I. Introduction
One of the most fascinating, yet relatively underexplored, recent judgments concerning the Aarhus convention within the EU is that resulting from the joint consideration of the cases C-212/21 P and C-223/21 P,Footnote 1 where the Court of Justice of the European Union (hereinafter: CJEU) scrutinised the transparency of a project financed by the European Investment Bank (hereinafter: EIB) from an environmental perspective.
The case, discussed in front of the SecondFootnote 2 and of the Third Chamber of the CJEUFootnote 3 , marked the first instance in which the court examined the applicability of the Aarhus Convention in the context of a financial institution. By adopting a broad interpretation of the notions of “administrative acts” and “environmental law” under the Aarhus RegulationFootnote 4 , the CJEU explicitly confirmed its applicability to all EU institutions and bodies for a wide range of acts, excluding those with a legislative or judiciary nature.
As a result, this landmark judgment sheds light on the transparency obligations of the EIB and other EU bodies with regard to the environmental impact of their decisions. Although the CJEU did not assess the substantive compatibility of the EIB’s acts with environmental objectives, it elaborated on the duty to provide adequate reasoning in environmental matters, as well as on the admissibility of requests for internal review under the Aarhus Convention.
The judgment has therefore the potential to inaugurate a new wave of requests for internal review, which may in turn give rise to further litigation before the CJEU. Moreover, it also raises broader questions regarding the applicability of the Aarhus convention to other EU institutions and bodies, particularly the European Central Bank. In this regard, a noteworthy aspect of the judgment is the court’s qualification of EIB’s resolutions and of its environmental policies, such as its Climate Strategy.Footnote 5 By rejecting the defendant’s pleas, the Court clarified that financing decisions, even when taken internally within an EU body, fall under the notion of “acts” captured by the Aarhus Regulation. It further held that internal environmental policies may constitute “environmental law,” with the consequence that decisions, acts, or omissions that are inconsistent with those policies may entitle private parties to request internal review.
Consistent with the EIB’s arguments in this case, concerns have also been raised regarding the applicability of environmental law to the ECB. For instance, academic scholarship as well as speeches by members of the ECB’s Executive Board have portrayed the ECB as a “policy-taker” rather than a “policy-maker”.Footnote 6 Its mandate would also constitute a barrier exempting it from complying with instruments such as the Paris Agreement.Footnote 7 Others have instead underscored the responsibility of the ECB in doing its fair share to advance EU climate law.Footnote 8
Against this backdrop, this article first analyses the core reasoning of the case. It then assesses the implications for the ECB’s mandate and decision-making.
In particular, Sections II and III provide a brief account of the two instances of the judgment in front of the Second and of the Third Chamber, focusing on the key facts and the arguments by the Court. Section IV reflects on the potential repercussions of the judgment for future requests for internal review under the Aarhus Convention, as well as for climate litigation more broadly. Building on these findings, Sections V assesses the applicability of the Aarhus Convention to the activities of the ECB, while Section VI delves into its relevance for environmental data that the Institution gathers. Section VII concludes.
II. The premises to the judgment: the internal review request and Second Chamber’s judgment
The starting point of the judicial saga was a request submitted by the non-governmental organisation (hereinafter: NGO) ClientEarth, seeking the review of a resolution of the EIB’s Board of Directors that led to the approval of a 60,000,000 € loan.Footnote 9 The financing supported the construction of a biomass power generation plant in the province of A Coruña, in Galicia (Spain), fuelled by forest waste. As the approval and first disbursement took place in 2018,Footnote 10 the construction of the project had already been ongoing for three years at the time the judgment was delivered. The request was based on the Aarhus convention,Footnote 11 ratified in the EU through the Access to Environmental information Directive.Footnote 12 The complementary Aarhus Regulation, regulating the applicability of the Aarhus convention to EU institutions and bodies, most recently amended in 2021,Footnote 13 enables NGOs (alongside directly affected parties) to challenge administrative acts or omissions in the field of environmental law.Footnote 14 Clientearth, in this instance, called into question the EIB’s assertions that the project would advance Spanish and EU’s renewable energy production, thereby contributing to broader environmental and sustainability goals.Footnote 15 It also contested the compatibility of the project with the EIB’s internal policies, including its Statute, that would require the prioritisation of climate change goals and of loans supporting renewable energy projects.Footnote 16
The EIB rejected the request as inadmissible, arguing that the internal resolution did not constitute an administrative act, nor an act infringing environmental law stricto sensu. In particular, it maintained that the resolution represented an internal measure falling within its commercial and policy discretion and did not produce externally binding legal effects. The mere approval of a project, it argued, could not in itself demonstrate compliance or non-compliance with environmental legislation.Footnote 17
Following the rejection of its request, Clientearth announced its intention to bring the matter before the EU Courts in a public statement issued on 19 January 2019. The legal basis was the Aarhus regulation, which, following the amendments introduced in 2021, empowers NGOs to initiate formal proceedings vis à vis the ECJ grounded in unsuccessful internal review requests.Footnote 18 ClientEarth notably alleged that the EIB had breached its obligation to state reasons (under Article 296 TFEU) and had adopted an unduly restrictive interpretation of the applicability of the Aarhus Convention to its financing decisions.
