Biodegradable and compostable plastic is becoming a more frequent option on store shelves as the demand for “green” products grows. Given the fact that a dump truck’s worth of plastic waste enters our oceans each minute, it’s not surprising that people are looking to use their purchasing power in ways that will presumably leave a smaller footprint.
The growing trend in plastic use is fueled by the assumption that if a product or its packaging is labeled as “biodegradable” or “compostable,” then it must be the more sustainable option. Unfortunately, that is not necessarily the case.
As the production of biodegradable plastics jumps from 1.5M metric tons to almost 5.3M in the coming years, understanding exactly how these materials are helping—or hurting—the environment is critical.
Let’s break down some of the common questions that can help clarify what biodegradable and compostable plastic mean for the environment:
What exactly is biodegradable and compostable plastic, and what is the difference between them?
Both biodegradable and compostable plastics can break down or “biodegrade” – which happens when microorganisms digest the building blocks that make up the material – but there are important differences between these two terms.
Biodegradable plastic is defined by its ability to break down completely into substances found in nature, and in a reasonable time frame. This sounds good in theory, but in practice, doesn’t often work.
While compostable plastic also biodegrades, it is specifically designed and tested to be processed in either home or industrial composting facilities. Compositing facilities enable specific conditions like temperature and moisture to turn the plastic into usable soil conditioner.
How do they play a role in helping the environment and reducing plastic waste pollution?
Biodegradable and compostable plastic alone will not solve the plastic pollution crisis. Instead, there are many levers that need to be pulled to reduce and reuse plastic and shift to a circular economy. In fact, we can’t even rely on the assumption that these materials will not cause environmental damage if they end up as litter.
All plastic—including biodegradable and compostable types—must be collected and paired with the right recovery systems, so that the material stays in the loop and out of nature.
However, for specific applications, compostable and biodegradable plastic can play a helpful role in reducing waste. Compostable take-out containers are a great example, since they can compost the remaining food residue alongside the container itself.
Additionally, biodegradable and compostable plastic is often made from biobased sources—like seaweed, sugar beets, or other plants—instead of fossil fuels. In this case, and if sourced responsibly, these materials can offer environmental benefits.
Can biodegradable and compostable plastic be bad for the environment?
Yes. If these materials are not managed properly once they become waste, then they likely will not break down as intended.
Compostable plastic must be recovered in either home or commercial compost, depending on what that specific item is designed for. Biodegradable plastic does not have defined conditions for breaking down the same way compostable plastic does, and this creates a problem.
Biodegradable plastic is tested to make sure that it breaks down under controlled conditions in a lab, including factors such as oxygen levels, UV exposure, temperatures, and others. But nature does not have controlled conditions, so it can never be certain that biodegradable plastic will actually biodegrade in the natural world if it is littered.
And when these materials do not break down, they have the very same consequences as their non-biodegradable counterparts – polluting the ecosystems and habitats that both nature and people depend on and contributing to the ballooning plastic pollution crisis.
Can I put biodegradable and compostable plastic in my home compost bin?
You can compost some materials at home; others are designed for an industrial facility. If you have a home compost pile, be sure to only put certified “home compostable” materials in it (this should be clearly labeled on the item).
If you have compost pick-up from your home, check your local program’s website to see what they accept. Many commercial composters don’t accept compostable plastic items even if they are certified as compostable.
Finally, compostable and biodegradable plastic can contaminate the recycling stream, so it’s important to check your local recycling guidelines and only recycle items that your program accepts.
In short – does it matter if we use biodegradable or compostable plastic?
The key takeaway is that both compostable and biodegradable plastic should only be used when it adds value, makes sense for the product use, and works with the systems that can recover it. We cannot rely on these materials alone to solve the problem. The companies that produce plastic products and packaging, and the people who use them, must also focus on what we know works: reducing and reusing plastic in the first place.
Read more about WWF's position on biodegradable plastic here, or check out the video to learn more: