In a move to address the environmental impact of plastics, G7 Environment, Energy and Oceans Ministers have received an OECD report on current plastics production and use, identifying the reasons for currently low plastics recycling rates, as well as what can be done about it.
Plastics are a remarkable family of materials that have gathered attention recently due to their ubiquity in the global economy, the low material recovery rates that they currently achieve, and the environmental impacts associated with current disposal methods. Although early forms of plastics were already in existence during the mid-19th century, plastics other than Bakelite were largely unknown prior to 1950. Since then, plastics have rapidly become one of the most commonplace materials on the planet. In 2015, global plastics production reached 407 million tonnes per annum (Mtpa), making it more than the production of paper (400 Mtpa), fish (200 Mtpa), and aluminium (57 Mtpa). If production continues to grow at similar rates, plastics production will reach 1 600 Mtpa in 2050.
The rapid growth of plastics production and use is largely due to the unique properties of the material. Plastics have a high strength-to-weight ratio, can be easily shaped into a wide variety of forms, are impermeable to liquids, and are highly resistant to physical and chemical degradation. Plastics can also be produced at relatively low cost. It is these properties that have led to the substitution of traditional materials (e.g. concrete, glass, metals, wood, natural fibres, and paper) by plastics in many applications.
Plastics are a diverse set of materials with specific chemical and physical properties. At least eight major polymer types are widely used5, and a range of chemical additives are introduced at the manufacturing stage in order to improve polymer performance. The diversity of plastics has important implications for their end of life management. In particular, it means that the issues that hinder material collection, sorting, and recovery can differ substantially across polymers. The versatility of plastics has led to their use in almost all major product categories. Plastics packaging is the largest application by weight, but plastics are also used widely in the textile, consumer goods, transport, and construction sectors. Some polymers of plastic are used primarily in a single application (e.g. polyethylene in packaging) while others are used more widely (e.g. polypropylene). This distinction also has implications for end-of-life plastics management: developing effective sorting and recycling technologies is likely to be simpler for polymers used in a narrower range of applications.
The widespread use of plastics has generated a number of benefits for society and for the environment. Plastics are often used to protect or preserve foodstuffs and, in doing so, help to reduce food waste. Plastics are also an important input in vehicles, where their relatively light weight results in lower fuel use and greenhouse gas emissions. Plastics are widely used in infrastructure applications, where their impermeability and durability can lead to water savings in urban areas. Finally, the use of plastics rather than materials derived from biomass (e.g. wood and paper) in a range of applications could slow land-cover change and biodiversity loss.
Environmental side effects
The increasing pervasiveness of plastics has not been without drawbacks. The production and disposal of plastics is responsible for significant greenhouse gas emissions and, when poorly managed, generates plastics pollution in the natural environment. In addition, the loss of natural resources resulting from current systems of waste management represents a missed economic opportunity. For example, it is estimated that 95% of the material value of used plastic packaging, or USD 80 – 120 billion, is lost annually.
Greenhouse gas emissions
Traditional plastics production involves the transformation of petroleum or natural gas into their constituent monomers. This process is highly energy-intensive, and was estimated to account for 400 million tonnes of greenhouse gas emissions (around 1% of the global total) in 2012. The fossil fuel feedstock used in plastics production also accounts for 4 – 8% of global oil and gas production9,10 and this share could increase further in the future. The hydrocarbon molecules that are bound into the structure of plastics are initially inert, but release carbon dioxide as well as other greenhouse gases when incinerated.
Plastics pollution
The proliferation of plastics use, in combination with poor end-of-life waste management, has resulted in widespread, persistent plastics pollution. Around 6 300 million tonnes of plastics waste are thought to have been generated between 1950 and 2015, of which only 9% were recycled, and 12% incinerated, leaving nearly 80% to accumulate in landfills or the natural environment12. Plastic pollution is present in all the world’s major ocean basins, including remote islands, the poles and the deep seas, and an additional 5 to 13 million tonnes are introduced every year.
Modelling suggests that around 10% of global plastics waste generation (or 30 Mt) was mismanaged in 201015,16. G7 countries are thought to account for less than 2% of this material: around half originates in ten large emerging economies (Figure 3). This highlights the importance of improving waste collection services in middle- and low-income countries.
Once in the ocean, plastics have a number of significant economic impacts. Marine wildlife is harmed through ingestion of plastics or entanglement, with negative implications for ecosystem health and the overall sustainability of fisheries17. Coastal tourism is also affected as tourists seek to avoid beaches known to have high concentrations of plastics litter. Taken together, the economic cost of these impacts has been estimated at USD 13 billion per year18.
Plastics pollution also poses risks for human health. The presence of plastic in seafood, including fish and shellfish, and their subsequent consumption by the public has led to concerns about chemical bio-accumulation in the food chain, although empirical evidence for this is currently limited. Plastics are also entering the food chain more directly. Research has found microplastic contamination in tap water and bottled water across a number of countries and plastic contamination has also been found in sea salts.
