1. Introduction
International investment arbitration has long been valued for its ability to depoliticize disputes between investors and host states while maintaining procedural efficiency within an internationalized setting.Footnote 1 To preserve manageability within this hybrid structure, the system has developed a distinctive procedural economy: arbitral tribunals reserve their most elaborate reasoning and remedial authority for the award, which determines whether a state has breached its international obligations and must pay compensation.Footnote 2 For issues of a merely incidental or procedural nature,Footnote 3 tribunals rely on separate, less formal decisions. This design reflects a deep commitment to judicial economy: to deploy the full adjudicative machinery of an award, with all its attendant procedural and analytical rigour, for every ancillary question would be, metaphorically, to use a sledgehammer to crack a nut. It is precisely to avoid such disproportionality that procedural instruments such as provisional measures exist. Yet, because these measures do not directly affect the parties’ substantive rights or lead to compensation, they have often been treated as peripheral.Footnote 4 However, when applied wisely and purposefully, provisional measures may achieve effects that are disproportionate to their modest procedural form, protecting public and private interests, preventing irreparable harm, and preserving the integrity of international adjudication. Sometimes, indeed, the nut could crack the sledgehammer.
This article argues that climate-related disputes in international investment arbitration provide an apt illustration of the foregoing dynamics. In recent years, climate change has evolved from a scientific and policy concern into a fully global issue.Footnote 5 The growing body of international instruments and jurisprudence reflects a shared recognition that states bear not only moral but also legal responsibilities to mitigate and adapt to climate impacts. Beyond the landmark Paris AgreementFootnote 6 and the Nagoya Protocol,Footnote 7 under the Convention on Biological Diversity (CBD)Footnote 8 a range of binding and soft-law frameworks – which include the United Nations Framework Convention on Climate Change (UNFCCC)Footnote 9 and its Kyoto Protocol,Footnote 10 the 2030 Agenda for Sustainable Development,Footnote 11 and the United Nations General Assembly (UNGA) Resolution 77/276 requesting an International Court of Justice (ICJ) advisory opinion on climate changeFootnote 12 – have consolidated the normative foundations of state obligations in this field. Parallel developments within international adjudicatory bodies further attest to the consolidation of climate-related obligations in general international law. In its July 2025 advisory opinion, the ICJ explicitly addressed state obligations in relation to climate change, including the legal implications of fossil fuel-related activities, emphasizing duties of prevention, due diligence, and the protection of the climate system for present and future generations.Footnote 13
International investment, for its part, is deeply intertwined with climate-sensitive sectors such as energy, natural resources, and infrastructure.Footnote 14 Measures adopted to fulfil climate commitments – such as the phase-out of fossil fuels,Footnote 15 the withdrawal of subsidies,Footnote 16 or the transition towards renewable energy – often directly affect foreign investments.Footnote 17 It is therefore unsurprising that the intersection between international investment law and climate obligations has become increasingly pronounced and inevitable. In practice, host states that seek to implement their international climate commitments by restructuring energy markets, reforming subsidy schemes, or tightening environmental standards, operate within a regulatory space shaped by obligations under international investment treaties, which include bilateral investment treaties (BITs), the Energy Charter Treaty (ECT),Footnote 18 and investment chapters in free trade agreements.Footnote 19 While recent jurisprudence and treaty practice suggest that this space may be more flexible than traditionally assumed,Footnote 20 its contours remain uncertain, and the risk of investment claims continues to influence regulatory decision-making.Footnote 21 Measures adopted in good faith to fulfil climate duties nonetheless may be challenged as violations of fair and equitable treatment,Footnote 22 indirect expropriation,Footnote 23 or legitimate expectations.Footnote 24 This dynamic creates a chilling effect, discouraging states from pursuing ambitious climate policies for fear of triggering costly arbitration.Footnote 25
Additionally, the dilemma extends beyond states. For arbitral tribunals, the uncertainty lies in whether and how to incorporate international climate norms when interpreting and applying investment treaties.Footnote 26 From the investor’s perspective, the challenge is equally complex. While foreign investment can advance climate objectives by facilitating the deployment of green technologies, renewable energy projects, and sustainable finance,Footnote 27 and international investment law may play a stabilizing role in protecting such long-term capital commitments,Footnote 28 investment protection can also entrench carbon-intensive activities as well as exacerbate environmental harm without clear mechanisms for accountability.Footnote 29 Together, these tensions crystallize what may be termed the ‘climate change dilemma’ in investor–state dispute settlement (ISDS), meaning a structural conflict between the collective pursuit of global public goods and the individualized logic of investment protection.
Current scholarly and arbitral attention has focused predominantly on addressing the climate dilemma within the merits phase of investment arbitration.Footnote 30 The first strand of analysis concerns the applicability of international climate law in ISDS. Tribunals and commentators, for example, rely on Article 31(3)(c) of the Vienna Convention on the Law of Treaties (VCLT)Footnote 31 to invoke systemic integration, thereby either directly incorporating climate treaties into the interpretative process or treating them as relevant factual context.Footnote 32 The second strand seeks to accommodate climate considerations through balancing mechanisms embedded in treaty interpretation. Proportionality analysis has been introduced to weigh investment protection clauses, such as expropriation or fair and equitable treatment, against the host state’s right to regulate for environmental and climate purposes.Footnote 33 Similarly, exceptions clauses and public policy defences have been invoked to justify climate-motivated measures,Footnote 34 reflecting an attempt to integrate climate imperatives within the existing treaty framework. However, these merits-centred approaches have proven inadequate to resolve the investment–climate dilemma in a coherent and systematic manner. The systemic integration method, though conceptually appealing, remains doctrinally ambiguous.Footnote 35 Article 31(3)(c) VCLT merely requires tribunals to ‘take into account relevant rules of international law’, yet it provides no clear criteria for determining what constitutes ‘relevance’, nor how such rules should be operationalized within the interpretative process.Footnote 36 Moreover, most climate-related norms, such as those contained in the UNFCCC and the Paris Agreement, are formulated as broad principles rather than concrete obligations, rendering their normative content difficult to transpose into the investor–state context.Footnote 37 Similarly, attempts to balance investment protection and climate regulation through exceptions clauses or proportionality analysis have yielded inconsistent results across arbitral practice.Footnote 38 Tribunals differ significantly in their recognition of climate objectives as legitimate public purposes and in the weight they afford to environmental considerations relative to investors’ treaty rights.Footnote 39 As a result, existing interpretative and balancing techniques fail to provide a stable and predictable framework for integrating climate concerns into ISDS.
