scientific evidence, local intergenerational experiences of lack of sustainability and injustices, and Indigenous Peoples’ and local knowledge systems.

Such a mutually supportive interpretation is innovative because while human rights and the environment has been a well-established area of international law scholarship since the 1990s,Footnote ⁸⁰ it has mainly focused on land-based issues and more recently on climate change.Footnote ⁸¹ Instead, little attention has been paid until very recently to human rights issues related to the protection of the marine environment, in particular of marine areas beyond national jurisdiction.Footnote ⁸² The case of the human rights dimensions of deep-seabed mining are quite instructive in this respect: international law scholarship started raising these questions only in 2019 from an Indigenous Peoples’ human rights perspective,Footnote ⁸³ and in 2022 from a general human rights perspective,Footnote ⁸⁴ with the UN Human Rights Office issuing a note in 2023.Footnote ⁸⁵ These interpretative developments can be explained on the basis of the emerging marine biodiversity evidence on the irreversible environmental impacts of deep-seabed miningFootnote ⁸⁶ and social science research and Indigenous knowledgeFootnote ⁸⁷ on the importance of the deep seabed for humankind.

As part of this ongoing process of cross-fertilization with these areas of international law, the One Ocean Hub researchers partnered with different UN bodies, whose mandates focused on human rights, the environment and the ocean, respectively. The partnership meant discussing research questions with UN officers to make sure that research findings could contribute to ongoing international negotiations or UN-led legal advisory and capacity-building initiatives to support the implementation of international law and guidelines at the national level. Interestingly, through these conversations, it also became clear which international law interpretation questions were identified but could not be investigated by UN officers themselves, either for lack of research time and resources, or for the risk of appearing to overstep their mandate. For instance, fully understanding the extent of the human rights–based approach to small-scale fisheries, particularly in as far as it related also to cultural rights and intangible ocean cultural heritage, required a new joint effort between Hub researchers, the Food and Agriculture Organization (FAO) and the Office of the High Commissioner for Human Rights (OHCHR), with the two UN bodies collaborating for the first time on that topic.Footnote ⁸⁸ In particular, social sciences and art-based participatory research in South Africa served to shed a light on the lack of understanding and consideration of intangible cultural and spiritual connection of certain Indigenous Peoples with the seabed. This in turn led to a disregard for their procedural rights in decision-making processes on offshore oil and gas exploration that would negatively impact also on their fishing activities and human right to food.Footnote ⁸⁹ These considerations, in addition, revealed the need to consider and protect the human rights of fishers also in the context of the conservation and management of marine areas beyond national jurisdiction, including from a climate change perspective.Footnote ⁹⁰ Conversely, it was difficult for FAO to integrate human rights considerations in its role as one of the relevant UN agencies involved in the development and implementation of the WTO Fisheries Subsidies Agreement.Footnote ⁹¹ So, an independent academic reflection on the need to interpret that Agreement and shape its implementation in accordance with the protection of human rights, including the human rights of small-scale fishers, was necessary. Such academic reflection allowed to carefully identify the role of FAO in supporting the human rights–based approach as part of its capacity-building mandate vis-à-vis States,Footnote ⁹² as opposed to a monitoring approach that would appear more appropriate for international human rights treaty bodies.

The collaboration between international law scholars and marine scientists under the One Ocean Hub was also distinctly instructive in supporting a mutually supportive interpretation between international biodiversity law, the law of the sea and international human rights law. Fisheries sciences experts were developing an evidence base of collapsing fisheries, and tools for the government to manage enhanced risks for the conservation and sustainable use of marine biodiversity due to other pressures, exacerbated by climate change. In addition, deep-sea biodiversity scientists clarified the current state of knowledge of the state and functioning of life in the depths of the marine environment, as well as the limitations of such knowledge that provide grounds for precautionary approach. Finally, ecosystem services research provided the essential bridging evidence between the knowledge of the functions of marine life and its complexes and benefits to human well-being (nutrition, health, cultural and spiritual well-being, purification of water and air, and resilience to climate change)Footnote ⁹³. In other words, ecosystem services research explained how and to what extent a healthy ocean contributes to the protection of a variety of human rights. At the same time, collaboration between international law scholars and marine scientists allowed to identify blind spots in the production of natural science evidence in terms of assumptions about undifferentiated human needs and vulnerabilities, as well as the limited capacity to integrate cultural rights or diverse knowledge systems within current methods for assessing, mapping and modelling impacts and responses for the protection of the marine environment.Footnote ⁹⁴

