Jacinta Bowler
Jacinta Bowler is a science journalist at Cosmos.
They were published in the Best Australian Science Writing 2023.
This article on bioplastic first appeared in Cosmos Weekly on 8 October 2021. For more stories like this, subscribe to Cosmos Weekly.
I have a confession – I’ve started buying compostable baking paper.
I’ll be the first to admit that I don’t know if it’s any better for the environment. I just saw it in the shops and got sold by the vague promises on the packaging of helping the environment. The label doesn’t even tell me what it’s made of. Is it plastic? Bioplastic? Made of something else entirely? Simply put, I’m well out of my depth.
It feels like bioplastics and other plastic alternatives have just suddenly appeared. It’s comforting – like an old friend contacting you out of the blue. Unfortunately, it seems that the friend might be peddling a pyramid scheme.
Just having the word “bioplastic” on the label doesn’t automatically make it better for the planet. In fact, in some cases, it could be worse.
“There are people [in the packaging industry] doing really great things,” says BehaviourWorks Australia waste researcher Jenni Downes. “Then there are people who are trying to capitalise on consumer sentiment, who are just trying to sell products. That’s greenwashing.”
You might have noticed a particularly green label on your takeaway drink, or like me you might have stumbled across a new “environmentally friendly” alternative at the grocery store. But Downes explains that just having the word “bioplastic” on the label doesn’t automatically make it better for the planet. In fact, in some cases, it could be worse.
“There are two types of plastics – oil-based plastics and bio-based plastics, [the latter] made from plant materials,” she tells me.
“Neither of those necessarily determine what can happen at the end of its life.”
During the 2018/19 financial year in Australia, a million tonnes of plastic packaging was created, and only 18% of that was recovered – and even less recycled.
Plastics are made by using oil or gas, so when they do finally start to break down, they release their greenhouse gas emissions – plus any chemicals that were added during the production – back into the environment. Then there’s the amount of energy (and therefore fossil fuels) it takes to just produce the plastic in the first place.
It’s a surprise to no one that we need to be limiting our reliance on fossil fuels, and therefore using bioplastics sounds like a huge win. But just like my compostable baking paper, finding out what packaging is made of can be tricky, and not all plant-based materials are equally “green”.
“There are companies producing plastic from crops like corn starch,” Downes says. “Corn is an incredibly high-intensity product to grow. We have to pull down forests in order to grow fields of corn.
“But other companies are beginning to use existing wastes such as food scraps and sugarcane waste (bagasse), which otherwise gets thrown out, and turning that into plastic.”
Unfortunately, that little recycling symbol with a number inside doesn’t actually confirm if it’s recyclable.
Then there are the companies who are doing a more insidious form of greenwashing. Some plastics that are currently labelled as “biodegradable”, for example, are just regular old fossil-fuel-based plastics, with chemicals added to help them break down into microplastics. With limited regulations surrounding how the word “biodegradable” can be used, consumers (and the environment) end up paying the price.
The EU has already banned this type of plastic, and the Australian Government has recently launched the National Plastics Plan to try and tackle the problem. They’ll be working with industry to phase out this degradable plastic by mid-2022.
But there’s another important question to ask. When you’ve finished your takeaway milkshake in a bioplastic cup, which bin should it go in?
“There’s this disconnect between what the plastic is made from and what we can do with it at end of life,” Downes says. “It’s very confusing, as there’s no clear-cut connection between them.”
There are myriad types of plastics, all with different requirements at the “end of life” – a term meaning the time after we’ve finished using them.
First, let’s think about regular plastic recycling. Unfortunately, that little recycling symbol with a number inside doesn’t actually confirm if it’s recyclable; it just tells the manufacturer what type of plastic it is.
Downes explains that there are some plastics that have a high recycling value. These are your clear plastic water or soft drink bottles (PET – or recycling number 1) and milk bottles (HDPE or recycling number 2). High proportions of these items are being recycled, and therefore they’ll hopefully have a long life after you’ve finished drinking your lemonade or milk.
Other plastics are not as valuable and so they get melted down together and used for low-value items, or are not recycled at all.
After all that confusion, most of the time we’d still just be swapping a single-use item for a single-use item.
There are lots of different types of plastic made from oil, which can vary their recyclability, and “then there’s a very particular plastic made from fossil fuels that is actually compostable, even though it’s not made from plants”, says Downes.
“And then you have the plastics that are made from plants – some of which are compostable and some aren’t.”
What you definitely can’t do (yet) with bioplastics is recycle them. Unfortunately, they’ll just end up as waste and be sent straight to the dump.
It seems that plastic verses bioplastic is a bit of a false dichotomy. What you really have is a huge number of fossil-fuel-based plastics, with varying abilities to be recycled, and lots of different types of bioplastics, some of which are compostable and some of which need to go to landfill.
This is so confusing that Downes and her team actually created a detailed infographic of which items can go in which bin.
After all that, is there a best option here? Well, not really. If you know the plastic is low value it might be a better option to go for a “good” bioplastic, but that changes if the item can’t be composted, or you don’t have access to a composting facility.
Plus, just like my composting baking paper, you might not know from the packaging just how compostable the item really is.
According to a joint report by the Australian Organics Recycling Association and the Australasian Bioplastics Association, the only compostable plastics are those which conform to the commercial standards (AS 4736) or the home composting standards (AS 5810).
“Regardless of claims about benefits of biodegradable plastics, products that do not comply with AS 4736 should not be included in the inputs for organics recycling,” they wrote in a 2018 report.
“To do so may cause unacceptable physical contamination (small pieces of plastic, chips or film) and render the finished organics product worthless.”
After all that confusion, most of the time we’d still just be swapping a single-use item for a single-use item. As much as it would just be easier to be able to replace one disposable item with another, it’s just not always the best option.
“The real solution is to avoid single-use items as much as possible and to use reusables,” Downes says. “People go, ‘oh well, I won’t get plastic, I’ll get a paper bag or paper plates or bamboo cutlery’, and obviously when you make something from paper or bamboo you still have to grow the trees, you have to cut down those trees, you still have to process them.
“So, for example, a paper bag can actually have a greater impact than a traditional oil-based plastic bag,” she adds.
“The real solution is to avoid single-use items as much as possible and to use reusables.”
Jenni Downes
Obviously reusable items come with their own set of questions, but if you are able to use the item dozens or even hundreds of times, you’re very likely to make back any extra resources it cost to make, compared to the disposable option. Just don’t keep buying new reusable items when you forget your old ones.
This also means that despite my good intentions, my compostable baking paper is probably not the best for the planet. So today I decided to buy myself a reusable silicon baking mat. Downes suggests it should take me somewhere around 20–50 uses to be able to recoup the extra resources it takes to make.
After dinner tonight, there’ll be only 49 uses to go.
This article first appeared in Cosmos Weekly on 8 October 2021. To see more in-depth stories like this, subscribe today and get access to our weekly e-publication, plus access to all back issues of Cosmos Weekly.Subscribe now