Causation in Climate Change: The International Court of Justice (ICJ)’s Climate Change Advisory Opinion vis-à-vis English Tort Law - Opinio Juris
Causation in Climate Change: The International Court of Justice (ICJ)’s Climate Change Advisory Opinion vis-à-vis English Tort Law
03 Mar Causation in Climate Change: The International Court of Justice (ICJ)’s Climate Change Advisory Opinion vis-à-vis English Tort Law
03.03.26
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[Dr. Juan-Pablo Peréz-León-Acevedo is a DPhil in Law candidate and a tutor at the University of Oxford. He also teaches at the Universities of Reading, Southampton, Oslo, and Abo Akademi (Finland)]
While the ICJ’s Obligations<br>of States in respect of Climate Change Advisory Opinion<br>(ICJ-AO) has been extensively analysed,<br>this post examines an issue that remains largely unexplored, namely, how the ICJ-AO<br>and a specific domestic legal system could interact in terms of causation in<br>climate change litigation. Thus, this entry examines whether causation in English<br>tort law (ETL) regarding attribution of liability for climate change diverges<br>or converges from the ICJ-AO findings on causation, which can inform<br>potential climate change litigation. ETL has been selected herein for two main<br>reasons. First, as key legal developments concerning tort-based climate change<br>litigation in other common law jurisdictions, such as New Zealand, arguably<br>show (examined later), English tort case law has usually been influential.<br>Second, since large multinational energy companies have their headquarters or<br>major branches in the UK, tort law litigation before English/British courts for<br>climate change-related damages caused in other countries (especially in the<br>Global South) is expected to take place, as already evidenced by some ongoing<br>proceedings in England (examined later).
Justification and Limits
This comparative analysis is justified because the ICJ-AO<br>examined causation (paras. 433-438), which is central to ETL jurisprudence that<br>has influenced common law jurisprudence, particularly in New Zealand’s<br>tort-based climate change litigation. A common law grammar regarding causation<br>in climate change litigation could potentially emerge. Moreover, the ICJ-AO<br>provides statements about treaty and customary international law obligations<br>binding on the UK, which could potentially involve ETL adaptations to climate<br>change litigation. Finally, the UK<br>participated in the ICJ-AO proceedings,<br>and despite its restrictive approach to applicable state obligations concerning<br>climate change, the UK’s intervention plausibly advanced links between ETL with the ICJ-AO.
Nonetheless, while ETL considers causation within liability<br>attribution, the ICJ-AO does so regarding remedies: after liability<br>attribution. Yet, causation still has to be determined in climate change litigation.<br>Although ETL targets private actors such as big polluters, and public offices<br>as defendants, the ICJ-AO addresses states. Nevertheless, the ICJ-AO’s<br>substantive law findings can impact future national/transnational litigation<br>against private companies.
Similarities and Differences
Common law courts, such as New Zealand’s Supreme Court (NZSC) in Smith v Fonterra, and the ICJ-AO invoked the UN-Intergovernmental Panel on Climate Change (IPCC) findings to provide scientific background to attribution questions, including causation. Conversely, English courts have not yet explicitly invoked IPCC’s findings. Nevertheless, there is not yet an English court judgment on purely tort-based climate change litigation.
The ICJ-AO rejected two extreme positions: causation cannot be established because of the diffuse nature of climate change, and causation cannot be presumed in climate change: causation is required for reparation (paras. 434-435). ETL, mutatis mutandis, could proceed similarly on tort claim litigation for environmental damage. As the NZSC in Smith v Fonterra remarked:
‘It may indeed be beyond the capacity of the common law to resolve climate change […] but we are not presently convinced […] that the common law is incapable of addressing tortious aspects of climate change’.<br>(para. 154)
Furthermore, ETL nuisance cases (such as St Helen’s Smelting) were invoked to emphasise that the common law of torts can rise to new environmental challenges:
‘As a consequence of the long, global industrial revolution, the common law had to deal with new, widespread risk and damage caused by air and water pollution and the escape of biohazards’<br>(Smith v Fonterra, para. 157)
ETL could also balance plaintiffs’ and defendants’ rights similarly to how the ICJ-AO did:
‘How the law of torts should respond to cumulative causation in a public nuisance case involving newer technologies and newer harms (GHGs, rather than sewage and other water pollution) is a matter that should not be answered pre-emptively, without evidence and policy analysis.’<br>(Smith v Fonterra, para. 166)
Under the ICJ-AO, the ‘sufficiently direct and certain causal nexus’ standard...