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Story Publication logo November 28, 2023

The Dirty Secret of Alternative Plastics

Microplastics in the Mediterranean Sea

We’ve seen the photos: the Pacific garbage patch, turtles choking on straws, oil spills visible from...


In the three decades since it was first introduced, the plastic, coin-sized sticker you see on fruit and vegetables has become a staple of modern agriculture, imparting essential information about the grower, brand, country of origin, and even price of fresh produce as it crisscrosses the globe. The Product Look Up (PLU) label is designed to be briefly scanned then discarded, destined for landfill. There, it might last for hundreds of years, joining an endless accumulation of plastic packaging also intended to be removed after purchase and immediately jettisoned.

Like most single-use packaging, the stickers are not easily recycled. Those that don’t end up in landfill collect in the environment, and then often end up clogging up our rivers and oceans. According to the United Nations Environment Program, nearly a garbage truck and a half’s worth of plastic ends up in rivers, lakes, and oceans every minute. Eventually those plastics break down into micro and nano plastic particles that poison our air, the water we drink, and our bloodstream. Approximately 40% of all plastic produced is designed for single-use purposes, and little of it is easily recycled. Like the PLU sticker, it is used just once and then thrown away. Yet the long-term consequences are enormous: The production of plastic, 98% of which is sourced from fossil fuels, is the cause of some 10% of all global greenhouse-gas emissions.

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One proposed solution is to replace these plastics with alternatives: biodegradable utensils, compostable wrappers, plant-based bottles, and compressed-fiber plates and bowls. Theoretically, these products could seamlessly slot into existing supply chains, requiring no sacrifice on the part of consumers, who are clamoring for more sustainable options. But production is limited in scale, more expensive than conventional plastic, and it’s not yet clear that the alternatives are actually better for human and planetary health: Most plant-based plastics are, on a molecular level, identical to their fossil-fuel-sourced siblings and last just as long in the environment. Other substitutes require many of the same toxic chemical additives as conventional plastics to keep them waterproof, flexible, durable, and colorfast.

Perhaps the biggest problem is that the infrastructure to ensure these bioplastics actually biodegrade or compost is very limited. That means that despite the best intentions of manufacturers and consumers, supposedly compostable plastic bags and supposedly biodegradable single-use cutlery may be causing just as much climate damage as conventional plastics. 

The future of such plastics, as well as the role of bioplastics in the global economy, is under negotiation. In November, representatives from 162 nations converged in Nairobi, Kenya, for INC-3, the third of five planned sessions for the Intergovernmental Negotiation Committee to develop a global treaty to end plastic pollution, a kind of Paris Climate Accords for plastic. So far, the delegates have put forth a wide range of options, ranging from greater recycling capacity to a tax on manufacturers, which would go to global cleanup projects. Among the more ambitious proposals is for global production of virgin plastic to be slashed, largely through a reduction in single-use products. Treaty negotiations are scheduled to conclude at the end of 2024.

A complete ban would not be enough to end the plastic scourge, but it’s a start. A new tool developed by the University of California Santa Barbara, UC Berkeley, and the Benioff Ocean Initiative shows that a 90% reduction of single-use plastics would remove some 286 million metric tons of ocean pollution by 2050—the equivalent in water bottles stacked end-to-end would cover the distance to the sun and back nearly six times. (Marc and Lynn Benioff, who support the Benioff Ocean Science Laboratory at UC Santa Barbara, also own TIME Magazine).

The composting complication

Practically speaking, there isn’t enough global supply of alternative materials to replace the amount of single-use plastic being produced today, and that may be a good thing, says Paula Luu, project director for the Center for the Circular Economy at impact investing firm Closed Loop Partners. That’s because, while plastic alternatives show a lot of promise, it won’t be realized unless their implementation is accompanied by an upgrade of current waste-collection systems, ongoing scientific research, and policy change. “Before we do a full switchover, we really need to focus on addressing a number of different challenges, including customer education, waste-recovery infrastructure, and the economic incentives to a full transition,” says Luu. “If it’s not done thoughtfully, with a whole-system view, it could result in unintended consequences.”

France’s effort to reduce single-use plastics is a case in point. In 2022, the country banned all non-compostable PLU tags. A win for French environmentalists, however, soon became a sticky problem for produce importers: In a globalized market where produce comes from all corners of the world, one country’s ban on plastic PLU tags only really works when every other country opts to do the same.

