1. Introduction
Faced with climate policies widely regarded as inadequate, a growing number of individuals and organizations are taking governments or corporations to court to force them to do more to mitigate climate change and adapt to its adverse impacts. A smaller set of actions seeks to temper the actions of public authorities in response to the climate emergency by challenging their jurisdiction or the legality of the policies adopted in this regard. This phenomenon, known as “climate litigation,”Footnote 1 emerged in the United States in the 1980sFootnote 2 and expanded internationally in the 2000s.Footnote 3 The trend has accelerated significantly since 2015; the number of cases worldwide has more than tripled — from eight hundred cases initiated between 1986 and 2015 to more than three thousand since then,Footnote 4 with a total of 4,926 cases recorded as of July 2026.Footnote 5
A. The rise of strategic climate change litigation
A subset of these cases has been characterized as strategic litigation, in that they deliberately target governmental or corporate climate policies with the intention of prompting broader societal change rather than producing effects limited to the specific parties involved. In these cases, the claimants are seeking “[to advance] climate policies, [to] create public awareness, or [to change] the behaviour of government or industry actors” or, on the contrary, to “challenge or undermine climate-aligned policymaking.”Footnote 6 In such cases, the law becomes a “weapon” used either to encourage authorities to adopt more ambitious measures to combat climate change or to prevent companies from pursuing projects that would generate substantial greenhouse gas (GHG) emissions.Footnote 7 The 2015 ruling of the Hague District Court in Urgenda Foundation v State of the Netherlands,Footnote 8 upheld on appeal in 2018 and by the Supreme Court of the Netherlands in 2019, has become emblematic of this form of litigation. For the first time, a domestic court required a government to meet its international, European, and national obligations on climate action by ordering the implementation of more stringent GHG-reduction measures.Footnote 9
Urgenda has since inspired similar lawsuits around the world, particularly in Europe. Notable examples include the action brought by the association Klimaatzaak before the Brussels Court of First InstanceFootnote 10 and a case initiated by four environmental non-governmental organizations (NGOs) before the Paris Administrative Tribunal.Footnote 11 Other strands of strategic climate litigation have targeted private actors, seeking to compel companies to reduce their GHG emissions and bring their operations into alignment with the long-term goals of the Paris Agreement. Footnote 12 In parallel, and particularly following these landmark European cases, similar forms of litigation have emerged in common law jurisdictions, including the United Kingdom, Canada, Australia, and New Zealand. In these jurisdictions, however, such claims have more frequently encountered constitutional objections relating to judicial competence, including arguments based on justiciability and the separation of powers.Footnote 13 Less prominently developed in many civil law systems, these objections have played a central role in shaping the judicial reception of claims invoking the Paris Agreement and form the primary focus of the present analysis.
The Paris Agreement is the third international treaty dedicated to addressing anthropogenic climate change, following the United Nations Framework Convention on Climate Change (UNFCCC),Footnote 14 which it complements without replacing,Footnote 15 and the Kyoto Protocol. Footnote 16 Open for signature for one year beginning on 22 April 2016, it entered into force on 4 November 2016, after fifty-five countries responsible for at least 55 percent of global emissions ratified it.Footnote 17 Although it represents a legally binding international treaty for its 194 parties,Footnote 18 its provisions vary considerably in terms of precision, enforceability, and substantive flexibility.Footnote 19 The Paris Agreement consists of a “core” set of goals and principles that primarily serve as guidelines,Footnote 20 accompanied, on the one hand, by binding obligations that are largely procedural in nature and, on the other hand, by implementing rules subsequently developed by the Conference of the Parties serving as the Meeting of the Parties to the Paris Agreement (CMA). This architecture allows the parties, acting through the CMA, to maintain an ongoing dialogue about the modalities of implementing the commitments enshrined in the agreement. It thus establishes a legal framework that combines long-term collective objectives with a key implementation instrument consisting in individual targets articulated in documents known as nationally determined contributions (NDCs).Footnote 21
Litigants have increasingly invoked the provisions of the Paris Agreement as the legal basis for their climate litigation.Footnote 22 However, the agreement presents significant limitations that constrain its reliance by parties before domestic courts — notably, due to the non-binding nature of many of its clauses,Footnote 23 its lack of direct effect,Footnote 24 and its weak reception in domestic legal systems.Footnote 25 Primarily designed as an instrument of inter-state cooperation, the agreement sets out only a limited number of binding obligations and grants no individual rights.Footnote 26 International treaties of this nature typically have no direct effect and, in so-called dualist legal systems, are subject to limited transformation into domestic law. Against this backdrop, this article seeks to answer the following research question: to what extent, and through which constitutional doctrines, have domestic courts restricted the invocation of the Paris Agreement in climate litigation against public authorities?
B. A two-step methodology
To answer this question, the article adopts a two-step empirical and qualitative methodology. The first step consists of the systematic identification of relevant case law. To that end, the study relies on the Sabin Center for Climate Change Law database, which compiles several thousand climate-related judicial decisions and associated documents from jurisdictions worldwide. A dedicated database was constructed from this material using automated data extraction techniques (Python scripts),Footnote 27 enabling the collection of both textual content and metadata for decisions available between December 2015 (the adoption of the Paris Agreement) and May 2025.Footnote 28 A text-mining tool was developed to identify all judicial decisions in which the Paris Agreement is expressly mentioned in a legally relevant manner. This automated screening was complemented by manual verification. This process resulted in the identification of approximately fifty domestic decisions in which courts used, or otherwise referred to, the Paris Agreement in their reasoning.Footnote 29 This corpus constitutes the empirical basis of the study.
This approach makes it possible to analyze, in a structured manner, the different ways in which domestic courts address arguments based on the Paris Agreement, including the extent to which they assess the merit or decline to engage with such arguments. In doing so, the analysis takes into account not only the role of the agreement itself but also the procedural and constitutional objections raised by the defendants — such as challenges based on justiciability, separation of powers, standing, or the absence of directly effective norms — which shape judicial responses to its invocation. In a second step, the analysis proceeds qualitatively, focusing on judicial reasoning and, where available, the arguments advanced by the parties. As written submissions are not systematically accessible, the study reconstructs the parties’ reliance on the Paris Agreement through judicial summaries of claims and references to specific provisions of the treaty. This approach is supported by the principle of non ultra petita, under which courts adjudicate only on the basis of arguments raised by the parties.Footnote 30 Judicial references to the Paris Agreement therefore provide an indicative, though not exhaustive, account of how litigants invoke the treaty.
Although the initial dataset is global in scope, the analytical focus of this article is more limited. The study concentrates on a subset of cases drawn predominantly from common law jurisdictions. This narrowing results from both methodological and substantive considerations. From a methodological perspective, the doctrines at the centre of the analysis — particularly justiciability and related concepts such as the political question doctrine — are most explicitly developed in common law systems through case law. This facilitates a structured comparison of how courts articulate and apply constitutional limits on judicial competence. By contrast, these doctrines are less clearly defined, differently conceptualized, or altogether absent in many civil law traditions, rendering systematic comparison difficult within a single analytical framework.
From a substantive perspective, the cases identified through the data collection process reveal that restrictions on invoking the Paris Agreement are most clearly articulated in litigation directed against public authorities. Accordingly, the study primarily examines cases challenging governmental action or inaction in relation to climate policy. While the dataset also includes litigation involving private actors, such cases often raise distinct doctrinal issues (particularly in tort law) that do not engage constitutional limits on judicial competence in the same manner. Focusing on litigation against the state allows for a more precise examination of how separation-of-powers concerns shape judicial reasoning. The resulting analysis is therefore not intended to provide a comprehensive account of global climate litigation. Rather, it offers a focused comparative inquiry into how certain domestic courts, operating within broadly shared constitutional traditions, invoke doctrines of justiciability to limit the use of the Paris Agreement. References to cases from other jurisdictions are included for contextual purposes, but they are not systematically analyzed. The findings should accordingly be understood as illustrative of specific constitutional settings and not as universally generalizable across all legal systems.
