The interface between EU climate and energy law

This article critically discusses the interface between EU climate and energy law. It argues that legal scholarship should explore and expose the interrelationships between these legal disciplines through shared understanding and evaluation of both the disparities and synergies found. It maps the origins of EU climate and energy law to demonstrate how they have evolved side by side, guided by separate legal rationales and distinct legislative developments yet sharing partially overlapping objectives and instruments. By comparing EU climate and energy law as legal disciplines, the article identifies dynamic and static attributes that characterize the interface between EU climate and energy law. These attributes, combined with the evolution of EU climate and energy law, are key elements in facilitating disciplinary convergence. As an outcome of the analysis, the article calls for critical legal scholarship that acknowledges the climate and energy law interface, allowing disciplinary convergence to develop between them.


Introduction
The EU climate and energy acquis is evolving at an unprecedented pace. In late June 2021, the European Union (EU) adopted the European Climate Law, which sets out a binding objective of climate neutrality in the EU by 2050 and a net greenhouse gas emission (GHG) reduction target of at least 55% by 2030. 1 In addition to the GHG emission reduction target, the climate neutrality This article contributes to EU climate and energy law scholarship by critically discussing the interface between them. The article considers climate law as broadly encompassing the legal governance frameworks needed to control the anthropogenic effects of climate change, and energy law as concerning the legal governance of energy resources from exploration and production to final consumption. 8 The article builds on the premise that climate law and energy law are two independent legal disciplinesboth are acknowledged as such in legal scholarship. 9 In this context, we address an important problem: the lack of understanding between climate and energy law as distinct yet deeply interconnected legal disciplines, jointly in charge of facilitating EU's transformation from fossil-fuel-based systems into a zero-carbon, climate-neutral society. By exploring and exposing the interrelationships between the legal disciplines, we work to enhance the understanding of climate and energy law's interface and encourage the active development of disciplinary convergence. We see disciplinary convergence as a mutual and shared understanding of the origins and the characteristic attributes between the two disciplines.
We acknowledge disciplinary convergence as an important contribution from legal scholarship to the society that is striving to transform from a fossil-fuel-dependent to a climate-neutral society. Climate and energy law scholars that wish to be able to convincingly speak of and to their counterparts should seek to understand the other discipline. Absence of mutual recognition of the origins of the disciplines and their characteristic attributes risks unnecessary conflict between EU climate and energy law scholarship. This issue is aptly reflected in discourses where, for example, legal scholarship views energy expertise reductively as 'operating within the arcane silo of energy security', 10 and lacks broader understanding of the plurality of objectives that affects the discipline. Similarly, energy law scholarship has voiced dismissive or confrontational views of climate and environmental expertise, 11 equally disregarding the disciplinary overlaps and differences between the two disciplines. These are alarming examples of situations where EU climate and energy law scholarship clash with one another due to a lack of mutual understanding between the disciplines. Considering For discussion on energy law as a legal discipline, see e.g. 'Over the past three decades, largely because of privatization and liberalization of energy markets across the globe, the ongoing 'energy transition' (primarily related to climate change considerations), and the internationalization of and changes in energy markets, energy law as a legal discipline has grown and matured'. R. Heffron  nvironmental lawyers, who mostly have no economic training or interest (and may even be hostile to economic analysis of environmental issues) and who are steeped in the prohibit-allow culture of public law and in sympathy with morally attractivethough often practically irrational -NGO campaigning' are pulled 'away from a realistic assessment of the cost and benefit of environmental action'. society's need to decarbonize through the transition away from fossil fuels, legal scholarship in this area cannot afford such conflict. More research is needed in the intersection between climate and energy law to help recognize these clashes and conflicts and, more importantly, the blind spots or misconceptions that cause them. Having said that, conflict is undeniably important in legal scholarship. At its best, it invites new and critical scholarly interventions, is built constructively on existing scholarship, and contributes to the evolution of legal disciplines. However, the conflicts between EU climate and energy law have primarily focused on substance and ongoing legal developments rather than on systemic analysis of the disciplines. 12 Such debates are not enough to foster disciplinary convergence between climate and energy law. It is important for the development of interdisciplinary discourse between EU climate and energy law that the deeper misconceptions are brought to light. If disregarded, the contribution of legal scholarship in these areas will never reach its full potential for the benefit of the EU's progressive objectives in the climate and energy sphere. This article is the first step in addressing this gap in existing legal scholarship. Furthermore, as EU climate and energy law are dynamic and fast-developing fields of contemporary and globally influential EU law, the perspectives highlighted in this article speak directly to a large group of European and international legal scholars.