This article argues that the climate–investment dilemma cannot be effectively resolved within the merits-based logic of ISDS adjudication. Rather than operating within or alongside this logic, it requires a procedural reorientation in which provisional measures are reconceptualized not as ancillary remedies, but as a primary mechanism of interim governance capable of addressing the temporal and collective dimensions of climate disputes. This procedural reorientation does not suggest that provisional measures can legally displace or substitute merits adjudication, nor that they preclude findings of expropriation or breaches of fair and equitable treatment as a matter of law. Rather, it examines how such measures may, in practice, alter the trajectory of climate-related disputes by stabilizing regulatory situations, preventing irreversible harm and, in certain circumstances, reducing the necessity of proceeding to a full merits determination.
Rooted in the inherent powers of the tribunal, provisional measures operate independently of party consent, allowing tribunals to weigh all relevant interests and circumstances when granting them.Footnote 40 Their core functions, to preserve rights, prevent irreparable harm and maintain the integrity of the proceedings, closely aligned with the preventive and cooperative logic of climate governance. By temporarily restraining unilateral or self-help actions, provisional measures foster cooperation between disputing parties, reflecting the collective responsibility required in climate action. Moreover, unlike the compensatory nature of final awards, provisional measures can provide forward-looking relief that safeguards community interests and accommodates stakeholders beyond the immediate investor–state dyad, including local communities affected by climate-related measures.Footnote 41 In this sense, they fill a structural gap within ISDS by offering a procedural mechanism that is both responsive to the urgency of climate harm and attuned to its inherently shared nature.
This article is organized as follows: Section 2 elaborates on the triangular dilemma of climate change in ISDS, revealing how the tension between states’ climate obligations and their investment commitments generates systemic conflicts. It also examines the existing doctrinal and procedural approaches adopted by arbitral tribunals, identifying their inherent limitations in addressing climate-related disputes. Section 3 proposes provisional measures as a doctrinal response to the climate dilemma, illustrating their potential to balance environmental imperatives with investment protection. Section 4 further explores the application of provisional measures in climate-related investment disputes, drawing insights from relevant arbitral practices and theoretical perspectives. Section 5 concludes by summarizing the main arguments and reflecting on the broader implications for the future evolution of ISDS in the era of climate governance.
2. The Climate–Investment Dilemma in ISDS and the Limits of Existing Approaches
2.1. The Triangular Dimensions of the Dilemma
While the structural roots of the climate dilemma in ISDS lie in the conflicting normative and institutional logics of both investment and climate regimes, the practical manifestation of this dilemma emerges through the interaction of three principal actors: the investor, the host state, and the arbitral tribunal.Footnote 42 Each operates within distinct legal mandates and expectations, yet each faces a comparable form of dilemma when climate imperatives intersect with investment protection.
Firstly, for investors, the accelerating green transition undermines the very stability that international investment law was designed to ensure. Long-term capital projects in energy, infrastructure, and extractive industries depend on such predictability for the valuation of assets, financing arrangements, and risk assessment.Footnote 43 Yet, climate imperatives compel states to restructure precisely these sectors through rapid decarbonization, the imposition of carbon pricing and emissions trading systems, and the gradual elimination of fossil fuel subsidies.Footnote 44 Each of these policy shifts disrupts the assumptions upon which many investment decisions were made, eroding the legal and economic predictability that investment treaties ostensibly protect.
Secondly, host states find themselves navigating two parallel but conflicting legal universes. Their climate commitments under the Paris Agreement, the UNFCCC and related frameworks demand ambitious domestic reforms, phasing out fossil fuels, transforming energy infrastructure, and promoting sustainable development. Yet, under BITs and investment chapters of free trade agreements, these same regulatory transformations may be framed as violations of investors’ protected rights, particularly under clauses on indirect expropriation, fair and equitable treatment, and legitimate expectations.Footnote 45 This contradiction is most visible in the energy transition context. The Netherlands’ coal phase-out legislation has prompted multibillion-dollar claims from RWE v. Netherlands Footnote 46 and Uniper v. Netherlands;Footnote 47 Rockhopper v. Italy Footnote 48 challenged Italy’s moratorium on offshore drilling, and Vattenfall v. Germany Footnote 49 questioned the consistency of environmental licensing reforms with investor guarantees.
Thirdly, the arbitral tribunals occupy the most paradoxical position within this triangle. Their mandate originates from the consent of the disputing parties, typically expressed through BITs or investment contracts.Footnote 50 In principle, tribunals are expected to resolve disputes strictly within the four corners of the applicable treaty, applying its provisions in accordance with the parties’ consent and VCLT. This shift gives rise to a profound dilemma. On one hand, a tribunal that adheres rigidly to textual consent, and eschews reference to external norms such as environmental law, human rights, or sustainable development, risks rendering decisions that appear legally correct yet morally tone-deaf, detached from the collective pursuit of climate justice.Footnote 51 On the other hand, when tribunals invoke external principles or integrate climate-related obligations into their reasoning, they invite criticism for exceeding their mandate and engaging in judicial activism.Footnote 52
Taken together, these tensions give rise to a form of triangular entrapment: investors seek legal certainty, host states require regulatory flexibility, and tribunals must reconcile these competing demands within a consent-based framework. Efforts to prioritize any one of these imperatives tend to undermine the others, revealing a structural tension that cannot be resolved within a merits-based framework alone.