In its judgment, the Second Chamber of the General Court considered the justifications provided by the EIB for rejecting the request sufficient, dismissing the first plea as unfounded.Footnote 19
Accordingly, the notions at the core of the judgment are those of “administrative acts,” which, pursuant to the Aarhus regulation,Footnote 20 entitle parties to request internal reviews, and of “environmental law,” which provides the benchmark to determine infringements.
In its reasoning, the Court started from the assessment of the second criteria. In the light of the open-ended wording of the Aarhus convention,Footnote 21 it rejected the argument that the term would merely capture acts with their legal basis in environmental legislation.Footnote 22 It instead tied the notion of “environmental law” to Art. 191(1) TFEU. In doing so, it also clarified that it would also go as far as to cover the internal policies and strategies of EU bodies, insofar as these are introduced to further the Treaty objectives.Footnote 23 Therefore, the CJEU also regards the environmental criteria for the granting of loans set out in EIB’s policies as part of EU’s laws in a broader sense.Footnote 24 This conclusion should, in principle, leave room for a potential scrutiny of the compatibility of subsequent EIB’s acts with such policies.
The Court likewise adopted a broad and systematic interpretations of “administrative acts,” which also encompass EIB’s activities and decisions, including the contested Board resolution. The decisive criterion lies in the legally binding effects of acts vis-à-vis third parties. Only preparatory acts, implementing measures, or purely internal acts without any external consequences fall outside the definition.Footnote 25
On the basis of these broad interpretations, the Court annulled EIB’s decision, opening the door to the internal review of the decision.Footnote 26
III. The Third Chamber’s judgment
The case was later appealed by both the EIBFootnote 27 and the European Commission.Footnote 28 In its joint discussion of the cases, the Third Chamber of the CJEU confirmed its interpretation in the first instance,Footnote 29 substantially endorsing most of the above-mentioned arguments. For instance, it confirmed that the role of the EIB as a financier of projects does not preclude its status as a public authority falling under the scope of the Aarhus convention.Footnote 30 It advocated for an interpretation of the term “administrative act”Footnote 31 in line with the original text of the Aarhus convention. Echoing the opinion of the Advocate general, it highlighted that some of the translated versions of the Regulation in other languages fail to use the term,Footnote 32 which suggests that their strictly administrative character is not a necessary condition.Footnote 33 It also reiterated that even internal policies, like EIB’s Climate Strategy, may qualify as environmental legislation.Footnote 34 On that basis, it upheld the annulment of the contested decision, de facto requiring the EIB to reassess the decision.
Another noteworthy aspect pertains to the scope of the judicial review. The court explicitly recognized EIB’s duty to justify and substantiate this decision in accordance with the principles of good administration.Footnote 35 Yet, the decision also failed to result in substantive scrutiny of the merits of the financing decision. Especially the Third Chamber judgment provides an explicit acknowledgment of the procedural barriers on the CJEU’s jurisdiction over acts by the EIB’s Board of Directors, which the Treaties only admit under restricted circumstances.Footnote 36 As a result, the Court de facto abstained from assessing whether the act was in practice contravening environmental legislation.Footnote 37
IV. The legacy of the judgments
The judgments are expected to have far-reaching implications for the activities of financing institutions, as well as for EU institutions and bodies more broadly.
