Friday, October 02, 2020

Solving the Plastic Problem: from Cradle to Grave, to Reincarnation.

This is a write-up of a talk that I gave to the Conway Hall Ethical Society, in London, recently. It is due to be published in the Society's journal "Ethical Record", but this has been delayed due to the present Covid-19 situation.


Introduction.

It is ironic, amid the current consternation over plastic pollution, that the first synthetic plastic (a form of nitrocellulose) was intended to provide environmental protection, by reducing demand for ivory, from which billiard balls were made, although these ersatz versions would occasionally explode when struck. Indeed, it has been reported that the American inventor, John Wesley Hyatt, who introduced it for this purpose, commented that, “in spite of their tendency to catch fire, cellulose nitrate saved the elephant”.

The subsequent, and profound, incorporation of plastics into the commercial fabric of civilization, substantially contributed to its growth, and to the creation of a consumer society. Thus in 1950, a total of less than 2 million tonnes of plastics were manufactured, a tally that was estimated to have reached 464 million tonnes in 2018, and which, according to different projections, might reach 1124 million tonnes or 1900 million tonnes in 2050. The proliferation of plastic materials in society is underpinned by their durability, cheapness and ease of production, along with strength, but low mass, as compared to other materials, for example metals.

Thus, public and private transportation vehicles can now contain up to 20%, by weight, of plastic materials, and for the Boeing “Dreamliner” Jumbo Jet, the proportion is around 50%, thus allowing an expected 20% reduction in the amount of fuel needed to be burned for each flight.

As a result of unremitting media coverage, the discharge of plastic waste into the environment, particularly the oceans, is now generally accepted to be a serious global problem, as was superlatively emphasised in the final episode of the Blue Planet II series on BBC television, narrated by Sir David Attenborough, which has led to what is known as “The Blue Planet Effect”: a galvanization of action across society to curb the unnecessary use of plastic, and reduce plastic waste, particularly from packaging.

However, in 2020, so called “Covid-waste”, which includes items such as facemasks, disposable gloves and hand-sanitiser bottles, along with other means employed to deal with the pandemic, have contributed a further burden of plastic pollution.


Failure of the linear economic system.

While application of the linear economic model, which uses resources in a “take-make-dispose” manner, has generated unequalled levels of growth, it results in the production of insuperable levels of waste, and the resource production rates required to support it have risen to non-maintainable levels. As applied to plastic production, a global environmental calamity has ensued, since some 90% of the items made from plastics are for “single use”, after which they are thrown away. Of the 8.3 billion tonnes of virgin plastic, manufactured since 1950, 6.3 billion tonnes has ended up as plastic waste, of which around 79% has accumulated in landfills or in the natural environment, and in the region of 8-9 million tonnes is believed to enter the oceans annually, perhaps 2.4 million tonnes of which is delivered there by rivers.

Plastics are extremely durable, and although this makes them highly useful in a myriad of applications, they are estimated to persist in the open environment for hundreds of years, and indeed, it has been argued that plastic never fully degrades, but merely fragments into increasingly smaller pieces (microplastics, and nanoplastics) that may impact, adversely, on marine life, and which are entering and propagating up the food chain. Hence, it is not only necessary to seek solutions to the problem of plastic pollution that already exists in the environment, but to achieve a future in which further such contamination by plastic is ameliorated.

The resource depletion/plastic pollution problem may be partly mitigated via the reuse economy, which involves some degree of reusing or repurposing of items, although non-recyclable waste is still generated, while the circular economy aims to avoid the production of waste altogether, with maximum recycling as an essential component, being modelled on the way natural systems operate, such as a forest, where outputs from some processes become inputs for others, e.g. the annual leaf litter from trees is cycled into the creation of new soil, which provides a medium for new growth, and nourishes and nurtures the entire ecosystem.

Thus, we see that improved design, in all respects of our civilization, may serve to address and mitigate many of the issues, including plastic pollution, that presently confront us, acknowledging that these are not individual problems (“the world’s woes”) that can be approached in isolation, but are interrelated symptoms (“cracks in the wall”) of a broader reality of global systemic failure. Thus, the term “the changing climate” has been used, rather than ”climate change” – i.e. as driven by fossil fuel burning/global warming – to encompass the many aspects of transformation that we currently experience.


Bioplastics.

Bioplastics are more correctly termed “biobased polymers”, and have been proposed as alternatives to petroleum derived plastics. However, it can be concluded that to replace the present ca 400 million tonne annual production of largely petroleum based plastics by biobased polymers would require ca 150 million hectares of arable land, or 11% of the total available on Earth, while to thus meet a projected growth in production/demand to 1900 tonnes, by 2050, some 52% of the Earth’s arable land would need to be commandeered, leading to a serious competition between using land to grow crops for food or plastic, similar to the issue of creating first generation biofuels from land based crops (i.e. should the priority be to feed people or to fuel cars?). Polylactic acid (PLA) has attracted particular interest due to the expectation that it will degrade more rapidly in the environment than the more usual petroleum based plastics, and thus be prevented from similarly accumulating there.

However, although items made from PLA, such as tumblers for drinks, are often labelled as “100% degradable” and “100% compostable”, both descriptors may be misleading. In particular, although the term “biodegradable” means that the component polymer molecules are expected to break down eventually, under the influence of microbial action, it does not specify any definite timescale for the process, which might take very many years. Similarly, the material does not readily break down in a garden compost heap, but requires the more aggressive conditions of an industrial composting facility to be decomposed into actual “compost.”