The technology exists—multinational fruit-labeling company Sinclair, among others, has been producing them for years—but the cost is higher given how cheap plastic is. A global ban on plastic stickers would certainly encourage competition and economic incentives, leading to lower prices for compostable versions. But without widespread access to composting facilities, most of those compostable stickers would end up in landfill anyway, where they could cause even more climate damage than conventional plastic. In a well-regulated composting facility, bacteria use oxygen to break organic materials down into carbon. In a landfill’s low-oxygen environment, that material creates methane as it decomposes, a greenhouse gas 25 times more potent than carbon when it comes to trapping heat in the atmosphere.

The terms “biodegradable” and “compostable” are often misinterpreted to mean that the products will melt away in the natural environment, which is rarely the case. To meet a baseline standard of compostability, 90% of a PLU sticker, or a fork, for that matter, must break down into carbon matter within six to 24 months under carefully regulated heat and moisture conditions. But if you just tossed a supposedly biodegradable fork into your backyard, it could last almost as long as your typical plastic cutlery. In one 2019 study, researchers left compostable plastic bags buried in soil or submerged in seawater for three years as a trial. At the end, some of the bags were intact enough to carry a full load of groceries. Which means that without a dramatically ramped-up global system of collecting and processing biodegradable packaging, compostable is little better than plastic for the environment.

In the U.S., only 27% of the population has access to food waste composting programs, and only 142 out of the 201 industrial composting facilities nationwide that process food waste will accept compostable packaging as well, according to a new survey conducted by the composting website BioCycle and the Composting Consortium, a business group that promotes effective composting. That means that the country is producing far more compostable cups, plates, and take-out containers than it can actually process, says BioCycle’s editor and publisher, Nora Goldstein.

Facilities that are reluctant to take compostable packaging argue that they can’t always tell the difference between conventional plastics and compostable, and they don’t want to risk contamination. A compostable sachet of pre-washed salad greens looks just like a polyethylene produce bag, says Goldstein. “If I can’t tell the difference, and I am a composting professional, your average consumer is just as likely to throw a plastic bag in the compost as a compostable bag in the recycling.” Both are bad: When plastic ends up in compost, the facility can’t sell it, which threatens the financial viability of the project. And when compostable packaging ends up in a recycling facility, it can gum up the machinery or, depending on how it is made, taint the next batch of recycled plastic.

Plant-based doesn't necessarily mean plant-friendly

Add plant-based plastics into the mix, and you have even more problems. Polyethylene terephthalate, the PET plastic used for most soda bottles (and also in many other single-use packaging products), is usually extracted from fossil fuels, but, in a process similar to turning corn into ethanol, it can also be manufactured from plants. The plant- and fossil-fuel-based versions are chemically indistinguishable—the only way to tell the difference is through radiocarbon dating (carbon molecules extracted from fossil fuels are older than ones that come from plants)—and like conventional PET, plant-based PET can be recycled.

But when consumers see a label saying a plastic is plant-based, “One in two Americans will say, ‘Oh, this belongs in a composting bin’,” says Luu of Closed Loop Partners, which recently conducted a survey of American attitudes to plastic alternatives. In other words, consumers might think they are doing the right thing, even if half of them are putting their plant-based PET products in the wrong place. Luu believes better labeling is the answer: “Just like we universally understand the stop sign, we should immediately understand that this package is compostable because it’s tinted green or is prominently labeled. If we don’t get labeling and design right, we could be creating problems for both the recycling and the composting industries.”

Another option, says Daphna Nissenbaum, CEO and co-founder of TIPA Corp, a multinational company producing a wide range of compostable plastic films and food packaging, is to go the fully compostable PLU route, and mandate, through global standards, that all flexible plastic packaging—sandwich wrappers, zipper bags, cling film, and shopping bags, for example—goes to the compost bin. TIPA’s technology, which is licensed to manufacturers around the world, can create compostable packaging for everything from dry cleaning to granola bars. The goal is for no one to ever worry about special labels, she says. “It will be intuitive. If it’s flexible, it will go in the compost with the banana peels.” On the other hand, if it’s rigid, like a soda bottle or a yogurt pot, it should go to recycling. 