This article approaches its key argument by comparing EU climate and energy law through their key substantive developments as well as their respective scholarship and jurisprudence. The distinct dynamic and static attributes, emerging from climate and energy law scholarship respectively, characterize the disciplines' central features. These attributes represent the differences and similarities between climate and energy law that facilitate the development of disciplinary convergence. The article first dissects its key argument and explains why legal scholarship should explore and expose the interrelationship between the disciplines (section 2). It then traces the evolution of EU climate and energy law and shows how the key substantive developments of the two fields are converging increasingly (section 3). Building on the origins of these two legal disciplines, it next identifies attributes that characterize the interface between EU climate and energy law (section 4). Exposing these attributes is of key importance in facilitating the convergence between the two disciplines and form important areas for further research in legal scholarship. Finally, conclusions are drawn (section 5).
2. The importance of disciplinary convergence in EU climate and energy law EU climate and energy law's paths are connected through the transformative agenda 13 executed through contemporary EU law. Climate and energy law are so 'obviously interrelated' that they will 'inevitably be drawn together'. 14 The EU's overarching objective of being a climate-neutral economy by 2050 is to be operationalized by means of a comprehensive legislative reform extending to key climate and energy law instruments. The progressive plan to deepen the substantive integration of EU climate and energy law underlines the need to promote further scholarly dialogue on their disciplinary convergence. 15 The distinction between the integration of legislative instruments and what we mean by disciplinary convergence should be emphasized. The former concerns integration in the traditional sense, requiring that climate change concernsalong with EU environmental objectives, principles and criteriabe integrated into energy policy. 16 It entails focus on legal substance, i.e., what is being legislated and how these substantive rules align or integrate with other rules. This kind of integration has been analysed in EU climate and energy law scholarship. 17 In contrast, EU climate and energy law scholarship lacks research that identifies the disciplinary interconnections beyond the integration of individual legal instruments and the mere overlap of scopes of application. 18 In surveying recent legislative developments in EU climate and energy law, we see that the legal fields no longer develop linearly in isolation from one another but also interdependently. The EU's transformative agenda can be regarded as a joint factor in bringing about the congruence between the two legal fields, almost by forcing it. 19 As Freeman points out, legal scholarship has not (yet) 'embraced convergence as an independent goal, but rather have achieved it incrementally and indirectly, as a consequence of pursuing their traditional missions during a time of change.' 20 In EU law, one legal discipline is not more imperative than the other nor is one subordinate to the other. This balance between the two fields allows legal scholarship to compare their legal rationales and realities in a way that enables the development of disciplinary convergence. However, disciplinary convergence between the legal fields does not simply happen on its own, but necessitates active recognition in EU legal scholarship. 21 Its development requires legal scholarship to go 'beyond prior work in describing the legal mechanisms through which greater congruence and coordination between the two fields have been achieved'. 22 That is to say that in addition to focusing on how lawmakers and policymakers should better integrate climate and energy law, climate and energy law scholars should also actively improve their understanding of one another's disciplines.
