A common exercise for international lawyers faced with a new global environmental problem consists in undertaking a review of the applicable law. Environmental principles generally feature extensively in such studies: their open-textured nature is recognized to facilitate a fluid adaptation of international law as new risks become apparent. Among these principles is the foundational prevention principle, which is based on the rationale that environmental damage is best avoided rather than repaired. Since its international recognition in the 1972 Stockholm Declaration on the Human Environment,Footnote 1 the prevention principle has gained an influential place in the work of environmental lawyers. While it is readily assumed that the principle is able to guide state responses to the plastics crisis,Footnote 2 its exact functions and legal implications in this context remain underexplored.Footnote 3 The purpose of this essay is to shed light on the different roles that the prevention principle can play in response to the proliferation of harmful plastics.
A Reassuring Response: The No-Harm Rule
The initial role of the prevention principle in the context of the plastics crisis is to offer a stabilizing response to this new type of harm. When new environmental risks emerge, international lawyers generally invoke a classic form of the principle: the well-established prohibition against transboundary harm (also known as the no-harm rule), which aims to protect the territorial integrity of states from external interference. By applying the no-harm rule, international lawyers posit that states are under an obligation to ensure that plastics do not cause significant harm beyond their jurisdiction or control. It is clear that plastics can cause significant harm to “persons, property or the environment.”Footnote 4 Impacts can be wide-ranging, affecting the environment, economic sectors such as tourism, as well as human health.Footnote 5 As plastic debris and microplastics are transported across borders by ocean and watercourse currents, the problem extends beyond national borders to affect other states as well as areas beyond national jurisdiction. Inevitably, therefore, the no-harm rule has been identified as an applicable norm in the context of the plastic pollution crisis.Footnote 6
However, it is also clear that no-harm cannot provide an adequate response on its own. First, the rule was originally conceived to regulate state-centric environmental problems—for instance, discharges of pollution into a transboundary river, or emissions of air pollutants responsible for acid rain in a neighboring state—that threaten territorial integrity, rather than to protect the environment per se. The proliferation of plastics is more complex than those problems. Indeed, the plastics crisis is much closer to climate change in terms of the challenges it poses with regard to attribution of damage, causation, and standard of proof.Footnote 7 Importantly, plastics are both chemicals and waste, pollute land, water, and air, and have biodiversity and health impacts. As a result, the plastics problem does not fit into a neat legal category and instead calls for a multi-perspective, integrated approach that draws upon a multiplicity of existing legal regimes.
Second, the rule presupposes that the risk of harm is foreseeable and of a certain magnitude.Footnote 8 Our scientific understanding of the quantitative impacts of plastics, in particular of marine litter and micro-plastics, is generally well-developed. However, significant uncertainties remain in relation to nano-plastics,Footnote 9 for which the more controversial precautionary principle, which holds that lack of full scientific certainty should not prevent the adoption of environmental measures, might be better suited. In addition, the no-harm rule triggers only once the risk of harm exceeds a certain threshold (usually defined as “significant”)Footnote 10 and is therefore ill-suited to address plastic pollution's impacts, which tend to be widespread, long-term, and cumulative.
Third, while the no-harm rule imposes a duty to avoid environmental damage from activities under the jurisdiction or control of the state of origin,Footnote 11 it is unclear how this duty applies in the case of the plastics crisis. The rule does not easily accommodate situations in which a source of pollution is deliberately and consensually transferred to another state. Throughout their life cycle, plastics are handled by numerous operators, potentially across dozens of borders, and undergo various transformations. Most stages of the plastics life-cycle occur outside of the manufacturing state, meaning that identification of the “state of origin” (understood as the location of the potentially harmful activity) is not a straightforward process. Responsibility becomes even more obscured as winds and surface currents transport discarded plastics across the world and break them down into smaller pieces. In the end, “virtually all States are likely to be responsible States as well as injured States.”Footnote 12
Fourth, it is questionable whether the no-harm rule can address plastic pollution that accumulates in areas beyond national jurisdiction. Although states are, as a matter of customary international law, under a duty to prevent harm in areas beyond their jurisdiction,Footnote 13 existing legal tools struggle to adequately respond to the accumulation of plastics in the oceans. For instance, assigning responsibility for the Great Pacific garbage patch, a collection of floating plastic of over six hundred thousand square miles, halfway between Hawaii and California,Footnote 14 raises contentious questions. Indeed, major uncertainties remain regarding inter alia the invocation of shared responsibility for harm originating from multiple states, the rights of non-directly injured states to protect the global commons as well as the nature and allocation of reparations.Footnote 15 The no-harm rule is too focused on protecting territorial integrity to adequately respond to environmental problems that manifest in these locations.
