Written by Richard C. Thompson OBE FRS, Professor of Marine Biology University of Plymouth
Richard C. Thompson is a marine biologist based in the United Kingdom who has been working on plastic pollution for over 30 years. He leads the International Marine Litter Research Unit at the University of Plymouth. Some of the evidence provided by his team has been key in helping define the problem of plastic pollution, in informing policy internationally and in helping to guide the way towards potential solutions.
This account is a personal reflection on the issue of plastic pollution and the pathway towards solutions:
I became concerned about the issue of plastic debris in the marine environment while training to become a scientist over 30 years ago. Working as a volunteer with the UK Marine Conservation Society to help clear some of my research sites from litter, I noticed that most items of plastic debris ending up in the environment were neither being removed nor recorded. That set me on a quest to identify the smallest bits of plastic in the ocean – the things we now call microplastics .
Over the last 30 years, my research has broadened to consider the wider environmental crisis of plastic pollution [2-4]. A large proportion of the microplastics result from larger everyday items including packaging, fishing gear , textiles [1, 6, 7] and car tyres . Hence measures addressing those larger items will be fundamental in reducing the accumulation of microplastic in the environment .
Over the last 30 years, the production of plastic has quadrupled, with a similar increase of its accumulation in the environment. Scientific reports on the problem date back to the early 1970s, with accounts of numerous fragments at the sea surface, in plankton tows and even in seabirds. By the 1980s, it was clear that hundreds of species were encountering plastic in their environment with multiple reports of harms and deaths from ingestion and entanglement . The pervasive nature of plastics and its unintentional transport to locations far from population centres, including the deep sea and the arctic became apparent [11, 12]. More recently negative effects in the form of economic harm, impacts on human health and wellbeing along the entire plastic value chain have been documented .
In the last 20 years, we have become increasingly concerned about particle and chemical toxicity associated with micro and nano plastics which are the smallest, most abundant and most biologically available forms of plastic debris. The smallest of these particles can travel from the gut to the circulatory system, yet and through the entire body of a marine creature . And there is growing evidence that this is also the case in humans . There are now thousands of scientific papers describing the problems caused by plastic entering our ocean, and a growing body of evidence in freshwater systems and on land . There is evidence of harmful effects at all levels of biological organisations from cellular to ecosystem level  and increasing evidence of the wider impacts on humans .
Plastic is central to modern life and economy [18, 19]. There will always be evidence gaps in our understanding of the harm it causes, and these could be used to argue for delays in taking the difficult and for some potentially expensive steps that are necessary to protect the environment and human health. I would argue we now have more than enough evidence to act. The evidence gaps that we still need to fill, lie more around the solutions than in defining the problem. We need to prioritise research, and funding, towards evidencing the actions needed to tackle global plastic pollution .
Scientific publications on the increasing quantity of plastics in the ocean have been instrumental in raising awareness. However, we also need to address the underlying cause why plastic accumulates in the environment: a business model that uses non-renewable fossil oil and gas in a linear way to produce plastic items which often have a very short life in service. That business model dates back to the 1950s when mass production dramatically reduced the cost of plastic items delivering the concept a of a throw away culture. Suddenly it was possible to have all types of plastic items for our brief convenience and to discard them without care. At that time, less than 5 million tonnes of plastic were being produced globally . Today, it is estimated around 460 million tonnes of plastic are produced every year and 40 percent of it is for single use applications . While these might bring momentary benefit, they will persist as litter and waste for centuries to come.
Taking a wider view, it becomes immediately clear that plastics are not cheap. On the contrary, the global environmental and human costs run into the trillions of US dollars annually, but these costs have largely been externalised from those producing, selling and using the plastic items . This lack of accountability perpetuates the unsustainable linear business model of the 1950s, while the environment and society -; especially the poor and those living in the Global South – pay the price for the externalised costs of plastic consumption. Unregulated plastic production and the resultant pollution is not a new problem nor is the understanding that it needs to be tackled. The concepts of Reduce, Reuse and Recycle originate from the Environment Day in 1970. More recently the necessity to Redesign products and practices to achieve this has been highlighted. However, production continues to increase at an ever faster pace vastly outstripping any measures to Reduce, Re-use or Recycle.
When considering the problem of plastic pollution, it is important to recognise that plastic products can bring considerable societal and environmental benefits. For example, light weight parts in cars and aeroplanes reduce carbon emissions and plastic packaging can help to reduce food waste. If used responsibly, plastics have the potential to reduce our environmental footprint on the planet and to alleviate suffering in ways that were not anticipated nearly a century ago . The solution definitely involves substantial reduction in current production and usage, but we should not try to eliminate plastics completely from our lives. For applications where plastics are the best material for the job we need to mandate responsible practices for the design, use and disposal of plastic products. Indeed, many of the benefits of plastic could be achieved without the wholesale accumulation of waste and litter in the environment and in managed systems.