Marine science experts were quite familiar with international environmental law concepts related to precaution and the ecosystem approach but were generally unaware of the connections between these concepts and international human rights law.Footnote ⁹⁵ In effect, the interpretative efforts of the 196 Parties to the CBD had already clarified that the ecosystem approach entails understanding and factoring in societal choices, rights and interests of Indigenous Peoples and local communities, along with intrinsic as well as tangible and intangible values attached to biodiversity, ultimately leading to a balance between local interests and the wider public interest. It also entails ensuring appropriate representation of community interests in the decision-making process.Footnote ⁹⁶ Instead, marine scientists generally saw their role as carrying out technical stakeholder consultations for the purposes of gaining social traction of their findings, while for their part they felt an obligation to treat all groups (be they large-scale business as opposed to subsistence fishers) equally despite power imbalances and differentiated vulnerabilities to environmental impacts. As a result, their evidence base and tools for decision-making would not support decision-makers to fulfil their international human rights obligations in the context of the protection of the marine environment. This is because such evidence did not include disaggregated data analysis, consideration of differentiated impacts on different sectors of society and an effort to prioritize the needs of the most vulnerable as part of ensuring environmental sustainability of ocean use or marine conservation.

The collaboration between international law scholars and social scientists, notably experts in educational sociology, ethnographic sociology, anthropology, human geography, history and political ecology, as well as art-based participatory research approaches, was crucial to understand lived experiences, living memories, the existence of distinctive knowledge systemsFootnote ⁹⁷ and the differentiated impacts of the degradation of ocean health and the modalities and impacts of exclusionary ocean research and governance practices on human rights holders. In other words, it allowed all researchers to realize where their own assumptions and the scope of their work had prevented consideration of relevant human rights and how to ensure the protection of persons against negative consequences of their scientific research or its applications on the environment.Footnote ⁹⁸ Further, earlier social sciences research on ocean-dependent communities, small-scale fisheries, environmental justice issues and exclusion in decision-making also revealed itself essential to ground the design and planning of transdisciplimary research, with a view to ensuring contextualization and avoiding ‘parachute science’.Footnote ⁹⁹ It also served to build or enhance the understanding and capacity of other researchers, from law and the marine sciences, to relate their own work to the local context and identify potential areas of interdisciplinary collaboration across the team. This allowed researchers to ensure that priorities for scientific research should focus on key issues for the most vulnerable and strive towards scientific progress that is critical to the enjoyment of the human right to health and other economic, social and cultural rights.Footnote ¹⁰⁰ These approaches were then essential to engage in a respectful way and ensure mutual learning and knowledge co-development with human rights holders themselves, without creating new exclusion or injustices in the context of other research under the One Ocean Hub.Footnote ¹⁰¹

In particular, environmental justice scholarship from the Global SouthFootnote ¹⁰² provides a plural and contextually located approach to contrast Western ways of thinking and doing,Footnote ¹⁰³ which are underlined by a perception that humans and other species of plants and animals are distinct and separate, on a universal scale.Footnote ¹⁰⁴ This area of scholarship unveils how today’s environmental injustices are profoundly shaped by persistent colonial legaciesFootnote ¹⁰⁵ and intertwined global and local power imbalances arising from competing economic interests, exploitative processes and inequality, which are increasing embodied in growing demand for marine resources, globally and nationally.Footnote ¹⁰⁶ Environmental justice scholarship from the Global South also critically reflects on how ‘these dominant frameworks frequently draw on science as the only legitimate form of knowledge for understanding our natural environments and developing related policies and regulations. This can inadvertently delegitimize and exclude other ways of knowing and living with the natural world, such as Indigenous science and local knowledge.’Footnote ¹⁰⁷ The dialogue with environmental justice scholars from the Global South, including their praxis as researchers and human rights advocates working in solidarity with human rights holders, supported imaginative thinking on alleviating planetary harms and socio-cultural and economic injusticesFootnote ¹⁰⁸ and fed into interpretative efforts at the intersection of international environmental law, international human rights law and the law of the sea.