By affirming the applicability of the Aarhus convention to the EIB, they reinforced the principle that decisions having an environmental impact by international financial institutions presuppose public participation. Prior academic analysesFootnote 38 and cases concerning the compliance with the conventionFootnote 39 had already articulated this idea.
The expansive interpretation of the terms “administrative acts” and “environmental law” could also pave the way for a broader and more wide-spread use of internal review requests under the Aarhus Regulation. This could, in turn, lead to a rise in litigation before the CJEU.
The central role of EIB’s Climate strategy in the judgments also points to the variety of legal bases that litigants in the future could rely on. Climate-related internal policies adopted by other EU institutions or bodies may not only become the subject of future requests and litigation, when they are alleged to breach environmental legislation, but they may also serve as benchmarks for assessing the legality of other acts. In other words, as the judgments at hand illustrate, decisions that are inconsistent with prior internal climate policies may be open to challenge through internal review mechanisms.
As regards future judicial cases, the EU’s record of compliance with the Aarhus Convention has historically been contentious, particularly in light of the procedural barriers that have limited (and, to some extent, continue to limit) the ability of NGOs to access the Court following unsuccessful internal review requests.Footnote 40 An interrelated question relates to the scope of judicial scrutiny in future cases arising from unsuccessful review requests, particularly given the restraint that the CJEU has traditionally shown in assessing the merits of discretionary administrative acts.Footnote 41 In the present case, the Court relied on procedural constraints linked to the EIB’s regime to avoid engaging in a substantive assessment, leaving this issue unresolved. It therefore remains uncertain whether the ECJ will, in future cases, go beyond the scrutiny of whether acts by other EU bodies require internal review, and proceed to assess their substantive legality under environmental law.
There are, however, compelling reasons to believe that the judicial review for acts by other EU institutions and bodies could be more pervasive. First, while the treaties introduce specific restrictions to the justiciability of EIB’s acts, such constraints do not apply in the same way to other institutions, such as the European Central Bank (hereinafter: ECB). Second, it is reasonable to expect at least the standard of “quasi substantive review” typically exercised in relation to other discretionary acts. This entails assessing, at a minimum, the existence of manifest errors and the appropriateness of the decision, based on whether all the available information would have reasonably led to that outcome.Footnote 42 Other cases grounded on the Aarhus convention also illustrate a gradual, albeit cautious, shift toward a more thorough assessment of the contested acts,Footnote 43 even though the Court ultimately refrained from assessing the legality of the contested measures in the end.Footnote 44 Other commentators have also advocated for a broader scope of judicial review across Aarhus-based proceedings, which would be more in line with the original spirit of the Convention. At the very least, such an approach would require verifying whether the institution took into account all relevant scientific and factual evidence available at the time,Footnote 45 a form of review that the Court has already acknowledged as falling within its competence.Footnote 46
Overall, the absence of comparable procedural constraints, combined with evolving case law and a purposive interpretation of the Aarhus Convention, suggests that the CJEU’s scrutiny of discretionary acts by other EU institutions and bodies may be more intensive.
The judgments do not, however, establish an open-ended right to seek review of all types of acts based on the Aarhus convention. In the Second Chamber judgment, the CJEU drew a clear demarcation between acts such as those at issue and acts of a judiciary or legislative nature, for which requests of review under the Aarhus Regulation would be precluded.Footnote 47 In subsequent cases it confirmed the exclusion of this type of acts, while clarifying that their qualification as such would depend on a case-by-case assessment of their substance and effects, rather than on the procedure for their adoption.Footnote 48
Moreover, the foreseeable increase in litigation under the Aarhus regulation, also involving entities with financing responsibilities, could further accelerate climate litigation.Footnote 49
It is worth noting that, in recent years, climate litigation in the financial sector has significantly expanded, with non-governmental organisations increasingly pursuing strategic litigation not only against governments and public bodies, but also against private financial institutions, including banks, asset managers and insurers.Footnote 50 This trend reflects the growing recognition that financial actors play a central role in enabling or constraining the transition to a low-carbon economy.Footnote 51 However, litigation targeting central banks raises distinct legal and institutional issues. Unlike private financial actors, central banks operate as public institutions under a specific constitutional and regulatory framework, shaped by mandates, public law constraints, and a high degree of institutional independence.Footnote 52 In the case of the ECB, the legal basis for potential claims is therefore substantially different, as any assessment of responsibility must account for the ECB’s unique position within the EU institutional architecture, as well as the delicate balance between independence, accountability, and judicial review.Footnote 53 As will be further elaborated in the following sections, these features make the reconstruction of legal responsibility considerably more complex than in litigation involving private financial institutions.
