Viktoriya Gurash, postdoctoral researcher at the University of Zurich
Introduction
In response to the International Court of Justice’s (ICJ) advisory opinion on the Obligations of States in Respect of Climate Change, the BBC summarized the opinion by stating that ‘a top UN court has cleared the way for countries to sue each other over climate change.’ Indeed, the opinion not only offers a comprehensive clarification of states’ substantive obligations regarding climate change but also engages with important aspects of State responsibility in view of the special features of climate change. The central challenge lies in the fact that numerous states both contribute to and suffer from climate change, albeit to varying degrees (see para. 421).
From the outset, the ICJ made it clear that its task was to identify, in general terms, the legal framework within which a State’s international responsibility may be invoked for an internationally wrongful act, as well as to outline the remedies available in the event of such a breach (see para. 406). Importantly, the opinion clarified that the well-established rules on State responsibility under customary international law – principally reflected in the International Law Commission’s Articles on State Responsibility (ARSIWA) – apply in the context of climate change (see para. 420). To this end the Court affirmed that mechanisms such as the Loss and Damage Fund and the non-compliance procedures established under climate treaties do not constitute a lex specialis to these rules (see paras. 413-419). In its examination of the law on State responsibility, the advisory opinion specifically engaged with the issues of attribution and causation. This blogpost analyses the ICJ’s interpretation of these key elements, which underpin the conditions for compensation of climate-related harm.
Attribution of International Responsibility
The ICJ emphasised that the internationally wrongful act is not the emission of greenhouse gases (GHGs) per se, but the breach of an international obligation (see para. 427). Since these obligations are characterized as obligations of conduct, a breach may be attributed to states that have not exercised due diligence in taking appropriate measures to protect the climate system from GHG emissions. Accordingly, establishing international responsibility requires the existence of an internationally wrongful act and its attribution to a state, regardless of whether the act results in actual harm (see para. 433). Therefore, according to the ICJ, the issue of causation is not essential for establishing a breach of an international climate obligation.
The ICJ’s interpretation of the attribution of internationally wrongful acts is closely tied to the nature of the underlying substantive climate obligations. The distinction between obligations of conduct and those of result is crucial to understanding the role of the causation in establishing international responsibility. In a case involving obligation of conduct, the question is not the extent of harm caused by the state, but rather whether the state has taken appropriate measure to prevent such a harm (see Nollkaemper, p. 38). Although obligations of conduct do not require examination that a specific event or harm materialized, the element of causation nevertheless retains its relevance. An assessment of due diligence depends on consideration of the nature of the risk and the state’s capacity to mitigate it. For example, the European Court of Human Rights (ECtHR) in the KlimaSeniorinnen case noted that ‘what is important, and sufficient to engage the responsibility of the State, is that reasonable measures which the domestic authorities failed to take could have had a real prospect of altering the outcome or mitigating the harm’ (see para. 444). With an obligation of conduct, the causal nexus between the foreseeable negative effects of climate change (general causation, see Nollkaemper, p. 40) and the State’s capacity to act should be analysed. In matters of general causation, the potential effects of climate change may be reliably established on the basis of IPCC reports and therefore do not present a significant evidentiary challenge.
Causation of Climate Harm
Causation plays a critical role in the assessment of reparation, especially with respect to claims for compensation arising from climate-related harm. The ICJ acknowledged that the existing legal standard for establishing causation, as developed in its own jurisprudence, is capable of being applied in the context of climate change (para. 436). The advisory opinion emphasized that causation requires establishing a causal link between the resulting climate-related harm and the conduct of a specific State or group of States. The ICJ observed that while the causal link may be ‘more tenuous than in the case of local sources of pollution’, its identification is not impossible and ‘must be established in each case through an in concreto assessment’ (see paras. 437-438).
The Court’s pronouncement offers limited guidance on resolving the issue of the allocation of compensation for climate-related harm between states (see Reetz, Paddeu and Jackson). Moreover, Judge Nolte elaborates on the challenges for contentious proceedings that were not addressed in the advisory opinion, in particular with respect to claims for climate damages. In his view, the Court should have highlighted those difficulties more openly, in order to avoid creating false hope that climate litigation could serve as a substitute for existing mechanisms of financial transfers and remedies addressing climate-related harm (see Declaration of Judge Nolte). The main difficulty, as emphasized by Judge Nolte, lies in determining a combination of wrongful acts sufficient to have caused harm to the climate system, along with the need for a normative assessment of whether a specific level of GHG emissions constitutes a breach of the obligation to exercise best efforts (Nolte, paras. 19-30).
The climate science (see the IPCC’s Sixth Assessment Report) is clear that not all climate-related harm can be prevented through mitigation measures alone. Arguably, an important frontier of climate justice is to provide redress when harm occurs (see Rocha, Tigre and Cohen). To date, no international court has definitively addressed the standard of causation required to determine compensation for climate-related harm. The International Tribunal for the Law of the Sea in its advisory opinion on Climate Change and International Law acknowledged that ‘given the diffused and cumulative causes and global effects of climate change, it would be difficult to specify how anthropogenic GHG emissions from activities under the jurisdiction or control of one State cause damage to other States’ (para. 252). Despite the Inter-American Court of Human Rights having recognised the need for ‘compensation measures based on appropriate methodologies to assess the losses suffered’ in its advisory opinion regarding the Climate Emergency and Human Rights (AO-32/35) (para. 558), it did not engage with the complexity of cumulative causation. Furthermore, since the ECtHR in the KlimaSeniorinnen case rejected victim status for individuals (paras. 527-535), and the applicant association (para. 647) did not submit a claim for damages, it remains unclear how the ECtHR will determine causation for the compensation purposes.
Inquiries into how the problem of cumulative causation should be addressed in the context of compensation for climate harm can be found in the literature. For example, Nollkaemper offers concrete proposals, presenting two main alternatives: first, an obligation to provide full reparation to individual states; and second, an apportionment of compensation based on each actor’s relative share of contribution (for more details see Nollkaemper, pp. 51-54). Overall, the author supports an approach that prioritizes fairness and climate justice over strict mathematical causation (p. 54). While the ICJ could have shed more light on resolving the complexities of cumulative causation, it nevertheless affirmed the role of litigation in compensation of climate damages (para. 438).
Conclusion
It is doubtful whether the Court’s role in issuing this advisory opinion should be understood as either encouraging or discouraging climate litigation. If litigation is expected to deliver global justice by allocation of responsibility to compensate for climate harm among all the states, it is doubtful that any court alone could fulfil such a task. Rather, the significance of the ICJ’s pronouncement lies in affirming that international climate litigation between states remains a potential avenue for seeking compensation for climate-related harm within the broader framework of international legal instruments.
Should claims for climate harm compensation come before international courts, causation will be a key issue. The way courts resolve it will significantly influence the effectiveness of litigation as a tool for providing redress. The ICJ has deferred this analysis to a future occasion, when it is presented with a concrete case featuring a claim for compensation and a claimant’s specific arguments concerning, for example, the role of historical emissions in determining causation. If a state brings a claim seeking redress for climate damages before the ICJ, provided the Court has jurisdiction and the claim is deemed admissible, it would be compelled to confront the causation puzzle. In this sense, the situation reflects the German saying, ‘was auf den Tisch kommt, wird gegessen’ – or, in other words, what is brought to the table must be dealt with.