The recent advisory opinion of the International Court of Justice (ICJ) on the Obligations of States in respect of Climate Change (AO) has widely been celebrated for its statements on the obligations and standards of conduct expected of States with regard to climate change. At the same time, the AO is under scrutiny for what it did not say. One such element of silence is the ICJ’s limited remarks on what it characterised as the ‘precautionary approach or principle’, which, for many States, would have been a key concept for addressing a timely issue—the permissibility of geoengineering under international law.
This post, briefly, highlights the uncertainties surrounding the use of geoengineering as a means to mitigating global warming. The views of States before the ICJ on how geoengineering may give rise to breaches of international law are examined, with a particular focus on the precautionary principle. Lastly, the post unpacks the limited way in which the ICJ discussed precaution, exploring how the AO may nonetheless offer ground to counter the permissibility of geoengineering.
The Issues Surrounding Geoengineering
With frustrations and cynicism around the reliability and effectiveness of the Paris Agreement and the United Nations Framework Convention for Climate Change (UNFCCC) in tackling climate change, there has been growing discussion of what last resorts may be available. Geoengineering is a prominent part of this discussion. It is a proposed process through which humankind would effect large-scale interventions into the climate system, aiming to counter the effects of climate change.
The main forms geoengineering could assume include, for example, Carbon Dioxide Removal (CDR) and Solar Radiation Management (SRM). CDR would involve extractions of carbon dioxide from the atmosphere, with the intention to store it in alternative forms, such as biologically (e.g., afforestation), geochemically (e.g., enhanced weathering), or technologically (e.g., direct air capture with carbon storage). With SRM, the goal would be to limit global warming by reflecting a percentage of solar radiation, through possible methods including stratospheric aerosol injection (injecting sulphate particles into the upper atmosphere), marine cloud brightening (spraying sea salt into clouds to increase reflectivity), and space-based reflectors.
The feasibility and scientific credibility of either CDR or SRM are doubtful. The Intergovernmental Panel for Climate Change has highlighted with high confidence the risks of both CDR and SRM technologies, including creating further climate hazards and disrupting weather patterns, compounding risks to biodiversity and food security, or ‘terminal shocks’ (any sudden stop in geoengineering causing catastrophic consequences, making it maladaptation rather than adaptation), among others (pp 19, pp 149-151).
The International Tribunal for the Law of the Sea (ITLOS) in its advisory opinion on climate change remarked that, within the United Nations Convention on the Law of the Sea (para 231):
…Marine geoengineering would be contrary to article 195 if it has the consequence of transforming one type of pollution into another. It may further be subject to article 196 of the Convention which requires States, inter alia, to take all measures necessary to prevent, reduce and control marine pollution resulting from the use of technologies under their jurisdiction or control… (emphasis added)
This is not a prohibition, yet a clear signal against resorting to marine geoengineering. As per a report of the Human Rights Advisory Committee, geoengineering technologies are ‘often supported by proponents of polluting industries’ who have ‘vested interests’, insofar as this could deter genuine efforts towards climate change mitigation and adaptation measures. The report notes, having discussed the speculative benefits of geoengineering, that (para 35):
In situations in which scientific evidence of the environmental impacts of certain activities is not yet conclusive, States are required to act cautiously and diligently to avoid any steps that may cause harm to human health or the environment.
While it may be argued that geoengineering poses risk of ‘significant harm’ to the climate system, such as to trigger the prevention principle, it is widely advised against on the lines of ‘scientific uncertainty’ as above, thus making the precautionary principle more directly applicable. Moreover, a particular geoengineering measure may initially be covered by the precaution principle, and then covered by the prevention principle if a risk of significant harm becomes objectively determinable subsequently (on the relationship between these principles, see Judge Charlesworth paras 4-7).
It is in this vein that the opinions of States and international organisations before the ICJ assume significance.
State Perspectives at the ICJ
While a few States suggested the possibility of some forms of geoengineering being valid climate mitigation measures (e.g., Russia pp 2, Kuwait para 136) the majority of States addressing the issue considered it within their statements on the ‘legal consequences’ of internationally wrongful acts, particularly cessation.
Many States argued against the view that geoengineering could constitute a valid form of cessation, arguing that any merit was purely speculative, and in any event, geoengineering would only mitigate the symptoms, not the causes of climate change (especially in case of SRM). Not just that, geoengineering risked drawing attention away from genuine measures which would have minimal potential negative impacts [e.g., Vanuatu para 571, Organisation of African, Caribbean and Pacific States para 166; African Union paras 78-80; Cook Islands para 106(d), Kenya para 5.8, Kiribati para 72; Melanesian Spearhead Group para 204, Saint Vincent and the Grenadines para 50(i), International Union for the Conservation of Nature para 89, Sri Lanka pp 5, Panama pp 3, Albania pp 10, Slovenia pp 2, Vanuatu and the Melanesian Spearhead Group para 28(b)].
