6.2.1 Establishment

The inclusion of State-to-State triggers as a means to encourage compliance with MEAs has historically been a contentious matter. Indeed, there has long been an ideological conflict within the international community about the best approach to guarantee States’ compliance with their international environmental obligations. The adversarial approach, on one hand, is typically where one State will ‘sue’ another for non-compliance in a confrontational manner. The State-to-State trigger is representative of this approach. The facilitative approach, on the other hand, involves ‘non-confrontational means to persuade State parties into compliance, through technical and financial assistance, aid with reporting requirements, advice, technology transfers and capacity building’.Footnote ⁴

Such tension is reflected in the negotiation processes to establish a number of MEAs. During negotiations on the compliance committee for the 1989 Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal (Basel Convention), for instance, Australia argued that ‘a right to raise the performance of other parties would not be consistent with the consultative, non-confrontational nature of the mechanism’,Footnote ⁵ and that ‘compliance should not be secured through threats or by creating a mechanism equipped with strong enforcement procedures’.Footnote ⁶ The draft decision from the ad hoc Legal Working Group that established the compliance mechanism was a matter of lengthy and heated debate,Footnote ⁷ resulting in a consensus that was not satisfactory to all States.Footnote ⁸ Similarly, provisions on the State-to-State trigger in MEAs such as the 1998 Rotterdam Convention on the Prior Informed Consent Procedure for Certain Hazardous Chemicals and Pesticides in International Trade (Rotterdam Convention) and the 2001 International Treaty on Plant and Genetic Resources were enclosed in square brackets during the drafting process ‘as no agreement [had] been reached on this issue between the Parties’.Footnote ⁹

The tension was particularly high in the context of the Paris Agreement. This was considered to be more ‘more sensitive’Footnote ¹⁰ than other MEA negotiations due to the high political implications, the focus on the complex matter of climate change and a wide range of issues covered in the Agreement (such as mitigation, adaptation, finance, transparency and technical support). The mere inclusion of a compliance mechanism was difficult to negotiate in the first place, but certain States managed to convince the majority that the inclusion of a compliance committee would add value and guarantee accountability to the world.Footnote ¹¹ However, reluctance remained regarding the acceptable ways to trigger such a committee. While many were initially willing to retain only a self-trigger,Footnote ¹² a committee trigger was eventually added.Footnote ¹³ Unfortunately, State-to-State triggers were ‘shut down immediately by some parties’.Footnote ¹⁴ Deemed ‘impossible to include’ and ‘something parties would never agree to’, this proposal was abandoned by its negotiators in favour of other ideas that could be more readily accepted.Footnote ¹⁵

Today, most MEAs contain many features that lean towards a facilitative rather than an adversarial approach. This facilitative approach is the essence of environmental compliance procedures, within which more adversarial State-to-State triggers can exist. While some may believe that an adversarial approach to non-compliance is more efficient, most opine that the facilitative approach characterising compliance procedures is ‘better suited to promoting compliance’ in this context, particularly as it is ‘easier to sell to states’.Footnote ¹⁶ It can therefore be said that the facilitative approach is at the core of the existence of compliance procedures.Footnote ¹⁷ However, compromises have been reached in some MEAs to allow a State party preferring a more adversarial approach to seize the compliance committee against another State party if so desired. When featured, the State-to-State trigger has therefore found itself incorporated as a concession; a square peg in a round hole.

6.2.2 Practice

This context indicates why the facilitative approach has become the preference in the majority of MEAs. To date, only three compliance committees have been triggered for review by a State against another State: the Aarhus Compliance Committee (twice), the Espoo Implementation Committee (nine times) and the Kyoto Protocol Facilitative Branch (once).