V. Potential implications for the ECB’s mandate
When assessing the broader implications of the judgments for other EU institutions and bodies, the ECB warrants particular attention, in light of its limited similarities with the EIB, its unique institutional position and the technical nature of its competences.
An important starting point, however, lies in their fundamentally different legal nature. While the EIB is an EU body with a specific mandate focused on facilitating the financing of projects,Footnote 54 the ECB is an EU institution recognised by the Treaties (though with a distinct statusFootnote 55 ) and entrusted with a broader mandate.
Yet, similarly to the EIB, the ECB holds and manages assets, including within its non-monetary policy portfolios. These portfolios are administered under its own responsibility, while remaining subject to internal policies and frameworks.
Moreover, the Treaties recognise the independence of both entities, under Article 7 of the ESCB Statute for the ECB and Article 308 TFEU for the EIB respectively. While this notion encompasses multiple dimensions,Footnote 56 it primarily refers, in both cases, to functional independence, namely the ability to determine policies and strategies for the fulfilment of their mandates without external influence.Footnote 57
Insofar as the management of these portfolios has environmental implications, it may fall within the scope of transparency and public participation obligations under the Aarhus Regulation. In this respect, the reasoning underpinning the Court’s judgment in the present case could apply, mutatis mutandis, to the ECB, for instance in relation to its investment decisions or asset eligibility criteria. Recent initiatives by the ECB may be seen as acknowledging the environmental relevance of such portfolio management activities. For instance, the ECB regularly publishes climate-related financial disclosures for these portfolios, setting out the principles guiding investments in its staff pension fund and its own funds portfolio.Footnote 58
However, the Aarhus framework may be relevant also beyond ECB’s non-monetary portfolios. As far as the latter are concerned, a recurrent critique is that setting environmental policies would fall outside the scope of ECB’s mandate.Footnote 59 The following sections will examine whether such obligations could extend more broadly to other functions performed by the ECB, including monetary policy and banking supervision, to the extent that these activities incorporate, or are influenced by, climate-related considerations.
1. Climate-related action within the ECB’s monetary policy mandate
Before assessing the implications of the Aarhus framework, it is necessary to clarify the legal basis upon which the ECB may take climate-related action in its core function of setting the EU’s monetary policy. Article 127(1) TFEU establishes a dual structure of objectives. The primary objective of the ESCB is to maintain price stability. Without prejudice to this objective, the ESCB shall also support the general economic policies in the Union.
Academic scholarship has identified the legal basis for climate-related action in both objectives.Footnote 60 On the one hand, climate change may directly affect price stability through its macroeconomic consequences, thereby justifying action under the ECB’s core mandate. On the other hand, climate-related measures may be pursued as part of the ECB’s supporting role vis-à-vis general economic policies.
The scope of the notion of “general economic policies” is therefore crucial. A broad interpretation of the notion, supported by both textual and systemic considerations, captures all EU and domestic policies with a general economic dimension, including environmental and climate policies.Footnote 61 The Treaties do not establish a rigid separation between economic and environmental policy; rather, they reflect an integrated approach in which environmental considerations permeate the Union’s economic framework. This conclusion is reinforced by Article 11 TFEU, which requires that environmental protection be integrated into the definition and implementation of Union policies and activities. While this provision does not alter the hierarchy of objectives underpinning the ECB’s mandate, it nevertheless supports the view that environmental considerations should be taken into account in the exercise of monetary and supervisory functions.Footnote 62 Importantly, this does not imply that the ECB is entrusted with an autonomous environmental mandate. As has been observed, the Treaties allocate primary responsibility for environmental policy to the Union’s political institutions.Footnote 63 Rather, Article 11 TFEU operates as an integration clause, shaping the manner in which existing competences are exercised.