Accordingly, promotion of much-needed disciplinary convergence between climate and energy law calls for a move away from the fragmented research approach where 'much academic analysis is based on the descriptive study of regimes in isolationoften understood as one-off successes and failureswithout a broader analytical perspective being taken'. 23 Fragmentation per se is not problematic, but if it 'results in a failure of scholars to focus on the legal interrelationships and commonalities', 24 then 'one probably should go further'. 25 It has been aptly pointed out that the diversity of knowledge to adequately approach environmental problems, such as climate change, 'is not just a nice thing to have', but also necessary for epistemological consistency and social justice. 26 Identification and acknowledgement of both disciplines' origins and characteristic attributes is the first step towards facilitating disciplinary convergence. However, the next generation of EU climate and energy law scholarship should do more than that, and actively take into account the deeper legal rationales and realities of the other discipline. While such steps may not be relevant for all EU climate and energy law, they are unavoidably key to EU law that operates in the intersection between the disciplines, such as renewable energy law. One possible future avenue for taking such steps may be found in the emerging just transition 27 and energy democracy 28 discourses, which emphasize the justice dimensions of societal sustainability transitions and are accordingly geared conceptually towards taking into account the legal rationales and realities affecting the EU's transformative agenda. Ultimately, the role of individual legal scholars is key to advancing the development of disciplinary convergence. We need self-reflection and 'heightened awareness' 29 of the blind spots and even biases that affect a climate law scholar's understanding of energy law and vice versa and should transparently share these shortcomings with the broader community of EU law scholars. 30 3. The origins of EU climate and energy law EU climate and energy law are both relatively new but in different ways and in different phases of their evolution. However, the developments in EU law over the last two decades have brought climate and energy law into proximity as they deal with two sides of the same coin: traditional energy sources have fuelled modern economies while bringing about one of our generation's greatest challenges by contributing to global warming. To expose the interrelationships between the disciplines and foster disciplinary convergence, we explore how EU climate and energy law have evolved to where they are todayas interrelated instruments of the EU's transformative agenda. Energy has a long tradition in EU law. 31 Governing the exploitation of energy was at the heart of the European peace project of the 1950s, as two of the three original Founding Treaties focused on the governance of steel, coal and nuclear energy. 32 Contrary to what might be expected, given the focus of the Founding Treaties, however, primary law was not systematically applied to the energy sector until the 1990s. 33 For decades after the entry into force of the Founding Treaties, the energy sector was too politically charged and considered too connected to sensitive national security interests to be governed at an EU level. 34 The 1990s marked the first extensive package of secondary law for the energy sector, followed by further packages in 2003 and 2009 and, finally, in 2018-2019, all progressively implementing the internal markets in electricity and gas and addressing an increasing number of objectives that continue to drive the energy sector. These legislative packages were accompanied by a progressively strengthening and robust institutional setup driven by regulators on both EU and national levels. 35 In contrast to the EU's longer legislative and institutional history concerning the energy sector, EU climate law is of more recent origin. Climate change has been a key global issue since the late 1980s, and a significant body of law has been developed in response to it. Since the 1990s, the EU has played a prominent role in the development of legal approaches to climate change. Climate law, in broad terms, addresses climate change and the main responses to it, which are essentially mitigation and adaptation. 36 Closely connected to developments in international fora and intertwined with the EU's internal political developments, the EU has established a gradually evolving and expanding legal framework on climate change. 37 After a slow start, EU climate law has evolved from sectoral instruments in the 1990s to the detailed legal framework now in place. 38 As demonstrated by the origins of both disciplines, EU climate and energy law have grown independently from one another and EU climate and energy law scholars have developed their disciplines in a similarly independent manner. Yet the roots of their close relationship in EU law were laid down decades ago. The interconnection between energy and environmental matters was acknowledged in EU law in the late 1980s and early 1990s. 39 The Treaty revisions then introduced a legal basis for environmental legislation that required the 'prudent and rational utilization of resources' 40 and limited EU competences where their usage would affect a Member State's 'choice between different energy sources and the general structure of its energy supply'. 41 Because of this early constitutional connection, the close relationship with energy was already built into the structures of EU competences when climate law began to make its mark as a discrete field of EU law.
The past decade has witnessed a remarkable increase in the Europeanization and convergence of the substance of EU climate and energy law, which is reflected in both primary and secondary law. 42 The objectives of EU climate and energy law, and the EU competences to pursue those objectives, were explicitly included in primary law under the Treaty of Lisbon in 2009. 43 EU climate law is included in the environmental policy provision of Article 191 TFEU, under which EU environmental policy will promote measures at international level to deal with regional or worldwide environmental problems and, in particular, combat climate change. 44 Accordingly, the climate objective operates in proximity to the broader EU environmental law objectives but has multidimensional scope. EU energy law was given its own legal basis in Article 194 TFEU, which establishes functioning energy markets, security of supply, the development of renewable energy and the promotion of energy efficiency, energy saving and the interconnection of energy networks as objectives of EU energy policy. In this constitutional context, it is the development of renewable energy, energy efficiency and energy savings that explicitly connect the objectives of EU energy law with EU climate law. EU action in both policy areas fall under shared competence and both are restricted by explicit competence limitations. 45 This increased interdependence between these legal fields increases the importance of grasping the differences and similarities between them at the interface of climate and energy law scholarship.