The only problem is that while TIPA’s films are compostable, they, like many other compostable products, are still made partially from fossil fuels. The technology exists to make a fully compostable, fully plant-based plastic product, but it is far more expensive than conventional plastics, and does not always work as well, especially if it is used to package food items that are acidic, or liquid, or require long-term storage. Blending plant-based and fossil-fuel sourced plastics to create a compostable product lowers the cost and improves performance.

The truth: 'Carbon is carbon'

That is the dirty secret of so-called bioplastics, says Ramani Narayan, a chemical engineering professor at Michigan State University and an expert on alternative plastics. “Carbon is carbon, it doesn’t matter where it comes from when it comes to biodegradability.”

What matters is how the long polymer chains that make the plastic, no matter the source of carbon, are configured: Insert oxygen molecules in the right place with the help of a chemical additive, and it opens the way for microbes that can accelerate decomposition. Compostability may help solve plastic pollution, but if compostable plastics are still made with fossil fuels, it does nothing to address the problem of carbon emissions.

Like conventional plastics, both plant-based and biodegradable versions—no matter their source—still need chemical additives to help with durability, fire resistance, waterproofing and colorfastness. Compressed fiber and paper plates, bowls, and cups are often lined with a plastic film to keep them from leaking. Those additives can be toxic for human health and dangerous for the environment, yet few have been studied.

Graphic by Aryn Baker and Lon Tweeten/TIME.

Pennie Lindeque, head of science for marine ecology and biodiversity at the U.K.’s Plymouth Marine Laboratory, is currently trying to do just that, investigating how the breakdown process of biodegradable plastics impacts the ocean ecosystem. Marine creatures still mistake fragments for prey, and chemicals released in the process of breaking down might have unforeseen consequences for other kinds of ocean life, including coral. “Biodegradable materials could help reduce the impacts of plastic waste in the ocean. However, we must be sure that such materials, and the chemicals they contain, do in fact demonstrate little or no impact on organisms and ecosystems,” she says. We don’t want to, as she puts it, “jump from the frying pan into the fire.”

One of the most promising plastic replacements is polyhydroxyalkanoate, or PHA, which is made by fermenting plant sugars that come from beets, corn, and other vegetable waste, or even biogas from landfill, in a process similar to brewing beer. As with other naturally-occurring polymers like silk or cellulose, PHA products degrade into nontoxic components within months. They can also be shredded, melted, and reformed into new products. Different kinds of bacteria, some naturally occurring, others specifically engineered, are used instead of chemical additives to create properties such as flexibility and transparency.

According to chemists that specialize in plastic alternatives, most conventional plastics could theoretically be replaced by PHA, but its biodegradable qualities are better suited for single-use and disposable items. That said, PHA is currently expensive and time-consuming to produce—current global capacity is 100,000 metric tons a year, compared to the 430 million metric tons of conventional plastic produced annually. And even Anindya Mukherjee, co-founder of GO!PHA, a global PHA-focused business coalition, admits that it could have other drawbacks that have yet to be discovered. Indeed, there is a glaring absence of scientific oversight for pretty much all the current alternative plastic options, he says. “Right now, anybody can say anything they want about how good their product is for the environment. There needs to be a scientific advisory board as part of the INC process, one that will regulate the development and the proliferation of alternatives. Otherwise, we will always have this problem.”

Better science plays an important role, but it is not enough, says Christina Dixon, ocean lead for the London-based Environmental Investigation Agency. To solve plastic’s underlying problem, we have to look beyond substitutes and rethink our reliance on disposable goods. “These new materials may seem like some sort of Holy Grail—walking and talking like a plastic without plastic’s impact—but all they are doing is shifting the burden somewhere else.” Instead, Dixon argues, we need to create circular systems that rely on reusable, refillable goods that last, instead of a linear trajectory from production through consumption to disposal. “Our goods should not be designed to end up in landfill, no matter what they are made of,” she says.

The alternative plastic world is a minefield, cloaked in sustainability marketing that at best is aspirational, and at worst causes as many problems as the products it is trying to replace. A ban on single-use plastics could level the playing field, allowing products that are better for the climate, for the environment, and for human health to rise to prominence. That also means questioning the very idea of disposability. That is, after all, what started all the problems in the first place. If plastic products were valuable, they probably wouldn’t end up polluting our oceans.


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