2.2. Existing Responses to the Triangular Dilemma and Their Limits
Existing doctrinal and procedural responses
In order to reconcile the potential conflicts between investment protection and climate obligations, ISDS tribunals have relied primarily on doctrinal strategies grounded in the interpretive logic of treaty provisions.Footnote 53 An example of the first doctrinal mechanism can be found in Saluka Investments v. Czech Republic,Footnote 54 in which the tribunal applied Article 31(3)(c) VCLT and emphasized that treaty interpretation must take into account ‘any relevant rules of international law applicable in the relations between the parties’,Footnote 55 a standard which the ICJ has confirmed includes general customary international law. Similarly, in Ioan Micula and Others v. Romania,Footnote 56 the tribunal recognized that multiple treaties must be interpreted in the light of each other, reflecting the parties’ assumed awareness of all their legal obligations.Footnote 57
Exceptions clauses and regulatory carve-outs provide a second doctrinal mechanism. In practice, ISDS tribunals have applied these mechanisms to reconcile investor protection with climate and environmental objectives. In Westmoreland v. Canada, the tribunal examined Canada’s coal phase-out policy adopted as part of its national climate strategy, acknowledging the legitimacy of climate objectives while assessing the foreseeability and reasonableness of the measures.Footnote 58 A more recent doctrinal development involves narrowing the scope of protected investment through the concept of ‘qualified investment’.Footnote 59 By excluding activities that are incompatible with host-state climate commitments, tribunals can prevent disputes that would otherwise pit environmental regulation against investment protection.
Procedural innovations complement these doctrinal approaches. Tribunals have experimented with bifurcation or preliminary assessments to separate questions of liability from quantification, allowing for earlier consideration of environmental or public interest issues. In Aven v. Costa Rica, the tribunal first examined jurisdictional and environmental compliance issues before addressing the merits, recognizing that the dispute was intrinsically linked to Costa Rica’s environmental protection framework.Footnote 60 The admission of amicus curiae submissions provides a formal channel for third-party stakeholders, including local communities and civil society actors, to present perspectives on the climate impacts of disputed measures. For example, in Biwater Gauff v. Tanzania, the tribunal admitted multiple amicus briefs from non-governmental organizations (NGOs) and international organizations, acknowledging their potential contribution to broader public interest considerations in cases involving natural resources and sustainable development.Footnote 61
Collectively, these doctrinal and procedural strategies constitute the current ISDS toolkit for mitigating the climate–investment dilemma. While they reflect an increasing sensitivity to the intersection of investment law and environmental governance, their practical effectiveness is limited by the structural features of arbitration, including the bilateral focus of disputes, the principle-based nature of climate norms, and the persistent uncertainty over interpretive standards.
The limits and deficiencies of current approaches and methodologies
Admittedly, the preceding approaches mark important attempts to recalibrate the relationship between investment law and environmental governance. They have injected a degree of flexibility and normative awareness into an otherwise rigid system. Yet, their promise remains largely unfulfilled.
Doctrinal innovations, such as narrowing the notion of investment, introducing exception clauses for environmental measures, and employing proportionality review, have emerged as ad hoc judicial responses to the tension between investment protection and environmental regulation. Tribunals often oscillate between deferential and intrusive standards of review without articulating a principled basis for determining when deference to host-state regulatory autonomy is warranted. For instance, in Parkerings v. Lithuania, the tribunal adopted a deferential approach, emphasizing that states retain a broad right to regulate in the public interest, particularly in the field of environmental protection.Footnote 62 By contrast, in Tecmed v. Mexico, the tribunal applied an intrusive proportionality analysis, finding that the revocation of an environmental licence violated the investor’s legitimate expectations, despite Mexico’s environmental justifications.Footnote 63 These divergent approaches reveal that arbitral reasoning lacks an overarching interpretive framework capable of reconciling investment protection with global environmental obligations.Footnote 64
Procedural innovations, such as amicus curiae participation and contextual interpretation of treaties, are commendable but largely symbolic in practice. Tribunals retain full discretion over the reasoning of awards. In Biwater Gauff v. Tanzania, the tribunal accepted amicus briefs from civil society organizations but ultimately treated them as ‘background context’ without integrating their arguments into the legal reasoning.Footnote 65 Similarly, in Glamis Gold v. United States, while the tribunal permitted NGO participation under Article 1128 of the North American Free Trade Agreement (NAFTA),Footnote 66 the environmental arguments of the amici had no discernible impact on the outcome.Footnote 67 Consequently, procedural openness has not translated into substantive engagement with environmental or climate-related values, limiting the normative reach of such reforms.
Moreover, the persistent shortcomings of doctrinal and procedural reforms ultimately reveal that the core difficulty concerning the climate-investment dilemma does not lie in the tribunals’ interpretive choices but in the very architecture of ISDS adjudication. The principal procedure of ISDS, centred on the final determination of state liability and the award of compensation, was never designed to accommodate problems of the scale, complexity, and temporality inherent in climate governance.Footnote 68 Climate disputes, by contrast, are multilateral and intertemporal in nature, implicating types of diffuse harm, shared responsibilities, and public goods that extend far beyond the disputing parties.Footnote 69 Moreover, the remedial logic of ISDS, providing monetary compensation for individual investors, stands in tension with the preventive and transformative objectives of climate law. In this sense, the principal adjudicatory process of ISDS is ill-suited to govern the evolving dynamics of climate transformation.
Thus, the difficulty is not that climate disputes fall beyond the jurisdictional or institutional reach of ISDS, but that they cannot be effectively resolved through its primary merits-based adjudication. Recognizing these functional constraints invites closer examination of how provisional measures, as an exceptional yet potent procedural device, might serve as a more responsive mechanism to mediate between investment protection and climate governance.
3. Provisional Measures as an Effective Response to the Climate Dilemma
Provisional measures are interim remedies adopted to preserve the rights of the parties and prevent aggravation of the dispute pending final adjudication.Footnote 70 In the field of international investment arbitration, their legitimacy has long been affirmed by numerous tribunals.Footnote 71 Under Article 47 of the Convention on the Settlement of Investment Disputes between States and Nationals of Other States (ICSID Convention)Footnote 72 and Rule 47 of the ICSID Arbitration Rules,Footnote 73 tribunals may recommend provisional measures to protect the integrity of the proceedings and prevent irreparable harm to either party. This procedural instrument thus provides a potential channel through which investment tribunals can engage with climate-related concerns before the merits stage. This section advances the central claim of this article that the climate–investment dilemma identified in Section 2 cannot be resolved within the merits phase of ISDS adjudication, but requires a procedural reorientation through provisional measures. Rather than functioning merely as ancillary remedies, provisional measures provide a structurally distinct mechanism through which tribunals can intervene prior to final adjudication to preserve rights, prevent irreparable harm, and stabilize the relationship between investors and host states in the context of climate-related disputes. Accordingly, this article argues that provisional measures should be reconceptualized not as ancillary safeguards but as a primary procedural mechanism through which ISDS tribunals can manage the climate–investment dilemma in real time.