The process towards a UN plastics treaty offers a momentous opportunity, giving clear consensus that over 180 nations consider current practices around design, production, use and disposal of plastic are unsustainable. It brings a mandate grounded in the decades of scientific evidence that has helped define the problem. The magnitude of evidence needed to get to this point is immense, perhaps disproportionately so in relation to the readily apparent nature, extent and scope of the problems. A regrettable consequence of this focus on defining the problem is that we lack clear evidence about the effectiveness of potential solutions .
Indeed, we know little about the details beyond reduce, re-use and recycle. Modelling and studies indicate all these strategies will be needed , but the granularity is lacking. Which products should be redesigned for re-use or for closed-loop recycling (for example, where an old plastic bottle becomes a new one)? How to do this safely without harmful side-effects? Which products do we simply not need at all? What are potential impacts of alternative materials? How do we engage consumers to embrace changes and unlock behavioural potential, and what polices are needed to facilitate this? How do outcomes vary between societal groups and nations with different cultures and waste management infrastructures [13, 20]?
Plastic products can deliver societal and environmental benefit, but failure by industry and regulators to act more swiftly on the evidence base around the negative externalities associated with production, use and disposal has resulted in the global environmental crisis we face today. Given this history, it seems almost incomprehensible to see a similar lack of due diligence, as we rush to adopt solutions that in many cases are inadequately tested. The limited evidence we have around the efficacy of solutions clearly illustrates the need for caution. The following are some examples from my team to help illustrate not all things that claim to be a solution are effective:
It is critical that we learn from the mistakes caused by inappropriate production, use and disposal of plastics in the past and take a far more cautious approach grounded in extended producer responsibility. It is an immense frustration to me that science uncovering the totally avoidable use of plastic microbeads in cosmetics  came decades after the first commercial patent was filled – did no one in the industry ever ask the question where are 100’s of thousands of tonnes of plastic microbeads going, and might they pose a risk? The transition to more sustainable practices must start now and the specific details that lie beneath the headline – Reduce Reuse Recycle and Redesign – must be guided by clear robust, independent evidence.
It is also critical to use an evidence-based approach to identify which aspects of the plastic crisis are best addressed by actions at an international rather than a national level. One example, from the work done by my team is that there are three main intervention points concerning the release of microplastic fibres from textiles: 1) increasing the availability and quality of wastewater treatment , 2) fitting filters to washing machines  and 3) reducing the rate of fibre shedding by changing fabric and yarn . All are effective to some extent. Some policy makers in the Global North tell me improving wastewater treatment and applying washing machine filters are attractive because they are easier to implement at a national scale. France is moving to mandate filters on washing machines and other countries are considering the same approach.
However, these interventions fall short compared to international measures targeted reducing the rate of fibre shedding right from the design stage. This is because 50 percent of all microfibre emissions occur while garments are being worn rather than while being washed . In addition, many of those living in the Global South do not have washing machines and advanced wastewater treatment, so these intervention points would be irrelevant for them. Meanwhile, there is clear evidence that action at the design stage could very substantially reduce fibre shedding, irrespective of the mode of release [6, 7]. Thus, international measures targeted at altering the design of textiles have the potential to address the release of microplastic fibres in a far more holistic and global manner that is decoupled from variations at a national level and from individual consumer actions.
Plastic pollution is a global environmental crisis that can be solved, and we are currently at a crossroads with opportunities to address the issue through the UN Plastic Treaty. Success will requires that political and commercial interests do not hold us back from urgent action based on the substantive body of evidence about the problem and at the same time that the urgency of the problem does not lead us act in haste by adopting ‘solutions’ that are either piece meal or not fully evaluated. UNEA 5.2 is an immense achievement – to deliver on its ambitions requires robust independent evidence from transdisciplinary research and stakeholder teams to indicate appropriate interventions. Scientific evidence is just as critical now, in guiding the way to solutions, as it was in in helping define the problems of plastic pollution.
Together we can solve this problem; but we do not have decades to turn off the tap, and the risk of unintended consequences from poor decisions is high. To work effectively and at pace, efforts must be coordinated at an international, rather than national level, and evidence synthesised and evaluated by a scientific advisory body guiding the way forward. Regrettably such a body does not currently exist, and I would urge Member States firstly to give UNEP a clear and urgent mandate to establish it and secondly to supply, what compared to the environmental and societal impacts is, the miniscule funding necessary to support it. In my view, the UN Plastic Pollution is a once in a planet opportunity, but robust independent scientific evidence will be critical to its success.