It has taken just decades for one of the most useful products ever created to compromise the integrity of the biosphere, and threaten the very fabric of life in the oceans. The international community seems finally to have woken to the scale of the threat. But will public outrage on plastics rouse politicians previously asleep at the wheel, as well as financiers and captains of industry? John Cunningham details the scale of the problem, and considers some possible solutions. 

Geologists of the future will look at the tiny toxic sliver of sediment laid down over the last eighty years of our watch and despair at our myopic stupidity. The stratigraphic record will reveal profound changes from the geological norm which bear testament to this evolutionary moment of madness. In a blink, at least in terms of geological time, humans have modified and disrupted almost every process of the biosphere. This has led to claims of a new geological epoch defined by anthropogenic impacts: the ‘Anthropocene’. The material most central to our near-complete metamorphosis of the living planet is plastic.

Public alarm over the ever-increasing impact of plastic debris in the marine environment has been growing in recent years. It has been primed by the UN Conference of the Sea, held in Malta in 2017, as well as the BBC Blue Planet 2 series and the long-running Oceans Rescue Campaign by Sky.  The dirty secret of plastic is revealed, but there remains a danger that public comprehension of the threats posed is focused merely on the shocking imagery of turtles, nets, birds and bottles. To properly understand the implications of plastics in the food chain, it is necessary to explore their nature, their forms,and how they behave and interact once in the oceans.

Zooplankton have been observed eating microplastics, demonstrating that all other marine creatures, bar the odd herbivore, do so too. Microplastics may be the least visible of marine plastics; however, their universal ‘bioavailability’ makes their impact almost immediate and perhaps the greatest cause for concern.


Hydrocarbon derivatives – plastics, in other words – drove the consumer revolution in the 1960s, permitting the rapid manufacture of an endless range of new products (many of which, consumers were previously unaware they needed). The first truly synthetic plastic, bakelite, was invented in New York in 1907. However the real revolution began in 1957 when bisphenol A (BPA), originally developed as a synthetic mimic of the female sex hormone oestrogen, was polymerised with phosgene to produce polycarbonate. This paved the way for multiple varieties of plastics with seemingly endless usefulness.

A 1950s era advertising sign displayed in a diner in Indiana, USA. Image:

Ironically, plastic once appeared the perfect solution to waste: it could convey perishable products to customers, extending shelf-life and geographical range, while replacing relatively more expensive, though considerably more benign, packaging such as glass, metal, and cardboard. Being relatively cheap, the convenience and versatility of plastics saw their range and application grow exponentially. They quickly found their way into every recess of modern life.

The effects of plastics on land may be ugly but in the marine environment, they are devastating. For as long as plastics continue to be manufactured, it is inevitable that they will end up in the sea, vectored there through multiple pathways and in a multitude of forms, from microscopic threads and beads to discarded fishing gear.

Plastic waste in the Water of Leith, collecting at Leith Docks. The visible evidence of discarded single-use plastics is shocking but this only hints at the true extent of the problem. Image: Edinburgh Greens [CC BY 2.0]

Much of the recent concern has centred round tackling the absurdity of single-use plastics. Prioritising attention to the lowest-hanging fruit in this way is understandable. But the problem as a whole is considerably more complicated and intractable. It is easy to comprehend why beaches might be less littered by plastic bottles were, for example, a deposit/return scheme to be universally employed. But it is also necessary to understand the mechanisms by which the most damaging microplastics are created, the way in which they break down and partially saturate to form a ubiquitous toxic ‘soup’, and the effect of this soup on organisms which interact with, and consume, it.

The single most useful material ever devised now threatens to become a curse for which there is no imminent remedy or detox. Plastic waste has been quietly, often invisibly, accumulating on the shores, the surface, and in the sediments of the world’s oceans for decades now. It concentrates in some of the remotest and most fragile coastal locations and forms seemingly unstoppable ‘ocean gyres’. One of these, the so-called ‘Great Pacific Garbage Patch’, at 1.6 million square kilometres, is now twice as large as France and still growing. Plastics of all shapes and types have blanketed beaches and saturated surface and sediments. Coral polyps across the tropics have developed gangrene-like symptoms due to plastic becoming trapped in their complex structures.

The ‘Pacific garbage patch map’. Image: NOAA [public domain]

Plastic bags and detritus have been discovered 10 kilometres below the Pacific in the Mariana Trench, the deepest point in all the oceans. Fragments are found suspended at all levels throughout the water column and even in the formerly ice-bound and inaccessible Arctic Ocean where large lumps of polystyrene have mysteriously appeared on isolated ice floes. Ice cores from remote areas of the Arctic reveal a historic legacy of locked-in microplastic particulates, several orders of magnitude greater than levels found even in highly contaminated waters. Shrinking and thinning Arctic sea ice threatens to release huge volumes of microplastics directly into already highly compromised ecosystems, with potentially devastating consequences.


