I’m going to start by simply stating that biodegradable plastics, bioplastics, and other substitutes have a lot of flaws.
They are certainly no silver bullet to the problem of plastic pollution worldwide, especially our oceans – however, they do represent significant advantages to traditional plastic in specific circumstances if we use them the right way.
Furthermore, there are multiple start ups and new technology developing in this field that either make many substitutes to conventional plastics more effective, cheaper – or they can replace one or more substitutes outright. We will talk about some of these exciting new start ups and technologies in a separate blog post!
For right now, we are going to talk about the substitutes and alternatives to conventional plastic that are available and being utilized TODAY.
The reason we feel it’s important to explore them is that we have to be realistic.
Although minimizing consumption dramatically, massive government/NGO/business cooperation and regulations/incentives etc. are likely to collectively be some of the best long-term solution for our planet – consumption trends aren’t going to drop overnight.
Similarly, single use plastic bans or other legislation could take years to implement even if successful.
Not to mention, the rise of populist presidents and prime ministers around the globe have even further diminished the hopes for significant change on this (at least in the near future) for many countries.
Sadly, we remain a society are addicted to convenience.
In order to create true and lasting change, we must be pragmatic and realize that most people aren’t going to completely change their lifestyle overnight, if at all.
Ever.
So, in our toolkit of solutions, we must have at least some solutions that allow EVERYONE (individual consumers, businesses, governments, NGO’s etc.) to assume that global plastic demand will stay similar to what it has been in the past.
Because even if substitutes and alternatives to plastics even make a small dent in reducing plastic pollution OR global CO2 emissions, it is a worthwhile endeavor.
BIODEGRADABLE PLASTIC
Let’s start with biodegradable plastics.
The best way to define biodegradable plastics (and not to confuse them with bioplastics or other substitutes), is to look at them as fairly similar to conventional plastics.
They are still non-biological and still made out of petrochemicals, however, biodegradable plastics have been engineered to break down faster and biodegrade under the right conditions.
But we have to be careful, here – especially when it comes to plastic products labeled as biodegradable, because they often don’t biodegrade easily!
Especially in our oceans!
As Jacqueline McGlade, chief scientist at the UN Environment Programme, explains to the Guardian:
“It’s well-intentioned but wrong. A lot of plastics labelled biodegradable, like shopping bags, will only break down in temperatures of 50C [122F] and that is not the ocean. They are also not buoyant, so they’re going to sink, so they’re not going to be exposed to UV and break down.”
Unfortunately, the problems with biodegradable plastics don’t end there.
Because they are made from petrochemicals, the residues they leave behind can often be toxic – for these reasons it is often extremely difficult to compost them.
Finally, if they DO break down faster in oceans (which depends largely on the amount of sunlight and oxygen present), they can still leave behind microplastics that are still non-biological and inorganic – for marine life and the environment, this is hardly better!
(If you want to learn more about microplastics, read one of our earlier posts HERE:)
However, despite all of its flaws, there are also benefits to biodegradable plastic may outweigh the negatives.
The reality is that biodegradable plastic is certainly not as landfill-friendly as it claims to be, but it can still biodegrade much faster than traditional plastic, especially under the right conditions and when made out the right materials.
And although the vast majority of biodegradable plastics won’t biodegrade that much faster than regular plastic – the few that are exposed to the proper combination of oxygen, moisture and sunlight can biodegrade quite rapidly – a difference of 3-6 months vs. 400-500 years!
The big question (which no one really knows) is: what percentage of biodegradable plastics actually biodegrades completely?
– either in landfills, or elsewhere? Is it .01%? 1%? 10%?
A bigger, much less debatable benefit would be overall energy savings.
According to Scienced.com, “Biodegradable plastics can also represent a significant energy savings. For example, the corn-based plastic polymer PLA uses 65 percent less energy than creating a similar polymer from raw petroleum.
In addition, it generates 68 percent fewer greenhouse gases during its manufacture, representing a significant environmental benefit.”
In summary, biodegradable plastics made from petroleum are excellent for energy savings when compared to conventional plastic, but overall it does little (at least with today’s technology) for future reduction of microplastics in our oceans or reducing existing plastic pollution.
BIOPLASTICS
There are also bioplastics, which are defined as plastics produced with at least 20% or more of renewable materials.
While they are used in many different market segments, they are primarily produced for various types of packaging, and this is largely due to the lack of biodegradability of traditional plastics.
Bioplastics generally consist of two types of plastic: PLA (polyactic acid) – this is generally made from the sugars in corn starch, cassava or sugarcane.
The second is PHA (polyhydroxyalkanoate) which is made by microorganisms that produce plastic from organic materials.
Unfortunately, it appears that bioplastics have some of the same problems with biodegradability as non-biological plastics that are manufactured to be biodegradable.
To truly biodegrade, they still both need to be exposed to higher temperatures that are likely not found in nature or especially any oceans!
Similar to petrochemical based biodegradable plastics, they are also unlikely to biodegrade in landfills.
Perhaps the biggest negative of bioplastics is that it requires farmland to “grow plastic” rather than grow crops for human consumption.
In addition of to the human costs and possible increases of hunger by using farmland to create bioplastics, it also takes significant resources such as water and fertilizer.
The pros when compared to petrochemical based biodegradable plastic, is of course that there are less (or in some cases, zero) petrochemicals!
It’s hard to quantify with so many different varieties, but it’s safe to say that bioplastics emit far less toxic residue in general/
And while still a grave concern, microplastics will all at least have some organic properties that one would hope affects marine wildlife and the ecosystem in a less negative way.
But here’s the main reason I’m not sold on biodegradable OR bioplastics……yet.
They risk contaminating existing batches of traditional, petrochemical based plastic in the process – because they cannot be recycled.
As explained by natural science writer, Chris Woodford, on Explainthatstuff,
“Bioplastics and biodegradable plastics cannot be easily recycled. To most people, PLA looks very similar to PET (polyethylene terephthalate) but, if the two are mixed up in a recycling bin, the whole collection becomes impossible to recycle.
There are fears that increasing use of PLA may undermine existing efforts to recycle plastics.”
Creating alternatives that reduce the effectiveness of recycling traditional plastic recycling sounds like a bad idea when traditional plastic manufacturing is at an all-time high – but the good news is, recycling rates are near an all-time high too!
CONCLUSION:
IF we can find a way to incorporate bioplastics/biodegradable plastics into our “portfolio” of solutions WITHOUT reducing traditional plastic recycling rates – the benefits likely outweigh the risks.
It’s certainly beats our outdated linear, non-sustainable system, that exists today.
We aren’t there yet – but due to some really exciting developments in new technology as well as new start ups pioneering these new materials and processes
…..we might be closer than you think!
We will discuss some of these new technologies and companies in our next blog post!
SOURCES:
https://www.sciencefocus.com/science/how-long-do-biodegradable-bags-take-to-decompose/
https://sciencing.com/benefits-biodegradable-plastic-22789.html
https://www.explainthatstuff.com/bioplastics.html
https://www.treehugger.com/ocean-conservation/great-awful-truth-about-biodegradable-plastics.html
https://www.ft.com/content/acd0e8b6-f3d2-11e8-ae55-df4bf40f9d0d