3.1. Theoretical Response: Reconciling Climate Protection and Investment Adjudication
Inherent powers and structural flexibility
Provisional measures constitute a recognized component of an ICSID tribunal’s inherent powers.Footnote 74 They do not depend on the parties’ prior consent beyond the tribunal’s jurisdiction but instead derive from the tribunal’s essential function to ensure that arbitration remains effective and that the rights of the parties are preserved.Footnote 75 Article 47 of the ICSID Convention authorizes tribunals to indicate provisional measures ‘to preserve the respective rights of either party’. While the text uses the term ‘recommend’, arbitral practice consistently treats such indications as binding orders. For instance, in City Oriente Ltd v. Ecuador, the tribunal held that ‘the word “recommend” is equal in value to the word “order”’.Footnote 76
The binding nature of provisional measures enables tribunals to stabilize the arbitral relationship between investors and host states at a time of heightened uncertainty.Footnote 77 Rather than merely preventing physical or environmental harm, provisional measures serve to ensure that neither party takes unilateral actions that could frustrate the purpose of the arbitration or render its outcome ineffective.Footnote 78 This function is particularly relevant in climate-related disputes, where regulatory reforms and investment activities are both dynamic and politically charged. By ordering interim restraint, tribunals can prevent the escalation of conflict and preserve the legal equilibrium necessary for impartial adjudication. For instance, in Rockhopper v. Italy, the tribunal issued provisional measures to maintain the status quo regarding offshore exploration pending a determination on the legality of Italy’s moratorium, thereby safeguarding the procedural purpose of the arbitration.Footnote 79 Similarly, in Perenco v. Ecuador, interim measures were invoked to ensure that neither the investor’s ongoing operations nor the state’s regulatory responses would aggravate the dispute.Footnote 80 These examples illustrate that the function of provisional measures extends beyond the prevention of harm: they operate as instruments of procedural governance, preserving both the integrity and the credibility of the arbitral process itself.
The inherent character of provisional measures also provides structural flexibility within the ISDS framework. Unlike the merits stage – which is constrained by bilateral obligations, treaty text, and a compensatory logic – provisional measures allow tribunals to adopt a broader, more holistic approach.Footnote 81 They can account not only for the immediate interests of investors and host states but also for the rights and welfare of third-party stakeholders, such as local communities affected by climate-sensitive investments. For instance, in Tethyan Copper Company Pty Ltd v. Pakistan,Footnote 82 the tribunal issued provisional measures to protect evidence and maintain the status quo regarding mining operations pending resolution of the dispute. In this sense, provisional measures operate as a procedural instrument capable of bridging the gaps identified in the triangular climate–investment dilemma, offering tribunals a mechanism to reconcile legal certainty, regulatory flexibility, and normative legitimacy.
Provisional measures thus offer a targeted response to the structural dilemma in climate-related ISDS disputes. By enabling tribunals to act prior to the merits stage, they provide a mechanism to prevent irreversible harm, safeguard ongoing investments, and maintain procedural integrity, without being constrained by the compensatory logic of the merit proceedings.Footnote 83 This flexibility allows tribunals to temporarily reconcile investor protection with the host state’s regulatory objectives, addressing the foundational tension between bilateral obligations and dynamic climate imperatives.
Substantive and procedural rationales: Preserving rights and integrity
From a substantive perspective, provisional measures aim to prevent irreparable harm that could render the final award meaningless. Climate-related harm is, by nature, irreversible: deforestation, mining operations, or the emission of greenhouse gases cannot be undone by monetary compensation.Footnote 84 Where ongoing investment activities threaten to cause permanent ecological loss, provisional measures allow tribunals to act preventively, thereby aligning the procedural architecture of ISDS with the precautionary logic of environmental law. For instance, in Chevron v. Ecuador, interim measures were requested to prevent the execution of domestic judgments that could have caused irreversible environmental consequences, reflecting the recognition that preservation of the status quo serves both ecological and legal stability.Footnote 85 This reorientation transforms investment arbitration from a reactive mechanism of redress into a proactive mechanism of protection. It directly addresses the investor–state dimension of the climate dilemma: investors retain access to adjudication, but are restrained from aggravating harm while the dispute is pending, thus preserving the legitimate interests of both parties.
Procedurally, the objective of preserving the integrity of the proceedings acquires renewed importance in climate disputes. Environmental controversies are uniquely sensitive to delays and asymmetries of power: the continuation of harmful activities during arbitration may render any eventual decision futile. In Quiborax v. Bolivia, for example, the tribunal granted provisional measures to prevent the state from pursuing parallel criminal proceedings that would have undermined the fairness and effectiveness of the arbitration.Footnote 86 Similarly, in Hydro v. Albania, the tribunal ordered provisional measures to ensure procedural equality and prevent the state from taking coercive actions that could impair the investor’s participation in the arbitration.Footnote 87 By granting provisional measures, tribunals safeguard the effectiveness and legitimacy of the arbitral process itself, ensuring that neither party, particularly investors with ongoing operations, unilaterally pre-empts the outcome. In this sense, provisional measures recalibrate the adjudicatory balance between investor protection and sovereign authority, strengthening the procedural credibility of ISDS in the public eye and paving the way for a more inclusive consideration of third-party and community interests in subsequent analyses.
Taken together, the substantive and procedural rationales of provisional measures directly mitigate the dual tensions that define the investor–state dilemma. Substantively, they safeguard investors’ legitimate expectations without allowing them to aggravate environmental harm or pre-empt regulatory action, thereby maintaining confidence in the arbitral process while respecting sovereign policy space. Procedurally, they restore equilibrium in the face of power asymmetries: by suspending irreversible acts and preserving the status quo, tribunals ensure that both parties remain subject to a neutral and effective adjudicatory order rather than strategic unilateralism. In doing so, provisional measures transform ISDS from a static forum of retrospective compensation into a dynamic mechanism of interim governance, capable of preventing further harm pending the final resolution of the dispute. This reconfiguration not only stabilizes the investor–state relationship but also lays the institutional foundation for incorporating broader community and ecological interests, a dimension to which the following section now turns.