The Aarhus Convention Compliance Committee saw its first State-to-State procedure in 2004 when Romania triggered a non-compliance procedure against Ukraine, in relation to the Bystre Canal project in the Danube Delta.Footnote ¹⁸ It alleged that the Ukrainian authorities had not complied with the obligations of public participation and had not let various local and international NGOs participate throughout the planning of the project. The second procedure triggered before the Aarhus Convention Compliance Committee was submitted by Lithuania against Belarus in 2015 with regard to the construction of a nuclear power plant in Belarus. Lithuania claimed that Belarus had denied the right to access detailed information of citizens to Lithuania during the preparatory and project implementation phases of the construction of the nuclear power plant.Footnote ¹⁹

The Espoo Implementation Committee has seen nine procedures initiated by a State party against another, making it the most successful to date. They are all related to large projects with transnational effects, such as nuclear power plants, oil and gas projects, mining, hydropower plants or modifications to river waterways.Footnote ²⁰ In these cases, the triggering parties argued that the transboundary environmental impact assessments were not carried out in accordance with the Espoo Convention.

Another interesting procedure was triggered before the Kyoto Protocol Facilitative Branch in 2006 by South Africa. In this case, South Africa made a submission, in its capacity as Chairman of the Group of 77 and China and on their behalf, about State parties’ non-compliance with Article 3.1 of the Kyoto Protocol.Footnote ²¹ The alleged non-compliance concerned the submission of national progress reports, as several countries had not submitted theirs six months after the set deadline.

There is further evidence of a sparing use of State-to-State procedures even beyond MEAs. For instance, before the UN human rights treaty bodies, the first inter-State communications ever to be submitted both occurred in 2018 before the Committee on the Elimination of Racial Discrimination (CERD).Footnote ²² The CERD dealt with an inter-State communication submitted by Qatar on 8 March 2018 against Saudi Arabia and the United Arab Emirates (UAE), and an inter-State communication submitted on 23 April 2018 by the State of Palestine against Israel.

There are several reasons that could explain the very sparing use of State-to-State triggers, despite their appearance in the guidelines or rules of procedure of all compliance committees. We identify two types of challenges: challenges related to the perception and behaviour of States vis-à-vis State-to-State triggers and challenges related to the institutional design and procedural mechanisms of State-to-State procedures.

6.3.1 Hostile Perception of State-to-State Compliance Procedures

The principal reason States may be discouraged from using State-to-State procedures is the adversarial and hostile perception of those State-to-State triggers, as mentioned in Section 6.2.1. This hostile perception means that States may think that triggering a compliance procedure against another State may be perceived as an escalation of tensions in their diplomatic relations. This is because the process of one State complaining about another State before a third party (judicial, quasi-judicial or non-judicial) is perceived negatively in international relations. Indeed, while the judicial avenue is theoretically an equal alternative to other forms of peaceful dispute settlement provided in the UN Charter,Footnote ²³ it tends to be a last resort in practice. Certain MEAs or international human rights conventions even provide that a court (most commonly, the International Court of Justice (ICJ)) may only be seized once negotiations have been exhausted.Footnote ²⁴ This indicates that States may turn to a third party when they are unable to communicate successfully between themselves, or, worse, when they have reached a political ‘boiling point’ or deadlock.Footnote ²⁵ In the context of human rights compliance committees, notable examples include the Israeli–Palestinian dispute before the CERD as part of a decades-long historical conflict with deadlocked negotiations.Footnote ²⁶ The other dispute before the same committee between Qatar and the UAE is also in the context of an important political conflict between these two countries which also made its way onto the ICJ’s docket.Footnote ²⁷

Tensions that lead to the triggering of a State-to-State procedure escalate more easily between neighbouring countries. In addition to the two disputes between neighbouring countries before the CERD, all procedures before the Espoo Implementation Committee have involved neighbouring States, where projects have had clear transboundary effects. Obligations around transboundary environmental impact assessments lend themselves naturally towards a bilateral and adversarial conflict, as they are easily ‘bilateralisable’. For instance, in 2019, Montenegro started a procedure against Albania regarding the ongoing build of a small hydropower plant on the Cijevna River, which is shared with Montenegro. It alleged that Albania had not considered the potential adverse impacts of the project on Montenegrin territory and people.Footnote ²⁸ This is a clear case of a ‘bilateralisable’ and adversarial problem arising within a multilateral treaty, where Montenegro is using similar rhetoric and seeking a similar outcome to what it would use, and seek, in a judicial procedure.