Finally, while procedural issues such as standing — including that of NGOs — constitute important thresholds in climate litigation, they are not examined in detail in this article except insofar as they intersect with broader questions of judicial competence. The analysis instead centres on how courts define the limits of their adjudicative role when faced with claims invoking the Paris Agreement.
C. The primary scope of the study: justiciability as an indirect barrier to the domestic enforceability of the Paris Agreement
The limits on the domestic enforceability of the Paris Agreement in climate litigation arise primarily from constraints relating to justiciability. These constraints concern the jurisdiction of domestic courts to assess the legality of governmental actions or omissions relating to climate change, including measures intended to fulfill obligations under the Paris Agreement. This issue directly touches upon the principle of separation of powers between the judiciary and the political branches. The application of these constitutional principles, which is central to this article, generally constitutes an indirect barrier to invoking the Paris Agreement as it constraints the capacity of litigants to bring before the courts matters pertaining to the political powers of the state.Footnote 31 In the jurisdictions examined in this article, constitutional norms prevent the direct application of the Paris Agreement, precluding it from serving as positive law applicable to the substance of a dispute. This article aims to clarify how justiciability functions as an indirect barrier to the domestic enforceability of the Paris Agreement. The analysis that follows examines these dynamics primarily within common law jurisdictions, where doctrines of justiciability and the separation of powers are most explicitly articulated in case law.
The division of powers between the judiciary and the executive and legislative branches effectively narrows the jurisdictional scope of the Paris Agreement in domestic climate litigation. Thus, domestic courts in the jurisdictions examined have repeatedly declined to assess the merits of claims grounded in this treaty, holding that decisions concerning national climate strategies and programs — particularly those relating to GHG emission reductions — fall primarily within the purview of the political branches, not the courts. As a result, these matters are treated as non-justiciable. As later sections illustrate, courts have held in several cases that framing claims in tort or human rights law in relation to the state’s climate obligations would place judges in an impermissible political role, thereby encroaching on the prerogatives of authorities tasked with designing and implementing public policy. In such disputes, defendants frequently invoke the concept of justiciability to shield administrative action related to climate change from judicial review or, more broadly, to prevent judicial intervention in matters perceived as fundamentally political or moral.Footnote 32
This article focuses primarily on the judicial review of administrative acts and omissions attributable to public authorities. These cases most directly engage constitutional doctrines governing the limits of judicial competence and therefore provide the clearest setting in which to analyze how justiciability operates as a barrier to invoking the Paris Agreement. By contrast, litigation involving private actors, particularly in tort law, raises distinct questions relating to the development of substantive standards of conduct and causation, which do not engage justiciability in the same manner and fall outside the central scope of this study. Although this article focuses specifically on the judicial review of the actions and omissions of the various bodies that form the executive branch of government, certain courts have also invoked justiciability in disputes concerning the conduct of private actors under tort law.Footnote 33
This study first outlines the concept of justiciability, which is extensively developed in case law and widely discussed in Anglo-American legal scholarship,Footnote 34 before examining its specific applications in domestic climate litigation. It then assesses whether, and to what extent, the Paris Agreement has reshaped traditional understandings and boundaries of justiciability. The article argues that courts approach the justiciability of climate-policy disputes with marked caution. While domestic courts do not simply accept or reject the Paris Agreement as a source of law, they tend to regulate its judicial use through constitutional doctrines — most notably, justiciability — which function both as threshold barriers and as tools for calibrating the intensity of judicial review. As a result, the agreement is neither fully excluded nor fully applied but, instead, occupies an intermediate position as a norm that may inform, but rarely determine, judicial reasoning.
3. A comparative examination of justiciability in domestic litigation
The analysis in this section proceeds in three steps. First, it identifies the principal procedural thresholds that condition access to judicial review in climate litigation, including jurisdiction, admissibility, and standing. Second, it examines the concept of justiciability as a constitutional limit on judicial authority, focusing on its role in demarcating the boundary between legal and political questions. Third, it situates these doctrines within a comparative framework by distinguishing between jurisdictions in which constraints on the invocation of the Paris Agreement are primarily articulated at the procedural stage and those in which they emerge through doctrines relating to the merits of the dispute, therefore outside the scope of the present study.
A. Navigating procedural thresholds: jurisdiction, admissibility, and standing
As in any case brought before a court, parties engaged in domestic climate litigation must navigate a series of procedural hurdles that determine whether the judge may examine the substance of their claims. These primarily concern the court’s jurisdiction, understood as its legal authority “to hear and determine a case.”Footnote 35 Parties to climate litigation, often in a defensive posture,Footnote 36 frequently challenge jurisdiction by contesting the court’s territorialFootnote 37 or subject-matter jurisdiction.Footnote 38 If successful, such objections may lead the court to declare the dispute non-justiciable, meaning “not subject to the jurisdiction of the courts”Footnote 39 or, in some cases, to refer the case to another forum.Footnote 40 Beyond jurisdiction, admissibility requirements ensure that a claim “meets the conditions required by law for its examination on its merits by the court to which it is referred.”Footnote 41 These may concern the claimant’s legal capacity to sueFootnote 42 or have standingFootnote 43 or interest in bringing proceedingsFootnote 44 as well as whether the questions raised are capable of judicial resolution. Courts have considered, for example, the ability of NGOs to initiate actions in the public interest,Footnote 45 the appropriateness of the group definition underlying collective actions brought on behalf of an entire age cohort,Footnote 46 or the admissibility of claims against corporations alleged to have contributed to climate change.Footnote 47
Particular attention should be drawn to issues of standing, especially in relation to NGOs, which frequently act as claimants in strategic climate litigation. In many jurisdictions, the ability of NGOs to bring claims in the public interest constitutes a significant threshold condition for access to the courts and may itself determine whether arguments based on the Paris Agreement can be advanced at all.Footnote 48 However, standing operates primarily as a general admissibility filter and does not derive from the legal nature or domestic status of the Paris Agreement itself. While it may prevent reliance on the agreement in practice, it is not specific to it. Accordingly, this article addresses standing only insofar as it intersects with broader constitutional limits on judicial competence. Even where standing is recognized, claims invoking the Paris Agreement may still fail at a later stage on grounds of non-justiciability. These procedural conditions, however, do not exhaust the limits on judicial intervention. Even where jurisdiction and admissibility requirements are satisfied, courts may still decline to engage with the substance of a claim on the basis that it raises questions falling outside the proper domain of judicial determination. It is at this stage that the concept of justiciability assumes particular significance.
B. Justiciability as a constitutional limit on judicial authority
Building on these procedural considerations, justiciability operates as a second-order constraint, addressing not access to the courts but, rather, the types of questions that courts are prepared to adjudicate. It is best understood as a limit on judicial authority, reflecting a fundamental distinction between disputes that can be resolved through legal reasoning and those regarded as lying within the domain of political decision-making. Domestic courts, whether operating within common law or civil law traditions, must routinely distinguish between disputes that fall within their jurisdiction and those that they must decline to hear because they exceed judicial competence.Footnote 49 Although the concept of justiciability most often concerns a court’s substantive jurisdiction, its treatment in practice varies, straddling questions of both jurisdiction and admissibility. Importantly, a finding of non-justiciability does not necessarily encompass the entire dispute: courts frequently retain competence over certain grounds deemed justiciable while dismissing others.Footnote 50
In common law systems, justiciability is generally conceptualized as an objection to a court’s substantive jurisdiction and encompasses a range of doctrines, including standing and the principle that certain decisions are immune from judicial review because of their inherently political character. More specifically, it is often articulated through two related but distinct dimensions. Primary justiciability concerns categories of acts or decisions that are, by their nature, excluded from judicial review, typically because they fall within the exclusive domain of the executive or legislative branches.Footnote 51 A ruling that the subject matter is non-justiciable therefore precludes any further inquiry relating to the grounds of review.Footnote 52 By contrast, secondary justiciability operates where courts accept jurisdiction in principle but decline to adjudicate particular claims on the ground that they raise issues insufficiently legal in character, such as those requiring the resolution of abstract, polycentric, or policy-laden questions.Footnote 53
Justiciability thus functions as a flexible mechanism through which courts define the boundaries of their institutional role, particularly in cases involving complex public policy choices, such as climate governance. In the jurisdictions examined in greater detail in this article — United Kingdom, Canada, Australia, and New Zealand — its contours have been developed primarily through case law as an expression of the separation of powers. These developments, strongly shaped by the constitutional architecture of each system, determine the degree to which courts are willing to engage with disputes implicating governmental action or inaction, including in relation to the implementation of the Paris Agreement.