The ubiquitous presence of microplastics.

The U.S. National Oceanic & Atmospheric Administration categorises microplastics as being less than 5 mm in diameter. Primary microplastics are plastic particles that were originally manufactured at those sizes in which they are encountered in the environment, and include microfibres from clothing, microbeads, and pellets (nurdles) from which plastic items are made. Secondary microplastics are formed by the degradation of larger plastic items, including bottles for water and other drinks, plastic bags and fishing nets. Evidence for the ubiquity of microplastic pollution is accumulating rapidly, and wherever such material is sought, it seems to be found.

Thus, microplastics have been identified in: Arctic sea ice, the air, soils, rivers, aquifers, remote maintain regions, food, drinking water, the oceans and ocean sediments, including waters and deep sea sediments around Antarctica, and within the deepest marine trenches of the Earth. They have also been detected in the bodies of animals, including humans, and as being passed along the hierarchy of food chains, up to marine top predators.


Using less plastic in the first place.

Although there are significant potentials that might be realised through technological advances, both in the manufacture of conventional plastics, and the design of items made from them (to make them more conveniently recyclable), through the introduction of biobased polymers (so long as food production is not compromised), and improved collection and recycling methods, these are all largely means to alleviate the status quo, but essentially to preserve business as usual. However, various lifecycle analyses identify the importance of reducing our demand for plastic materials per se.

Around one half of plastic waste (by mass) arises from plastic packaging, and if the 90% of all plastic items that are used once, and then thrown away, are tallied together, some 50% of the total mass of manufactured plastics is thus accounted for. The “Blue Planet Effect” has stimulated several UK supermarkets to offer plastic-free alternatives, although in some cases such “loose” fruit and vegetables are more expensive to buy than their plastic wrapped counterparts.

It has been argued that plastic packaging results in food lasting longer, with less being wasted; however, this is only necessary as part of a global/industrial food production/distribution network, and a counterargument is that it leads to more food being bought, e.g. “buy one get one free” deals, but which is often then thrown away. However, when food is grown locally, more of it tends to be eaten, and more quickly, with a reduced necessity for plastic packaging. In addition, such a more “localised” approach means that fewer vehicles are necessary, and hence less plastic is needed to fabricate their various components, along with a reduction in microplastic pollution, e.g. from tyre abrasion on road surfaces.

Campaigns to reduce waste from carrier bags (Polyethylene) and drinks bottles (PET) in Europe suggest that behavioural adjustments are possible, but plastics are such a deeply entrenched feature of our modern, consumer society that to break free from them entirely seems a remote prospect, at least without drastic changes to the fabric and mechanism of that society. Given that only 20% of global plastic waste is recycled, currently, considerable and fundamental amendments are required, and urgently, to make a real impact on eliminating plastic waste.


The future of plastics.

Despite the concern for the environment engendered by plastic pollution, which has led to a current sense of “all plastics are bad”, and the declaration of a “War on Plastic”, it is very unlikely that society can manage entirely without plastic materials, at least for the foreseeable future. The availability of cheap and diverse kinds of plastic has underpinned the growth of the consumer society, by unleashing a flood of consumer goods, e.g. the vast proliferation of mobile phones and related devices might not have occurred if they had to be made of something else, such as metals, and while plastics are indeed wonderful, they serve to drive and maintain a culture of modern consumerism. To reduce our use of plastic would necessitate fundamental changes to our behaviour and value systems. In the main, plastics would be best reserved for particular applications where they are not easily substituted for by other materials.

It has been reckoned that, in 2050, 20% of the global oil supply will be consumed by the plastic industry. Oil is needed for many other purposes, but depletion means potential problems in maintaining overall production, in particular if the fracking industry, which is currently running at a financial loss, stalls. In 1955, the American, Life Magazine, celebrated the dawn of “Throwaway Living”, but we have since learned that there is no “away” where we can throw anything. Plastics are indeed wonder-materials, and have facilitated the creation of the modern, industrialised world. However, their robustness means they degrade only slowly and poorly in the environment, and are now identified as a ubiquitous source of pollution throughout the planetary bodies of land, air and water.

The emergence of nanoplastics in the environment poses a new set of potential threats, although, as with microplastics, any human health consequences are as yet unknown, save, as indicated from model studies. Nonetheless, there are significant grounds for concern, and indeed, plastic pollution is just one element in the overall matrix of a changing climate ("the world's woes"), and must be addressed as part of an integrated consideration of how we use all resources, and the need to change our expectations, goals and lifestyles. Hence the word “reincarnation” in the title of this article, refers to a future civilization that is recast in using its resources to achieve regeneration, rather than degeneration, of the natural environment.


References.

Rhodes, C.J. (2019). Solving the plastic problem: From cradle to grave, to reincarnation. Science Progress. 102(3), 218-248. Rhodes, C.J. (2018). Plastic pollution and potential solutions. Science Progress. 101(3), 207-260.

4 comments:

Lee seung eun said...

Dear professor Chris Rhodes
Hello, My name is Seung eun and I'm a high school student in Korea.
I am interested in environmental problems and want to be an engineer.
I read your columns and I'm writing to ask for your advice.
First of all, I want to know what made you interested in environmental issues.
I also wonder why biodegradable plastics have not been commercialized.
How can I solve environmental problems?
If you give me an answer, It will help me to achieve my dream.
Thank you :)

All the best,
Seung eun

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