A similar conclusion follows from Article 7 TFEU, the so-called “consistency clause,” which requires the Union to ensure consistency between its policies and activities. In this light, it is not only appropriate but legally required that the ECB ensures that its policies are consistent with the Union’s broader climate objectives.Footnote 64 This interpretation finds support in the case law of the Court, which has held that the ECB’s actions must not undermine the effectiveness of general economic policies.Footnote 65
A potential objection to the application of the Aarhus framework to the ECB is that it would effectively impose novel obligations to introduce environmental policies, whose responsibility lies with the Union’s political institutions.Footnote 66 However, the argument advanced here is not that the ECB should adopt “green” policies. Rather, it follows from the judgments above that, where the ECB adopts monetary policy decisions with an environmental impact, it will be accountable toward third parties based on the Aarhus Convention and its implementation in EU law. This conclusion also stems from Article 216(2) TFEU, which provides that international agreements concluded by the Union are binding upon its institutions.Footnote 67
In practice, the ECB has increasingly enhanced the transparency of its monetary policy decisions from an environmental perspective. The 2020–21 Monetary Policy Strategy Review marked a significant shift in the institution’s thinking, explicitly incorporating climate change considerations into its analytical framework and operational toolkit.Footnote 68 This evolution confirms that climate-related action is now an integral part of the ECB’s policy landscape.
2. Monetary policy and supervision: the limits of the “Chinese wall”
The integration of climate considerations raises important questions concerning the relationship between the ECB’s two main functions: monetary policy and banking supervision. Traditionally, this relationship has been governed by a model of organisational separation, enshrined in Article 25 of Regulation (EU) No 1024/2013 (SSM Regulation), which establishes a so-called “Chinese wall” between the two functions.Footnote 69
However, climate risks challenge this model of separation. By their very nature, such risks cut across policy domains, affecting both macro-economic conditions and the micro-prudential soundness of individual institutions. This raises the question whether the existing model of functional separation remains fully adequate in the light of climate-related action.Footnote 70
Within the supervisory framework, the integration of climate risks appears relatively straightforward. Article 2 SSM Regulation defines the ECB’s supervisory objectives as ensuring the safety and soundness of credit institutions and the stability of the financial system. Environmental and climate risks are increasingly recognised as drivers of traditional risk categories, including credit, market, and operational risks.Footnote 71 As such, they fall squarely within the scope of the ECB’s supervisory mandate.
At the same time, supervisory decisions addressing climate risks may have significant environmental implications. By influencing the allocation of credit and the behaviour of financial institutions, such decisions may indirectly affect the transition towards a low-carbon economy. This creates a functional link between prudential supervision and environmental policy, even in the absence of an explicit environmental mandate.
In the field of monetary policy, the situation is not dissimilar. Measures incorporating climate considerations are not always presented as environmental measures, even where they produce significant environmental effects. In practice, the ECB tends to justify such measures by reference to its primary objective of price stability, thereby avoiding the need to explicitly balance other potentially conflicting objectives, like the support for EU’s environmental policies.Footnote 72 This gives rise to structural ambiguity. As previously observed, the economic and environmental dimensions are closely intertwined, as climate risks may directly affect inflation dynamics.
For the purposes of the present analysis, the broad interpretation of the Aarhus Regulation by the court, particularly of the notion of “environmental law,” reinforces the idea that the formal classification of ECB’s measures does not count, insofar as they incorporate climate-related considerations or contribute to the attainment of environmental objectives.
3. The scope of external review over ECB’s acts
In the case at hand, the Court only excluded acts of a judicial or legislative nature from the scope of the Aarhus Regulation. When acting in its monetary or supervisory capacity, the ECB does not fall within these exceptions. The broad interpretation of “environmental law” endorsed in the judgments also has significant implications for the ECB. It suggests that not only acts formally based on environmental legislation, but also other monetary policy or supervisory measures, may fall within the scope of environmental law where they are motivated by climate-related considerations.