This distinction also has a comparative dimension. While common law systems articulate both primary and secondary justiciability as explicit limits on judicial authority, often operating at the threshold stage, civil law systems generally do not recognize an equivalent overarching doctrine of justiciability and, in particular, lack a unified concept corresponding to secondary justiciability. While they may acknowledge certain limits to judicial review analogous to primary justiciability, these are typically framed through specific doctrines rather than a general principle.Footnote 54 One example is the act of state doctrine, under which courts decline to review certain acts of public authorities, particularly those relating to foreign affairs or high-level governmental policy, on the ground that such acts fall outside the proper scope of judicial scrutiny.Footnote 55 Beyond such narrowly defined exclusions, civil law courts are more likely to accept jurisdiction and admissibility and to articulate limits to their intervention within the reasoning on the merits rather than through a generalized doctrine of non-justiciability. A comparative perspective is therefore necessary to situate justiciability within a broader landscape of judicial techniques used to delimit the role of courts in climate litigation and to understand how different constitutional frameworks shape the conditions under which claims invoking the Paris Agreement may be examined.
C. Procedural versus merits-based constraints: comparative perspectives on invoking the Paris Agreement in climate change litigation
The focus on these jurisdictions reflects the empirical foundation of this study. While the initial dataset encompasses decisions from a wide range of legal systems, constitutional doctrines limiting judicial competence — particularly, justiciability and related concepts such as the political question doctrine — emerge most clearly in a subset of cases arising from common law jurisdictions. In these systems, such doctrines are explicitly articulated and regularly invoked by courts and litigants when addressing claims involving the Paris Agreement.
By contrast, decisions from civil law jurisdictions tend to express comparable constraints through different doctrinal categories, often relating more directly to the merits of the dispute, such as statutory interpretation or the question of the direct effect of international norms.Footnote 56 Rather than excluding claims at a preliminary stage through a general doctrine of non-justiciability, these courts more often engage with the substance of the dispute while limiting the legal relevance or normative force of the Paris Agreement within the applicable domestic framework. This pattern is reflected in several of the decisions examined in this study, including, for example, the Luxembourg administrative judgment discussed below, where the court declined to assess the lawfulness of the impugned conduct against the Paris Agreement due to the absence of binding legal standards capable of guiding judicial review rather than on jurisdictional grounds.
As shown above, procedural thresholds determine whether claims may be brought before a court, while justiciability operates as a second-order constraint defining the types of questions that courts are prepared to adjudicate. In common law jurisdictions, these limits tend to crystallize at the threshold stage, through doctrines that exclude certain claims from judicial determination on the ground that they raise issues more appropriately resolved by the political branches. In civil law systems, by contrast, comparable limits are more often internalized within the assessment of the merits, through the interpretation of applicable legal norms and the determination of their domestic effectiveness. The comparison is therefore not one between systems that do or do not constrain the invocation of the Paris Agreement but, rather, between systems that structure these constraints differently. In common law jurisdictions, limits are predominantly framed in constitutional terms as restrictions on judicial competence grounded in the separation of powers. In civil law jurisdictions, similar outcomes are more frequently reached through doctrinal techniques that limit the legal effect of international commitments in the absence of sufficiently precise, directly effective, or implemented norms.
This comparative distinction also informs the methodological approach adopted in this study. Drawing on the framework of comparative international law, the analysis focuses not on international law in the abstract but, rather, on how domestic courts engage with international norms — in particular, the Paris Agreement — within their own constitutional and doctrinal settings.Footnote 57 This approach does not examine international law in the abstract; rather, it focuses on “domestic law relating to international law.”Footnote 58 In other words, it invites an investigation into how domestic courts in various jurisdictions apply substantive international law in accordance with their own legal, doctrinal, and institutional contexts.Footnote 59 This analytical framework provides the basis for the examination that follows. It makes it possible to assess, in a structured manner, how courts in different constitutional settings respond to arguments invoking the Paris Agreement and, in particular, how doctrines of justiciability operate as an indirect barrier to its judicial use in domestic climate litigation.
Beyond these semantic and procedural complexities lies a second set of culturally rooted challenges.Footnote 60 These relate primarily to the breadth of judicial discretion in reviewing matters that implicate public-policy choices, a question shaped by the distinct constitutional structures of each state.Footnote 61 They concern, in particular, the role of the judiciary within the broader architecture of government. In addition to the horizontal separation of powers — that is, between courts and political branches — questions of justiciability may also touch, albeit less frequently, on the division of competences in climate governance (including implementation of the Paris Agreement) between different levels of government, as in federal states, or between the European Union and its member states.Footnote 62
Interpretive practice further complicates comparative analysis. In some legal systems, such as Canada, courts regularly interpret constitutional provisions, including rights protected under the Canadian Charter of Rights and Freedoms,Footnote 63 under the supervision of a single apex court, the Supreme Court of Canada.Footnote 64 By contrast, other jurisdictions, such as France, maintain a clearer distinction: judicial and administrative courts primarily interpret infra-constitutional norms, while constitutional review falls within the exclusive jurisdiction of the French Constitutional Council.Footnote 65 This fragmented institutional design may produce divergent interpretative approaches depending on whether a dispute arises under public or private law, thereby complicating comparisons with the more unified model found in Canada, where the Supreme Court ensures consistency in the development and application of interpretive principles. To date, these structural differences have not played a decisive role in the climate litigation analyzed for this study.
In sum, while the doctrinal expression of judicial limits varies across legal systems, the underlying function remains comparable: domestic courts seek to delineate the boundaries of their authority when confronted with claims implicating climate governance and international commitments. As shown above, this may occur either at the threshold stage, through doctrines such as justiciability, or at the level of the merits, through limitations on the domestic operability of the Paris Agreement. This analytical distinction provides the basis for the examination that follows. It makes it possible to assess, in a structured manner, how courts in different constitutional settings have responded to arguments invoking the Paris Agreement and, in particular, how doctrines of justiciability operate as an indirect barrier to its judicial use in domestic climate litigation.
4. Applying the concept of justiciability to administrative acts implementing the Paris Agreement
In principle, climate change constitutes a domain amenable to judicial review.Footnote 66 Legal scholarship has consistently emphasized that neither the common lawFootnote 67 nor constitutional and administrative law empower courts to decline jurisdiction ab initio solely because climate change raises novel or complex questions.Footnote 68 This principle applies primarily to the review of governmental actions and omissions under statutory or constitutional norms, but it may also extend to challenges concerning the constitutionality of legislation, particularly when human rights are implicated.Footnote 69 Objections based on the allegedly political nature of measures implementing the Paris Agreement have centred on the complexity and innovative character of the issues before the courts, especially when human rights arguments have been advanced. Several courts have nonetheless held that the difficulty of the questions raised by climate litigation does not in itself deprive them of jurisdiction to review administrative action where appropriate. In other cases, however, the complexity or novelty of issues arising from the implementation of the Paris Agreement has led domestic courts to decline jurisdiction.
A. Judicial review of administrative acts implementing the Paris Agreement
Most climate-related cases found non-justiciable fall outside the court’s jurisdiction under what is commonly referred to as the presumptive or secondary branch of justiciability. To date, no court in the climate cases examined has declined jurisdiction on the basis of the nature of the contested act. Instead, courts have relied primarily on the absence of sufficiently defined legal criteria enabling judicial resolution of the dispute.
