PARLEY AIR: Bioplastics
How ‘eco-friendly’ are bioplastics?
Traditional plastics aren’t working. The toxic material is fueling climate change and has polluted virtually every corner of the planet. It also could be making us sick. A 2020 study estimated that if we stay on the current trajectory, the amount of plastic waste being produced will triple in the next two decades. But that doesn’t have to happen.
Single use plastic bans are starting to take hold across the world, which is a great start to tackling the plastic pollution crisis. As these bans go into effect, we need alternatives. Replicating all the functions of plastic — from yogurt cups to medical devices to shoes and clothing — is difficult to do, but we’ve never had so many resources going towards eco-innovation. Bioplastics can work in many of the same ways as plastic made from fossil fuels. And they’re definitely up and coming. Although bioplastics only make up less than 1% of the plastics market, the global bioplastic market will be worth almost $44 billion by this year.
Are bioplastics better than other plastics? It depends. They’re meant to provide a sorely needed alternative to traditional plastic made from fossil fuels, but that doesn’t make them perfect. The Material Revolution is just getting started and creating actual solutions to the plastic pollution and climate change crises will require major shifts in the way we consume.
"The fact is that single-use bioplastic items are still not sustainable for the environment. The environmental cost for these items is still high given their short life time versus their environmental cost. We need to change the way we consume and use materials by making sure we use it for an extended period of time rather than throwing it away after just a few minutes."
Dr. Sarah-Jeanne Royer — Parley science advisor
The production of chemicals, including plastics, has increased 50-fold since 1950 and is expected to increase again by the same amount in the next three decades. Plastic production increased 80 percent between 2000 and 2015 alone. Today, the mass of all the plastic on this planet is twice as much as the mass of all the mammals. In a recent report, scientists found that the amount of chemical waste in our ecosystem has reached dangerously high levels for humans and the plants and animals we share Earth with.
Bioplastics are a promising step forward and a hallmark of the Material Revolution that's about to explode, but we need to tread carefully. Before we can embrace emerging "bio-materials,” we need to examine them more closely. If we don’t, we risk making the same mistakes that caused the current plastic crisis. We need truly biodegradable materials that work in harmony with nature. We also need to reimagine the systems and thinking that led us to the place we’re in now.
Here’s what you need to know about where we’re at with bioplastics now and what the future of biodegradable plastic alternatives might look like.
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WHAT ARE BIOPLASTICS
Ninety-nine percent of traditional plastic is made from ethane, a material that comes from fossil fuels. But bioplastics are made at least in part from renewable resources. These are mostly plants and biological materials, which has some scientists experimenting with everything from lobster shells to DNA from salmon sperm to create plastic alternatives.
Essentially, bioplastics use protein and carbohydrate molecules that naturally occur in some plants and algae to create flexible, sturdy plastics that can replace plastics made entirely from fossil fuels. The two most common types are polyhydroxyalkanoate (PHA), which is usually made from sugars that are grown from algae, and polylactic acid (PLA), which is made from the sugar from corn and sugarcane. Most bioplastic items will be stamped with either PHA or PLA, letting you know which one it is.
Algae like spirulina, which is at least half protein, is a particularly good renewable source of building blocks that can be used to create malleable bioplastic. This type of PHA bioplastic can fill the need for plastic-like material in medical devices but can also make single-use plastics like cups and cutlery easier on the planet. It’s also a good alternative to polyethylene terephthalate (PET), the type of fossil-fuel-based plastic most plastic bottles are made from.
The other main type of bioplastic, PLAs, are made from starchy plants like cassava and corn. The starch mimics polyethylene, the type of plastic used in plastic films, packing and bottles. It can also be formed into a safer version of styrofoam. A 2017 study estimated that switching from traditional plastic to corn-based PLA would cut U.S. greenhouse gas emissions, which are the highest in the world, by 25%. The effect could be even bigger if these bioplastics are made using renewable energy. And because PLA is often made in the same facilities that produce ethanol, it’s the cheapest source of bioplastic we have right now.
Some bioplastics are biodegradable or even compostable in industrial facilities. Under optimal conditions, microorganisms can turn a bioplastic bottle into water, carbon dioxide and compost within a few months. But not all bioplastics biodegrade. Some still need to be recycled.
AN IMPERFECT SOLUTION
No solution to the plastic pollution crisis comes without some caveats, and bioplastic is no exception. Systems aren’t yet set up for bioplastics, so a lot of it ends up in the wrong bin, in landfill or in the natural environment – including the oceans.
A detailed study published in May 2023 by Parley Science Advisor Dr. Sarah-Jeanne Royer and colleagues at UC San Diego’s Scripps Institution of Oceanography found that natural and wood-based cellulose fabrics degraded within a month when submerged off a pier at the university. Synthetic textiles, including so-called compostable plastic materials like polylactic acid (PLA), and the synthetic portions of textile blends, showed no signs of degradation even after more than a year submerged in the ocean.