Any compliance arrangements in general may already be viewed as hostile, discouraging States from setting ambitious environmental targets or even joining the MEA altogether.Footnote ²⁹ However, State-to-State triggers would naturally be seen as particularly undesirable. One participant recalled that ‘parties are very reluctant to be pointed the finger at. They want to avoid that’.Footnote ³⁰ This could, at least partly, be due to the disclosure of sensitive information or the attraction of potentially negative public opinion during proceedings.Footnote ³¹ It could also be due to costs associated with such proceedings where relevant. Another reason could be the risk of a ‘boomerang effect’, whereby the initiating State may be under closer scrutiny from the alleged non-complying State, who is looking for retaliation. The latter may become vindictive and look into whether the triggering State is also complying. Such a ‘boomerang effect’ could also take place with respect to another MEA, as there are chances that both States are parties to multiple treaties. States could even bring other issues beyond the scope of the MEA in question to the forefront. The committee would be ‘open to misuse’,Footnote ³² creating a space for political issues other than the compliance with the treaty in question. However, such risks can and will be mitigated by the committee itself, which will decide on its jurisdiction and the scope of its work. Unfortunately, this was not a sufficient guarantee in the negotiations of the PAICC, possibly because of the high political stakes under the Paris Agreement.

The hostile perception of State-to-State triggers could also explain why the dispute settlement mechanisms featured in MEAs are rarely used.Footnote ³³ Indeed, a few MEAs feature a clause giving State parties the option to resort to the ICJ or possibly arbitration if a dispute arises about the interpretation, application of or compliance with the relevant convention.Footnote ³⁴ Therefore, in theory, a State could resort directly to judicial bodies as opposed to non-compliance procedures on a matter of another State’s non-compliance with their shared convention. These procedures are separate.Footnote ³⁵ However, ‘there appears to be widespread avoidance of resort to third-party dispute resolution’.Footnote ³⁶ This may in part be due to the fact that most non-compliance is due to capacity issues as opposed to the legal interpretation of a provision in an MEA.Footnote ³⁷ It is however mainly due to the confrontational nature of dispute settlement, requiring the existence of a dispute where States ‘hold clearly opposite views concerning the question of the performance or non-performance of certain international obligations’,Footnote ³⁸ with one party’s claim being ‘positively opposed’ by the other.Footnote ³⁹ It is also likely due to the binding nature of dispute resolution procedures, disliked by States who prefer more flexibility with regard to their environmental commitments.Footnote ⁴⁰

6.3.2 Lack of Motive to Defend Communal Interests

Many of the obligations contained in MEAs are arguably obligations erga omnes partes. This means that a State party owes such obligations towards all the other States parties to the same treaty, due to the treaty’s protection of collective interests. Therefore, all State parties have their own interests on the one hand and communal interests on the other hand.Footnote ⁴¹ By ratifying those treaties, they have agreed that the protection of environmental rights is worth joint efforts. The pursuit of this ‘common good’, however, does not seem to have inspired many States to date. They may lack motivation to pursue such proceedings due to both the absence of perceived personal gain and the novelty of the practice itself. Indeed, from a jurisdictional perspective, States have a legal interest in safeguarding community interests before a judicial body or a compliance committee, if such obligations are erga omnes partes. However, international jurisprudence has recently distinguished between specially affected States – directly and tangibly impacted by the breach of an obligation – and non-specially affected States that may be concerned about ensuring respect for the erga omnes partes obligation but are not directly and tangibly impacted by its breach.Footnote ⁴² While States occasionally demonstrate altruism in international relations,Footnote ⁴³ they may generally hesitate to start a procedure against another State if they are not specially affected by the breach in question. This may particularly be the case as the practice is quite novel.