Safeguarding community interests through procedural restraint
The normative justification for incorporating community interests into provisional measures lies in the very nature and purpose of interim relief. Provisional measures are not intended solely to preserve the respective rights of the parties but to ensure the proper administration of justice by preventing actions that could frustrate or render the adjudicatory process meaningless.Footnote 88 When a dispute implicates broader public goods (such as environmental integrity, public health, or human security) the protection of these collective values becomes an integral part of the preservation of justice itself.Footnote 89
This broader understanding resonates with Bruno Simma’s seminal notion of community interests, which he defined as ‘a consensus according to which respect for certain fundamental values is not to be left to the free disposition of states individually or inter se but is recognized and sanctioned by international law as a matter of concern to all states’.Footnote 90 Although the international legal system has not yet developed institutional mechanisms specifically dedicated to their enforcement, provisional measures have emerged as a pragmatic means through which courts and tribunals can offer procedural protection to these collective values within existing adjudicatory structures.
This tendency is observable in the jurisprudence of both the ICJ and the International Tribunal for the Law of the Sea (ITLOS). The ICJ, while traditionally confined to interstate disputes, has occasionally invoked provisional measures in ways that implicitly acknowledge community concerns. In the Nuclear Tests cases, the Court’s order sought to prevent further atmospheric testing that might cause irreparable environmental harm to humanity as a whole.Footnote 91 Similarly, in Certain Activities Carried out by Nicaragua in the Border Area (Costa Rica v. Nicaragua), the Court emphasized the need to prevent irreparable harm to the fragile ecosystem of the San Juan River basin, with several judges referring explicitly to environmental protection and public welfare as factors justifying interim relief.Footnote 92 The ITLOS has gone further in articulating this rationale. Under Article 290 UNCLOS, it has prescribed provisional measures ‘to prevent serious harm to the marine environment,’ thereby extending the reach of interim relief beyond the rights of the disputing parties to encompass the protection of global commons.Footnote 93 Cases such as Southern Bluefin Tuna Footnote 94 and Land Reclamation by Singapore in and around the Straits of Johor Footnote 95 demonstrate willingness of the tribunal to exercise this community-oriented function, highlighting an emerging procedural consensus across international adjudicatory bodies.
Within the context of investment arbitration,Footnote 96 this evolution acquires particular significance. Many scholars have described investment arbitration as a form of global administrative law, highlighting its public function in regulating cross-border economic activity. For instance, Gus Van Harten characterizes investment treaty arbitration as a species of global administrative law,Footnote 97 while Stephan Schill emphasizes the public function of ISDS and the significance of arbitrators in shaping the international economic order.Footnote 98 Moreover, in the ISDS context, tribunals have begun to reflect this broader perspective in practice. In Quiborax v. Bolivia, the tribunal noted Bolivia’s immediate pardoning of the claimants’ key witness after he pleaded guilty in related criminal proceedings.Footnote 99 The tribunal interpreted this as evidence that Bolivia did not consider the individual, or others at risk of similar charges, to constitute a threat to society, thereby implicitly recognizing a societal interest in the protection of individuals beyond the immediate disputing parties.Footnote 100 Similarly, in City Oriente v. Ecuador, the ICSID tribunal granted provisional measures to ensure that ongoing operations did not compromise sensitive environmental and community resources pending the arbitration, balancing the investor’s interests with broader societal concerns.Footnote 101 These examples demonstrate that, although ICSID tribunals do not serve as a ‘world court’ like the ICJ, they are increasingly acknowledged as actors with a global governance function, capable of integrating community interests into procedural decision-making.
Therefore, although ISDS is structurally bilateral, the social and ecological implications of climate-related disputes invariably extend to non-parties, local communities, future generations, and the broader international public. Provisional measures thus offer tribunals a procedural mechanism to account for these interests indirectly.Footnote 102 By restraining actions that risk aggravating environmental harm or undermining domestic regulatory efforts, tribunals not only preserve the rights of the disputing parties but also maintain the broader ecological and social balance affected by the investment. In doing so, provisional measures help to alleviate the triangular dilemma inherent in climate-related disputes: investors’ procedural rights remain protected, the regulatory authority of states is preserved, and community interests receive a measure of procedural recognition.
3.2. Procedural Response: Operationalizing Collective Responsibility in ISDS
While the theoretical justification for provisional measures lies in their capacity to balance investment protection with environmental responsibility, their practical value depends on how tribunals operationalize this balance through procedural innovation.Footnote 103 In this respect, the mechanism of provisional measures provides a procedural gateway through which the logic of collective responsibility can enter a system that is otherwise built on bilateral contestation. These procedural developments are not merely technical adjustments, but form part of a broader reorientation of ISDS towards managing the structural tensions identified in Section 2.
Firstly, the interpretative flexibility inherent in the criteria for granting provisional measures enables tribunals to accommodate environmental and collective concerns within established legal frameworks. The conventional tests of urgency, necessity, and irreparable harm are not rigidly defined; international courts and tribunals have interpreted them in the light of the broader factual and normative context of each dispute. For example, in Pulp Mills on the River Uruguay (Argentina v. Uruguay), the ICJ emphasized the need to prevent deterioration of shared natural resources during proceedings,Footnote 104 effectively recognizing that the protection of the environment could itself constitute an urgent circumstance. Similarly, in Costa Rica v. Nicaragua, the Court relied on environmental concerns to indicate new provisional measures, requiring both parties to refrain from aggravating ecological damage.Footnote 105 Comparable tendencies are now visible in ISDS. In Perenco v. Ecuador, the tribunal ordered provisional measures to ensure that Ecuador’s environmental counterclaims would not be prejudiced during the proceedings, recognizing the state’s interest in ecological protection as a legitimate procedural concern.Footnote 106 In Occidental Petroleum v. Ecuador, the tribunal refused to order provisional measures that would have limited Ecuador’s ability to regulate and maintain public order, recognizing that the state’s responsibilities in safeguarding environmental and social stability could take precedence over the investor’s purely economic interests.Footnote 107 These cases illustrate that the notion of irreparable harm is gradually expanding to include injury to shared ecological interests and public welfare, not merely private investment losses.
