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, 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, its exact functions and legal implications in this context remain underexplored. 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.

As an internationally-traded commodity, plastic waste has long followed the profitability dynamics of the global waste and recycling market, leaving in its trace a disproportionate environmental and health burden on the world's most vulnerable populations. East Asian and Pacific countries, where most globally generated plastic waste has been exported since the late 1980s, are marked by underdeveloped, inefficient, or non-existent waste management infrastructures. Despite the highly visible environmental and human health impacts of plastic pollution, the global plastic waste trade has predominantly operated outside the scope of the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal. In 2019, however, this treaty was amended to explicitly bring all but a narrow stream of plastic waste within the category of wastes controlled as “hazardous waste,” or “waste requiring special consideration.” This essay explains the international legal implications of the amendment and discusses potential challenges related to its implementation and enforcement. It argues that in order to be effective, the new plastic waste trading rules will require further legal clarity, greater transparency in plastic waste trade that is not regulated under the Convention, and stronger law enforcement cooperation between customs and environmental protection authorities, both within and between countries. Since controlling all plastic waste trade at point of export is, in practice, impossible given the state of global shipping infrastructures and container traffic volume, the most effective approach to curbing plastic waste pollution and illegal trade lies outside the mandate of the Basel Convention, notably, in assigning financial and environmental responsibility for plastic waste within plastic product supply chains.

The UN General Assembly and the UN Environment Assembly (UNEA) have expressed concerns about the pollution of the sea by plastics, which adversely impacts ecosystems, some economic activities (e.g., tourism and fishing), and possibly public health (e.g., consumption of contaminated fish). In December 2017, the UNEA decided to establish the Ad Hoc Open-Ended Expert Group on Marine Litter and Microplastics to examine ways to combat marine plastic pollution. The group met three times in 2018 and 2019, and at least two more meetings are planned. Among potential responses to the issue of marine pollution, the group briefly considered—but eventually dismissed—the possibility of creating a liability or compensation regime. This essay evaluates the prospects for such a regime. As the essay will show, compensation faces significant conceptual problems, not the least of which is the absence of an obvious recipient. However, some form of liability could be imposed on corporations that produce plastic, or on states that fail to regulate them. Such a liability regime, even without financial compensation, could foster the prevention of further marine plastic pollution.

The notion that a plastics treaty is necessary is gaining traction, but there is less agreement as to its content. Some, including this author, have suggested that a plastics treaty should be modelled on treaties such as the Montreal Protocol, which sets out a broad commitment to end the use of a particular material and then introduce regulations to ban particular forms of that material over time. This approach has an immediate appeal—it sends a signal to states and to industry that they must change their behaviors and products, while giving time to adapt to the new regulation and develop alternative materials or ways of working. The potential drawback of this approach is that some states simply will not accept such rigid standards. In addition, some states may prefer a second approach that is more obviously rooted in the principle of common but differentiated responsibilities, which assigns different obligations to parties according to their respective capacities. Within the climate change regime, the Paris Agreement takes both approaches, asking states to set their own nationally determined contributions (NDCs) to emissions reductions (common but differentiated responsibilities) and then to revise these NDCs over time through an iterative process to deliver progressively more ambitious targets for emissions reduction (moving toward a ban) or mitigation. In reality, neither approach is entirely suited to regulating plastics, so a new approach to treaty-making is required. This new approach should focus on the outcomes desired rather than the practices that need to be regulated.