For the Aarhus Regulation to apply, acts must be legally binding and produce external effects. In the context of the ECB, a wide range of acts could meet these requirements, such as policy documents or resolutions aiming at taking climate risks into account within the ECB’s activities. This is even more evident in the field of supervision, where decisions directly affect the rights and obligations of supervised entities. Arguably, recent case law also suggests a potentially broad scope for judicial review over ECB’s supervisory decisions. In particular, in Case T-610/24, the Court confirmed the reviewability of an informal email communication among supervisors, emphasising the need to assess the substance rather than the form of the act.Footnote 73 By prioritizing the practical consequences of denying judicial access, the Court strengthened the ability of supervised entities to challenge supervisory positions that de facto affect third parties.
This development is particularly relevant to determine the applicability of the Aarhus framework. A broad range of decisions may be subject to internal review and, ultimately, to judicial scrutiny. In turn, this enhances the effectiveness of access to justice in environmental matters.
4. Judicial review, independence and the role of evidence
The applicability of the Aarhus framework to the ECB may raise concerns regarding the preservation of central bank independence. However, these concerns should be carefully qualified. The extension of Aarhus-based guarantees does not necessarily entail a substantial review of monetary policy or supervisory decisions. Rather, it reinforces procedural safeguards, including access to information, motivation and the possibility of internal review.
A wide range of recent cases of internal review requests, especially following the 2021 amendments to the Aarhus regulation, has indeed targeted the scientific evidence underpinning decisions by EU institutions, often as a first step toward litigation.Footnote 74
Yet, the CJEU has consistently held that judicial review of ECB acts must remain limited, particularly in areas involving complex economic assessments. In the Gauweiler case, the Court recognized that its review is confined to verifying whether the ECB has committed manifest errors of assessment and whether it has provided sufficient evidence to support its decisions.Footnote 75 These conclusions are also consistent with the Court’s restraint in assessing the legality of discretionary administrative acts by other EU institutions, as discussed above.Footnote 76
Prior case law thus suggests that potential future cases may lead to a limited judicial review over the compatibility of ECB’s decisions with EU’s environmental legislation. At the same time, the applicability of the Aarhus Framework should act as a guarantee for the quality of the scientific evidence on which decisions are based and for transparency on these matters. In the absence of reliable and verifiable data, both stakeholders and courts are unable to assess whether decisions are scientifically sound.
VI. Potential implications for ECB’s climate data
The central implication of the analysis developed thus far is that data play a pivotal role in enabling transparency and access to information related to ECB’s measures that have environmental implications. The availability of climate-related data arguably constitutes a structural condition to ensure the accountability of EU institutions, including the ECB, under the Aarhus Regulation. Where such data are fragmented, inaccessible, or insufficiently structured, the effectiveness of internal review mechanisms is significantly undermined.
This leads to a broader conclusion. As new functions, such as the integration of climate risks, are incorporated into the ECB’s activities, the need for corresponding mechanisms of accountability arises.Footnote 77 Concluding that the Aarhus Regulation applies to the ECB therefore primarily gives rise to procedural and informational duties instrumental to public participation and to access to justice duties on environmental matters. Instead of a transformation of its mandate, the judgment arguably calls for a reassessment of ECB’s accountability. In other words, the Aarhus Convention should ensure that the ECB’s increasing involvement in climate-related matters also comes with adequate safeguards of transparency, reviewability, and scientific robustness.
In the following sections, we will focus on the extent to which the applicability of the framework should also translate into a duty to structure climate-related data in an organised and standardised format.
1. The ECB’s statistical function under Article 5 of the ESCB Statute
Article 5 of the ESCB Statute provides that, in order to undertake the tasks of the ESCB, the ECB, assisted by the national central banks, shall collect the necessary statistical information either from competent national authorities or directly from market actors. This provision establishes the legal basis for the ECB’s statistical function, which plays a crucial role in the exercise of its monetary policy powers.