Plastics in the form of microparticles, microbeads, microfibres, cigarette butts, bottles or bags, are routinely washed into watercourses. These all ultimately connect with the oceans, and the oceans with each other. Synthetic microfibres have been discovered embedded in the living tissue of filter feeding shellfish.

Interestingly, research points to domestic washing machines as one of the greatest sources of microfibre pollution as they flush out millions of invisible, flexible, synthetic needles during each wash cycle. The European Union has moved to ban non-recyclable plastics by 2030 but this will do little to prevent microscopic plastic fibres entering the sea through laundry. Legislation might be enacted to ensure washing machines are manufactured with built-in microfibre filters but this may be some way off. The filters used by municipal waste water treatment facilities are often incapable of removing these microscopic hairs, beads and particles, permitting them to flow directly into drains, watercourses, estuaries, and ultimately the sea.

The European Union has moved to ban non-recyclable plastics by 2030 but this will do little to prevent microscopic plastic fibres entering the sea through laundry.

Plastics have, literally, become woven into the very fabric of our society to such an extent that a plastic-free life is now almost impossible. Even tea bags are sealed with polypropylene and many otherwise recyclable products like cardboard food containers often contain hidden plastics. Contrary to the hype and regardless of the type, plastics don’t break down – they break up. Fragments of every item of plastic ever manufactured, unless incinerated, still exists in some form somewhere. The greatest impacts of marine plastic are often felt furthest from their point of origin.

Levels of microfibres in Scapa Flow, in relatively remote Orkney, were recently discovered to be similar to those found in the Forth and Clyde estuaries. The Gulf Stream, which warms and enriches the waters of the north-east Atlantic, acts as a conveyor for the plastic detritus of industrial Europe. It mops up toxic synthetic chemicals in transit before their eventual deposition on remote shores where they wreak havoc with wildlife. Lying directly in the path of the Gulf Stream, the Lofoten Islands and Svalbard off the north coast of Norway are particularly vulnerable.

Depending on tides, local currents and shore topography, plastics rapidly accumulate in certain locations. Over time, they are weathered and broken down through wave action and sunlight exposure. As the pieces become smaller, they increasingly become ‘bio-available’ to be eaten by birds, absorbed into the sediments to be ingested by worms and burrowing shellfish, or washed back out to sea.

Contrary to the hype and regardless of the type, plastics don’t break down – they break up. Fragments of every item of plastic ever manufactured, unless incinerated, still exists in some form somewhere.

Scientists have observed plastic in the intestines of over 700 marine species, including whales, seals, fish, mollusks and even microscopic zooplankton.  Filter feeding macrofauna, such as baleen whales, basking sharks and rays ingest a disproportionate quantity of plastic fragments with no means of ejecting them. Seabirds appear particularly vulnerable, with some studies indicating that amongst species like fulmars which feed exclusively at sea, 90 percent have plastic in their stomachs and intestines.

Brightly coloured plastic tops from tubes of Smarties recently recovered from remote beaches were discovered to be up to seventy years old, providing a unique timeline for their degradation. Particles from foam products, polystyrene and polypropylene rope all continue to exist in some form indefinitely. Microparticles from synthetic tyres are easily washed into drains and watercourses. According to the Scottish environmental charity Fidra, an estimated 53 billion lentil sized ‘nurdles’, the pellet-like feedstock of the plastics industry, are released into British waters annually.

Microplastics in the Azores. Image: Raceforwater [CC BY-SA 4.0]

An estimate published in Business Insider suggested 165 million tonnes of plastic could currently be in circulation in the world’s oceans. A proportion of this lies buried in the deep sediments of the abyssal plains or, in the form of rice sized grains and smaller, suspended between the surface and seabed. The remainder is either perpetually rotating, marooned on shores, or simply locked in the foodchain. The amount of plastic entering the ocean is calculated to double every ten years, with half of all plastic in the ocean appearing in the last 15 years.

It has been, and remains, very difficult to arrive at a reliable figure for the total volume of plastic in the world’s oceans. Sampling in varied sea states can produce dramatically different results. A generally accepted estimate, however, is that there are 5.25 trillion pieces of plastic in our oceans.

China, by far the world’s largest consumer of recyclable plastic, has launched a campaign against ‘Yang Laji’ (‘foreign garbage’). The Chinese ban has prompted calls for the urgent creation of an effective recycling industry throughout the developed world, and a greater focus on recyclable plastics. But new recycling infrastructure is unlikely to be operational before much further damage has been done. All in all, it seems a grim picture.


In June 2017, in the face of very powerful vested interests, the European Union moved to restrict the production and use of Bisphenol A (BPA). Of the 3.8 million tonnes of BPA produced globally, European industry consumes one-third. Highly toxic and persistent, it wreaks havoc with the endocrine systems of all exposed organisms.

