Remember when grocery clerks would ask this question at the checkout counter? Now stores simply default to plastic bagging. I have always assumed that plastic bags became the grocery industry’s packaging of choice because of the cost savings to the grocers. This is basically true. I have also assumed that paper bags were better for the environment. But going beneath these assumptions a little further, the environmentally sound choice between paper and plastic bags is not at all clear.
Plastic bags started to appear nationwide in the 1970s and soon captured 80% of the bag market. Walmart, one of the largest grocers in the country, does not offer paper grocery bags at all. Almost all grocery chains offer reusable bags for sale at around a dollar a pop, and these are probably a better alternative than either paper or plastic bags. But even this turns out to be debatable depending on what they are made from and how many times they are used.
There are several factors to consider when deciding whether paper or plastic bags are more environmentally friendly. First, whether the raw materials that go into the manufacture of the bag are renewable. Next, how much electricity and water are used to produce them and how much greenhouse gas is emitted in each manufacturing process. Then how readily each type of bag can be recycled. Finally, how biodegradable each type of bag is at the end of its life cycle.
On the question of renewability of resources, paper bags are the clear winner. They are made from trees. Plastic bags on the other hand are made from petroleum, which is a non-renewable resource that produces greenhouse gas when burned.
But when considering the use of resources and the release of greenhouse gas in the manufacturing process, plastic bags are the clear winner. Making a paper bag consumes four times as much energy and three times as much water as making a plastic bag. And because 1000 paper bags weigh over nine times the same number of plastic bags, transporting them also consumes more energy.
The question of recycling further adds to the muddle. While paper bags can be recycled into other paper bags, the recycling process is inefficient, often taking more energy than it would to make a new bag. Furthermore, it takes about 90% more energy to recycle a pound of paper than a pound of plastic. But plastic bags are a recycling nightmare – most curbside recycling operations are not capable of recycling these bags because the thin plastic melts and fouls the machinery. It is estimated that only 12% of plastic bags are recycled.
So plastic bags often end up in landfills, where they can sit for 500 to 1000 years. And plastic bags don’t ever “biodegrade.” Instead they “photodegrade” when exposed to light into smaller plastic particles. The more serious problem with plastic bags is that they don’t end up being disposed of properly but end up as litter. They are everywhere, fouling land and water. Plastic waste is deceptive to birds and mammals, who often mistake it for food.
So perhaps the way to avoid this bag conundrum is not to use either type of single-use bag. The reusable bags offered for sale by grocery stores are a good option – if you use them long enough. A heavy-duty plastic bag must be used five times to reduce its carbon footprint to that of a single-use plastic bag. A reusable cotton bag must be used 173 times.
Jefferson County Delegates John Doyle and Sammi Brown introduced legislation in the 2019 Legislature that would ban single-use plastic bags in West Virginia. The legislation was referred to committee, where it awaits some sort of action in the 2020 session.