Secondly, provisional measures can transform ISDS from an adversarial model into a framework of procedural cooperation. Climate change presents an inherently collective problem, whereas ISDS operates on a bilateral structure centred on individual claims. Provisional measures offer a procedural mechanism to bridge this gap. By ordering the parties to cooperate – for instance, to exchange environmental data, suspend harmful operations, or jointly monitor contested areas – tribunals can temporarily replace confrontation with collaboration. This cooperative function has already emerged in international adjudication: in Costa Rica v. Nicaragua Footnote 108 and in the Request for Interpretation of the Temple of Preah Vihear,Footnote 109 the ICJ involved external institutions in supervising compliance with its orders, thus initiating a model of institutional collaboration. Such practices exemplify how judicial creativity can foster collective problem-solving within inherently bilateral proceedings.
Thirdly, the procedural versatility of provisional measures allows for a more dynamic interaction between arbitral tribunals and other institutional actors. Environmental disputes often require technical expertise and ongoing oversight that exceed the tribunal’s capacity alone.Footnote 110 By referring to, or coordinating with, specialized international or regional institutions (such as the United Nations Environment Programme (UNEP), the UNFCCC Secretariat, and regional environmental commissions) tribunals can enhance both the legitimacy and the effectiveness of their orders. As mentioned above, the ICJ collaboration with the United Nations Educational, Scientific and Cultural Organization (UNESCO) in Temple of Preah Vihear (Interpretation) to protect a disputed heritage site marked a significant step in institutional cooperation. Similarly, ISDS tribunals could envisage involving multilateral environmental bodies in monitoring compliance with provisional measures, particularly where disputes concern transboundary or climate-related risks. Such procedural integration would embody collective responsibility in concrete institutional form, ensuring that investment adjudication contributes to, rather than fragments, global governance. Moreover, this procedural reconfiguration helps to reconcile the asymmetrical logic of ISDS with the cooperative nature of climate governance. Traditional investment arbitration distributes obligations asymmetrically, imposing duties primarily on host states while granting investors extensive rights.Footnote 111 Provisional measures, however, can impose reciprocal procedural obligations (such as transparency, data sharing, and mutual restraint), which promote cooperation in good faith. In doing so, they mitigate the perception that ISDS is structurally biased towards private interests and reinforce the tribunal’s role as a neutral guardian of procedural integrity rather than a passive arbiter of private grievances. Through cooperation-oriented provisional measures, tribunals can cultivate a shared sense of responsibility between disputing parties, reflecting the collective nature of climate challenges.
Ultimately, the procedural innovation of provisional measures allows ISDS to evolve into a more responsive instrument of global governance. By leveraging interpretative flexibility, fostering cooperation, and engaging institutional partners, arbitral tribunals can integrate community interests into their procedural logic without departing from the consent-based foundations of arbitration. In this way, provisional measures are transformed from a temporary procedural safeguard into a structural mechanism for reconciling private adjudication with public responsibility. This functional reorientation provides the foundation for the argument developed in the following section: namely, that provisional measures should be understood not merely as ancillary remedies, but as a central mechanism for integrating climate considerations into ISDS adjudication.
4. Defining the Threshold for Climate-Related Provisional Measures
While the potential for provisional measures to integrate collective environmental concerns into investor–state arbitration is significant, their legitimacy depends ultimately on the discipline with which they are applied. The concern that provisional measures may be abused or invoked strategically to delay proceedings or exert political pressure is not unfounded. Consequently, both ICSID tribunals and other international courts have emphasized that provisional measures are extraordinary remedies, to be ordered only in exceptional circumstances. This section examines how the classical four-part test – which includes prima facie jurisdiction, preservation of rights, urgency, and necessity/irreparable harm – should be interpreted in the context of climate-related disputes. Properly understood, these criteria not only guard against abuse but also provide a principled framework for applying provisional measures to climate challenges.
4.1. Prima Facie Jurisdiction
The first threshold concerns the existence of prima facie jurisdiction. This does not require the tribunal to determine its jurisdiction conclusively, but merely to satisfy itself that jurisdiction is plausible on the face of the record.Footnote 112 The rationale, firmly grounded in the jurisprudence of the ICJ and applied consistently by ICSID tribunals, is to prevent the tribunal from issuing orders in matters where it might later find itself incompetent. Accordingly, tribunals undertake a preliminary factual and legal appraisal of the claimant’s allegations to determine whether, at first sight, the dispute falls within their jurisdiction ratione personae, ratione materiae, and ratione temporis.Footnote 113
In environmental and climate-related investment disputes, this test assumes heightened significance and complexity. Such disputes often arise from regulatory measures adopted to pursue climate objectives (such as renewable energy reforms, carbon pricing mechanisms, and emissions reduction policies) that intersect with investors’ economic expectations. At this preliminary stage, tribunals must therefore examine whether these sovereign acts are sufficiently connected to an ‘investment’ within the meaning of the applicable treaty, and whether the alleged breach genuinely falls within the scope of treaty protection. This ensures that provisional measures are not used to advance global environmental objectives per se but only to protect rights or obligations arising within the treaty framework. In Maffezini v. Spain, the tribunal clarified that provisional measures must relate to the ‘subject-matter of the dispute’.Footnote 114 Applying this logic, where climate-related measures are at issue (such as challenges to host-state decarbonization policies or the withdrawal of fossil fuel subsidies), the tribunal must verify that these measures fall within its jurisdictional remit under the treaty, and that any provisional order will not transform the arbitral process into a forum for general environmental advocacy.
This careful jurisdictional control preserves the legitimacy of the arbitral function while still allowing tribunals to consider environmental protection as an incidental, yet relevant, dimension of the dispute.Footnote 115 In this way, the prima facie jurisdiction test acts as both a procedural safeguard and a normative boundary, ensuring that ISDS remains an instrument of international adjudication, not of global environmental governance, even as it increasingly engages with sustainability-related conflicts.
4.2. Preservation of Rights
The second condition governing the issuance of provisional measures is that they must serve to preserve the rights forming the subject matter of the dispute. Traditionally, this requirement aimed to protect the procedural integrity of arbitration by ensuring that the tribunal’s eventual decision is not rendered futile.Footnote 116 However, in the emerging body of climate-related investment disputes, this notion has evolved towards a broader understanding that integrates both private and public dimensions of preservation.
