By the end of this year, we may have international, legally binding rules on how to reduce plastic pollution, and not a moment too soon. This could be a game-changer in combatting global plastic pollution. The fifth, and potentially final, session is coming up in the Republic of Korea in November. We’re taking a look at why it matters, what’s next, how it’s key for soil plastics to be considered for the treaty to meet the Sustainable Development Goals.

Why the UN Plastics treaty matters

It’s no longer news that plastic pollution, from litter to nanoparticles, contaminates every corner of our planet, from the polar ice caps to deep ocean trenches. Nano-plastics are deposited from the atmosphere, contaminating soil and water globally. In small quantities, we eat, drink and breathe them, and they are found inside human tissues from the brain to the placenta. The impacts of this on people, animals, and the environments on which we depend are becoming clearer.

Much like CFCs in the atmosphere, plastic pollution has no borders. Atmospheric CFCs are now in decline, thanks to international agreement on the Montreal Protocol. Global problems need global solutions, and the plastics treaty is an historic opportunity to address this worsening crisis. What’s more, currently, low- and middle-income countries carry a disproportionate burden of plastic waste, as the responsibility for recycling is often shipped offshore by wealthier countries, to those that don’t necessarily have the infrastructure to deal with it.

The overlooked issue: microplastics in soils

The treaty is the first comprehensive effort to address plastic pollution on a global scale, aiming to tackle the entire lifecycle of plastics: production, design, usage, and disposal. Research and public attention to plastic pollution is dominated by ocean plastics, which are one vital part of the picture. Here at MINAGRIS, where we are investigating the impact of micro- and nano-plastics on agricultural soils, the treaty needs to address the equally pressing issue of land-based plastic pollution.

Image credit: Huerta Lwanga et al. 2022

The United Nations Environment Programme, leading the negotiations, has tied plastic pollution to three of the Sustainable Development Goals:

• 12: Responsible Consumption and Production.
• 13: Climate Action
• 14: Life Below Water.

However, it would be an omission to neglect SDG 15, Life on Land, in the discussions about plastic pollution. Globally, the conversation on ocean plastics has outstripped that on soils, but around 80% of ocean plastics originate on land. From here,  it travels through waterways, the atmosphere, and food chains.

MINAGRIS is working to understand the impacts of micro- and nano-plastics on soil health and productivity. Soils have a critical role in food production, carbon storage, and ecosystem health. Micro- and nano-plastics in soils can affect soil structure, water retention, nutrient cycling, and overall fertility, which has downstream effects on crop production and food security. In addition, microplastics can enter the human body through the food chain. Micro-plastics are increasingly found in human organs, with unknown long-term health consequences.

A call for a comprehensive, lifecycle approach to plastic pollution

The health of people, animals and the environments on which we depend are fundamentally interlinked, and soil plastics pose a risk to this. Now, an international group of researchers, Scientists’ Coalition for an Effective Plastics Treaty, says two decades of research have generated sufficient knowledge about the sources and effects of microplastics to allow world leaders to agree measures to address them.

Calls for a comprehensive approach to limiting plastic pollution are growing. At the previous round of negotiations, nearly 200 countries agreed that a treaty must tackle plastic pollution at every stage of its existence, from oil production and refineries to factories, shops and homes.

Reducing plastic production, redesigning materials to be more sustainable, and improving waste management infrastructure globally will all be important parts of the solution. Given the enduring nature of plastic pollution (once it is in the environment, it is very difficult to get rid of, particularly as it fragments into smaller and smaller pieces) a precautionary approach to preventing plastic pollution could arguably be justified as urgent.

The role of science in guiding the treaty

The science on the impacts of plastic pollution has evolved significantly over the past 20 years. In line with this, the United Nations have now agreed that plastics present a serious environmental issue, and have a mandate for global change. It is now important that the next stage of negotiations prioritise scientific evidence in decision-making on how to prevent and remediate plastics pollution.

Meanwhile, projects like MINAGRIS must continue to improve our understanding of the lesser-known impacts of micro- and nano- plastics. In the soil, plastics can interfere with aspects including soil water handling, crop productivity, and the microbial communities that support healthy soils. The effects of this may be far reaching but are not yet comprehensively understood. To stay up to date on our cutting-edge research on this and more, follow us on LinkedIn, Facebook, or X, and subscribe to our newsletter on our homepage here.

Looking ahead: prospects for change

At the next round of negotiations in November, the process may be challenging; countries involved will have different economic interests and capacities. Plastics currently play an important role in society; they help limit food waste and are important in medicine. They are one of the tools available to us to reduce water and pesticide use in agriculture, and they provide affordable clothes, furniture, sports equipment and technology to many.

In this sense, the picture isn’t clear. However, when we consider the impacts of plastic pollution, and the pervasive nature of micro- and nano-plastics, it quickly becomes apparent that we need to question the appropriateness of using plastic for some purposes. The costs of plastics’ affordability and convenience, which emerge in their impacts on environmental and human health, might be difficult to capture, but they are increasingly stark.

If you are an expert or institution who have read and contributed to the multidisciplinary literature on plastic pollution, you can sign the scientists’ declaration here: https://www.plasticstreaty.org/scientists-declaration/. The tide is turning on plastic pollution, but we need to remember that it’s not just the oceans that matter. Our soils, and the life they sustain, need protection too.