(i) Acts implementing the Paris Agreement are not inherently immune from judicial review
Historically, few climate cases have involved categories of acts that are excluded ex ante from judicial review under the so-called preclusive or primary branch of justiciability. This branch rests on an ad hoc examination of the individual claim on the premise that all disputes are, in principle, justiciable rather than on a presumption that certain acts are immune from review due to their nature.Footnote 70 When state action on climate policy falls within these exceptional categories, domestic courts refuse review because they lack a constitutional mandate to scrutinize such acts.Footnote 71
None of the decisions identified to date conclude that an act implementing the Paris Agreement is, by its nature, non-justiciable. For instance, an appeal filed in the United States challenged President Joe Biden’s decision to rejoin the Paris Agreement on the ground that it was a treaty requiring Senate consent.Footnote 72 The Court dismissed the case but on an entirely different basis: the claimant’s lack of standing, without reaching the merits.Footnote 73 Nonetheless, it remains possible that future cases may prompt courts to declare themselves incompetent to review acts lying exclusively within the executive’s prerogatives in the international sphere, such as decisions to withdraw from the Paris Agreement,Footnote 74 to submit (or fail to submit) a NDC under Article 4(3), or even matters relating to the content and implementation of the NDC as such.
(ii) Courts’ competence to review administrative measures implementing the Paris Agreement’s commitments
Courts have repeatedly affirmed their jurisdiction to review the legality of administrative acts intended to implement state commitments under the Paris Agreement, with or without implementing legislation. This jurisdiction remains contingent on the existence of a justiciable question of law and a clear legal basis in statute, common law, or constitutional law. Once jurisdiction is established, the intensity of review varies, depending on the degree of deference accorded to the executive and the nature of the measures at issue.
(iii) Recognition of domestic courts’ jurisdiction to review climate change policy
The climate-related litigation analyzed here reveals that courts generally accept jurisdiction to review governmental actions and omissions relating to climate change. Although the strength of this principle varies among jurisdictions, no court has adopted the position that judicial review of climate-related acts must be deemed non-justiciable as a matter of principle. Domestic judges tend to ground their competence in statutory or constitutional authority, thereby enabling them to scrutinize administrative action. Among the cases studied, New Zealand courts have been particularly explicit in affirming their jurisdiction to review government climate policies in light of the legislative framework implementing the Paris Agreement domestically. In Movement v Waka Kotahi, the High Court stated:
This Court has indicated on a number of occasions that in relation to climate change it will intervene by way of judicial review in appropriate circumstances. The fact that climate change involves difficult and multivalent issues, often described as “polycentric” or “socio-economic” issues, does not detract from the Court’s role.Footnote 75
The Court was asked to determine whether New Zealand’s national transport agency had properly considered GHG emission reduction targets in preparing and adopting its national land transport program.Footnote 76
The High Court reaffirmed this position in Thomson v Minister for Climate Change Issues, where it rejected arguments of non-justiciability, though in more cautious terms:
[I]t may be appropriate for domestic courts to play a role in Government decision-making about climate change policy. Indeed the claims have all succeeded to some extent, with the exception of Friends of the Earth v Canada which is one of the earliest cases and was decided in the context of the Kyoto Protocol difficulties. The courts have not considered the entire subject matter is a “no go” area, whether because the state had entered into international obligations, or because the problem is a global one and one country’s efforts alone cannot prevent harm to that country’s people and their environment, or because the Government’s response involves the weighing of social, economic and political factors, or because of the complexity of the science. … The various domestic courts have held they have a proper role to play in Government decision-making on this topic, while emphasizing that there are constitutional limits in how far that role may extend.Footnote 77
In the United Kingdom, the High Court of Justice reached a similar conclusion. In Friends of the Earth v Secretary of State for Business, Energy and Industrial Strategy, the Court was asked to determine whether the guidelines and policies adopted by the secretary of state were sufficient to meet the statutory carbon budgets, consistent with the objectives of the Paris Agreement. Footnote 78 The Court reiterated that ministerial accountability to Parliament does not exempt a member of the executive from judicial scrutiny:
Sometimes the principle of Parliamentary accountability is used to justify restraint in judicial review, or even non-justiciability. … In this case, the Secretary of State has not argued that his functions under s.13(1) are non-justiciable. He was right not to do so. Although the court may need to tread carefully in relation to some issues and apply an enhanced margin of appreciation, s.13(1) does not merely confer a power on the Secretary of State. It imposes a duty, compliance with which may be the subject of judicial review. Footnote 79
The Court therefore concluded that the secretary of state was under a statutory duty to develop government policies capable of achieving the carbon budgets set to meet the 2050 carbon neutrality target under the Climate Change Act 2008 (CCA),Footnote 80 a target that forms a central component of the United Kingdom’s contribution to the Paris Agreement. Footnote 81 These policies, the Court held, had to rest on both quantitative and qualitative analyses sufficient to demonstrate their capacity to deliver the required emissions reductions.Footnote 82 According to the Court, the secretary of state did not have access to certain information that was essential for exercising rational judgment before adopting these policies, as required by section 13(1) of the CCA. Footnote 83 The question of whether the government had the information required by law to make an informed decision was a justiciable issue, according to the Court.
(iv) A legal issue and legal criteria against which to conduct judicial review
Another New Zealand case, Lawyers for Climate Action v Climate Change Commission, illustrates how courts tend to affirm their jurisdiction in climate-related disputes when a sufficiently clear legal framework enables them to evaluate government action without substituting their own policy preferences. The issue before the Court was whether the advice of New Zealand’s Climate Change Commission was consistent with global efforts to limit warming to 1.5 degrees Celsius above pre-industrial levels.Footnote 84 The applicant alleged that the commission had made a methodological error that resulted in an under-estimation of the emissions-reduction pathway required to meet this target.Footnote 85
When ruling on admissibility, the Court emphasized that it could not replace the judgment of public authorities where no single correct answer exists to a complex question of public policy:
As discussed in Thompson v Minister of Climate Change, decisions on climate change are justiciable but may require the Court to defer to the decision maker (in that case, the Minister) on constitutional and institutional grounds depending on the ground of review. For example, where a ground of review requires the Court to weigh public policies that are more appropriately and better able to be weighed by those elected by the community, and there is no single right answer to how those policies should be weighed, the Court is not to substitute its view as to the outcome that best meets the statutory purpose. Footnote 86
In this case, the claimant had alleged that the commission had committed a logical and methodological error, misapplied the objectives and criteria set out in the governing statute, and misunderstood how progress towards New Zealand’s emissions-reduction targets should be assessed.Footnote 87 In particular, she argued that the commission had focused exclusively on achieving the 2050 carbon neutrality target set in domestic law rather than on what would be required to meet the Paris Agreement’s 1.5 degree Celsius temperature goal.Footnote 88
The Court considered these issues justiciable and applied a heightened standard of judicial review,Footnote 89 while emphasizing the need for judicial restraint when examining the decisions of a specialized expert body.Footnote 90 After careful review, the Court concluded that the commission had not exceeded its statutory mandate to provide advice consistent with the purpose of the Climate Change Response Act. Nor had it acted unreasonably or irrationally.Footnote 91 Although the Court accepted that carbon budgets are a means of achieving the temperature objectives of the Paris Agreement, it also noted that each state determines for itself the scale of emissions reductions needed to contribute to global temperature goals. As such, the commission was entitled to focus on domestic statutory requirements, including the 2050 net-zero target.Footnote 92
The Court of Appeal upheld this conclusion, underscoring the commission’s “central role” in “[charting] appropriate course and hold successive governments to account for maintaining course over the decades to come.”Footnote 93 Given the influence of the commission’s advice on the minister’s powers, the Court held that judicial review was justified to verify whether the commission had exceeded its authority through a significant error in its reasoning.Footnote 94 Although no such error was found, the appellate judgment confirms that, where legislation entrusts an administrative entity with an advisory mandate — including in the climate context — the Court may review both its methodology and the substance of its advice against applicable legal standards. A similar calibration of review appears in Thomson v Minister for Climate Issues, in which the Court concluded that “it may be appropriate for domestic courts to play a role in Government decision-making about climate change policy,”Footnote 95 after noting that
