Plastic Bags versus Paper Bags

The Existential Question That Paralyzes Hippies at the Checkout Counter

It has long been a source of discussion and contemplation whether or not to elect for a paper or a plastic bag when checking out at the grocery store. And over the years, I have always assumed that paper was the better choice, environmentally speaking. I mean, paper biodegrades and plastic does not, right? Yet, there are rumblings, even amongst environmentalists, that plastic bags have a smaller ecological impact than paper bags. So, in this blog post I will seek to better understand which option is superior from an ecological perspective.

To begin, both options have their downsides. Paper bags require more emissions to create than plastic bags, which is an upfront negative for the stability of the global climate. Plastic bags, on the other hand, can take centuries, if not thousands of years to biodegrade, all the while toxifying water, soil, air, and living beings (like whales, turtles, and people). So, how does one choose between plastic and paper bags? Let’s look at some relevant research on the matter.

According to a 2011 report created by Britain’s Environment Agency about the life cycle of plastic bags in grocery stores, a paper bag would have to be used three times for it to be as environmentally friendly as a polyethylene plastic bag. Thus, there is a larger footprint produced by paper bags to create them, when compared to single-use plastic bags. Accordingly, if one were to choose a paper bag over a plastic bag, it would need to be used three times before its environmental footprint would be considered equivalent.

Yet, it is important to consider the entire life cycle of a product, not just the embodied energy that exists in it. Human beings aren’t always good at making sure their trash ends up at the recycle center or in the dump. Sometimes our refuse ends up blowing out of trashcans in a storm, or some simply don’t have access to trash services and, therefore, litter and/or burn their trash. So, one should consider the fact that a significant portion of trash, even within the global north, never actually reaches a recycling center or a dump.

Furthermore, given that only 9 percent of plastic materials are recycled per year globally, according to the Industrial Ecologist Roland Geyer, there is a whole lot of plastic refuse that ends up going into landfills, incinerators, and into the environment. And, even if something like a plastic bag is recycled in the United States it will likely be sent to global south nations where it is not always done in a safe and ecologically sound manner, thereby finding its way into the environment (See this report for more information on this matter: https://www.theguardian.com/us-news/2019/jun/17/recycled-plastic-america-global-crisis).  Meaning, a significant portion of plastic bags put in a recycling can hold the very real potential of never being recycled and even ending up in the environment as litter.

Additionally, new research is beginning to shed light on the fact that plastics, as they degrade, emit methane and ethylene gases into the atmosphere. That means that when a plastic bag blows into a field, or some other ecosystem, it continues to emit green house gas emissions into the atmosphere. (See the relevant paper here: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0200574.) There is not sufficient data on the exact amount that degrading plastics emit, but researchers theorize that it could be significant – given the sheer volume of plastics that are created globally.

To conclude, the research that was conducted for this blog post just scratches the surface. Yet, a lot of information available suggests that paper bags, although they have a higher embodied energy to create, are a superior choice. Plastic bags require less energy to create in the beginning, but over their lifetime, which can be a very long time (thousands of years of more), are capable of polluting the atmosphere with greenhouse gases and ecosystems via the bioaccumulation of toxins. Therefore, it seems that paper bags are the superior choice. So, the next time you forget your reusable bag at the grocery store, ask for paper, and try to re-use it three times…