A mess of plastic: It is not clear what strategies will be most effective in mitigating harm from the global problem of plastic pollution. Borrelle et al. and Lau et al. discuss possible solutions and their impacts. Both groups found that substantial reductions in plastic-waste generation can be made in the coming decades with immediate, concerted, and vigorous action, but even in the best case scenario, huge quantities of plastic will still accumulate in the environment. Science , this issue p. 1515 , p. 1455

Plastic pollution has become one of the largest environmental challenges we currently face. The United Nations Environment Program (UNEP) has listed it as a critical problem, comparable to climate change, demonstrating both the scale and degree of the environmental problem. Mortalities due to entanglement in plastic fishing nets and bags have been reported for marine mammals, turtles and seabirds, and to date over 690 marine species have been reported to ingest plastics. The body of literature documenting plastic ingestion by marine megafauna (i.e. seabirds, turtles, fish and marine mammals) has grown rapidly over the last decade, and it is expected to continue grow as researchers explore the ecological impacts of marine pollution. Unfortunately, a cohesive approach by the scientific community to quantify plastic ingestion by wildlife is lacking, which is now hindering spatial and temporal comparisons between and among species/organisms. Here, we discuss and propose standardized techniques, approaches and metrics for reporting debris ingestion that are applicable to most large marine vertebrates. As a case study, we examine how the use of standardized methods to report ingested debris in Northern Fulmars (Fulmarus glacialis) has enabled long term and spatial trends in plastic pollution to be studied. Lastly, we outline standardized metric recommendations for reporting ingested plastics in marine megafauna, with the aim to harmonize the data that are available to facilitate large-scale comparisons and meta-analyses of plastic accumulation in a variety of taxa. If standardized methods are adopted, future plastic ingestion research will be better able to inform questions related to the impacts of plastics across taxonomic, ecosystem and spatial scales.

Plastic pollution is strewn across beaches and in oceans, bays, and estuaries. Tiny particles of plastic debris (often called microplastics) are so pervasive in aquatic ecosystems that we find them in seafood (1) and table salt (2). Marine organisms ingest or are entangled by plastic, sometimes with fatal consequences. Research suggests plastic pollution may impact biodiversity, ecosystem services, food security, and human health. In short, plastic pollution is a global threat. Plastics are accumulating across the globe at an astounding pace, even in remote places like the one pictured here—the uninhabited Henderson Island in the South Pacific. The time is ripe for an international agreement with measurable reduction targets to lessen the plastic pollution in the world’s oceans. Reprinted with permission from ref. 19. Despite the ubiquity, persistence, and cross-boundary nature of plastic pollution, stemming it is not an insurmountable task. Motivation for addressing the issue is building at the international level. The time is ripe for the initiation of an international agreement with measurable reduction targets to lessen the plastic pollution in the world’s oceans. An estimated 4.4–12.7 million metric tons of plastic are added to the oceans annually (3). Like many other contaminants (such as greenhouse gases and ozone-depleting substances), plastic is not constrained by national boundaries, because it migrates via water and air currents and settles in benthic sediments. More than 50% of the ocean’s area sits beyond national jurisdiction, including the infamous “garbage patches” in oceanic gyres where plastic accumulates. Plastic can affect organisms at every level of biological organization—altering gene expression, cells and tissues, causing death, and altering population size and community structure (4). Microplastics can impair reproduction and development (5) and alter how species function, disperse, and assemble (4, 6). These impacts, combined with evidence for accelerating plastic production and emissions into …

The ecological and societal impacts of plastics production, use, and waste are a complex global challenge. Management strategies to mitigate the impacts of plastics, such as recycling, waste-to-energy, and replacement with alternative materials have impacts of their own. Achieving long-term sustainability of plastics use therefore requires considering the externalized impacts of such management strategies. Here, we assessed the literature on the most common plastic waste management strategies to identify their impacts in relation to the sustainable development goals. We reviewed impacts of bans, levies, and taxes; alternative products; recycling; waste-to-energy; plastic recovery; and extended producer responsibility. Our analysis identified a total of 259 measured impacts of plastic waste mitigation strategies, from 113 papers. Ninety-three impacts were negative, 104 were positive, 11 were neutral, and 51 depended on the context of implementation. Consideration of the impacts of both plastic materials and management strategies is necessary to avoid perverse outcomes of plastic pollution mitigation efforts.