These are terms often used to describe products that market themselves as “green” and “eco-friendly.” The truth is more complicated (as it usually is).
First, an important distinction needs to be made in terminology. Biodegradable and compostable implies that products can break down into natural elements (not necessarily that they will… but more on that later). Bioplastics are plastics derived from plant-based material instead of petroleum.
Not all bioplastics are biodegradable. Not all biodegradable plastics are bioplastics.
In 2011, Coca-Cola announced it’s PlantBottle. The first version replaced 30% fossil fuels with plant based fuels. In 2015, the announced their 100% plant based bottle. Seems exciting right, the worlds largest beverage company is going to take on plastic use and pollution… think again. The truth about the PlantBottles is that they use plant materials (cool!) to make plastic (what!?). The bottles themselves are PET, just like every other plastic bottle. If they end up in the ocean, the act just like every other plastic bottle. So what’s the big deal? The company claims that by using renewable resources the new bottle has a smaller carbon footprint than conventional bottles. These types of comparisons can be surprisingly complex, but there is evidence to suggest that bioplastics do have smaller carbon footprints. In terms of pollution potential, PlantBottles are not better than conventional bottles. They are still PET. They can still contain harmful chemicals like BPA. They are recyclable just like all PET bottles, but if lost to the environment, represent the same risks to wildlife.
Biodegradable plastics can be made from plant materials, or fossil fuel petrochemicals with additives that enhance breakdown. This breakdown requires very specific environmental conditions, especially temperature and microorganisms which are not commonly found in landfills. These products are not recyclable, which leads to endless confusion by consumers. The sad irony is that these bottles still pose the exact same threat as conventional bottles to the environment. They do not biodegrade in the ocean, and they represent the same risk to wildlife.
Possibly more troubling than the fact that these different types of plastic are just as notorious as conventional plastic is the fact that they might be making things worse. Confusion about recycling biodegradable plastics can compromise the recycling industry. Instead of focusing on reducing plastic use and consumption, these products perpetuate high usage, by insinuating that their plastics are better for the environment, and consumers shouldn’t feel guilty about buying them. In fact, they should reward themselves and go buy another. Though I commend the researchers who are tackling the issues with plastic bottles, bioplastics and biodegradable plastics are not the solution.
Read about the carbon footprint of bioplastics here
Read the report from the Plastic Pollution Coalition here