Remember when grocery clerks would ask this question at the checkout counter? Now you practically have to leap over the counter to prevent your groceries from immediately going into plastic bags. 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 are both biodegradable in landfills and recyclable into other products, while plastic bags are not biodegradable and rarely recycled. 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. The principal grocers in Jefferson County – Food Lion, Martins and Walmart all default to plastic bags at the checkout counter. Paper bags are available only on request at Food Lion and Martins, which are both owned by the Dutch company Ahold Delhaize. Walmart does not offer paper grocery bags at all. One won’t find any explanation of the default to plastic bags on the websites of these chains.
All the 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. Most of these reusable bags are woven plastic of some sort.
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. Paper bag manufacturers do not typically use trees from Amazon rain forests, but rather tree farms of fast growing species. While they are growing these trees capture carbon. 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.
It is difficult to pin down exactly how much more greenhouse gas is emitted by the manufacture of paper bags than plastic bags. But it is a certainty that paper bag manufacturing is dirtier. The Sierra Club reports that you have to reuse a paper bag four times to reduce its carbon footprint to that of a plastic bag. Another study from 2008 asserts that paper bag manufacturing emits 80% more of this gas. A plastic bag manufacturer asserts that “solids” emitted into the air in the manufacture of paper bags is roughly twice what is emitted in the manufacture of a plastic bag.
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. This would lead you to think that paper is the better choice. But here is the big surprise. A paper bag that ends up in a landfill does not biodegrade much faster than a plastic one photodegrades.
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. Heavier reusable plastic bags and cotton bags also have the freight of energy and resource consumption in their manufacture and their own greenhouse gas emission problems. 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.
There might also be a political solution to the problem. Eight states—California, Connecticut, Delaware, Hawaii, Maine, New York, Oregon and Vermont—have completely banned single-use plastic bags. Some cities and localities have also instituted bans, including Montgomery County, Maryland. 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 next session.
Most likely, however, we will have to change our behavior voluntarily. That’s not to say we couldn’t use a nudge. The German grocer Aldi, which is a small player in the market, provides that nudge. That chain will happily sell you a plastic or paper bag for about 10 cents each. Aldi claims this saves them money that they return to customers in the form of lower prices. Perhaps.
But there is no doubt that Aldi’s price on single use bags acts as a tax with the predictable result of encouraging shoppers to come up with their own bags or reuse bags they have previously purchased at Aldi or elsewhere. While this approach doesn’t completely eliminate the problems associated with single-use bags, it gets us moving in the right direction without government intervention. My conservative friends like this.