For some States, cessation would also have to respect the rights of future generations, and as an uncertain measure which would postpone addressing the real problem was not acceptable [e.g., Kiribati paras 77, 78(23), Saint Vincent and the Grenadines para 50(b)(i)].
Among these participants, many went beyond the issue of cessation, further highlighting the possibility that geoengineering may amount to a distinct breach of international legal norms, including, prominently, the obligation to exercise ‘due diligence’ in preventing significant harm to the climate system; especially because the standard of due diligence subsumed a precautionary approach [e.g., Vanuatu para 573, African Union para 97(c), Mauritius paras 107, 213, International Union for the Conservation of Nature paras 88-89]. It was not just that geoengineering would not suffice as a way for illegally acting States to reach cessation; further risk from geoengineering could give rise to standalone or discrete breaches of their obligations [e.g., Cook Islands para 106(d), Melanesian Spearhead Group paras 204-205].
With such insights, the ICJ had an opportunity to highlight the role and implications of prevention, precaution, and cessation, as regards the question of geoengineering.
Insights from the AO
Three preliminary observations from the ICJ’s AO are noteworthy: 1) unlike in the AO of the ITLOS, ‘geoengineering’ is not referred anywhere within the AO, or in the opinions or declarations of any Judges; 2) the ICJ decided not to address questions of State responsibility, including cessation, in the abstract, because this was considered an in concreto assessment, resulting in only a pithy and general statement on cessation (para 447); and 3) while much of the AO provided enriching insights on the prevention principle, the ICJ devoted only one paragraph substantially addressing the ‘exercise’ of ‘precaution’ (para 158).
In this regard, the ‘precautionary approach or principle’ was found to be a guiding principle for interpreting and applying the ‘most directly relevant legal rules’ (para 161). The main takeaway is that precaution was not affirmed as a self-contained principle under international law, and indeed, referred to confusingly as both an ‘approach or principle’ (something Judges Yusuf and Charlesworth criticised for its ambiguity). The likely reason for this ambiguity was wide disagreement concerning the formal status of precaution under the sources of international law.
However, the view that precaution was pertinent in interpreting and applying the ‘most directly relevant legal rules’ has clear implications for geoengineering. The absence of scientific certainty regarding the expected harm to the climate system cannot be used as an excuse for non-compliance with specific norms. In particular, the ICJ stated, with regard to the principle of prevention that (para 294):
The Court agrees with the conclusion reached by ITLOS that “where there are plausible indications of potential risks”, a State “would not meet its obligation of due diligence if it disregarded those risks” and, in that sense, the “precautionary approach is also an integral part of the general obligation of due diligence” under the duty to prevent significant harm to the environment…the Court considers that the precautionary approach or principle, where applicable, guides States in the determination of the required standard of conduct in fulfilling their customary duty to prevent significant harm. (emphasis added)
In other words, elements of precaution have been incorporated under the prevention principle. The conceptual implications of this statement are not perfectly clear, as the prevention principle applies at a different, and later stage (risk of significant harm) from precaution (scientific uncertainty) [e.g., see Judge Charlesworth paras 4, 6]. Nevertheless, that precaution has been incorporated under prevention gives credence to, and perhaps followed from, the opinions of those States that highlighted precisely this formulation, opining that it rendered geoengineering impermissible. Although not stated in so many words, it is worth noting the language of the ICJ elsewhere in discussing the exercise of due diligence (para 286):
Further, the availability of technological means to prevent or mitigate relevant harm influences what can reasonably be expected of a State. Where a risk can be addressed with readily available technologies, States are expected to use them. However, when technologies pose further risks, States are expected to use them with prudence and caution… (emphasis added)
The similarity of the last sentence to the submissions of States on geoengineering is striking. Thus, the messaging of the ICJ to geoengineering is comparable to ITLOS—not a complete prohibition, but a signal that geoengineering could amount to an internationally wrongful act, under the standard of conduct of due diligence.
Conclusion
Compared to the ICJ’s more direct statements on issues like fossil fuel activities, the absence of any direct engagement with geoengineering may fall short of the high expectations of the many States that opined on the issue. Probably, this was the result of the ICJ’s decision not to to address discrete specific forms of conduct, leaving that for future cases, as seen in its limited engagement with State responsibility matters (which is where many participants raised concerns about geoengineering). Nevertheless, the AO is not void of statements suggesting the impermissibility of geoengineering. It is advisable, to err on the side of (pre)caution for States, not to invest in geoengineering, and focus on more acceptable adaptation and mitigation measures.
Abhijeet Shrivastava is a public international lawyer and researcher, with an LLM from Cambridge University and BA, LLB(Hons) from Jindal Global University.