It also depicts the statistical function as instrumental, supporting the effective exercise of the ECB’s core tasks. The collection of statistical data is justified by, and limited to, what is necessary for the performance of the ESCB’s functions, including monetary policy.Footnote 78 The availability of accurate and reliable information is thus a prerequisite for informed decision-making.
Traditionally, this ancillary nature has been interpreted as confining the ECB’s data-related activities to what is strictly necessary for its internal purposes.Footnote 79 However, such an interpretation may be overly narrow in the current context. The increasing integration of climate-related considerations into monetary policy and financial stability analysis has significantly expanded the scope and complexity of the data required by the ECB. Climate risks are inherently forward-looking, multidimensional and dependent on a wide range of environmental, economic and financial variables.
This evolution is reflected in the ECB’s own initiatives. In recent years, the ECB has adopted a series of measures aimed at improving the availability and quality of climate-related data, including its climate action plan and the integration of climate considerations into its statistical agenda,Footnote 80 for instance through the design of dedicated climate indicators.Footnote 81 These developments confirm that the collection and processing of climate data have become essential tasks enabling the ECB to fulfil its mandate.
2. Climate data in supervision: between the SSM Regulation and Aarhus Convention
While Article 5 of the ESCB Statute provides a clear legal basis for the collection of statistical data in the context of monetary policy, its applicability to supervisory data is less straightforward.Footnote 82 The supervisory function of the ECB is governed by the SSM Regulation,Footnote 83 which does not contain an explicit equivalent to Article 5 concerning statistical data collection.
Nevertheless, the ECB’s supervisory activities necessarily rely on extensive data collection from supervised entities. As environmental risks are now widely recognised as drivers of traditional prudential risks,Footnote 84 their assessment requires granular and forward-looking data.
In the absence of a specific provision equivalent to Article 5, the legal basis for the collection and use of supervisory data must be derived from the ECB’s supervisory mandate itself, which includes ensuring the safety and soundness of credit institutions and the stability of the financial system.Footnote 85 To the extent that climate risks affect these objectives, the collection of relevant data might implicitly fall within the scope of the ECB’s supervisory powers.
However, the Aarhus framework introduces an additional layer of complexity. As argued in the previous section, supervisory decisions that incorporate climate-related considerations may fall within the scope of “environmental law” and, therefore, be subject to the procedural guarantees of the Aarhus Convention. This implies that the data underlying such decisions may also be subject to dissemination obligations as laid down in Article 5 of the Regulation (EC) No 1367/2006.
3. Principles governing data collection: efficiency, proportionality and burden minimisation
The ECB’s data collection activities are subject to a number of principles aimed at ensuring efficiency and proportionality, like the need to rely on existing data as far as possible, to assess the costs and benefits of collecting new information, and to minimise the reporting burden on data providers.Footnote 86 These principles reflect the need to balance the ECB’s informational needs with the constraints faced by reporting entities.
At the same time, the ECB enjoys a significant degree of discretion in determining which data are necessary for the performance of its tasks, as a further corollary of its functional independence.Footnote 87
However, this discretion is not unlimited. As the previous analysis has shown, the application of the Aarhus framework introduces additional considerations related to transparency and accountability. In particular, the ECB must ensure that the data underlying its decisions are sufficiently robust, accessible and verifiable to enable effective scrutiny by courts and stakeholders.
This creates a tension between two sets of objectives. On the one hand, the ECB must preserve its independence and avoid imposing excessive reporting burdens. On the other hand, it must ensure that its decision-making processes meet the standards of transparency and accountability required by EU environmental law.
4. Confidentiality, anonymization and the use of data
A further challenge related to environmental data held by the ECB concerns the confidentiality of supervisory data. Information collected from individual credit institutions is often subject to strict confidentiality requirements, reflecting the need to protect sensitive business information and to preserve financial stability. The European legislation provides for the protection of confidential information, while also allowing for its use for statistical and research purposes under certain conditions.Footnote 88
From the perspective of the Aarhus framework, confidentiality cannot be invoked as a blanket justification for withholding environmental information. Rather, it requires a careful balancing of competing interests. On the one hand, there is a legitimate interest in protecting sensitive financial information. On the other hand, there is a public interest in ensuring transparency and accountability in relation to climate-related decision-making.