The following sections identify and analyse six attributes that characterize the interface between EU climate and energy law as legal disciplines. These attributes emerge from the contemporary context of EU climate and energy law scholarship and are repeatedly dealt with and analysed in 39 both climate and energy law scholarship. These attributes are found in shared discourses: they are features and approaches that are fundamental to both EU climate and energy law. While this is not an exhaustive list of what characterizes the interface between EU climate and energy law, it exposes the different attributes of EU climate and energy law interface that both facilitate or even expedite the convergence between the disciplines but also create friction and differentiation between the disciplines.

Exposing the attributes in the interface between EU climate and energy law
A. The dynamic attributes bringing EU climate and energy law together 1. Climate and energy law are irreplaceable parts of the European transformative agenda. The EU is on a quest for 'deeply transformative policies'. 46 Indeed, the European Green Deal prescribes comprehensive legal revisions or policy reforms reaching several regulated areas beyond climate and energy law, from the internal market to digitalization and social aspects, and new mechanisms and tools for regulation. 47 Although the EU's strategic vision for the future affects EU law across legal disciplines, climate and energy law are at the core of the strategy for the achievement of a more sustainable Europe. 48 The production and use of energy account for approximately 75% of the EU's GHG emissions and decarbonization of the entire energy system is crucial in order to meet the climate targets. 49 Climate and energy law are irreplaceable parts in the legal evolution required by the European transformative agenda as the moulders and facilitators of the underlying regulatory preconditions. 50 In the context of this transformation, climate-related legislative instruments translate climate considerations into legally enforceable targets and mechanisms for their implementation, while energy law remodels the energy sector to ensure the action required by the transition is effectively executed. 51 Without further efforts to understand EU climate and energy law's interface, the EU's ambitious transformative agenda cannot succeed.
Therefore, the most obvious shared feature as between EU climate and energy law is that both contribute to the European transformative agenda driven by the European Green Deal. Most importantly, they are in the key role to ensure that the European economy transitions away from fossil-fuel-based energy systems. There is a clear scientific causality between the GHGs produced 46 by the energy sector and global warming. 52 This causality has also brought these two into proximity in the context of law and lawmaking. The existing and forthcoming EU law and policy also make climate and energy law integral mechanisms that facilitate the European Green Deal's new growth strategy into action. 53 2. Interdisciplinarity is a distinct approach in EU climate and energy law. EU climate and energy law are inherently interdisciplinary, as reflected in the ways in which they incorporate aspects from other areas of law and pervade beyond law entirely different disciplines and areas of expertise. Climate and energy law are both well known to absorb normative material from other legal disciplines, 54 and scholarship on both disciplines acknowledges that the disciplines borrow normative material from other fields of law 55 and, in that sense, they admit to the absence of a single or autonomous 'climate law' or 'energy law'. Due to its widespread impacts and inherently complex nature, climate change cannot be confined under a single legal structure. 56 Instead, the scopes of both disciplines are defined by societal needs to address climate change and to secure a reasonably priced energy supply. These ineliminable societal needs make climate and energy law characteristically political and accordingly blur the lines between law and policy in these areas. 57 It makes sense that legal disciplines with such problem-based scopes systematically invade the legal spaces of other legal disciplines to benefit from their normative developments. 58 Both are known to step into each other's arenas 59 and into fields such as constitutional law, human rights law, administrative law, environmental law, investment and trade law, contract law, criminal law and tax law. 60 For example, the fossil fuel phaseout inevitably raises questions as to the right to property and the freedom to conduct business enshrined in the EU Charter of Fundamental Rights. 61 Compensation for the shutdown of energy activities is often assessed under investment law and not climate or energy law. 62 In the 2021 Shell case, a climate claim was decided on the basis of Dutch tort law. 63 Similarly, the construction of electricity and natural gas infrastructures involves many environmental and administrative permitting processes. In other words, EU climate and energy law comprise the sum of EU legal norms that govern climate change and the energy sector. 64 However, EU climate and energy law are not just the routine application of any EU law to climate change or the energy sector. 65 Instead, the legal disciplines are fundamentally shaped by intrinsic connections between law and other disciplines. Climate and energy law cannot be treated as self-contained disciplinary and regulatory areas that manage their objectives without integrating themselves within the broader regulatory framework, in both international and national contexts. Lawmaking and legal scholarship in these areas are often meshed with fields such as economics, geography, environmental sciences, engineering, atmospheric physics and social sciences. 66 The role of science is crucial in adopting and applying climate and energy law. For instance, the scientific basis for climate change is widely acceptedthe extensive regulatory frameworks would not be in place without the input of scientific knowledge. 67 Similarly, the achievement of legal objectives in the energy sector can be either enabled or prevented by technologies developed by engineers, among others. 68 For example, the fact that electricity cannot be stored on a large scale means that EU legal and policy frameworks must be able to ensure security of supply even when the wind does not blow and the sun does not shine. 69 Science pervades EU climate and energy law, and this is reflected in the way EU climate and energy law scholarship is conducted: scholars adopt and absorb facts, theories and methods from these external disciplines. This interdisciplinarity has important implications for the drafting and interpretation of EU law. For example, an EU climate or energy law scholar that has not grasped the basic physical limitations of energy technologies as regards, for example, the storability of electricity, 70 may be at risk of suggesting legal solutions that are unfeasible in practice.