the appropriateness and ability of the Court to review the decision … reflects the constitutional concern that the courts perform the functions which are properly within their domain. It also recognizes the practical point that the courts are not equipped to balance competing policy factors, and are unlikely to have sufficient information about them to do so in the context of a legal dispute, absent certain legal criteria against which they can be determined. Footnote 96
A Luxembourg administrative court applied a similar line of reasoning, albeit within a different doctrinal framework. When asked whether the investment decisions of Luxembourg’s sovereign pension fund adequately took climate-related risks into account, the Court did not decline jurisdiction but, rather, refrained from engaging in a substantive review of the fund’s conduct against climate-related considerations derived from the Paris Agreement, stating:
It should in particular be emphasised that the issue of the current lack of binding legal or regulatory standards requiring, in particular, the FDC [Luxembourg Sovereign Pension Fund] to make investments taking into account the integration of climate-related sustainability risks falls, at present, within the sphere of purely political considerations which escape the review of the administrative court.Footnote 97
The Court further clarified:
In other words, the question of any failure by the Luxembourg State to comply with its political and moral obligations arising, inter alia, from the Paris Agreement in relation to the FDC, and the possible absence of an overarching governmental climate policy, ultimately constitute issues foreign to the present dispute; the undersigned is not called upon to assess either the legality of such policy, or, a fortiori, its appropriateness. Footnote 98
The Court nonetheless declared itself competent and the claim admissible, and it ultimately dismissed the application on the merits.Footnote 99 This reasoning illustrates how, in civil law systems, limits to judicial intervention may be articulated without recourse to a general doctrine of non-justiciability. Rather than excluding the claim at a preliminary stage, the Court accepted the review in principle but declined to assess the lawfulness of the conduct against the Paris Agreement or analogous climate standards derived from international law. It grounded this refusal in the absence of sufficiently precise, clear, and unconditional norms to be invoked before domestic courts as well as in the absence of specific domestic legislative measures governing the sector at issue. In these circumstances, the Court considered that the issues raised, including the alignment of investment policy with the objectives of the Paris Agreement, fell within the sphere of political decision-making rather than judicial determination.
The common thread across these cases is the courts’ refusal to substitute their own judgment for that of the political authorities when claims are overly broad, insufficiently substantiated, or lack a clear legal foundation. Whether the claim concerns an incomplete opinion issued by a specialized agency, an allegedly imprudent investment decision by a sovereign wealth fund, or a public policy said to rest on flawed reasoning or to contradict its stated objectives, courts rarely intervene in the absence of well-established legal criteria that allow meaningful judicial scrutiny. Nevertheless, where the applicable legal framework provides such criteria, courts may conclude that the existing measures are inadequate and order the government to revise them in accordance with the governing legal requirements.
(v) Adjusting the intensity of judicial review of administrative acts implementing the Paris Agreement
Another method by which courts may affirm their jurisdiction despite the political character of the issues at stake is by calibrating the intensity of the judicial review. Under this approach, justiciability is no longer framed as a binary determination — either the court has jurisdiction or it does not – and, rather, is framed as a continuum permitting variable degrees of scrutiny. This flexibility enables courts to afford the executive greater discretion in domains traditionally viewed as lying firmly within governmental authority. In certain circumstances, courts may therefore accept jurisdiction in principle, while limiting the extent to which the Paris Agreement functions as an operative legal standard. The judgment of the UK High Court concerning the standard of review applicable to executive decision-making in the field of international law exemplifies this development, although such an approach has not yet been widely adopted in climate litigation invoking the Paris Agreement. In Friends of the Earth v UK Export Finance, the defendant conceded that the central question — whether the state’s financing of a project in Mozambique was consistent with the United Kingdom’s obligations under the Paris Agreement — was justiciable.Footnote 100 This concession appears to have influenced the Court’s willingness to tailor the applicable standard of review, particularly given the absence of any jurisdictional objection.
The judge nevertheless suggested that the issue fell outside the ordinary scope of matters typically subject to judicial review. This observation, in turn, served to justify the adoption of a less stringent standard on the basis that the dispute did not neatly fall within the domain of questions that domestic courts are institutionally equipped to adjudicate:
[I]t is actually an application of the constitutional law principle of dualism: the court cannot and should not second-guess the executive’s decision-making in the international law arena where there is no domestic legal precedent or guidance. The standard for judicial review may be, and is in this case, less intense where the issue is one that is not properly within the province of the domestic court. Footnote 101
The question of whether the UK Export Finance had committed an error of law in concluding that the project financing complied with the United Kingdom’s obligations under the Paris Agreement had to be assessed, according to the Court, by determining whether the decision-makers had adopted a tenable view rather than by applying the more demanding correct view standard.Footnote 102 The former requires only that the executive’s position be reasonable, thus leaving it a measure of discretion in identifying the appropriate course of action to advance the United Kingdom’s interests on the international stage.Footnote 103 By contrast, the correct view standard would oblige courts to ascertain the precise conformity of the impugned decision with the proper interpretation of international law, thereby significantly narrowing the executive’s margin of appreciation.Footnote 104
Although it is premature to articulate a comprehensive comparative framework governing the justiciability of climate-related measures adopted by the executive branch, the decisions rendered thus far point towards an emerging pattern. Domestic courts tend to: (1) affirm, at least in principle, their jurisdiction to review administrative acts connected to the state’s climate policy, including actions taken to fulfill international or domestic commitments under the Paris Agreement; (2) condition such review on the existence of clear legal criteria derived from statutory law, common law, or constitutional provisions; and (3) calibrate the intensity of their scrutiny in accordance with the degree of deference owed to the executive and the nature of the measure under review.
B. Judicial limits arising from the complexity and novelty of implementing the Paris Agreement
Domestic courts’ ability to handle new, complex, or politically sensitive cases is particularly strained in the context of climate litigation. On the one hand, courts have traditionally been hesitant to enter domains in which jurisprudential guidance is scarce, especially where resolving the dispute would require them to construct legal frameworks in lieu of governments or legislatures that are, at times, unwilling to do so. On the other hand, the technical complexity and innovative character of certain climate-related claims often prompt litigants to rely on unconventional legal arguments, a strategy that may further dissuade courts from engaging fully with the merits.Footnote 105
Within climate litigation, domestic courts have tended to decline jurisdiction in two main categories of cases: (1) actions seeking to hold major corporate emitters, or their governments, liable in tort or under common law for their contribution to climate change and (2) actions challenging executive measures or legislation on the basis of emerging interpretations of human rights in the context of the climate crisis. What unites these claims is the judicial reluctance to displace the legislature by determining matters that are perceived as belonging to the democratic realm because of their broad societal implications. As a result, justiciability operates as an indirect barrier to relying on the Paris Agreement to resolve such disputes.
(i) Recognition of new standards of conduct
The complexity inherent in tort-based climate litigation frequently leads defendants to raise objections to the court’s jurisdiction, particularly because these claims require judges to determine whether specific private or public actors bear responsibility for exacerbating climate change and to order them, where appropriate, to compensate claimants for the resulting harm. Regardless of whether these actions target private entities or public authorities, courts have so far been reluctant to articulate new standards of conduct in response to the climate emergency. Adopting such standards would, in practice, compel courts to assume a quasi-legislative role, which is an outcome they have consistently sought to avoid.