Recent cases demonstrate that the preservation of rights increasingly entails a balance between the investor’s treaty-based entitlements and the host state’s prerogatives in pursuing energy transition and environmental protection. In Westmoreland Coal Company v. Canada, the investor challenged Canada’s phase-out of coal-fired electricity as an expropriatory measure.Footnote 117 The tribunal’s reasoning, though procedural, illuminated the tension between maintaining the investor’s economic position pending arbitration and safeguarding the state’s sovereign right to implement climate policies in good faith. The preservation of rights in such contexts cannot be divorced from the urgent and irreversible nature of environmental degradation that climate regulation seeks to avert.Footnote 118 Instead, it must ensure that both the investor’s legitimate expectations and the host state’s regulatory space are maintained in equilibrium. The reasoning reflects a growing judicial awareness that environmental and economic interests are not mutually exclusive but mutually constitutive in the era of climate governance. The tribunal in the Hydro v. Albania case reinforced this point by observing that a provisional measure should not restrain a state from exercising its regulatory powers in pursuit of legitimate public and environmental objectives.Footnote 119 Environmental and climate objectives, particularly those derived from multilateral commitments or domestic sustainability strategies, constitute a legitimate dimension of those public interests. Thus, the preservation of rights extends to maintaining a regulatory environment that allows states to meet their environmental obligations while respecting procedural fairness towards investors.
Hence, in the climate context, the requirement of preserving rights acquires a dual structure. On the one hand, it safeguards investors’ procedural and substantive entitlements under the treaty, while on the other, it recognizes the host state’s inherent right, and indeed its duty, to protect the environment and pursue energy transition policies.Footnote 120 For instance, where the continuation of certain activities would lead to irreversible ecological damage, the tribunal may consider provisional measures aimed at maintaining environmental stability as integral to the preservation of rights. This broadened interpretation situates the tribunal not as an arbiter of environmental policy but as a guardian of the procedural equilibrium between competing claims. It acknowledges that environmental degradation may irreparably frustrate both the state’s regulatory capacity and the investor’s ability to obtain meaningful relief. In this sense, preservation becomes not merely a procedural safeguard but a reflection of the intertwined material conditions of investment and sustainability. The jurisprudence of Westmoreland Coal and Hydro v. Albania thus reveals a maturing arbitral sensibility: one that perceives ‘rights’ in investment arbitration as embedded within broader ecological and societal realities.
Accordingly, the phrase ‘preserving the rights at stake’ should be interpreted in a balanced manner that acknowledges the mutual interdependence of economic and ecological interests. In climate-related investment disputes, this balance entails recognition that the environment itself may constitute an object of preservation in as much as its degradation would frustrate both the investor’s long-term economic viability and the state’s ability to meet its climate commitments. Such an understanding situates the arbitral tribunal not as an arbiter of environmental policy, but as a procedural custodian of the intersecting rights and responsibilities that define the climate–investment interface.
4.3. Urgency
The third requirement, urgency, concerns the temporal relationship between the threatened harm and the tribunal’s ability to act effectively before the final award.Footnote 121 As articulated in Plama Consortium v. Bulgaria Footnote 122 and reaffirmed in City Oriente v. Ecuador,Footnote 123 urgency exists where delay would risk rendering the tribunal’s eventual decision meaningless. This temporal dimension ensures that provisional measures are a preventive tool, not an instrument for strategic delay or political pressure.
In climate-related investment disputes, the notion of urgency takes on a distinctive character arising from the accelerated and often irreversible nature of environmental harm. Unlike purely commercial disputes, where losses can typically be quantified and compensated ex post, climate-related harm such as deforestation, large-scale carbon emissions, or destruction of ecosystems unfold along non-linear trajectories. Once a tipping point is crossed, restoration becomes impossible within human timescales. Thus, tribunals assessing urgency in such contexts must account not only for immediate material risks but also for the temporal dynamics of environmental degradation.
More recent energy transition cases, such as Uniper v. Netherlands Footnote 124 and RWE v. Netherlands,Footnote 125 arising from the Dutch coal phase-out legislation, further underscore this temporal complexity. Investors claimed that the accelerated closure of coal-fired plants caused severe and immediate economic harm. Had provisional measures been sought, the tribunal would probably have had to weigh the imminence of financial losses against the state’s pressing need to meet climate deadlines and avoid long-term ecological damage. This juxtaposition of short-term investor harm and long-term environmental urgency illustrates how the tribunal’s assessment must remain contextually sensitive. A purely economic understanding of urgency risks overlooking the structural time asymmetry between investment protection and climate protection: while financial loss is reversible through compensation, lost time in emissions reduction is not.
Therefore, in climate-related investment arbitration, urgency must be evaluated through a dual temporal lens. Firstly, tribunals must determine whether the investor faces imminent procedural or economic prejudice that would make the arbitration ineffective. Secondly, and increasingly relevant, they must assess whether the absence of provisional measures would permit irreversible environmental degradation that frustrates the host state’s sovereign capacity to meet its climate obligations.Footnote 126 This latter dimension does not expand the tribunal’s mandate into environmental adjudication; rather, it recognizes that the failure to act promptly may undermine both the integrity of the dispute and the legitimacy of the arbitral process itself. Crucially, urgency should not be conflated with political expedience or economic inconvenience. In the climate context, this means that the tribunal must identify a direct nexus between the absence of provisional relief and the potential for irreversible environmental or procedural harm, such as the destruction of carbon sinks, large-scale methane release, or the dismantling of renewable energy infrastructure subject to dispute.
By interpreting urgency through this refined lens, arbitral tribunals can prevent the misuse of provisional measures as instruments of regulatory freeze while remaining responsive to the temporal realities of climate governance. The function of urgency thus becomes twofold: it shields the integrity of the arbitral process from imminent prejudice and, concurrently, safeguards the environmental conditions that render the ultimate award meaningful. In this way, the requirement maintains its classical procedural rigour while adapting to the accelerated temporality of climate-related disputes.