Anonymisation and aggregation techniques offer a possible way to reconcile these objectives. By transforming raw supervisory data into forms that are no longer attributable to individual institutions, the ECB may be able to make climate-related information available without undermining confidentiality. This approach is consistent with the logic of the Aarhus Convention, which seeks to maximise access to environmental information while allowing for narrowly tailored exceptions.
In this sense, the obligation to organise data can be understood as an implicit corollary of existing legal duties. It does not create new competences, but rather shapes the way in which existing competences must be exercised in order to comply with EU environmental law.
5. The use of climate data for policy purposes and for the access to justice
A final question concerns the extent to which climate-related data collected by the ECB may be used for policy purposes. As noted above, the statistical function of the ECB is instrumental to the performance of its tasks. This raises the issue whether the use of such data for broader policy considerations, such as supporting climate objectives, is compatible with the ESCB Statute.
In principle, the use of data must remain within the scope of the ECB’s mandate. Climate-related data may be used insofar as they are relevant for achieving price stability, supporting general economic policies, or ensuring financial stability. This is consistent with the integrated approach to climate action discussed in the previous sections.
At the same time, the use of such data must respect the limits imposed by the principle of conferral.Footnote 89 The ECB cannot use its statistical function as a vehicle for pursuing autonomous environmental policies. However, insofar as climate considerations are lawfully integrated into its mandate, the use of relevant data becomes necessary. From the perspective of the Aarhus Convention, the key issue is not the purpose, but rather the means for processing, generating and disclosing such data. The availability of high-quality climate-related data is instrumental to effective policy-making and ensures the accountability of the decision-maker.
In conclusion, the applicability of the Aarhus convention to the ECB should also elevate climate-related data detained by the ECB to a core safeguard of public participation and access to justice.
The effectiveness of judicial and administrative internal review mechanisms hinges on the availability of reliable, verifiable and accessible information. Without such information, the procedural guarantees enshrined in the Aarhus framework risk remaining largely ineffective. In line with the conclusions within the previous sections, the ECB’s obligations in relation to climate data should thus be understood as part of a broader transformation of its accountability framework.
VII. Conclusions
The judgments discussed in this contribution are the first to address the applicability of the Aarhus Regulation to financing decisions of an EU body. They consolidate the emerging principle that transparency and public participation constitute cornerstones of decision-making with potential environmental impact.
Particularly significant are the Court’s expansive interpretations of “administrative acts” and “environmental law.” In particular, the qualification of the latter does not depend on the formal legal basis of the measure, but on its substantive link to the Union’s environmental objectives. The judgments may therefore trigger a new wave of review requests and litigation anchored in the Aarhus framework, aimed at seeking internal or judicial reassessment of the compatibility of internal policies with EU climate goals.
A further, less immediately visible implication, which the contribution aimed to unpack, concerns the potential relevance of the reasoning for the ECB, not only in relation to its (non-monetary) portfolio-management activities.
The questions left open regarding the scope of judicial review are likely to resurface in future cases. The precise contours of the Court’s scrutiny remain difficult to anticipate, particularly in light of its traditionally restrictive approach to reviewing the legality of discretionary administrative acts, both under the Aarhus framework and in relation to the ECB’s technical decision-making more broadly.
At the same time, a more indirect consequence of the judgment(s) may lie in an emerging expectation that relevant institutions systematically collect, structure and disclose climate-related information underpinning key decisions. While the ECB’s statistical function has traditionally been regarded as ancillary to its core tasks, the Aarhus Regulation, coupled with other provisions regulating ECB’s mandate and activities, arguably reinforce the centrality of environmental data within its accountability framework. In this context, effective access to justice in climate-related matters depends not merely on the existence of data, but on their accessibility, standardisation, and usability. From this perspective, the gradual development of a climate data infrastructure at ECB level can be understood as a necessary corollary of the evolving transparency and accountability regime.
Competing interests
The author(s) declare none. Whilst the article is entirely the result of shared reflections, Sections I–IV can be attributed to Federica Agostini, Sections V–VII to Nicolo Galasso. The views expressed in the article are solely those of the authors and do not involve the responsibility of the institutions to which they belong.
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