3. Climate change and the energy sector are both governed at multiple levels. The third shared approach of EU climate and energy law is that both are identifiable as dynamic participants in a multilevel system of governance. Given its sui generis legal nature as a supranational organization, the EU's governing system could be understood as inherently multilevel and multisectoral. 71 The context described here bespeaks a broader notion of multilevel governance as an integrated perspective on law and regulatory approaches. 72 Addressing climate change and the challenge of energy governance necessitates legislative and regulatory responses at all levels, from global to local, across jurisdictions and between different levels of governance. 73 Climate and energy law scholars agree that their respective disciplines have a shared complementary yet constituent dimension stemming from their multilevel character. 74 A multilevel governance approach facilitates consideration of the polyvalent nature of climate and energy policies 75 and, due to its more decentralized and disaggregated features, accommodates the hybridity of legal interferences within a broader governance framework. 76 This is a precondition for coherent governance of the complex climate and energy fields.
The fragmentation of climate and energy law's domains make multilateral governance a suitable approach to them. Given the borderless nature of the climate change challenge, climate law needs to be able to cater for different views and multiple levels of action. 77 Furthermore, gradual changes in the governance of the energy sector have moved energy governance beyond the unilateral context towards a more interconnected system. 78 The close interdependence between different legal initiatives and the need to coordinate the levels of legislative and regulatory action are features shared between climate and energy law, and aspects captured by multilevel governance. 79 Identifying the different levels on which EU climate and energy law operate and acknowledging the ways in which they interact, within and beyond the EU legal order, is crucial for the operation of the dispersed domains of the climate and energy acquis.
B. The static attributes differentiating EU climate and energy law 1. International and national pressures affect energy and climate law differently. Climate law is more tied to international developments (i.e., the global climate regime) while energy law traditionally focuses on safeguarding security and affordability interests at national level. Although climate change and the energy sector are extensively governed by EU law, the pressure for EU action in these areas emerges from distinct interests on different governance levels in view of the fact that energy has traditionally been a national matter with close linkages to state sovereignty and national security. 80 As distinct from EU energy law, the EU's climate governance framework has largely emerged in response to international developments. 81 This divergence between energy and climate law is comprehensible within the broader contexts of global warming and the energy sector. Climate change is inherently global. It cannot be addressed on national and local levels alone, nor can its effects be prevented from crossing national borders. 82 Energy, conversely, is infrastructure-dependent and highly susceptible to delicate national security interests. 83 The linkages between infrastructure and security 84 explain why energy infrastructures have traditionally been constructed within national borders to serve predominantly national, not transnational or European, interests. 85 While global geopolitics are often the source of energy security concerns and protecting energy security has also become an issue of EU law, 86 the governance of the energy sector still remains at the heart of national sovereignty and impacts EU competences. 87 The notion that, in the EU context, climate law is international while energy law is national is a simplification of the nuances involved. In fact, it is clear that energy law has internationalized and climate law has localized. 88 Due to energy's geopolitical aspects, international considerations as to exploring for and supplying energy can never be dispensed with. 89 Energy trade and investment are nowadays profoundly international and the externalities of global energy activities make energy sector governance a global issue. 90 Similarly, climate law and, in particular, the actions needed to comply with international climate commitments undeniably require deep political commitment on national and local levels. 91 Furthermore, the EU has assumed a role as a leading global actor in both policy areas, but especially in the field of climate law. 92 The EU has actively engaged with the strategy of 'leading by example' in international climate policy for decades. While perceptions of its leadership have varied over the years, 93 it is clear that the EU's pronounced climate actorship and presence in international fora have strongly shaped its internal legal efforts on climate change. 94 However, these nuances do not change the basic structural setting that underlines EU climate and energy law: energy is predominantly driven by national and climate by global pressures. National preferences in energy law and international political compromises in climate law are factors that impact on the EU's legal instruments and approaches. 95 Consequently, in order for EU climate law initiatives to succeed, EU climate law scholarship must understand and take into account the national interests underlying energy law, including energy security and the protection of national economies. These issues are reflected in the recent European Climate Law for example, 96 and should also be acknowledged in legal scholarship.
