Australia Is Smart to Ban Biodegradable Plastics

The idea of plastics that literally disappear is still very much a pipe dream.

Biodegradable plastic bag
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Australia has pledged to get serious about plastic pollution. The government released its first-ever National Plastics Plan earlier this month and it includes steps to phase out problematic plastics, maintain plastic-free beaches, support sustainable product design innovation, and shift to more easily-recycled plastics. 

There's one part of the plan that stands out, however, and that is Australia's decision to ban biodegradable plastics. It is a bold move that goes against what other places (such as China and Capri, Italy and grocery stores in Amsterdam) are doing in an attempt to wean people off petroleum-based plastics; but it is a smart one because, as research has shown, biodegradable plastic isn't much better than conventional plastic.

Biodegradable Plastic Is Not the Answer

An article in The Conversation explains, "Biodegradable plastic promises a plastic that breaks down into natural components when it’s no longer wanted for its original purpose. The idea of a plastic that literally disappears once in the ocean, littered on land or in landfill is tantalizing — but also (at this stage) a pipe dream."

This is basic physics. Nothing disappears completely. Something might dissolve, evaporate, compost, or degrade, but it doesn't just cease to exist; everything has to go somewhere. The article goes on to say,

"Many plastics labeled biodegradable are actually traditional fossil-fuel plastics that are simply degradable (as all plastic is) or even 'oxo-degradable' — where chemical additives make the fossil-fuel plastic fragment into microplastics. The fragments are usually so small they’re invisible to the naked eye, but still exist in our landfills, waterways and soils."

Plastics Today cites the Australasian Bioplastics Association's definition of degradation: "The fragmentation or breakdown of the material without micro-organic activity, leaving only smaller and smaller pieces of plastic." In other words, the plastics might break down and disappear from sight and mind, but that doesn't mean they are gone. They remain insidious in a different kind of way.

Biodegradable plastics can be made from varying ratios of plant-based material and fossil fuel-based plastic resins and synthetic additives, also known as "residue." The book "Life Without Plastic" says a so-called biodegradable bag need only contain 20% plant material in order to be labeled as such – a surprisingly low proportion.

Furthermore, biodegradable plastics require precise conditions in which to break down, such as sunlight and heat (usually at least 50 F), but often these are not met when plastics are discarded. Jacqueline McGlade, chief scientist at the UN Environment Programme, told the Guardian that reliance on biodegradable plastics is "well-intentioned but wrong." They won't break down in the ocean, either, where it's too cold and they may sink to the bottom and not get exposed to UV rays that could speed along breakdown. 

Compostable Plastics Are Troublesome, Too

Australia has said that it will work toward "100% of packaging being reusable, recyclable or compostable" by 2025 – and while the first two goals are good, the third is questionable. Compostable plastics aren't much of an improvement over biodegradable. 

While compostable plastic does have to adhere to certification standards (unlike biodegradable), most compostable plastics are designed only to break down in industrial composting facilities, which are few and far between. "Even those certified as 'home compostable' are assessed under perfect lab conditions, which aren’t easily achieved in the backyard" (via The Conversation).

It gets worse. When compostable plastics end up in landfill, they release methane, just as food waste does when it breaks down. This greenhouse gas is even more potent than carbon dioxide and is precisely what we want to avoid adding to the Earth's atmosphere right now. 

Another issue revealed in a Greenpeace report on China's shift to biodegradable plastics is that many industrial composters don't even want compostable plastics because they break down at a slower rate than organic material (kitchen waste takes six weeks) and add no value to the resulting compost. Anything that fails to degrade fully must be treated as a contaminant, so it's hardly worth the effort.

What's the Solution?

All this is to say, Australia is forging the right path by recognizing biodegradable plastic's many shortcomings right away, but it should not start pushing compostables in its place. The best solution is to rethink food and retail packaging overall and to prioritize reusables and refillables, as well as materials with high recycling rates that can be converted into an equally valuable product, such as metal and glass.

If you must choose plastics, always opt for those that contain recycled material because that drives down demand for feedstock and increases the value of recycling overall. Manufacturers would do well to label their plastic products more boldly, to make it easier for people to know what to do with them when they're finished. 

Incorrect disposal of items causes all kinds of headaches for waste management staff, not to mention the environment. The University of Technology Sydney has an interesting infographic on how to discard various kinds of plastics. It's useful for seeing how recycling can actually be worse than landfill when it comes to biodegradable plastics and that nobody should ever engage in "wishcycling" (hoping something will be recycled just because you want it to be), as this can contaminate and devalue actual recyclables.

We've got a long way to go to address the problem of single-use plastics, but Australia is moving in the right direction by recognizing biodegradables' inadequacy. As Lloyd Alter has written many times for Treehugger, "To get to a circular economy, we have to change not just the [disposable coffee] cup, but the culture." We need to rethink totally how we buy our food and carry it around.

View Article Sources
  1. "Prevention—Addressing Plastics at the Source." Australian Government Department of Agriculture, Water and the Environment.