As much as this can explain some of the reasons States are reluctant to use State-to-State compliance procedures, it does not make such procedures redundant. Contrary to the common perception that State-to-State proceedings are hostile, it can be argued that they were designed to allow for collegial co-operation and solidarity between States. Indeed, a State-to-State compliance procedure is communal in nature.Footnote ⁴⁴ Even if the procedure itself opposes two parties, the purpose of the procedure has a larger communal objective. In this sense, it is possible to view such procedures not as hostile, but as co-operative, aspiring towards a ‘common good’.

On one hand, there are many instances where the initiating State is specially affected by another State’s non-compliance, and therefore communal obligations can be ‘bilateralisable’ such as the case of the Espoo Convention on Transboundary Environmental Impact Assessments. On the other hand, there are instances where a State can be non-specially affected by another State’s non-compliance with communal obligations, such as in the case of the Kyoto Protocol. In both types of cases, a shift in States’ understanding of State-to-State procedures may be used as is necessary: individual adversarial procedures can be conducted for the defence of community interests. Although the more bilateral nature of a State-to-State procedure may be at odds, from the perspective of State parties, with the communal spirit of the treaties under review, they are not incompatible.

6.4.1 Jurisdiction

Questions such as when a compliance committee should pursue a State-to-State procedure are worth exploring, as they show that it is not only States that can be the reason why State-to-State procedures do not proliferate, but it is also committees themselves that can prevent procedures from being heard. This means that even when State-to-State triggers are initiated, the process can be impeded by a hesitant committee.

The case submitted by South Africa to the Kyoto Protocol Facilitative Branch – one of the two branches of the Protocol’s compliance committee – shows that the committees themselves may not be as familiar as expected in dealing with State-to-State compliance procedures. Potential reasons for this may be that they have so little prior experience. In this case, as soon as the submission was not exactly in line with the set procedures, the committee decided to end the procedure altogether.

As mentioned, the submission by South Africa was made, on behalf of the Group of 77 and China, against various parties for failure to communicate national reports. The Facilitative Branch dismissed the submission on procedural grounds. Indeed, two questions needed to be answered: Can a party submit on behalf of a group, and can a party submit against multiple other parties? These questions were not answered clearly in the Branch’s rules of procedures. Therefore, the committee decided the procedure could not continue. In only two instances, concerning Slovenia and Latvia, the Branch closed the procedure, as these two countries had in the meantime complied with their obligations, making the compliance procedure redundant.Footnote ⁴⁵

The fact that the Branch did not engage with the merits of the claim brought by South Africa shows a strict application of the rules of procedures, despite there being easily justifiable grounds to continue the procedure. Indeed, the committee decided that South Africa did not name the States against which it was making its submission, but South Africa stated clearly that those States who were six months late in submitting their reports were the object of the submission, and sent the submission to the relevant fifteen States. Therefore, despite the fact that it did not clearly name the parties against which it was initiating the procedure, it was in fact clear who it was aimed at. This level of respect for the procedural rules may be seen as contrary to the Kyoto Protocol’s objective to, inter alia, ‘[c]ooperate with other … Parties to enhance the individual and combined effectiveness of their policies and measures’.Footnote ⁴⁶ The decision shows great commitment to the wording of the rule, which could be explained by a lack of confidence on the part of the committee in its own ‘jurisdiction’ to rule on such matters. It also shows an unwillingness on the part of the committee to take matters into its own hands. An explanation for this behaviour may be that the committee does not have a traditionally ‘judicial’ mandate as do international courts and tribunals, and may have hesitated to take action without such traditionally understood ‘judicial’ legitimacy. This may contribute to an unclear institutional framework for the use of State-to-State procedures.