(ii) Corporate accountability for contributions to climate change
Domestic courts have, in several instances, emphasized the limits of their technical expertise and constitutional mandate when asked to adjudicate claims seeking to hold companies liable for their contribution to climate change, particularly where legislatures have already addressed the issue. As the New Zealand High Court observed in Smith v Attorney-General, the judiciary is not institutionally equipped to design or supervise comprehensive climate policy, a task more appropriately assigned to political branches:
Unlike the ministries and other entities within the executive, the courts have neither the technical capacity nor the political mandate to co-ordinate in an integrated way to mitigate the effects of climate change. In contrast, the government’s response to climate change is dynamic. The steps it takes will depend on the environment and ongoing developments. There is already a legislative framework in place designed to respond to the threats.Footnote 106
This reasoning has led some courts to refuse to substitute themselves for governmental agencies when evaluating the conduct of private actors. In American Electric Power v Connecticut, the Supreme Court of the United States found that, with respect to specialized administrative bodies such as the Environmental Protection Agency (EPA), federal judges “lack the scientific, economic, and technological resources an agency can utilize in coping with issues” raised by climate change.Footnote 107 The case involved an action brought by several states, New York City, and private entities against five public and private power companies, alleging that their emissions constituted a public nuisance under federal or state law. The central question was whether the judiciary could order reductions in GHG emissions on this basis. The Court ultimately declined to do so for multiple reasons, including the existence of a statutory framework entrusting such determinations to the EPA.Footnote 108
Although decided prior to the entry into force of the Paris Agreement, and, therefore, not engaging with it directly, the case illustrates how courts confronted with claims seeking to regulate emissions through adjudication may frame such issues as falling within the domain of specialized agencies or the political branches. This reasoning closely parallels that adopted in later cases in which the Paris Agreement was invoked, where its existence as part of a broader framework of international climate governance reinforces judicial reluctance to assume a role in determining appropriate emissions reductions. More recently, US federal courts have continued to reject tort-based climate actions against fossil fuel companies on similar grounds. In one case, a federal District Court declined jurisdiction over a claim seeking to hold several fossil fuel companies liable for global emissions, reasoning that “the immense and complicated problem of global warming requires a comprehensive solution” and that adjudicating such claims would “severely infringe upon the foreign-policy decisions that are squarely within the purview of the political branches of the U.S. Government”:Footnote 109
Here, the City seeks to hold Defendants liable for the emissions that result from their worldwide production, marketing, and sale of fossil fuels. … Such claims implicate countless foreign governments and their laws and policies. This type of claim is the subject of international agreements, including — although the United States has expressed its intent to withdraw — the Paris Climate Accords. … To litigate such an action for injuries from foreign greenhouse gas emissions in federal court would severely infringe upon the foreign-policy decisions that are squarely within the purview of the political branches of the U.S. Government. Accordingly, the Court will exercise appropriate caution and decline to recognize such a cause of action.Footnote 110
In this case, New York City made limited use of the international framework to argue that climate change risks had long been recognized at the international level, thereby supporting the contention that the consequences of defendants’ conduct were foreseeable and that their contribution to global warming took place against a background of acknowledged global concern.Footnote 111 The defendants, by contrast, invoked international climate agreements, including the Paris Agreement, to characterize the regulation of GHG as a matter of coordinated international governance.Footnote 112 The Court adopted the latter approach, using the Paris Agreement to characterize the dispute as implicating foreign policy and to justify declining judicial intervention. Upon appeal, the Federal Court of Appeals further held that imposing liability on fossil fuel companies would circumvent the various diplomatic channels through which the United States addresses climate change, including the UNFCCC and the Paris Agreement. Footnote 113 It was therefore the complexity of both climate change itself and the far-reaching economic and international governance consequences of such a ruling that led the Court to declare the case non-justiciable. As the Court explained,
[t]o hold the Producers accountable for purely foreign activity (especially the Foreign Producers) would require them to internalize the costs of climate change and would presumably affect the price and production of fossil fuels abroad. It would also bypass the various diplomatic channels that the United States uses to address this issue, such as the U.N. Framework and the Paris Agreement. Such an outcome would obviously sow confusion and needlessly complicate the nation’s foreign policy, while clearly infringing on the prerogatives of the political branches.Footnote 114
In New Zealand, Smith v Fonterra involved a similar claim by a Māori litigant, who accused seven major New Zealand companies, identified as significant emitters and deemed to be heavy emitters, of public nuisance, negligence, and breach of a novel tort duty that would render companies liable to the public for their GHG emissions. On 6 March 2020, the High Court dismissed the first two causes of action: public nuisance, on the grounds that no specific harm directly attributable to the defendants had been established,Footnote 115 and negligence, due to the absence of a duty of care and of reasonably foreseeable and sufficiently proximate damage.Footnote 116 However, the Court allowed the third claim to proceed to trial:
[I]t may be that a novel claim such as that filed by Mr Smith could result in the further evolution of the law of tort. It may, for example, be that the special damage rule in public nuisance could be modified; it may be that climate change science will lead to an increased ability to model the possible effects of emissions. These are issues which can only properly be explored at trial.Footnote 117
The Court of Appeal upheld the High Court’s dismissal of the first two claims but concluded that the third claim was also non-justiciable.Footnote 118 It reasoned that the development of a new tort duty in response to the climate crisis was not an appropriate function of the judiciary, stating that tort law was not suited to addressing the global and systemic nature of climate change:
[It] is not to suggest the courts have no meaningful role in responding to the exigencies of climate change. They do in fact have a very important role in supporting and enforcing the statutory scheme for climate change responses and in holding the Government to account. Our point is simply that it is not the role of the courts to develop a parallel common law regulatory regime that is ineffective and inefficient, and likely to be socially unjust. Footnote 119
The claimant appealed this ruling, challenging in particular the Court of Appeal’s view that imposing tort liability would conflict with the purpose of the existing legislative framework — most notably, New Zealand’s Climate Change Response Act, which seeks, inter alia, to limit GHG emissions in order to avoid dangerous warming beyond 1.5 degrees Celsius and to enable New Zealand to comply with its international commitments under the Paris Agreement. Footnote 120 In his submission, excluding any form of tortious liability for major emitters, paradoxically, would “make it harder for New Zealand to achieve reductions consistent with 1.5°C and to meet its international commitments.”Footnote 121
Without ruling on the substantive merits of this argument, the Supreme Court overturned the Court of Appeal’s decision and ordered a full trial on all claims. It held that “Parliament had left a path open for common law to function, develop, and evolve within the New Zealand legislative landscape” and concluding that it was “not convinced … that the common law is incapable of addressing tortious aspects of climate change.”Footnote 122 The hearing on the merits, scheduled for April 2027, may thus mark a decisive moment in the evolution of common law approaches to the potential tort duties of multinational companies in the face of the climate emergency and in defining how such duties interact with statutory frameworks implementing the Paris Agreement. Taken together, such decisions reflect a consistent judicial concern: determining the appropriate allocation of responsibility for global emissions would require courts to make inherently political, globally consequential choices — choices that lie beyond their institutional role and constitutional mandate.