Despite these inherent limitations, references to the no-harm rule in the context of global plastic governance tell us something about its role in international environmental law. That is, references to the rule often fulfill a moral, rather than strictly legal, role. The rule offers a foundational basis to argue that harm arising from the plastics crisis cannot be deemed acceptable and to call for the adoption of more appropriate international legal responses.
A Gap-Filler: Prevention and the Duty of Due Diligence
While the no-harm rule is unlikely to provide a satisfactory response to the plastics crisis, the prevention principle has evolved to encompass not only the negative duty established by that rule, but also a positive duty emphasizing the expected proactivity of states in the face of risk. In this latter sense, the prevention principle imposes a due diligence obligation and fills in gaps left by the fragmented state of the applicable international law in the absence of a global treaty to combat plastic pollution.
Although existing instruments fail to cover the entire life cycle of the plastic problem in all its material and spatial dimensions,Footnote 16 the international legal landscape is not completely irresponsive to the plastics crisis. The existing legal and policy framework is very sophisticated, ranging from general obligations to prevent pollution under law of the sea treaties to policy objectives to reduce marine debris under the Sustainable Development Goals.Footnote 17 The normative landscape is particularly intricate given the relevance of oceans, waste, and biodiversity law in the governance of plastics.
In this context, the principle of prevention, through its due diligence standard, acts as a “legal connector”Footnote 18 that brings coherence to international legal frameworks and clarifies existing state duties in the face of plastics harm. Activities below the threshold of significance required to trigger a breach of no-harm remain governed by the duty of due diligence, which is not limited by the same threshold.Footnote 19 Moreover, the potential lack of clarity about whether the level of scientific knowledge is enough to trigger a preventive duty is not necessarily problematic when focusing on the duty of due diligence, which provides that a state may be required or entitled to take precautionary measures even in the absence of scientific certainty as to the existence of risk of significant harm.Footnote 20 And an assessment of whether a state has acted diligently to anticipate the risks posed by plastic pollution can draw upon jurisprudential clarifications of the due diligence standard. For example, the legal reasoning of the South China Sea arbitral tribunal, which assessed the level of due diligence required under the UN Convention on the Law of the Sea “against the background of other applicable international law” (including treaty obligations to protect biodiversity),Footnote 21 provides guidance on how to rely on, and interpret, fragmented and sectoral legal frameworks to assess the reasonableness of state actions.Footnote 22
A Policy Idea: Prevention as a Normative Idea of Harm Avoidance
Finally, the prevention principle manifests not as a legal norm but rather as a policy of harm avoidance. As the international community started to mobilize to find solutions to the plastics crisis, consensus rapidly built over the applicability of the principle of prevention,Footnote 23 alongside other environmental principles, including the precautionary approachFootnote 24 and the polluter-pays principle.Footnote 25 Notably, prevention has become a recurring theme in the UN Environment Assembly resolutions relevant to plastics governance, where it is explicitly recognized as the preferred approach to the plastics problem and endorsed as a policy to guide the further actions of the international community.Footnote 26 Conversely, questions of liability and compensation have not been completely put aside but are presented as a secondary, complementary, route.Footnote 27
In its manifestation as policy, the principle of prevention channels discussions and informs decision-making. In the context of the plastics crisis, policy-makers rely on its sophisticated manifestations in the waste sector, including in the form of the concept of “waste hierarchy,” for inspiration.Footnote 28 The preventive rationale can be broken down into several goals to offer a kaleidoscope of preventive options, including the reduction of waste, reuse, recycling, recovery, and the optimization of final waste disposal. While it is increasingly recognized that the plastics problem is best addressed at the source, the prevention principle applies throughout the lifecycle of plastics, including upstream preventive action as well as mitigation and removal efforts downstream.Footnote 29 Because it does not prescribe a specific plan of action, the principle accommodates different policy agendas and fosters international cooperation despite the existence of diverging state interests.
Conclusion
Principles are powerful instruments in the toolbox of international environmental law. In the context of the plastics crisis, the prevention principle plays a pervasive and diffuse role. Compared to other principles such as precaution, its impacts on legal processes are often more subtle. And it is both ineffective and promising at the same time: On the one hand, the principle has failed to avert environmental degradation from plastics in the first place. Moreover, the principle is not clearly adaptable to a problem that is much more complex than the traditional forms of inter-state pollution that it was originally designed to address. On the other hand, thanks to its abstractness and flexibility, the prevention principle can inform assessments of the level of diligence required of states in the face of the plastics problem, help to adapt existing legal frameworks, and encourage creativity in lawmaking. As a familiar principle of environmental policy-making, the principle resonates well with the international community and could become an influential tool in the governance of the plastics crisis.
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