6.4.2 Evidence

Another procedural hurdle contributing to the scarce use of State-to-State triggers is the requirements for and handling of evidence during a State-to-State procedure. State-to-State triggers in MEAs allow for a State party to seize another State party before the compliance committee on the grounds of concern alone. In the 1972 London Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter the party must have an interest where it is affected or likely to be affected.Footnote ⁴⁷ In the 2000 Cartagena Protocol on Biosafety and in the Rotterdam Convention it must be ‘directly affected or likely to be directly affected’.Footnote ⁴⁸ The Basel Convention Compliance Mechanism is the most demanding in this respect, requiring a specific, bilateral relationship between the two parties involved in order to be triggered.Footnote ⁴⁹ In all other MEAs, however, State parties may trigger this procedure without having to prove involvement or interest.Footnote ⁵⁰ The benefit of this is that it facilitates the ability for States to easily trigger the procedure.

However, non-specially affected States may have more difficulty obtaining evidence that a certain State has violated an obligation in their shared convention. Indeed, States are still required to provide evidence of their claim in the form of an informational report. However, there are two obstacles to fulfilling this requirement.

First, it is perhaps difficult to imagine how a State would substantiate its claims in such a report if it were not directly affected. It is easier to substantiate claims and provide information for a matter that is of direct relevance to a State, as more information about the effects of the non-compliance is in the country itself. This closely mirrors traditional judicial inter-State disputes before international courts and tribunals.

Second, it is generally difficult for State parties to be aware of the level of compliance of other States. This would not be as much of a problem before international courts and tribunals because, at the ICJ for instance, proceedings involving erga omnes partes obligations have tended to be high-profile cases where evidence has already been collected by UN fact-finding missions or media outlets.Footnote ⁵¹ Therefore, even if the effects of the violation could not be measured on the State’s territory, it could still obtain enough evidence to support its claim.Footnote ⁵² States’ compliance with MEAs, however, does not garner the same level of publicity.

It is therefore more difficult for States who are not directly affected to corroborate their claims before compliance committees. This could explain why, in practice, only specially affected States have resorted to State-to-State triggers to date.Footnote ⁵³ Regarding the attempt made by South Africa before the Kyoto Protocol Facilitative Branch, its submission was also rejected because it ‘was not supported by corroborating information and did not substantiate how the question related to any of the specific commitments of the relevant parties under the Protocol’.Footnote ⁵⁴

6.4.3 Expertise of Members of Compliance Committees

State-to-State procedures would also benefit from clearer rules surrounding the appointment and expertise of compliance committee members, if their use is to be enhanced. The range of expertise needed in order to be able to sit on a compliance committee is a point of contention, as the technical nature of a compliance committee may require non-legal skills, yet legal knowledge is essential to make adequate decisions. In order to make a decision on compliance, compliance committees need to rely on both legal and scientific or technical knowledge. This is often reflected in the rules, which might say for example that members ‘shall have expertise relating to the subject matter of the Convention in areas including scientific, technical, socio-economic and/or legal fields’, in the case of the Basel Convention Implementation and Compliance Committee.Footnote ⁵⁵ Similar language is used for the PAICC.Footnote ⁵⁶ This is an advantage that compliance committees may have over international courts, as the latter are often criticised for their lack of ability to handle scientific evidence.Footnote ⁵⁷ One of the challenges of international adjudication, especially in an environmental context, is how judges handle complex facts, especially when they involve complex science, and how that affects their decision-making.Footnote ⁵⁸

However, it is not always clear whether the requirements concerning the legal and/or scientific skills of the committee members are fulfilled in practice. Before the Montreal Protocol Implementation Committee, member States of the Montreal Protocol appoint their representatives. This means there is no requirement to co-ordinate between member States, and therefore no guarantee that the committee itself will be composed of individuals with balanced and complementary expertise.Footnote ⁵⁹ Even in the human rights context, the CERD stated explicitly in the Qatar v Saudi Arabia case that it initially could not take any decisions due to ‘the legal complexity of the issues broached and a lack of resources’.Footnote ⁶⁰