Beyond the economic and diplomatic implications that judicial intervention may entail, domestic courts’ deference to the executive can also be explained by the novel nature of the legal issues raised by climate change. These issues increasingly intersect with human rights protection at a time when both executive and legislative branches are actively adopting domestic measures to fulfill their NDCs in accordance with Article 4(2) of the Paris Agreement. Footnote 123
(iii) Challenging government accountability for inadequate climate policies
Litigants in certain climate-related cases have invited courts to recognize new standards of conduct derived from common law or tort law. Courts have, however, been cautious in accepting such arguments, often declining to articulate new duties of care for governments on the ground that doing so would effectively require them to override or replace legislative policy choices. While judges, particularly within common law traditions, generally acknowledge that the law must evolve to address emerging societal challenges, they also insist that such evolution must remain within judicial boundaries. This tension is illustrated by the Federal Court of Appeal in La Rose v His Majesty the King, which affirmed that
the fact that a pleading raises a novel point of law, with few jurisprudential antecedents, cannot justify striking it out. … To the contrary, as the history of the common law demonstrates, it may be essential that a novel, but as-yet unprecedented argument proceed to an in-depth analysis. It is only in this way that the common law can evolve to respond to the challenges of modern society.Footnote 124
In this case, fifteen young people brought a lawsuit against the queen and the attorney general of Canada, alleging that Canada’s GHG emissions were incompatible with a stable climate.Footnote 125 They argued that the government’s conduct violated their rights under sections 7 and 15 of the Canadian Charter of Rights and Freedoms as well as the rights of present and future generations of children under the public trust doctrine. They relied explicitly on the Paris Agreement as part of the factual and normative framework of their claim. They identified Canada’s commitment under the agreement — its NDC of a 30 percent reduction below 2005 levels by 2030 — and used it as a benchmark against which to assess state conduct. In particular, they relied on the Paris Agreement to demonstrate a gap between Canada’s commitments and its projected emissions trajectoryFootnote 126 and to support the contention that existing targets are inconsistent with what climate science requires.Footnote 127 The agreement was also incorporated implicitly into the legal argument insofar as the claimants allege that the impugned conduct was incompatible with Canada’s obligations under international climate agreements.Footnote 128
While the La Rose case has yet to be decided on the merits, the recognition of a new standard of behaviour in response to the climate emergency — particularly one informed by international law, including the Paris Agreement — presupposes that the claim raises a genuinely legal (rather than purely political) question and that courts can anchor their reasoning in established common law principles. These issues have arisen in petitions seeking to establish new duties of diligence or vigilance, often inspired by Urgenda v Netherlands. Footnote 129 The decision in Sharma v Minister for the Environment illustrates these challenges. Eight young Australians petitioned the Federal Court to prevent the expansion of a coal mine in New South Wales.Footnote 130 They asked the Court to order the minister for the environment to refrain, during the approval process, from breaching a duty of care owed to all persons under the age of eighteen ordinarily residing in Australia — a duty they sought to have judicially recognized.Footnote 131 They argued that the mine’s expansion would increase total coal production from 135 million to 168 million tonnes and that the resulting combustion would generate approximately one hundred million tonnes of additional carbon dioxide, emitted outside the remaining carbon budget consistent with limiting warming to two degrees Celsius.Footnote 132 According to the claimants, approval of the expansion would expose Australian children to a known and foreseeable risk of serious harm associated with rising global temperatures, thus violating the minister’s duty of care, given her special statutory responsibilities. Although the applicants relied only minimally on the Paris Agreement to establish this proposed duty, the minister invoked it extensively in arguing that such matters belonged to the political branches.Footnote 133
While the claim succeeded at first instance,Footnote 134 the Federal Court of Appeal declined to recognize the proposed duty of care. It held that imposing such a duty would require the Court to make determinations involving high-level policy considerations inappropriate for judicial resolution. On appeal, the minister maintained that the decision whether to approve the project was a “discretionary decision involving high policy considerations made according to a process of evaluation that is prescribed by the Act.”Footnote 135 The Court agreed, holding that
[a] duty that calls up such questions should not be imposed: It is one of core, indeed high, policy-making for the Executive and Parliament involving questions of policy (scientific, economic, social, industrial and political) which are unsuitable for the Judicial branch to resolve in private litigation by reference to the law of torts and potential personal responsibility for indeterminate damages, if harm eventuates in decades to come.Footnote 136
The Court concluded that the government, acting pursuant to the applicable Act,Footnote 137 had already taken account of the emissions associated with new extractive projects by requiring the minister to assess “matters of national environmental significance.”Footnote 138 Although the Act does not explicitly refer to GHG emissions or climate change, the assessment process — by virtue of established administrative practices and guidelines — includes consideration of the environmental impacts of projects, encompassing both direct and indirect emissions (including scope 3 emissions resulting from the combustion of exported coal in Japan, South Korea, and Taiwan). In this case, the Court held that, if any duty existed, it was “a political duty, not a legal duty of care.”Footnote 139
The Federal Court of Australia adopted a similar approach in Pabai Pabai v Australia, a case concerning the alleged existence of a governmental duty of care towards the inhabitants of the Torres Strait Island. The applicants argued that this duty required the state to set national GHG emission targets aligned with the best available scientific evidence and to finance adequate adaptation measures. In the Court’s view, the application raised several matters that lay beyond judicial competence.Footnote 140 First, it required the Court to interpret the nature and scope of Australia’s obligations under the UNFCCC and the Paris Agreement, particularly in relation to setting emission-reduction targets and communicating NDCs.Footnote 141 Second, it asked the Court to determine whether these international obligations compelled Australia to base its targets on scientific evidence and to identify the policy measures that the executive ought to adopt to address the climate threat.Footnote 142 According to the Court, these questions were squarely outside its jurisdiction. Relying on the reasoning of the Federal Court of Appeal in Sharma, it dismissed the application, stating:
It is in my view abundantly clear the issues raised by the applicants’ posited targets duty of care and its alleged breach concern matters of core or high government policy and political judgments. They are the very types of issues that the authorities that were discussed in detail earlier indicate should not be subjected to a common law duty of care in negligence, essentially because they are unsuitable for resolution by courts of law. Footnote 143
The Court added that any assessment of governmental conduct in setting national climate targets and reporting them to the UNFCCC must be made “at the ballot box … not in the courts,”Footnote 144 concluding that Australia could not owe such a duty of care to the inhabitants of the Torres Strait.Footnote 145
In New Zealand, Smith v Attorney-General involved a comparable claim. The Māori claimant also involved in the ongoing Smith v Fonterra litigation argued that successive governments had failed to take adequate mitigation measures, relying on a proposed duty of care requiring the state to “take all necessary steps to reduce NZ emissions and to actively protect the plaintiff and his descendants from the adverse effects of climate change.”Footnote 146 The High Court dismissed the application on the basis that the duty sought did not correspond to any recognized legal obligation and exceeded the “incremental development from existing law.”Footnote 147 In this case, the Paris Agreement formed part of the factual and normative background against which the claimant’s arguments were framed. The claimant relied on New Zealand’s signature and ratification of the agreement, together with earlier instruments such as the UNFCCC and the Kyoto Protocol, as evidence that the state had long been aware of the risks posed by climate change and of the need to adopt sufficiently ambitious mitigation measures.Footnote 148 In his pleadings, Mr. Smith argued that these international commitments, read in light of the scientific consensus reflected in Intergovernmental Panel on Climate Change (IPCC) reports, demonstrated that the Crown knew that significant reductions in GHG emissions were required and that a failure to act accordingly would cause foreseeable harm.Footnote 149
On appeal, the Court invoked the reasoning of the Federal Court of Appeal of Canada in La Rose v Canada,Footnote 150 which had refused to recognize a governmental fiduciary duty to conserve and protect public resources. The Court held that New Zealand’s legislative framework, which provides a comprehensive response to climate change, left no room for the application of the public trust doctrine, recognizing that such a duty would “cut across the balancing of those interests entrusted to the Minister and, ultimately, Parliament.”Footnote 151
These cases indicate that, to date, tort law has proved a more promising avenue than common law for imposing a duty of care on governments — and even on legislators — in response to the risks posed by climate change, including in relation to governmental conduct.Footnote 152 Yet, when situated within the broader framework of this article, they also reveal an important limitation; even where tort claims succeed in framing climate harm in terms of foreseeability, responsibility, and injury, the Paris Agreement itself never crystallizes into a concrete standard guiding the duty of care. Instead, it circulates within the reasoning as a background point of reference, sometimes invoked by claimants to demonstrate knowledge and the seriousness of the risk, sometimes by defendants and courts to emphasize the international and coordinated nature of climate governance. The result is that the Paris Agreement, while present in the argumentative structure of tort claims, tends to be ultimately displaced at the decisive stage of adjudication.