In particular, social sciences and art-based participatory research in South Africa served to shed a light on the lack of understanding and consideration of intangible cultural and spiritual connection of certain Indigenous peoples with the seabed. This in turn led to a disregard for their procedural rights in decision-making processes on offshore oil and gas exploration that would negatively impact also on their fishing activities and human right to food. These approaches place the experiences, needs, knowledge and human rights of local actors at the outset as a way to interrogate different meanings of international law, to identify how to best respond to local understandings of sustainability and justice, as well as be aligned with the natural sciences evidence and, on that basis, assess whether national law was in compliance with the underlying international treaties.Footnote ¹⁰⁹

Over time, this approach allowed the Hub to contribute to the development of new international interpretative guidance on the human rights of the child and a healthy environment,Footnote ¹¹⁰ as well as integrate such interpretation in ongoing research efforts.Footnote ¹¹¹ Hub interdisciplinary research on the importance of marine biodiversity for children’s human rights, including their right to development and culture,Footnote ¹¹² as well as on the importance of a healthy ocean for climate change mitigation and adaptationFootnote ¹¹³ and insights arising from partnerships with children rights organizations at the ocean-climate nexus,Footnote ¹¹⁴ were shared in various ways during the development of the 2023 UN General Comment on Children’s Human Rights and the Environment, with a focus on Climate Change.Footnote ¹¹⁵ As a result, the General Comment clarifies that children’s human right to a healthy environment includes obligations for States to take ‘immediate action’ to ‘conserve, protect and restore biodiversity’, ’prevent marine pollution, by banning the direct or indirect introduction of substances into the marine environment that are hazardous to children’s health and marine ecosystems’ and ‘ transform industrial fisheries to produce healthy and sustainable food aimed at preventing malnutrition and promoting children’s growth and development’.Footnote ¹¹⁶ This guidance, therefore, enshrines a mutually supportive and evolutive interpretation of international human rights law, international biodiversity law, international climate change law and the law of the sea,Footnote ¹¹⁷ on the basis of new (natural and social) scientific evidence of the interdependence of their respective objectives as reflected in children’s own understandings. Such a holistic interpretation of children’s human right to a healthy environment has then supported further interpretative work by the One Ocean Hub, as part of international civil society networks advocating for the respect of children’s human rights in the international climate change regime. This co-development led to the integration of interpretative arguments prioritizing ocean-based and other nature-based solutions to climate change,Footnote ¹¹⁸ as opposed to unproven and dangerous technologies to mitigate climate change.Footnote ¹¹⁹ These contributions were in addition to interpretative arguments focused on enhanced social protection for children in the face of the negative impacts of climate change. These are further examples of mutually supportive interpretations based on international biodiversity law and international human rights law that underpin an evolutive interpretation of international law of the sea and international climate change law based on a new understanding of the interdependence of their respective objectives in the light of local experiences of lack of sustainability and injustices, interdisciplinary scientific evidence and Indigenous science and local knowledge systems.

8.5 Aligning Interpretative Efforts: The Case of Ocean Defenders

This section now delves into a particular area of co-development of a mutually supportive interpretation that emerged from the interactions among the non-judicial actors involved in the One Ocean Hub: the concept of ‘ocean defenders’ as part of environmental human rights defenders. Environmental human rights defenders were defined by former UN Special Rapporteur on Human Rights Defenders Michel Forst, as the individuals and communities that raise awareness about the negative impacts on human rights of unsustainable decisions on the environment.Footnote ¹²⁰ Environmental human rights defenders are increasingly the object of (often lethal) attacks by governments or private actors, as well as harassment, denigration or side-lining.Footnote ¹²¹ They are recognized and studied as agents of change,Footnote ¹²² including for their role in preventing unsustainable and unjust uses of the environment that may lead to conflict.Footnote ¹²³