6.4.4 Impartiality and Independence of Members of the Compliance Committees

Another difficulty in relation to the members of the compliance committees contributing to the limited use of State-to-State triggers relates to their impartiality and independence. An important procedural safeguard that ensures a fair procedure is to separate the relationship between the individual members and the State(s) of which they are citizens. Guaranteeing that the members are not influenced or manipulated by outside forces, especially by potential parties to a compliance procedure, is a key element to achieving a fair outcome. It is a well-established rule in the judicial context and has also been integrated into the provisions and rules governing most compliance committees.Footnote ⁶¹ The reason why the two notions of impartiality and independence are especially important in State-to-State compliance procedures is that the role of the compliance committee is more akin to that of an arbiter between two parties in such a procedure. This role requires the committees to show fairness and equality in the process, and this is ensured, inter alia, by having impartial and independent members.

In order to ensure independence, a lot of compliance committees require that their members act in their personal capacities, and not as representatives of their member States.Footnote ⁶² Indeed, once they have been elected, often according to rules of geographical and/or gender representation, they need to be able to decide in their own name, separately from the States that nominated them. An example of how to operationalise the concept of impartiality can be seen in the context of the PAICC, where ‘[m]embers and alternate members shall perform any duties and exercise any authority in an honourable, independent, impartial and conscientious manner’,Footnote ⁶³ and they have to confirm in writing that they will do so at the beginning of their mandate.Footnote ⁶⁴ They also have to ‘disclose immediately any interest in any matter under discussion before the Committee that may constitute a real or apparent, personal or financial conflict of interest or that might be incompatible with the objectivity, independence and impartiality expected of a member’, which then prevents them from being involved in matters related to the issues they disclosed.Footnote ⁶⁵

However, not all compliance committees are structured in the same way, and some important committees still have their members sit as representatives of parties, such as the Montreal Protocol and CITES.Footnote ⁶⁶ When rules on impartiality and independence are not as clear, it can negatively affect the functioning of the committee. For instance, issues may arise when a member of the committee has a duty, as a civil servant, to relay information to its State.Footnote ⁶⁷ This can impact the procedures and decision-making processes of the committee, as States before the committee may not feel free to share all necessary information for the committee to decide in the best possible way.

These guarantees of impartiality and independence may not be as essential in other roles performed by the compliance committees, especially as facilitators in compliance processes. However, when they act as arbiters in adversarial procedures, these guarantees are necessary and when they are lacking, this seriously undermines the State-to-State compliance procedures.

6.4.5 Participation and Transparency

Another procedural challenge in State-to-State procedures is the transparency of proceedings from the moment a State triggers the procedure against another State. While the State whose compliance is being called into question fully partakes in the proceedings and has the right to be heard, the same cannot systematically be said for the State who initiated the procedure. Typically, the latter State will be excluded from the procedure going forward and will have no opportunity to take stock of matters with which it was initially concerned. In fact, meetings between the compliance committee and the party whose compliance is in question are closed to the public.Footnote ⁶⁸ This is possibly favourable towards the party in question who can avoid public scrutiny, potential embarrassment and the divulging of sensitive information. However, it does an injustice to the State triggering the procedure who has expressed concern.

This is particularly so in instances whereby the State triggering the procedure is required to be affected or have an interest of some sort. For instance, regarding the 2001 Stockholm Convention on Persistent Organic Pollutants, one author has observed a contradiction between the fact that a party must be particularly affected in order to trigger the procedure – reflective of a more ‘traditional, bilateral, state-to-state dispute approach’ – but cannot participate in the consequent proceedings.Footnote ⁶⁹ Similarly, transparency before the Basel Convention has been described as ‘remarkably poor as far as … the Party triggering the mechanism [is] concerned’.Footnote ⁷⁰

Before international courts and tribunals, State litigants are given equal rights of participation. Third States making requests for intervention are likewise fully integrated in written and oral proceedings if their request is granted.Footnote ⁷¹ Transparency is also an important feature of proceedings before international courts and tribunals. Before the ICJ, for example, written parties’ submissions may be made public on or after oral proceedings with the parties’ consent,Footnote ⁷² while oral hearings are made open to the publicFootnote ⁷³ and streamed live online.Footnote ⁷⁴ At the International Tribunal for the Law of the Sea (ITLOS), written pleadings of the parties are publicly accessible even before oral pleadings commence.Footnote ⁷⁵ The World Trade Organization (WTO) Dispute Settlement Mechanism’s contrasting practices (confidential submissions by parties and closed oral hearings) have been widely criticised, demonstrating the increasing importance that transparency yields in international law.Footnote ⁷⁶ Generally, participation and transparency have become increasingly significant in international judicial processes.