Plastics pollution warrants considerable attention for two additional reasons. The first relates to the longevity of plastics: those that accumulate in the natural environment will only decompose over hundreds, or even thousands of years, during which time they fragment into smaller microplastics and nanoplastics. The second relates to uncertainty about the magnitude of the damages. Significant quantities of plastic have only been introduced into the natural environment relatively recently. While the full impact on marine and terrestrial ecosystems will only emerge in the longer term, some environmental effects of plastics pollution are already clearly visible.
The environmental side effects of plastics can be addressed in several ways.
1: Changes in product design, such as through the use of alternative materials in the place of plastics, could reduce the production, use, and disposal of plastics in the first instance. Changes in design practices, such as through product light-weighting, could also help to prevent the generation of plastics waste25. Shifting towards bio- based or biodegradable plastics could reduce the adverse environmental impacts of plastics more directly by reducing their environmental footprint.
2: Better waste management systems, by facilitating higher waste collection and recycling rates, would allow waste plastics to be captured before they begin creating problems in the natural environment.
3: Clean up and remediation activities, such as beach clean-ups and technology to collect plastics from oceans, would allow the removal of plastics already in the natural environment.
Each of these approaches has considerable potential, as well as a set of associated risks and costs. The use of alternative materials in the place of plastics can reduce the use of plastics, but may magnify environmental burdens elsewhere. Substituting away from plastics may also negate the use-phase energy savings (in transport for example) that plastics can bring in the first place. Shifting to bio-based or biodegradable plastics may also have unintended consequences. In particular, enhanced biodegradability can increase the dispersion of microplastic fragments in the environment if degradation is incomplete26. Finally, clean up and remediation activities can come at a significant cost and are unlikely to be effective at addressing microplastic pollution.
Higher waste collection and recycling rates are not without problems, but have the twin advantages of allowing the continued realisation of the beneficial aspects of plastics use, while also addressing the associated adverse environmental side effects. Higher recycling rates, to the extent that they are driven by the emergence of an economically sustainable recycled plastics industry, could also become a source of long-term job creation.
The greenhouse gas footprint of recycled plastics is a fraction of that of virgin plastics and high quality waste management systems reduce the risk of plastics leaking into the environment. The development of better waste management systems can also be seen as a form of “future-proofing”. Plastics production and use is projected to increase significantly in coming decades, and some proportion of this material will inevitably make its way into the environment unless waste management systems improve.
A large number of life-cycle assessments (LCAs) have been carried out on the relative environmental impacts of various options for end-of-life plastics management. Several recent meta-analyses of this body of work unambiguously conclude that plastics recycling has a significantly smaller greenhouse gas footprint than plastics incineration or landfilling. Around three quarters of the individual LCA studies assessed in WRAP31 found that the global warming potential associated with plastics recycling was, at a minimum, half of that associated with incineration or landfilling. The displacement of virgin plastics by their recycled equivalents is one important reason for the relative desirability of plastics recycling.
International co-operation
Increased international co-operation is needed to boost innovation and support improved environmental standards in fast growing markets. Governments of G7 countries can also address the barriers that hinder markets for secondary plastics through various forms of international cooperation.
First, by showcasing the public policy developments and private sector initiatives taking place in their respective countries, the G7 could help to promote the spread of best practices elsewhere. As touched upon in the Charlevoix Ocean Plastics Charter, this type of knowledge exchange could be enabled through the establishment of an international platform dedicated to plastics management.
Second, G7 countries can go beyond sharing of best practices by promoting increased international cooperation in the area of plastics management.
• G7 countries could use official development assistance to support the development of effective and environmentally sound waste collection, sorting, and recycling infrastructure, including incentives or requirements for plastics source separation. A lack of collection capacity in emerging market economies leads to a significant loss of potentially recyclable material each year and limits the scale of the market for recyclable plastics. Globally, about 2 billion people do not have access to basic waste collection services. This is a key driver of marine plastics pollution and deprives the recycled plastics industry of scale, and the cost efficiencies that potentially come with scale.
• G7 countries could promote stronger environmental standards in plastic sorting and recycling in emerging and developing countries. Convergence of environmental standards relating to material recovery would allow waste plastics to flow towards countries with a comparative cost advantage in sorting and recycling activities, thereby helping to boost global recycling rates while also generating shared economic benefits and improved environmental outcomes.
•G7 countries can co-operate to boost innovation that supports product design for reuse and recycling. This would facilitate recycling, reduce contamination in the waste stream, reduce costs, and provide better quality recycled plastic, as laid out by G7 leaders at their recent meeting in Charlevoix66. Coordinated efforts on the provision of public R&D support and incentives for the development of more efficient processing technologies could also help to lower the overall cost of material recovery activities and improve material quality. OECD can support the G7 in addressing these challenges.
OECD