Environmental human rights defenders are entitled to all the rights and protections set out in the 1998 UN Declaration on the Right and Responsibility of Individuals, Groups and Organs of Society to Promote and Protect Universally Recognized Human Rights and Fundamental Freedoms (Declaration on Human Rights Defenders).Footnote ¹²⁴ To respect defenders’ human rights, States must ensure a safe and enabling environment for them to operate free from threats, harassment, intimidation and violence, including by providing appropriate training for security officials. Protection further entails publicly recognizing the contributions of defenders to society and ensuring that their work is not stigmatized.Footnote ¹²⁵ Heightened levels of protection are needed for child defenders.Footnote ¹²⁶

As for other areas of cross-fertilization between international human rights law and international environmental law, however, international interpretative guidance on environmental human rights defenders has mainly focused on land-based issues, and in fact there are often references to ‘land and environment human rights defenders’.Footnote ¹²⁷ As a result, the specific challenges faced by ocean defendersFootnote ¹²⁸ have not yet been specifically included in these interpretative efforts, which have very practical implications in terms of ensuring the prompt release of financial, legal and security support from UN country offices to defenders at risk. Nevertheless, One Ocean Hub researchers from an international law and social sciences background have contributed to UN consultations on this issueFootnote ¹²⁹ and are collaborating with researchers and activists around the world to increase the documentation and understanding of the work and risks of ocean defenders.Footnote ¹³⁰ They are also raising awareness among conservation organizations and marine scientistsFootnote ¹³¹ about the significance of scientific evidence on environmental vulnerabilities and specific needs for environmental protection with demands for environmental protection of ocean defenders. These demands are based on their interconnected human rights to livelihoods, health and culture, and to a healthy ocean. In other words, innovative solidarity practices emerged in connecting different bodies of evidence (from within and outside academia), whereby natural science evidence aligned with ocean defenders’ priorities in terms of environmental protection, and therefore also backing the protection of ocean-dependent human rights. In this case too, mutually supportive interpretations based on international biodiversity law and international law of the sea underpin an evolutive interpretation of international human rights law based on a novel understanding of the interdependence of their respective objects and purposes.

These inter- and transdisciplinary bases for mutually supportive interpretation have also been brought together into submissions to the three international tribunals requested to issue an advisory opinion on States’ climate change obligations – the International Tribunal for the Law of the Sea,Footnote ¹³² the ICJFootnote ¹³³ and the Inter-American Court of Human Rights.Footnote ¹³⁴ In all these submissions, mutually supportive interpretations drawing on the Hub’s inter- and transdisciplinary research emphasized the need to understand States’ obligations under the international climate change regime also in the light of the law of the sea, international biodiversity law and international human rights law, because of what biodiversity science shows about the role of the ocean in the global climate regulation, which is still overlookedFootnote ¹³⁵ under the international climate change regimeFootnote ¹³⁶ and the social science evidence and views of ocean defenders, including child and young ocean defenders.Footnote ¹³⁷ These submissions then included new interpretative arguments that State obligations across the treaties related to climate change, the sea, biodiversity and human rights imply a due diligence obligation to ensure the meaningful participation of ocean defenders in the design, implementation, financing, monitoring and review of climate, biodiversity and ocean policies, plans and actions, including ‘just transition’ or ‘blue economy’ policies, plans and actions, as well as marine protected areas and other marine conversation measures.Footnote ¹³⁸ This was accompanied by another interpretative argument about the need for States, as part of their human rights obligations related to climate change, to protect ocean defenders that protest against deep-seabed mining.Footnote ¹³⁹ The latter argument found support in statements made by the UN Special Rapporteur on Toxics and Human Rights and the Aarhus Convention Special Rapporteur on Defenders in March 2024 to the States members of the International Seabed Authority.Footnote ¹⁴⁰

8.6 Institutionalizing Treaty Interpretation Co-development under Existing Treaty Structures

There are opportunities as part of the implementation of treaties to advance these interpretations and in fact embed similar processes of interpretation co-development with ocean defenders as well as a range of diverse experts and knowledge holders, by re-imagining the composition and approaches of treaty-based implementation review bodies and/or technical and scientific advice committees.