Greater transparency and participation are certainly imaginable before non-compliance procedures,Footnote ⁷⁷ without jeopardising their facilitative spirit. In the case of the 1987 Montreal Protocol on Substances That Deplete the Ozone Layer, for example, ‘[a]lthough [it] is based on facilitative and amicable principles, it also envisages principles of due process, such as notification, right to a fair hearing and impartiality, which are usually found in traditional dispute settlement mechanisms’.Footnote ⁷⁸

6.4.6 Outcomes of State-to-State Compliance Procedures

The lack of clarity in the outcome that States can get from triggering such procedures may further discourage their use. Indeed, the political cost of triggering a compliance procedure may not justify such an uncertain outcome. The question States may ask is: What can they get out of a State-to-State compliance procedure? The answer to this question is twofold and can partly explain why State-to-State compliance procedures have not been popular so far.

First, the fact that the decisions are not final and binding renders the overall effect of the decisions weaker. Indeed, the decisions taken by compliance committees ‘generally do not possess any legally binding force. Even if a non-compliance procedure results in giving an appropriate response to non-compliance, such a response would still be of only a preliminary nature, because it is up to the Conference of the Parties to take a final decision’.Footnote ⁷⁹ The decisions taken by compliance committees are mostly endorsed by the Conference of the Parties – the governing body of the treaty – but theoretically the latter could depart from the initial decisions, or only adopt a part of them. In many instances, the compliance committee can take some decisions that are facilitative in nature, but when more punitive measures have to be taken, or those with financial consequences, the Conference of the Parties is the body that will take this type of decision.Footnote ⁸⁰ This is contrary to judicial decisions rendered by international courts and tribunals, which are binding and final.

Second, the range of options available to compliance committees is also uncertain, rendering the outcome less predictable. Some measures that can be decided upon by compliance committees may also not necessarily suit a State-to-State compliance procedure. Facilitative measures include providing advice and information about how to facilitate compliance and requesting special reporting or action plans from the non-complying party. These may not be the desired outcome of a State-to-State compliance procedure.

Some potential outcomes could be more suitable from the perspective of a State triggering a non-compliance procedure, such as a declaration of non-compliance or a suspension of specific rights under the treaty. For instance, in the case between Lithuania and Belarus concerning Belarus’ non-compliance with the Aarhus Convention, the Committee was able to conclude that Belarus had ‘failed to comply’ with a number of provisions of the ConventionFootnote ⁸¹ and therefore recommended that ‘the Party concerned takes the necessary legislative, regulatory and administrative measures and establishes practical arrangements’.Footnote ⁸² This type of decision raises a number of questions pertaining to the law of State responsibility and the law of treaties, which have been the object of debate.Footnote ⁸³ The lack of clarity on these points may contribute to a misunderstanding of the role of State-to-State compliance procedures.

In sum, it is not the case that compliance committees do not have the means to address State-to-State requests, as shown in the Aarhus Committee decision regarding Belarus’ compliance, but their role encompassing a broad range of actions may deter States from triggering them. Moreover, the frameworks within which compliance committees operate may prevent the latter from being more assertive in their decision-making, since they can only make recommendations that have to be adopted by the Conference of the Parties, which is constituted of States parties to the treaty in question. In other words, compliance committees may not have the tools necessary to make bolder decisions, as their overarching aim is still only facilitative – even in a more adversarial procedure – and their decisions are not final.