Bioplastics, Part 2: Full Environmental Picture

Do you know the difference between PLAs, PHAs, and PHBs? If not, you might consider reading the first post in our Bioplastics series to break down these different types.

If you’re already familiar, carry on!

Petroleum-Based vs. Plant-Based Plastics

We know that petroleum-based (traditional) plastics are inexpensive to create, lightweight, and convenient for many everyday uses. But at what cost?

Traditional plastics never fully decompose. They may technically “break down” over time, but the result is microplastics, which are still toxic to most life, like the plankton that eat it.

The problem remains, just invisible to the human eye. Plankton at the bottom of the food chain eat microplastics. You can check out Ren Kyst - got a spare afternoon? for the full, startling story.

The prospect of a bioplastic future feels promising. We love the idea of plant-based plastics. They offer big promises of sustainable production methods and compostability.

However, there are some important factors to consider.

The Bioplastic Lifecycle

We position bioplastics as more eco-friendly than traditional petroleum-based plastics. However, when we analyze the entire life cycle of these newer materials, that’s not quite the reality. A 2010 plastic life cycle study from the University of Pittsburgh suggests that bioplastic production can result in a net increase in pollutants.

First, to produce bioplastics at the scale needed to replace traditional plastics, we need extensive land. These crop fields for bioplastics technically compete with fields to grow food. So we have a choice: Bioplastics...or food crops?

Next, we use fertilizers and pesticides to grow and protect the crops. Of course, many farmers do this for our own food crops too, but bioplastics represent a need for net new crops. After harvest, chemicals transform this organic matter into bioplastics. This introduces another chemical-driven, non-biodegradable step in the production process.

Most farming and processing machinery also operate on fossil fuels. That adds to the demand for more oil, and it releases additional carbon dioxide into the atmosphere.

Recycling vs. Dumping Bioplastics

Proper recycling and sorting remains another challenge. For example, it can be relatively easy for bioplastics to accidentally mix with recycled petroleum-based PETs. We know polyethylene terephthalate, which is the same as polyester, as the plastic used for water and soda bottles.

Not all facilities have effective, strict separation methods, so this remains a risk. When dirty or accidental mixing occurs, the entire load of recyclables can be labeled as contaminated, rejected, and sent to a dump.

You can investigate the specific plastic numbers your local waste management company accepts. That at your grocery stores, try to only buy these specific plastic (or bioplastic) types.

At landfills, bioplastics are little better than traditional plastics, which take hundreds or thousands of years to biodegrade. Most landfills are not actively turned or mixed. That means that little oxygen exists in the deep piles to facilitate active composting. Believe it or not, bioplastics like PLA face a similar lifespan if not properly composted.

As a result of this slow, oxygen-deprived decomposition, bioplastics can release methane. This is just like traditional plastics and other decomposing materials do in landfills. Methane is a far more damaging greenhouse gas than carbon dioxide, so the problem grows more complicated.

Greenhouse Gas Emissions

A more recent 2017 study on greenhouse gas mitigation from bioplastics offers a rosier outlook. According to researchers, there is no net increase in carbon dioxide from bioplastics.

All plants, including those that form bioplastics, naturally absorb carbon from the atmosphere. They “exhale” oxygen, making them a beautiful compliment to us humans. When bioplastics break down, they release the same carbon dioxide that they absorbed when they grew as plants.

The study offers a relatively simple suggestion for the U.S. If we switched to corn-based PLAs, we could reduce greenhouse gas emissions 25% from our current petroleum-based plastics. Alternatively, if we continue with traditional plastics but produce them with renewable energy sources, we could reduce greenhouse gasses by 50-75%.

That’s huge.

Swap to bioplastics or produce traditional plastics in a more sustainable way, and we significantly reduce the risk of climate change.

Bringing It All Together

Clearly, there is more than meets the eye when it comes to bioplastics. They offer a promise of a cleaner, plastic-free future, but there is room to grow to support this transition.

Arguably most important is adopting the habit of reusing whenever possible. Start by replacing plastics with reusable glassware and bamboo containers. This is a minor sacrifice to convenience, and a huge step towards mitigating the risk of climate change. It’s also not that difficult to do, so long as we commit to being mindful consumers.

Next, we can start buying bioplastics, so long as our waste management companies can properly compost them. To learn more about proper composting, check out Backyard vs. Commercial Composting, the next post in our Bioplastics series.

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Our hope is to inspire people to perform their own small-scale beach cleanups whenever they visit our beautiful oceans. Every bit helps, so we hope you join the community and share your stories.

Thanks, and we’ll see you on the next wave!

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