2. Energy law has many objectives while climate law is more clearly guided by one. EU climate and energy law also differ in their approaches to legal objectives: climate law has a clearer single goal of combating anthropogenic global warming 97 while energy law is characterized by a plurality of goals. This, again, is a simplification of the nuances involved, but is a justified observation for reasons discussed below.
It is well established that energy law is driven by various potentially conflicting objectives, 98 which, in EU law, are set out in Article 194(1) TFEU. In energy law scholarship, these conflicting interests are referred to as the 'energy trilemma': the balancing of competitiveness, security and environmental interests in the energy sector. 99 This amounts to a conceptualization of the means by which to ensure the uninterrupted availability of affordable energy to citizens and industry while protecting the environment. In practice, the plurality of goals means that choices made in energy law and policy contexts must balance these mutually competing interests against each other. 100 For instance, heavy reliance on indigenous coal resources can be a useful energy policy in terms of ensuring affordable and secure energy, while being detrimental to the environment and the climate. There is no standard mechanism by which to balance these objectives, 101 nor does EU law prioritize one objective over the others. Instead, all EU legal instruments on energy entail ad hoc balancing of competing interests. The Commission's legislative initiatives have 'rested on the linking of differently valued issues between DG Energy and DG Environment', 102 whereas 'DG Environment favoured a stringent climate policy' 103 and 'DG Energy was more concerned with energy security'. 104 In contrast, climate law is geared towards achieving a single yet multidimensional goal: tackling anthropogenic global warming. This is reflected through EU Treaty provisions that establish combating climate change as one of the objectives of EU environmental law 105 and require that climate change considerations are integrated into other EU policies. 106 The multidimensionality of climate law's objective is also present in secondary law instruments: for instance, the EU emissions trading system, which has one primary goal, namely the reduction of GHGs, and multiple secondary goals, including cost-effectiveness and technological (low-carbon) innovation. 107 Although the central objective of tackling global warming operates among environmental objectives, it has a distinct, prominent and dynamic scope. The objective of combating climate change affects a diverse group of interests and actors that are addressed through different fields of EU law. Therefore, the divergence between EU climate and energy law is much more nuanced in practice. 108 The singularity versus plurality of objectives in EU climate and energy law respectively has profound implications for the mindset of both legal disciplines. Climate law instruments aim to facilitate achievement of the overarching goal of tackling anthropogenic global warming, while, in the energy law context, climate considerations are one of three objectives that compete with one another on an equal basis. Consequently, energy law sometimes seems conservative and resistant to legal responses in climate law, while climate law finds common cause with energy law's sustainability objective but focuses less on the need to ensure energy security and competitiveness.
3. Climate law is more mature as a legal discipline than energy law. Partly owing to the mounting effects of global warming and the urgency of developing legal responses to climate change, understanding of climate law as an independent legal discipline has advanced relatively swiftly since the development of the first regulatory responses. There is no full scholarly agreement on climate law's exact properties as a legal discipline as views on it vary 109its disciplinary boundaries are 'unquestionably porous'. 110 Nevertheless, the scholarly discourse moulding and informing our perception of climate law has been vibrant for a couple of decades already. 111 Therefore, climate law's disciplinary characteristics (i.e., key concepts, principles and objectives) can be identified to the extent that we perceive it as a distinct legal discipline.
