Hidden Emissions Impact

Most discussions of plastic pollution say the problem is that plastic never breaks down. A new study turns that assumption on its head, arguing the problem is that it always does – at least to some degree.

In the study, researchers introduce the concept of the “plastic particle footprint,” the mass of plastic micro- and nanoparticles that will eventually enter the environment when a given item disintegrates. Mounting evidence indicates that these plastic particles pose a risk to human and environmental health, but until now there has been no way to incorporate those concerns into standard study methodologies.

Applying their concept to four everyday manufactured objects, the researchers demonstrate how the plastic particle footprint can radically change our understanding of the sustainability of different consumer choices. “The carbon footprint only tells part of the story,” says study team member Valérie Guillard, a researcher at the University of Montpellier in France.

The plastic particle footprint is the mass of virgin plastic required to produce a given item, minus the amount of plastic that will be molecularly destroyed (such as by incineration or in the rare case of truly biodegradable plastics, by microbes) at the end of the item’s lifetime.

No one has ever proven that macro-plastics won’t crumble into micro-plastics in the medium to long term, so we must assume that they will, the researchers argue. In the long run, in other words, all plastic becomes microplastics. “The irreversibility of this pollution requires a precautionary approach,” Guillard argues.

The researchers analyzed data from published life cycle analyses of four common objects: kettles (one made of 30% plastic and another made of 50% plastic), beverage containers (glass, plastic, or aluminum with plastic liner), crates (wood or plastic), and T-shirts (cotton or polyester—a form of plastic).

When carbon footprints are comparable as in the case of the two kettles, different plastic footprints can help guide consumer choices, the researchers suggest.

The item with the smallest carbon footprint does not always have the smallest plastic footprint. A cotton T-shirt has a slightly larger carbon footprint than a polyester one—but virtually no plastic footprint. Plastic bottles and aluminum cans have smaller carbon footprints than glass bottles because they take less energy to manufacture. But glass bottles and aluminum cans have smaller plastic particle footprints. And the plastic lining inside aluminum cans can leach into beverages and be ingested by consumers – making glass bottles look better and better in the final reckoning.

Sometimes the tradeoffs are not so clear. A reusable plastic crate saves 280 grams of greenhouse gas emissions compared to a wooden one, but results in 21 additional grams of plastic particle pollution. Which is worse in the big picture? How many grams of carbon dioxide is a gram of plastic pollution worth?

In order to weigh up the choices quantitatively, future research will need to link a given mass of plastic particles to a given cost to society from health impacts and so on. The time scale of impact also requires careful thought. While the carbon footprint of items is often concentrated during the manufacture and use phases, for plastic bottles and polyester clothing more than 90% of the plastic particle footprint comes after an item is discarded. “We are building a reservoir of plastic, with a toxicity debt that future generations will inherit,” Guillard says.

https://www.anthropocenemagazine.org/2026/05/your-carbon-footprint-is-only-half-the-story/