One of the most heated subjects of debate in the world of international climate change law is whether States may – or may not – be held responsible for the conduction of wrongful conduct in violation of environmental law norms and, more specifically, whether international actors can be held responsible for their contribution to the occurrence of an environment-related harmful event. In the context of such debate – which by itself showcases many levels of complexity (Dupuy, 1991) – the attribution of conduct represents a particularly troubling aspect. Whenever a climate change-related disaster occurs, is it possible to trace back the concrete elements of causation that have determined such an event or connect these causes to the specific conduct perpetrated by some States?
One of the great scientific hardships specifically concerns the tracing of emissions by each State and the linkage of these emissions to the verification of acute climate-related occurrences. Climate change, by its own definition, represents a global problem. It involves, although in different quantities, contributions by all States. Yet, on the other hand, the geographical distribution of the effects of climate change has no connection to the geographical distribution of greenhouse gas emissions: States which are culpable of producing the most emissions do not necessarily coincide – and, in fact, almost never do – with the States which are most affected by the results of climate change (Shaheen Moosa, 2020). In this sense, the whole phenomenon can be considered profoundly inequitable.
This article aims to investigate why the distribution of responsibility for climate disasters represents such a challenging issue and to illustrate some of the most recent scientific signs of progress made to overcome these problems.
The Law on Responsibility
International responsibility in connection to environmental law breaches can arise from three essential binaries: the 2001 “Articles on the Responsibility of States for Internationally Wrongful Acts” (thereinafter, ARSIWA), adopted by the International Law Commission, which cover State responsibility triggered by a breach of an international obligation; the wide-spread and diversified adoption of Multilateral Environmental Agreements (MEAs), in the form of “soft law” and “hard law” (Skjærseth et al., 2006); and liability norms triggered by the occurrence of harm, often dependent upon national regulation (Le Moli, 2021).
In this article, the focus will be primarily on claims of international responsibility susceptible to being filed under the ARSIWA. The notion of international responsibility, as declined by the International Law Commission, moves from the two essential elements of attribution and wrongfulness. These two notions are well described by Article 2 of the ARSIWA, which states that: “There is an internationally wrongful act of a State when conduct consisting of an action or omission: (a) is attributable to the State under international law; and (b) constitutes a breach of an international obligation of the State” (International Law Commission, 2001). From the perspective of international environmental law, both of these requirements are highly problematic.
With reference to the second requirement enunciated by the above-mentioned norm, there is no doubt that some of the obligations existing in international environmental law sources can be considered binding in the general sense of the term. However, in international environmental law, it often occurs that even obligations which use a clearly binding tone and phrasing can be hard to distinguish separately as self-standing. The reason can be found in the delicate balance which characterises environmental law sources, often torn between the necessity for widespread adoption and the need for great precision in the indications. Experience has shown that the more clearly enunciated the binding of the obligation is stated, the less likely it is to be widely adopted.
To concretely establish responsibility on the basis of environmental law primary obligations is therefore difficult: the phrasing of the most recent and notable climate pacts is rarely detailed, while often surrounded by contouring provisions which lack normative content, providing context instead (Rajamani, 2015). The refined technique of calibration between hard and soft law can be considered an efficient method for the creation of legal instruments which successfully combine broad recognition and States’ willingness to comply with their provisions. However, on the other hand, vaguely phrased obligations create a hardly surmountable obstacle for any attempt at establishing State responsibility in case of a breach.
The problem also applies when considering general principles of customary law, which have been considered applicable to environmental law, for example, the “no-harm rule” with which it is hard to frame the exact content of a principle and to determine if it also conveys a specific obligation (Negré, 2010). Even here, if the principle in question is not understood in an unequivocal way, it will be impossible to determine the existence of a corresponding obligation whose breach may be susceptible to establishing the international responsibility of the breaching party (Negré, 2010).
Moving from the hardships which reside in the possibility to verifying a breach of an environmental obligation by itself, equally complex – if not even more – is the task of assessing whether a certain harmful event has been caused by an action or omission perpetrated by an international subject. Without delving excessively into the matter, rules on attribution of conduct largely revolve around the concept of causal linkage between harmful events and reprehensible State behaviour (Ago, 1977).
With environmental disasters, the establishment of such a link can be relatively smooth in typical case studies, such as a massive drain of toxic chemicals in a transboundary river which causes environmental damage to the neighbouring State. Much less straightforward is the connection between, e. g., a sudden and violent snowstorm and the failure of a State to contain its emissions under a previously set legal limit. Although scientific evidence is unambiguous in recognising that the increase in extreme weather events is strictly connected to the global increase in temperatures (Seneviratne et al., 2021), it legitimately appears an impossible task to draw a causal link between an acute weather event, circumscribed in time and space and a global issue, like climate change, which deals with completely different orders of magnitude. Climate change, for one, results from the contributions of public and private actors altogether (Wewerike-Singh, 2019) and, furthermore, it is contributed to by all States in the world, with no exceptions. In this sense, just until very recently, it was considered scientifically impossible to attribute specific climate impacts to individual climate change contributors – i.e., emitting States (Nollkaemper & Nedeski, 2022).