A reduction in availability of BPA could act as a timely catalyst to the global plastics crisis, forcing a comprehensive transition to ecologically neutral, biodegradable bioplastics. Algal plastics can replace most of the single-use products such as bottles and food packaging. Made from sodium alginate and calcium chloride, algal plastic water bottles are currently being manufactured for €.01 per unit. The limiting factor in the universal uptake of algal containers may be manufacturing capacity as demand is expected to rapidly outstrip supply. With such a positive ecological footprint, it would make sense for all governments to actively encourage and incentivise the development of an algal plastics industry.

With such a positive ecological footprint, it would make sense for all governments to actively encourage and incentivise the development of an algal plastics industry.

In March 2013, the ecological visionary David Katz recognised the economic potential of the thousands of tonnes of plastic litter washed up on the shores of some of the world’s most impoverished nations. He established the Plastic Bank which created monetary value from recovered recyclable plastic, reducing its occurrence while providing those collecting it with economic dignity and a higher purpose. A moratorium on new fossil plastic production could add impetus to the Plastic Bank programme, and encourage the creation of an economy based upon mining the plastic which circulates in the world’s five main ocean gyres and their sub-gyres. Ocean plastic recovery craft are currently in development with recovery operations expected to accelerate in coming years.

Plastic in general, and marine plastic in particular, is now an obvious Enemy Number One and – as with the widespread institutional divestment from fossil fuels – corporate food retailers have been clamouring to pledge dates by which their products will be plastic-free. It is important to note, however, that the reaction of the plastic manufacturing industry, and its heavily subsidised twin the oil industry, has been conspicuously muted.

As the hold of the Anthropocene tightens, and what has been described as the sixth Great Extinction continues to accelerate, our species must act to avert biological catastrophe. Strategies are required to encourage the capture of existing plastic currently in circulation, perhaps locking it up permanently in roads and buildings. Civil engineers report encouraging results in testing plastic granules as a substitute for sand in concrete. Pursuing this option might also alleviate the devastating consequences of the often-unregulated extraction of building sand from alluvial deposits across the world.

Waves on North Shore Oahu, Hawaii. Image: Anthony Quintano [CC BY 2.0]

All plastics should be recyclable. Yet it is inevitable that much will still end up in the sea. Were punitive taxes applied to all plastics, and biodegradable alternatives incentivised, alternatives would be rapidly developed. Non-recyclable and single-use plastics must be banned outright or taxed into extinction. Binding legislation should be enacted to ensure effective recycling of mixed plastic products. At the same time, financial and tax incentives would encourage the development and use of genuinely biodegradable alternatives.

Algal bioplastics, as we have seen, are rapidly emerging as the holy grail of alternatives. There are no limitations on the supply of feedstock for the algal plastic industry, especially if it comes from seaweed aquaculture. Indeed, cultivating seaweed has a positive environmental impact, sequestrating marine and atmospheric carbon as it grows, as well as resulting in a corresponding decrease in the need for hydrocarbon extraction. Not only the ideal choice, in other words, but the only rational choice.

The Great Disruption our species has precipitated comes from our failure to observe that our linear economies do tremendous damage and are not sustainable.

Governments must do more – and they must adopt a more holistic approach. The UK government stands accused of hypocrisy for promoting ambitious recycling targets in Westminster while opposing them in Brussels. Norway, with a highly effective deposit /return scheme, leads the European field in the importation of plastic for incineration. Oslo alone burns 410,000 tonnes of plastic annually – 45,000 tonnes of this coming from Britain. There are 420 similar waste–to-energy facilities currently operational throughout Europe. However, since it is composed of solid fossil hydrocarbons, the incinerated plastic is seamlessly transformed into greenhouse gasses, adding further to climate destabilisation.

For its part, the Scottish government has undertaken to ban all single-use plastics by 2030, in line with the EU pledge. As Frans Timmerman, vice-president of the European Commission has said: “single-use plastics take five seconds to produce, are used for five minutes and take five hundred years to break down. If we don’t change, by 2050 there will be more plastic in the oceans than fish”.

Plastics already in marine circulation will continue to poison the food chain for generations. Their effects will haunt our grandchildren unless a comprehensive international programme of retrieval is undertaken. The Great Disruption our species has precipitated comes from our failure to observe that our linear economies do tremendous damage and are not sustainable. If we are to stand any chance of developing economic models with no negative environmental impact, we must embrace one golden rule: ‘all economies must be circular’.

John Cunningham is a veteran photojouranlist and writer of 18 years standing, specialising in marine issues. His work has taken him from the Barents to Bearing seas, and to the Southern Ocean. John studied Geography and Marine Science at the University of Glasgow and is the Marine Science Editor of the pan Atlantic, pan Arctic JoNAA Magazine. He resides on a croft in the Outer Hebrides and aspires to be a seaweed farmer.

Feature image: NOAA [public domain].