The same cannot be said in the context of energy law, which some prominent energy law scholars still consider to be a relatively new area of law, despite its extensive legislative history. 112 While climate scholarship has gradually matured and been shaped through active scholarly debate, energy law has not 'evaluated itself' or 'grown theoretically' through established academic literature. 113 The issue is debated, but it may be that the perceived maturity of EU climate law, as compared to energy law, stems from the proximity of its developmental paths to, and its constitutional connections with, EU environmental law, which has a longer tradition of legal scholarship relating to the theoretical foundations of the discipline. 114 Although energy law scholarship has not yet exhaustively mapped its characteristics as a legal discipline compared to that of climate law, debate on this issue is emerging within the energy law community. 115 These emerging debates promote views, inter alia, on the principles, 116 properties 117 and theoretical dimensions 118 of energy law.
As shown by the preceding analysis, the normative foundations and evolution of climate and energy law converge. Each has benefited from normative developments elsewhere 119 and, as dynamic fields of modern EU law, this process is likely to continue. EU energy law scholarship could, for example, look to the debates of climate law to ascertain what has shaped it as a legal discipline. Disciplinary convergence 120 between the two fields is one of the most interesting aspects of this mutual learning process.

Towards disciplinary convergence: Concluding thoughts
To highlight the divergence in legal thinking in EU climate and energy law respectively, this article began with a simple question: why do climate and energy law scholars have such different perceptions of the level of ambition of EU climate and energy law? The divergence in legal thinking was also uppermost in our minds while writing this article. We ceaselessly sought out shared language that could capture the essence of both climate and energy law rather than that of one or the other exclusively. Our debates on the shared characteristic attributes of climate and energy law formed the framework for the arguments advanced in this article. These challenges offered further evidence that there is divergence between these disciplines that we wanted to address in our analysis. This required co-first authorship and a symbiotic process of writing. Such an approach was essential not only because of the choice of writing style, but also because of the nature of our research agenda.
Motivated by the value of bridging contrasting views, the article built gradually towards its argument as to the necessity of exploring and exposing the interrelationship between EU climate and energy law. After dissecting this key argument, the article traced the evolution of EU climate and energy law and showed how the key substantive developments of the two fields are converging increasingly. Building from the origins of these two legal disciplines, the article identified six key attributes that characterize their interface. This exercise was carried out for the purposes advancing shared understanding on and development of disciplinary convergence between climate and energy law. Climate and energy law's central contribution to the European transformative agenda towards a lowcarbon society as well as the inherent features of interdisciplinarity and multilevel governance facilitate or even expedite the convergence between the two disciplines. They are shared attributes that unify EU climate and energy law and solidify the interconnections between these two disciplines. In contrast, EU climate and energy law's interactions with international and national pressures, the objectives driving climate and energy law's legislative action and the ways in which the two have positioned themselves as legal disciplines can create friction and differentiation between the disciplines. They are characteristic attributes that separate EU climate and energy law and have the potential to generate conflicts or misconceptions between EU climate and energy law scholars.
In our view, recognizing these characteristic attributes and voicing our differenceseven exposing our blind spotsis the way to enhance disciplinary convergence between EU climate and energy law. We believe that our observations better equip energy and climate law scholars to advance a mutual and shared understanding between the two disciplines. We call for critical legal scholarship that acknowledges these attributes and enables the two disciplines to capture the legal evolution required by the EU's objectives in EU climate and energy law.
We view the shared understanding as contributing to the EU's efforts to fully capture the facilitative potential of these two legal fields. Perspectives and targets promoted by the EU's transformative agenda, such as the climate neutrality target for 2050 and the acceleration of the clean energy transition, 121 demand a thorough alignment of EU policies across all sectors. While EU law's overall contribution is pivotal in turning transformative policies into action, EU climate and energy law specifically perform a key role in prompting the EU's transition to a low-carbon future. This deep interconnection combined with EU law's transformative agenda highlights the need for EU climate and energy law scholars, respectively, to better comprehend each other's conceptual underpinnings at the interface between them. Hence, the heightened role for climate and energy law also extends to legal scholarship. Our analysis suggests that while both EU climate and energy law can handle their share of the legal problems emerging from Europe's transformative agenda as autonomous legal disciplines, the pooling of efforts will help us to effectively tackle the challenges that lie ahead.