19 July 2017
Tim Wallace
Past epochs of human development – the stone age, the bronze age, the iron age – are known by the dominant materials used to make tools. If future archaeologists stick to this rule they may well dub our time, based on the artefacts now being deposited in the sedimentary record, the plastic age – with the tools being throw-away items serving short-term convenience.
“Plastic waste is now so ubiquitous in the environment that it has been suggested as a geological indicator of the proposed Anthropocene era,” say the researchers behind what is credited as the first global analysis of all mass-produced plastics ever made.
Their research calculates that 8.3 billion metric tonnes of plastic has been produced in the 65 years since the beginning of the 1950s – the decade in which mass production of plastics began. About 60% of that, or 4.9 billion tonnes, has already ended up in landfill or polluting the environment.
If current production, use and waste management trends continue, the study projects the total amount of plastic dumped in landfill or polluting the natural environments by 2050 will be 12 billion tonnes – though the paper does note that a material flow analysis of this kind requires multiple assumptions or simplifications, so projections are subject to uncertainty and cannot necessarily be regarded as solid predictions.
The authors of the paper “Production, use, and fate of all plastics ever made”, published in Science Advances,
are Roland Geyer of the University of California Santa Barbara, Jenna
Jambeck of the University of Georgia, and Kara Lavender Law of the Sea
Education Association in Massachusetts.
They note that though plastic recycling has increased greatly since the 1980s (when it was virtually non-existent) its capacity to reduce future plastic waste generation depends on displacing primary plastic production; otherwise it simply delays rather than avoids final disposal.
The only certain and proven way to stop produced plastic ending up in landfill is “thermal destruction” – which has historically meant incineration with variable environmental and health impacts depending on design, management and emission controls. Emerging technologies, such as pyrolysis (extracting fuel from plastic waste) and biodigestion (using polymer-digesting organisms), offer some hope of mitigating the amount of waste in the future.
In a given year, about three-quarters of plastic produced globally is discarded, the authors’ reported numbers suggest. (The available data, they acknowledge, is limited.) While some plastic products do last decades, the biggest use of plastics is in packaging, where actual use can be measured in weeks, days, hours or even seconds.
Europe has achieved the highest plastic recycling rate (30%), followed by China (25%), with the United States lagging behind at about 9%. Waste management information for 52 other countries for 2014 indicates the rest of the world has recycling and incineration rates similar to the US.
The analysis shows plastic waste by sector use, and by polymer type.
“The growth of plastics production in the past 65 years has substantially outpaced any other manufactured material,” the authors conclude. “The same properties that make plastics so versatile in innumerable applications – durability and resistance to degradation – make these materials difficult or impossible for nature to assimilate. Thus, without a well-designed and tailor-made management strategy for end-of-life plastics, humans are conducting a singular uncontrolled experiment on a global scale, in which billions of metric tons of material will accumulate across all major terrestrial and aquatic ecosystems on the planet.”
Related reading: Australian invention to fix recycling crisis