By Jonas Niederberger, Master in Development Studies student at Geneva Graduate Institute

Cars leave traces, not just in the air, also in the soil and ocean. Tire abrasion produces half a million tons to microplastic pollution a year in Europe alone – with consequences for the planet’s ecosystems and to human health. Yet, the root causes of the problem are still inadequately addressed. With the UN Environment Assembly’s (UNEA) resolution to negotiate an internationally binding agreement on plastics by 2024, there is a window of opportunity for the EU to take the lead by introducing harmonized testing protocols, labelling for consumers, and minimum thresholds for tire production, incentivized by the SDGs.

It is estimated that humans ingest around a credit card’s weight in plastic particles each week, and microplastics have now been detected in human placentas. Microplastic particles (less than 5 millimeters in diameter) have implications for human health, and their spread is very likely to have negative implications for terrestrial and marine ecosystems. In addition, plastic pollution is often “poorly reversible,” as weathering and fragmentation processes can make recovery impossible.

Friction in the Anthropocene

Though the plastic bag has become a symbol of plastic pollution, one highly consequential source of microplastics are tire wear particles (TWP), called TRWPs when merged with road particles. Current tires consist of 19% natural rubber and 24% synthetic polymers (plastics), as well as metal and other materials. Particles caused by the wear and tear of tires spread not only to the surrounding environment but are carried to the most remote places on the globe through waterways and by air. During its lifetime, a car tire loses around 1 kilogram of its weight through tear, and a truck tire around 8 kilograms. A busy urban highway produces as much as 9 kilograms of microplastics per kilometers daily. A study done for the European Commission in 2018 suggests more than 500,000 tons of TWP/TRWP are generated yearly in Europe alone, and the tendency is rising. Approximately one-fourth of microplastics in the world’s oceans stems from tires. Yet industry actors, citing their own studies, argue that it is premature to draw conclusions of negative effects of TWP/TRWPs.

Wicked problems

While producers and consumers, especially in the developed world, are scrambling to transition to electronic vehicles (EVs) as a possible climate-friendly alternative to fossil fuel vehicles, the tires remain the same. Regulators have focused on reducing exhaust emissions from vehicles, but paid little attention to TWP/TRWPs, to the extent that particle pollution from tires is likely to be almost 2,000 times higher than that from exhausts. EVs are generally heavier and bulkier, which also increases tire friction and TWP/TRWP emissions. TWP/TRWPs show how addressing a crisis, such as climate change, can have unintended negative consequences if not addressed holistically.

Microplastics in the SDGs?

Microplastics are invisible to the human eye, and they are not easily found in the SDGs either. Despite not being explicitly mentioned in the 2030 Agenda for Sustainable Development, adopted by the UN General Assembly (UNGA) in 2015, TWP/TRWPs still threaten the attainment of several SDG targets relating to human health (3.9), clean water (6.3), as well as the conservation of terrestrial (15.3) and marine ecosystems (14.1). This supports action through three measures.

Testing, labeling, and minimum thresholds

In May 2021, the EU introduced new labelling requirements for tires, however, these do not include indicators on abrasion of TWP/TRWPs. Considering the spread of TWP/TRWPs and their impacts on health and the environment, the EU needs to apply preventive measures to reduce TWP/TRWPs and minimize possible risks. The establishment of harmonized test protocols to measure tire abrasion should constitute the foundation of a label indicating TWP/TRWP abrasion. With a clear label consumers are sensitized on the topic and supported in making more reflected buying decisions. Legal thresholds for tire wear should also be implemented, phasing out the most polluting tires.

These measures, which can be considered a technical regulation under Annex I, paragraph 1 of the Agreement on Technical Barriers to Trade (TBT), obligate both European and non-European manufacturers to produce tires according to – and above – a certain standard if they want to sell their products on the European market. This might have positive transboundary effects on production globally, setting the groundwork for international standards. International legal precedent would not stand in the way of such labelling regulation (see US – Tuna II). The regulation can be considered to constitute a legitimate objective under TBT Article 2.2 to protect human health or safety, animal or plant life or health, or the environment. A clear label or an addition to the EU’s tire label, currently under revision, with thresholds based on a harmonized testing regime for tire wear would ensure legitimate regulatory distinction and a level playing field for all manufacturers and hence not constitute arbitrary or unjustifiable discrimination. Efforts to curb tire pollution through import prohibitions on the other hand, have proven untenable before international tribunals because of violations of the non-discrimination principle and national treatment (see Brazil – Retreaded Tyres).

The policy measures proposed must work in concert with advocacy, recycling, refitting roads to manage runoff, and gradual phase-out of older tires. Also central to change are industry efforts to address TWP/TRWPs by developing technology to capture the spread of particles, inventing new designs, and changing the chemical composition of tires. These efforts would also contribute to SDG targets 9.4 on clean and environmentally sound technologies and 12.5 on waste reduction. Although there are considerable developments in the field, broad public attention to the problem of TWP/TRWPs is needed to help catalyze urgent and comprehensive action.

This article is a result of the Spring 2022 class, ‘Law of Sustainable Development,’ Geneva Graduate Institute, taught by Dr. Charlotte Sieber-Gasser and Dr. Manuel Sanchez.