Bioplastics and the Truth About Biodegradable Plastic

As marketable as biodegradable and compostable plastics like PLA are, there's often more to these claims than meets the eye. For example, in most cases biodegradable bioplastics will only break down in a high-temperature industrial composting facility, not your average household compost bin.
01/11/2016 11:04 am ET Updated Jan 11, 2017

Nestled within the market for consumer plastics is an ever-growing industry for bioplastics -- plastics made from plant biomass, such as corn. In an increasingly sustainability-driven world populated by more conscious consumers and green-minded individuals than ever before, this growing focus on plant-derived plastics should come as no surprise.

However, as is often the case in the world of sustainability, there is more to this conversation than many consumers are aware of. Thanks to some persistent green marketers, the true viability and environmental impacts associated with bioplastics have in many ways been obfuscated. And of the many bioplastic varieties currently on the market or in development, no variant has attracted more attention than those dubbed "biodegradable."

Durable vs. Biodegradable Bioplastics

Bioplastics can be broadly broken down into two categories: durable and biodegradable. For consumers, the differences between the two are not always clear. For instance, the PlantBottle is a durable bioplastic alternative to traditional PET bottles made by Coca-Cola. Made with up to 30 percent ethanol sourced from plant material, the PlantBottle won't decompose, but it can be recycled with traditional PET containers and bottles.

Biodegradable bioplastics on the other hand, like increasingly popular PLA (polylactic acid), are exactly as they sound: in theory, they break down naturally in the environment or may be composted. This is unique, as the vast majority of plastics today will never break down. Petroleum plastics may degrade into smaller and smaller pieces, but most won't decompose or be absorbed by the surrounding environment.

The Problems with Biodegradable Bioplastics

As marketable as biodegradable and compostable plastics like PLA are, there's often more to these claims than meets the eye. For example, in most cases biodegradable bioplastics will only break down in a high-temperature industrial composting facility, not your average household compost bin. However, this important distinction is often not made clear to consumers, who may mistakenly assume it will decompose in a reasonable time frame in their compost piles. Without giving any further instruction, telling consumers that these plastics are readily biodegradable is misleading.

This wouldn't be as much of a concern if we had a great composting infrastructure, but we don't. With only about 200 industrial composting facilities in the United States and 50 million tons of organic waste still ending up in landfills across the country each year, we are obviously ill-equipped to adequately compost any meaningful volumes of biodegradable plastic. In fact, many operational industrial composting facilities today won't even accept PLA and other biodegradable plastics -- they are seen as contamination risks.

Biodegradable plastics don't make all that much sense in a long-term context either. Plastic is a complex, highly refined synthetic material -- why create something that requires a significant amount of energy to manufacture, only to have it disappear forever into the soil? Of course, this assumes that the plastics will actually find their way to an industrial facility, which as I've pointed out, seems unlikely today.

A Better Solution

While I believe we should be skeptical of biodegradable bioplastics, a better solution might be to start adopting durable bioplastics that are made from plant materials, but can still be recycled so those valuable energy and material inputs can be kept in the production cycle longer. It also makes far more sense to build a bio-based plastic that fits into our existing infrastructure, rather than building an entirely new biodegradable plastic composting infrastructure from scratch.

Exciting innovations are being made today that could make bioplastics far more viable and the production of them more sustainable. Today, we currently do not have the land space available to grow more bioplastic feedstocks (sugarcane, corn, etc.) without cutting into farmland already used for food production. To make matters worse, bioplastic feedstocks can have a significant water footprint, and growing feedstocks like sugarcane could lead to more deforestation in tropical regions and countries like Brazil. However, recent developments in the world of vertical farming could make this less of an issue.

Still, if we hope to truly make durable bioplastics as viable as they could be, we will need to start curbing the demand for plastics overall. With less demand, the market will be in a far better place to meet demand with more contained impacts to the environment.

How do we reduce the demand for plastic? It will be an uphill battle given that we manufacture approximately 300 million tons of plastics every year across the world, but I believe it can be done. We can take the legislative approach and pressure our political leaders to ban particular plastic materials and products, and to support extended producer responsibility legislation. An educational approach may also work--if sustainability leaders, educators, environmental activists and social entrepreneurs collaborate to engage with consumers, motivating individuals to make more sustainable purchasing decisions may not be as hard as we think.

So the next time you see a plastic labeled "biodegradable," think twice before falling for the marketing. They sound great, but the sustainability claims remain questionable. On the other hand, durable bioplastics we can recirculate through the consumption and production cycle over and over again present us with a unique, far "greener" opportunity. Who knows, one day we may be able to remove petroleum from the plastic equation entirely.