(iv) Interpreting human rights in the context of the climate crisis
In several domestic climate litigation cases, litigants have invited courts to interpret fundamental rights in light of the adverse effects of climate change on individuals and their environment. These claims take various forms. They may, for instance, challenge specific governmental decisions, such as the authorization of an extractive project or the adoption of particular programs or targets.Footnote 153 They may also allege that the inaction or insufficient action of public authorities violates the claimants’ rights to life and security.Footnote 154 Some claims go even further by seeking to establish a positive obligation on the state to reduce GHG emissions in line with scientific data in order to prevent a dangerous rise in global temperatures.Footnote 155 While climate litigation invoking human rights has proliferated across jurisdictions, relatively few decisions engage in detail with the question that animates this article: how international climate commitments — and, in particular, the Paris Agreement — are translated into justiciable standards within domestic legal orders. The selected cases are therefore not intended to be representative of all climate-related rights claims but, rather, to illustrate distinct emerging arguments in climate change litigation. To date, courts have approached these more ambitious claims with caution.
In Canada, courts have demonstrated scepticism towards such claims,Footnote 156 much as they have in cases based on social or cultural rights.Footnote 157 However, they generally consider themselves competent where claims concern specific actions or omissions by public authorities and raise legal questions.Footnote 158 The Supreme Court of Canada has indeed reiterated that courts must rule on any claim alleging a violation of a right guaranteed by the Canadian Charter of Rights and Freedoms. Footnote 159 Nevertheless, because the Charter does not contain any explicit environmental rights, the question of whether the conduct of public authorities in relation to climate change violates Canadians’ rights to life, liberty, and security of the person raises a number of novel issues,Footnote 160 including that of justiciability and of the standards against which governmental conduct should be assessed.
In Mathur v Ontario, seven young people challenged the provincial GHG emissions reduction target, arguing that it was incompatible with sections 7 and 15 of the Canadian Charter of Rights and Freedoms. The claimants explicitly grounded their claim in the Paris Agreement framework, thereby invoking the “Paris Agreement temperature standard” of limiting warming to 1.5 degrees Celsius or well below two degrees Celsius and sought an order requiring Ontario to adopt a “science-based” target consistent with that standard.Footnote 161 At first instance, the application was dismissed, but the Court of Appeal allowed the appeal and remitted the matter for a new hearing. In doing so, it clarified that the claim was justiciable because it challenged a specific statutory measure, the provincial emissions target, and that the case did not seek to impose a free-standing positive obligation but, rather, to assess whether a statutory scheme voluntarily adopted by the state complied with Charter requirements.Footnote 162 The Court recognized the Paris Agreement’s relevance as part of the legal and evidentiary framework, including Canada’s own GHG targetsFootnote 163 and noted that Ontario’s target had been designed to align with them.Footnote 164 More significantly, the Court accepted that international standards and scientific benchmarks could provide a basis for evaluating the adequacy of domestic measures,Footnote 165 thereby opening the door to their use as a reference framework through which courts may assess whether state climate action exposes individuals to constitutionally significant risks to life, security, and equality. However, this type of appeal, directed against an individual measure, remains fragile. The repeal of the 2018 Cap and Trade Cancellation Act, which imposed these targets on 25 November 2025, could render the appeal moot.Footnote 166
In contrast, in La Rose v Canada, the Federal Court of Appeal held that the claim, as pleaded — without targeting specific governmental acts — was too expansive and diffuseFootnote 167 but, nonetheless, granted leave to amend so as to render it more specific, insofar as the action identified objective standards against which Charter claims could be assessed:
[T]he appellants link the section 7 deprivation to the failure of Canada to meet its commitments in the Paris Agreement (Nationally Determined Contributions), commitments ratified by Parliament, and hence legally defined, objective standards against which the Charter claims can be assessed. The claims do not seek to tell Canada how to fulfill its commitments.Footnote 168
Domestic courts are generally more reluctant when claimants challenge the entirety of a legislative or regulatory framework, arguing, for example, that the government’s overall response to climate change is inadequate and violates their fundamental rights. In New Zealand, in Smith v Attorney General, the Court of Appeal dismissed claims based on section 8 (the right to life) and section 20 (cultural rights) of the Bill of Rights Act 1990 (NZBORA), on the ground that they effectively sought a declaration that the entire climate legislation framework was inadequate.Footnote 169 The claimant argued that the state had “failed to put in place an effective legislative and administrative framework properly designed to provide effective mitigation against the climate change risk in accordance with the best available science and New Zealand’s international and domestic legal obligations.”Footnote 170 The Court ruled that these claims were “untenable,” reasoning that the existing legislative framework already established mechanisms for emissions reduction, risk assessment, and adaptation designed to enable New Zealand to meet its international obligations. The alleged shortcomings were instead matters of political choice, reserved to Parliament under New Zealand’s constitutional framework.Footnote 171
Nevertheless, the Court of Appeal introduced two important nuances. First, it acknowledged that it was not “clearly untenable” that the rights to life and to culture protected by the NZBORA could impose positive obligations on the state to protect against the effects of climate change, even though the claims were not justiciable in the case at hand.Footnote 172 Second, it observed that, as the “window for the necessary action for a stable climate close,” judicial review of the reasonableness of public decisions will require closer scrutiny.Footnote 173 In other words, future claims that are more targeted, focus on specific measures, and demonstrate the proximity and predictability of the alleged risks may be able to overcome the obstacle of justiciability.Footnote 174
5. Conclusion
This article has shown that constitutional law may constitute an obstacle — albeit an indirect one — to the use of the Paris Agreement in domestic courts when determining judicial competence. Courts rely on the concept of justiciability to decline jurisdiction in cases they consider more appropriately resolved by political authorities. Primary justiciability relates to the very nature of the contested act: certain acts are, by their nature, incapable of judicial review. To date, few cases involving the Paris Agreement fall into this category. However, in light of a precedent concerning the Kyoto Protocol in Canada,Footnote 175 as well as a legal challenge in the United States contesting President Biden’s decision to rejoin the Paris Agreement — which was rejected on other groundsFootnote 176 — such scenarios cannot be ruled out in the future.
Most of the difficulties encountered by claimants arise instead from issues of secondary justiciability, which relate not to the nature of the act but, rather, to the absence, or perceived absence, of legal standards enabling courts to review decisions characterized as excessively political. In this context, it is not the binding or non-binding nature of the Paris Agreement that proves determinative but, instead, the extent to which its objectives can be translated into judicially manageable criteria. The case analysis shows that this translation operates unevenly across doctrinal settings. In tort and public law, courts tend to treat the Paris Agreement as contextual or deferential background; in human rights litigation, by contrast, it is more readily mobilized as a source of reference capable of structuring legal reasoning, though its reception remains cautious, and the contours of this approach are still being shaped in pending cases.
This differentiated reception invites a more critical assessment of the balance struck by courts. On the one hand, the insistence on judicially manageable standards reflects a legitimate concern for the separation of powers. By resisting invitations to set emissions targets themselves or to supervise climate policy as a whole, courts preserve the institutional role of legislatures and executives in matters involving complex socio-economic choices and scientific uncertainty. From this perspective, the doctrine of secondary justiciability operates as a mechanism of constitutional restraint. On the other hand, the analysis suggests that this restraint comes at a cost. By requiring highly specific claims and clearly defined standards, courts risk excluding precisely those cases that seek to address the systemic and cumulative nature of climate change. The effect is to favour challenges directed at discrete measures, while marginalizing claims that contest the adequacy of an overall regulatory framework.
The emerging case law nonetheless reveals a possible avenue for reconciling these tensions. Where litigants succeed in translating the Paris Agreement into measurable and legally cognizable benchmarks — whether through statutory incorporation, scientific consensus, or rights-based arguments — courts are willing to engage with the merits. In such instances, the Paris Agreement informs the interpretation of domestic legal standards, including constitutional rights, rather than operating as a directly binding norm. This suggests that the obstacle posed by justiciability is neither absolute nor immutable but contingent on the availability of intermediate normative frameworks capable of bridging international commitments and domestic legal reasoning. Ultimately, the current state of the law reflects a partial accommodation between international ambition and constitutional safeguards. Whether this evolving approach provides an adequate response to the climate emergency remains uncertain.
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