Participatory governance and iterative learning from treaty implementation have already been considered in the literature on international environmental law as essential pre-conditions to ensure the effectiveness of certain treaty regimes because of the complexity of the subject matter and the need to understand different experiences of equity, as well as potential impacts across the biodiversity research, innovation and governance landscape.Footnote ¹⁴¹ Such an approach would be a departure from current practices focusing only on technical expertise and natural sciences background in subsidiary treaty bodies. Instead, the membership of these bodies could include experts from different communities of practices in the Global North and the Global South (scientists from different geographies and disciplines), notably with social scientists, Indigenous Peoples and local knowledge holders.Footnote ¹⁴² The role of social sciences experts would be essential to support the overcoming of stereotypes about the relevance and capacity of diverse knowledge holders to meaningfully contribute to international processes.Footnote ¹⁴³

This is also true for the genuine inclusion of children’s voices in these processes,Footnote ¹⁴⁴ which is something to which the whole UN Systems is committed to.Footnote ¹⁴⁵ Along similar lines, UN General Comment No 26 also clarified that

Methodologies developed by children’s rights experts could be adapted to international treaty bodies,Footnote ¹⁴⁷ with the benefit that these methodologies could also support transformative legal interpretation among adults,Footnote ¹⁴⁸ as they rely on fun, play and artsFootnote ¹⁴⁹ to challenge vested interests, power asymmetries and tendencies towards short-term decision-making.Footnote ¹⁵⁰

Thus re-conceived, these treaty-based review and advisory processes could support iterative interpretations of treaties in the light of changing scientific practices, scientific understandings of the status of the marine environment and the flow of its benefits to humankind, as well as evolving understanding of environmental sustainability and equity in the life experiences of ocean defenders. These treaty bodies could therefore integrate the insights from inter- and transdisciplinary dialogue into co-developed iterative interpretations of a treaty, which in turn would shape funding modalities, taking into account the range of needs of relevant human rights holders and setting research priorities to further support collaboration with diverse knowledge holders at national and local levels. They could also generally look at questions of efficacy together with questions of equity, with a view to suggesting clarifications in interpretation for the consideration by the governing body of the treaty. Given the need for systemic interpretation and joined-up implementation of treaties in the areas of climate change, biodiversity, the ocean and human rights, these subsidiary bodies could also maximize opportunities for regime interaction and cross-regime learning.Footnote ¹⁵¹

8.7 Conclusions

The triple planetary crisis (climate change, biodiversity loss and toxic pollution) and its multiple impacts on human well-being increasingly require evolutive and systemicFootnote ¹⁵² interpretation of State obligations across international environmental law, the law of the sea and international human rights law. Collective interpretative practices by non-judicial actors can support an understanding of how international law can effectively respond to these challenges, on the basis of the lived experiences of the most vulnerable human rights holders, across scales. This chapter calls attention towards inter- and transdisciplinary research projects as potentially fertile and flexible spaces for UN and other international bodies that provide advisory services to States on how to implement international law to co-identify critical legal questions and co-develop evolutive interpretative solutions with researchers in law, natural and social sciences and the arts, based on local-level experiences of lack of sustainability and injustices, interdisciplinary scientific evidence, Indigenous science and other knowledge systems.

These interpretative efforts can support national public authorities in ensuring the effectiveness of their treatiesFootnote ¹⁵³ and in shifting towards the transformation of environmental governance into more inclusive, sustainable and fair approaches that also contribute to the protection of human rights. Equally, they can support multilateral cooperation, and possibly be institutionalized under treaty law, as part of treaty bodies focusing on implementation review and on technical and scientific advice.

The importance of these interpretative collaboration efforts cannot be overestimated, as a form of transdisciplinary governance that can lead to the transformation needed to effectively tackle the triple planetary crisis – a systemic change across sectors and scales that ‘empower those whose interests are currently not being met and represent transformative sustainability values’,Footnote ¹⁵⁴ such as ocean defenders.