Compostable plastics are compost.
It was disappointing to see Saahil Desai’s latest article in The Atlantic’s Planet section entitled “Compostable Plastic is Garbage.” While the general point Desai was trying to make is well intended, the research lacked rigor, leading to a distorted view of a growing compostable products industry.
Presenting factual metrics can be a powerful tool; however, presenting metrics without sources is misleading and irresponsible. Opinion articles like this, full of half-truths and headline “soundbites,” do nothing to enhance the current climate issue; they only serve to strengthen the apathy and inaction that got us to this point in the first place.
So much of the discussion around compostables is fixated on the end-of-life options; however, we see the value of compostables from a beginning-of-life perspective too, which is supported by life cycle assessment (LCA) data.
The eco-profile of corn-based Ingeo™ polylactic acid (PLA) determined that U.S. production of polypropylene produced three times more greenhouse gas (GHG) emissions than PLA per kg of polymer. Polyethylene terephthalate (PET) was an even worse offender, producing over four times more GHG emissions than PLA per kg of polymer for U.S.-based production.
Desai quotes a compost expert as saying, “Eventually, any form of compostable plastic should break down…” then references a study on single-use plastic bags placed in various environmental conditions, including sea, soil, and open air. These materials are designed to biodegrade and disintegrate in very specific environmental conditions established through aerobic microbial activity, as Zang et al. proved – not as litter in the environment.
The assertion that PLA products release methane when discarded in a landfill can be disproved with the research conducted by Kolstad et al. The fact is the degradation of PLA products in the landfill is inert and does not directly contribute to methane production.
We take particular umbrage with the labeling of polylactic acid as an “onerous” bioplastic. As a plant-based material, carbon dioxide from corn feedstock, i.e. biogenic carbon, is not released back into the environment but stored in PLA. By contrast, virgin petrochemical plastics cannot claim any biogenic carbon storage. The biogenic carbon in PLA may be released back into the atmosphere when composted, adding to the carbon stock of a compost pile, or the PLA item may continue to sequester carbon as an inert material. Additionally, with regards to compostability, PLA adheres to ASTM D6400 standards for commercial compostability, even if facilities are not available, a point Desai correctly points out.
It is undeniable that commercial composting infrastructure is lacking. The Sustainable Packaging Coalition does meticulous work monitoring the status of composting facilities across the country. This data supports our opinion that while commercial composting outlets are not very prevalent today, that doesn’t mean we should give up on compostable products. As more compostable products are sold, there will be more demand for the composting facilities to process them.
Industry organizations, advocates and public representatives are all continuing to educate themselves and decision-makers at all levels of government to emphasize the positive contributions compost and compostable products can have on climate change and waste reduction targets. California’s recent passage of SB1383, requiring mandatory organic waste collection, is evidence of that collaboration.
Like Desai, we also believe that both the materials and the composting network will improve over time. Publishing articles that more positively represent the opportunities of bio-based materials rather than highlighting the challenges of the current system will help us get there faster.
About World Centric:
World Centric is a mission-driven B Corp that aims to reduce the environmental impact of the food service industry by creating certified compostable products made from renewable plant-based materials. By utilizing plants like bamboo, sugarcane, corn, and wheat straw, they are able to use valuable renewable resources and reduce the reliance on fossil fuels to create food service packaging. World Centric also donates 25% of profits every year to communities at the intersection of extreme poverty and climate change. Since 2009, they have given over $13M to fund 260 nonprofit projects that have created change and positively impacted tens of thousands of lives.