This approach, although unjust for victims, felt just on the offenders’ side. Even if the conduct held by one specific State could be causally linked to a harmful event with sufficient precision, moving from the knowledge that such contribution is likely to have merely added to the already existent factors, would it be fair to hold the one State whose contribution can be causally linked to the harmful event accountable for the whole harmful event? As Le Moli (2021) said, “should a State that adds the straw that breaks the camel’s back be responsible for placing an additional straw or for breaking the camel’s back?”
Scientific research obviously plays a significant role in the ambit of climate change law litigation. All of the above suggestions moved from the assumption that emissions by a single State are essentially untraceable in their effects. Such a premise, however, may be not true anymore, or largely re-scaled anyway. A recent study claims that “it is scientifically possible to quantify historical responsibility of individual countries/regions for specific extreme events” (Otto et al., 2017). Taking into exam the 2013-2014 Argentinian heatwave, it was possible to successfully determine the individual contribution to increase the likeliness of the event of emitters such as the US and the EU. It was found, for instance, that the emissions of the latter made the event 37% more likely to occur (Otto et al., 2017).
The criteria of international actors’ contribution to the likeliness of the event in climate law litigation are almost necessary to adopt. Extreme weather events occur as a result of the combination of human contribution and the chance that they were going to happen anyway (Stuart-Smith et al., 2021). Historically, the inability to demonstrate that the harmful event would not have occurred anyway has represented one of the most vulnerable spots of many climate change-related litigations, with plaintiffs on their quest to establish responsibility often resorting to emphasising the magnitude of the event, instead of on its likeliness (Stuart-Smith et al., 2021). The ability to calculate the percentage of the added risk attributable to a State can emerge as a crucial tool in climate litigation.
It is too early to affirm whether this change may prove itself decisive for the future establishment of State responsibility for climate change-related behaviour, but it certainly can be said that recovering scientific evidence of causality significantly reduces the space left to judicial efforts. The demonstration that wrongful conduct has increased the likeliness of a harmful event up to a certain percentage represents an irrefutable datum, which judicial organs will not be allowed to ignore. Instead, it is likely to imagine that, in the following years, the international legal spectrum of causation theories will be further expanded: legal causation represents a concept which is common to all domestic legislation, but which can considerably differ from one country to the other in terms of the criteria used to establish causal links (Stuart-Smith R.F. et al., 2021).
Ago, R. (1977). Sixth report on State responsibility, A/CN.4/302 and Add.1, 2 & 3.
Dupuy, P. M. (1991). L’Etat et la réparation des dommages catastrophiques, in: International Responsibility for Environmental Harm. Graham & Trotman: 141–145.
Le Moli, G. (2021). State Responsibility and the Global Environmental Crisis. Ejil: Talk!.
Nedeski, N. & Nollkaemper, A. (2022). A guide to tackling the collective causation problem in international climate change litigation. Ejil: Talk!.
Otto, F. E. L., Skeie, R., Fuglestvedt, J. et al. (2017). Assigning historic responsibility for extreme weather events. Nature Climate Change 7: 757–759.
Negré, C. (2010). Responsibility and International Environmental Law. In: The Law of International Responsibility.
Rajamani, L. (2015). The 2015 Paris Agreement: Interplay Between Hard, Soft and Non-Obligations. Journal of Environmental Law, 28: 337–358.
Seneviratne, S. I. et al. (2021). Weather and Climate Extreme Events in a Changing Climate. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Chang. Cambridge University Press.
Stuart-Smith R. F. et al. (2021). Attribution science and litigation: facilitating effective legal arguments and strategies to manage climate change damages. Summary report for FILE Foundation.
Stuart-Smith, R. F., Otto, F. E. L., Saad, A. I. et al. (2021). Filling the evidentiary gap in climate litigation. Nature Climate Change 11, 651–655.
Skjærseth J. B., Stokke O. S., Wettestad J. (2006) Soft Law, Hard Law, and Effective Implementation of International Environmental Norms. Global Environmental Politics; 6 (3): 104–120.
Shaheen Moosa, C. (2020). Individual Obligations, Climate Change, and Shared Responsibility. Edukacja Etyczna (17): 42-67.
Wewerike-Singh, M. (2019). State Responsibility, Climate Change and Human Rights under International Law, Hart Publishing: 85.
Cover figure: Janssen, V. M. A. (n.d.). Climate Activism [Photograph]. Retrieved from https://www.pexels.com/it-it/foto/persone-in-possesso-di-banner-2561628/
Figure 1: Emissions from a powerhouse [Photograph]. Pixabay. Retrieved from https://www.pexels.com/it-it/foto/fotografia-di-paesaggio-di-fabbrica-459728/
Figure 2: Matheus Henrique. (n.d.). COP27 flag [Photograph]. Retrieved from https://eccoclimate.org/it/events/cop27/
Figure 3: Denniz Futalan. (n.d.). Flooding in Bangladesh [Photograph]. Retrieved from https://www.pexels.com/it-it/foto/donna-che-tiene-l-ombrello-verde-giallo-e-bianco-che-sta-vicino-alla-tv-crt-nera-1344265/
Figure 4: Georges Desipris. (n.d.). Seastorm [Photograph]. Retrieved from https://www.pexels.com/it-it/foto/grandi-onde-sotto-il-cielo-nuvoloso-753619/
Figure 5: Argentinian Heatwave [Photograph]. San Diego Union-Tribune. Retrieved from https://www.sandiegouniontribune.com/en-espanol/sdhoy-argentina-emerges-from-heat-wave-2014jan01-story.html