Should Cities Throw Away Plastic Bag Bans? It's Complicated

Single-use plastic bags are a scourge on the environment. Americans alone use 100 billion of them every year, according to the Center for Biological Diversity (CBD), which says it takes plastic bags 1,000 years to degrade in a landfill. And even then, plastic bags don’t break down completely. Instead, they photo-degrade, becoming microplastics that absorb toxins and continue to pollute the environment. In the meantime, birds, sea turtles, and fish routinely mistake discarded plastic bags for food, which can cause illness and death up and down the food chain.

For those reasons and many others, environmentally-conscious communities around the world have banned restaurants and retailers from using single-use plastic bags. Instead, businesses and consumers are encouraged to use recyclable paper bags or reusable cloth bags, based on the logic that they are better for the Earth.

California became the first U.S. state to pass a plastic bag ban in 2014. Since then, six more states have followed suit with statewide bans, and more than 500 municipalities in 28 states with local bans, reports PlasticBagLaws.org, a website dedicated to information about laws that limit plastic bag use.

No doubt, the architects of plastic bag bans feel they are doing right by the environment. New research from the University of Georgia (UGA), however, suggests their efforts might actually do more harm than good.

The reason is simple: Single-use plastic bags aren’t actually single-use. Although consumers don’t typically reuse them when they go shopping, they do reuse them in other ways—as wastebasket liners, for example. In communities where they don’t receive plastic bags at stores, consumers, therefore, look for alternatives. Often, that means buying small plastic garbage bags, which increases instead of decreases the population of plastic bags in landfills and the environment.

“We know there is a demand for using plastic bags, and we know, if these policies go into effect, some bags will disappear or will become more costly to get,” Yu-Kai Huang, a postdoctoral researcher at the UGA Warnell School of Forestry and Natural Resources, said in a news release. “So, we wanted to see the effectiveness of this policy in reducing bag usage overall.”

While previous studies have looked at the effect of plastic bag bans on plastic bag consumption, Huang and his colleague, Richard Woodward of Texas A&M University, wanted to look deeper. So, they measured plastic trash bag sales in counties that have plastic bag bans or taxes, then compared them to plastic trash bag sales in counties that don’t. Their findings were stark: In California, sales of 4-gallon trash bags increased by 55% to 75% in communities with bag policies, while sales of 8-gallon trash bags increased 87% to 110%. Meanwhile, sales of 13-gallon trash bags—the size typically used in kitchen trash cans—remained relatively unchanged.

The increased sales are measurable not only in dollars but also in pounds. For example, extra sales of 4-gallon trash bags caused plastic consumption to increase by 30 to 135 pounds per store per month, Huang and Woodward found. Extra sales of 8-gallon trash bags likewise caused plastic consumption to increase by between 37 and 224 pounds per store per month.

“Carryout grocery bags were substituted for similar sizes of trash bags before implementing the regulations,” Huang wrote in the study. “After the regulations came into effect, consumers’ plastic bag demand switched from regulated plastic bags to unregulated bags.”

A 2017 study by Recyc-Québec, an environmental organization based in Montreal, also suggests plastic bag bans may be problematic. Not only because they can be reused as wastebasket liners, but also because they are less energy- and material-intensive to produce.

And yet, communities shouldn’t necessarily rush to repeal their plastic bag bans. Because in high-volume stores, bans might still be able to make a positive impact. For stores that generate at least 326 carryout plastic bags per day, for example—nearly 10,000 per month—plastic bag bans do result in sending fewer plastic bags to landfills.

There's no denying that reducing plastic demand and production is the way to go to curb the larger plastic pollution problem and bag bans can be one part of the bigger solution. Still, this study spotlights how well-intentioned policies may have unforeseen drawbacks.

Concluded Huang, “There’s no clear answer for this. Whether the provided free carryout grocery bags are reused is a key to determining the overall effectiveness of the related grocery bag policies.”

Huang and Woodward’s analysis—which includes variables such as income and population density, both of which can affect the amount of trash that communities generate—appears in the journal Environmental and Resource Economics.