4.4. Necessity and Irreparable Harm
The fourth and most stringent condition is necessity, often coupled with the requirement that the harm to be prevented be irreparable. ICSID tribunals, following Quiborax v. Bolivia Footnote 127 and Paushok v. Mongolia,Footnote 128 have clarified that ‘irreparable’ does not mean harm that is impossible to compensate, but rather harm that cannot be adequately remedied through monetary damages or post hoc restoration. In this sense, the test of necessity functions as a proportionality filter: provisional measures should be granted only when they are indispensable to prevent an irreversible loss that would render the final award ineffective.Footnote 129
In climate-related investment disputes, this requirement assumes heightened relevance because environmental harm is typically cumulative, transboundary, and temporally irreversible. The destruction of carbon sinks, emission of greenhouse gases, or degradation of fragile ecosystems cannot be undone through financial compensation; nor can their global consequences be contained within the bilateral framework of an investment treaty. Thus, tribunals confronted with disputes touching on climate measures must adapt the necessity assessment to reflect both the ecological irreversibility and the temporal immediacy of the threatened harm. The reasoning in Eco Oro v. Colombia provides a useful analogy. Although the case did not directly concern climate regulation, the tribunal acknowledged that the protection of an environmentally sensitive area (the Santurbán Páramo) represented a legitimate and non-compensable public interest.Footnote 130 If provisional measures had been requested, the necessity threshold could have been satisfied on the basis that continued mining would cause irreversible damage to a unique ecosystem central to Colombia’s environmental obligations.
Necessity in the climate context, therefore, requires tribunals to consider the qualitative nature of the threatened harm rather than its immediate economic value. Activities such as deforestation, large-scale extraction, or industrial expansion within protected zones may cause systemic climate effects that, while not easily quantifiable, represent clear cases of irreparable loss. This understanding aligns with the approach taken in South American Silver v. Bolivia, in which the tribunal acknowledged that the protection of local communities and environmental integrity may justify precautionary measures that temporarily limit investment activities.Footnote 131 Equally, tribunals must be attentive to the proportionality dimension of necessity. Provisional measures should not transform investment arbitration into a de facto environmental enforcement regime. The objective is not to advance abstract ecological goals, but to prevent concrete and imminent degradation that would frustrate the tribunal’s eventual ability to render justice. For example, in Gabriel Resources v. Romania, the dispute over a proposed gold mining project raised complex issues concerning environmental permitting and cultural heritage.Footnote 132 Had provisional measures been sought, the necessity test would have required a careful balance between the investor’s interest in maintaining project viability and the state’s duty to prevent irreversible ecological and cultural damage.
Accordingly, in climate-related investment disputes, necessity operates as both a constraint and an enabler. It constrains tribunals from overstepping their jurisdiction by demanding that environmental urgency be directly linked to the subject matter of the dispute; yet, it enables preventive action where failure to intervene would lead to irreversible consequences that undermine both the environment and the legitimacy of the arbitral process. The assessment should thus focus on three interrelated factors: (i) the material irreversibility of the harm; (ii) the causal connection between the harm and the measures requested; and (iii) the proportionality between the interests affected and the preventive purpose served.Footnote 133
5. Conclusion
The intersection between investment arbitration and climate governance exposes the limits of an adjudicatory model designed for bilateral disputes when confronted with collective and intertemporal challenges. This article has argued that provisional measures, traditionally viewed as exceptional procedural instruments, can be reconceptualized as a procedural site of intervention within ISDS, capable of engaging climate-related tensions at an earlier and more preventive stage of adjudication. By operating before irreversible harm occurs, provisional measures may help to stabilize regulatory situations, preserve environmental interests, and temper the escalation of disputes, without displacing or predetermining the tribunal’s subsequent assessment of the merits.
A contextual interpretation of the four established criteria – prima facie jurisdiction, preservation of rights, urgency, and necessity – demonstrates that climate-related disputes require a dynamic understanding of what constitutes ‘rights’, ‘harm’, and ‘preservation’. When interpreted in the light of environmental vulnerability and temporal fragility, these criteria allow tribunals to prevent ecological degradation, maintain the integrity of arbitral proceedings, and encourage mutual restraint between investors and states within the limited procedural space available to them. In this sense, provisional measures do not resolve the substantive tensions between climate regulation and investment protection, but they can shape the conditions under which those tensions unfold.
Building on this contextual understanding of the four criteria governing provisional measures, the article suggests that interpreting these four criteria in a climate-conscious manner does not expand the tribunal’s mandate beyond its consent-based limits; rather, it refines how traditional principles are applied in the light of new global realities. Properly applied, the prima facie jurisdiction test prevents jurisdictional overreach; the preservation criterion maintains focus on the rights under dispute; the urgency requirement limits orders to genuinely time-sensitive situations; and the necessity test ensures that only non-compensable harm justifies intervention. Together, these standards form a coherent safeguard against the misuse of provisional measures, while enabling tribunals to respond to the distinctive temporal and collective dimensions of climate change. The threshold, therefore, is not lowered for environmental protection. Rather, it is contextually adapted to account for the irreversible nature of environmental harm. In doing so, the existing procedural framework of provisional measures proves capable of addressing climate-related risks without destabilizing the consensual architecture of investor–state arbitration.
The broader implication is that ISDS need not be conceptually opposed to global climate governance. While provisional measures cannot neutralize the structural risks of regulatory chill or preclude findings of expropriation or breaches of fair and equitable treatment at the merits stage, they nonetheless provide a context-sensitive procedural mechanism through which tribunals may respond to the urgency and irreversibility of climate harm while remaining faithful to a consent-based mandate. This procedural turn thus represents not a substitute for substantive reform, but a modest yet meaningful adaptation of existing doctrine to the realities of planetary governance, where the preservation of adjudicatory legitimacy increasingly intersects with the preservation of the global commons.
Acknowledgements
The author gratefully acknowledges Guiguo Wang and Xu Qian of Zhejiang University Guanghua Law School for their guidance and support. An earlier draft of this article was presented at the European Society of International Law (ESIL) 2026 Research Forum International Economic Law Interest Group workshop. The author is also grateful to the organizers and participants of the workshop for their valuable comments and suggestions, including Ines Willemyns (Stanford University), Carlo De Stefano (Roma Tre University), Sonia Rolland (Northeastern University), Maria Laura Marceddu (Edinburgh Law School), Patrick Abel (University of Passau), and Gustavo Prieto (Ghent University). The author further thanks the anonymous reviewers of TEL for their constructive comments and assistance in improving the manuscript.
Funding statement
Not applicable.
Competing interests
The author declares none.
Open access