Most bioplastics also won’t decompose in your backyard compost bin. They need industrial facilities that use the very specific amounts of heat and moisture the material needs to break down –– and the infrastructure isn’t quite there yet. In the U.S., only about 15% of industrial composting facilities accept some form of compostable packaging –– rather than just food scraps –– and most of these are concentrated in the largest urban areas. Canada has just one composting facility that accepts bioplastics.
“Biodegradability time is much shorter for natural materials, such as cellulose and cotton, and most bioplastics don’t degrade in natural environments at all,” says Royer. "There is a lot of greenwashing around bioplastic and these products being advertised as a sustainable replacement for single use plastics, but unless you put these materials under high pressure and high temperature conditions, they will not biodegrade and hence remain in the environment for an unlimited amount of time.”
The fact that bioplastics aren’t made from oil is a huge game-changer. But plastic alternatives, especially those made from terrestrial plants, pose some other problems. Petrochemicals used for fertilizer, which are made from traditional plastics, are still widely used in agriculture around the world. This is especially true for monoculture crops, which are needed to produce PLA, the type of bioplastic made from plants rather than algae. Increased demand for farmland to produce starchy plants for bioplastics could also add to the already rapidly expanding farmland that drives deforestation. Right now PLA only makes up around 10% of all bioplastics, but the market for bio-materials is poised to explode.
Bioplastics aren’t perfect yet, but scientists are working to develop better plastic alternatives and they’re getting close. Since PHAs are made from bacteria, they have a much smaller carbon footprint than PLAs. Some research suggests they may also break down in seawater within a few years. Other innovators are working on creating bioplastic made from seaweed that can be composed in a regular backyard bin. Seaweed is a crop that grows faster than land-based crops, doesn’t require deforestation and absorbs 20 times as much carbon as land forests. Last year, scientists also revealed a new type of bioplastic embedded with enzymes that are activated by warm, moist soil. They digest the polymers that make up the bioplastic. Thanks to the enzymes, the PLA-based plastic breaks down in regular compost in about a week.
According to Royer, if you can’t use reusables in place of single-use plastic items, products made from tree pulp or paper are better than the synthetic bioplastics available right now since they actually biodegrade: “Consumers who are concerned about plastic pollution should be mindful of the materials they are buying.”
WHAT TO DO WITH YOUR BIOPLASTICS
Because bioplastics are made from different materials, it’s really hard to determine whether a certain bioplastic should be composted or recycled, and whether or not it’s actually possible to do either with current systems. So what should you do if a bioplastic crosses your path?
First, look for a label so you can figure out what type of bioplastic it is. Bio-PE and Bio-PET are chemically very similar to PE and PET plastics, and usually still contain mostly traditional plastics, so these can be recycled normally. Coke’s PlantBottle, which still contains 70% oil-based plastic, is a Bio-PET.
Just like fossil-fuel-based plastic film, biodegradable plastic film can’t be recycled. But if it’s labeled PLA or PHA, you can route it to an industrial composting facility. The problem is, not all places have municipal composting available, so bioplastics that can only biodegrade in very controlled environments end up sticking around in landfills for hundreds of years. They can also end up in the ocean, where standard PLA and PHA won’t biodegrade.
To make sizable change, shifts need to happen on a system-wide level. Become an activist. Push for change. This can be advocating local officials to implement industrial composting facilities in your community. Or for better communication about what people should do with bioplastics from the businesses that have adopted them.
“It’s important that you have teams which represent systems thinking in every dimension, from science, design, and engineering, to environmental justice. At the education level we need to bring in more teaching around things like green chemistry. We need to be studying biology and biomaterials, nature’s materials, in order to really understand them. We need to be using the latest tools of synthetic biology to build new materials that unlock nature’s building blocks,” said Suzanne Lee, founder of Biofabricate in an interview with Parley founder Cyrill Gutsch.
“Then we want to put those building blocks together in such a way that not only have the functionality that we’re looking for, but they have the ability to break down into the units that go back into a nutritious cycle for the planet. That really is the holy grail for what so many people are looking for across lots of different sectors.”
You can also make small, sustainable changes in your own life while pushing for big change. Audit the places you can reduce plastic in your life, whether they come from bioplastics or plastics made from fossil fuels. Bioplastics still take energy (and greenhouse gases) to make and transport, so reducing and reusing should be your first plan of attack, even with plastic alternatives. If you see a coffee shop that has switched to compostable cups, push them to have stronger messaging about how to dispose of their bioplastics.
In case you missed it, here’s our realistic guide to start eliminating plastic from your daily life.
TAKE ACTION
Read up, make noise, spread the word and give others the tools to do the same. Systemic change won’t come unless we demand it.
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