Recent studies are finding paper bags and reusable cloth totes are really not as eco-friendly, once you factor in the costs of production. And studies of population behavior in places where plastic bags are banned have found that getting rid of plastic is actually easier said than done.
It turns out that many of those grocery bags had second lives as trash-can liners and pet-waste bags. In cities where they're no longer allowed, people are turning to thicker (so, more wasteful) and more expensive purchased garbage bags.
A recent study on the effects of disposable plastic bag regulations discovered that while the various city and state regulations led to 40 million fewer pounds of plastic trash per year, that result was offset by a massive increase in sales of small plastic garbage bags. These garbage bags actually contain more plastic than disposable grocery bags do—offsetting the plastic trash reduction by 12 million pounds. While 28 million fewer pounds of plastic trash per year is a success, there are certainly still some kinks in the plan that need to be worked out.
Rebecca Taylor, Ph.D., the study's lead author, told NPR another consequence of banning plastic bags is the surge of paper trash that results. Taylor's team discovered a massive increase in paper bag usage in cities and counties banning plastic—resulting in an estimated additional 80 million pounds of paper trash per year.
Of course, the paper bags are biodegradable, which is a major plus. But after factoring in the effects of production, their place as the more eco-friendly option becomes complicated. In a few important ways, paper bags are no better—and in some cases actually worse—for the environment.
One study supported by the Scottish Environment Protection Agency noted, "It is a misconception that paper bags are environmentally friendly because they are biodegradable. The increased volume of waste and the impact of their manufacture and transportation all need to be taken into account."
While paper bags do reduce nonbiodegradable litter (yay!), the greenhouse gas emissions resulting from their production could be more hazardous (boo!). Paper bag production requires chopping down and processing trees, and that involves much more water use, a variety of toxic chemicals, more fuel and the use of heavy machinery. And unfortunately, things get even worse from there.
Ah, but what if you bring your own bags? That beats both paper and plastic, doesn't it? Well, likely not—and a lot of it depends on whether the plastic bags get reused.
One study conducted by the U.K. government found that if you're choosing a 100 percent cotton bag (which seems like the most eco-friendly option) you would have to reuse it 131 times to make it less wasteful than a disposable plastic bag—and that's if you're throwing all your plastic bags away after just one use. If you shop once a week, this means you'd need to bring your cotton bag to the store for approximately 2 1/2 years—without breaking or tearing it.
However, if you reuse your plastic bags (as trash-can liners, lunch carriers, for pet waste, as very terrible balloons, or in some other inventive way), their environmental impact drops even more. You would need to use your tote bag 327 times to have a smaller environmental impact than those reused disposable plastic bags. That's more than 6 years of weekly grocery trips.
What's even more disturbing: A Danish study from 2018 looked at the issue more comprehensively, taking into account factors besides greenhouse gas emissions—like air pollution and water use—and found you would have to use an organic cotton bag 20,000 times more than a plastic grocery bag to make it more environmentally friendly. That's approximately 384 years of weekly grocery shopping trips.
And according to the study, organic cotton bags are actually worse for the environment than nonorganic ones. The authors of the study noted, "The environmental impacts connected to the production of the organic cotton bag were considerably higher than those of the conventional cotton bag. This is due to the fact that organic cotton production does not involve the use of synthetic chemicals such as fertilizers and pesticides, which lowers the yield of the cultivation. Eventually, more resources and land are required to produce the same amount of cotton than in conventional cotton cultivation processes."
The U.K. study also found cloth reusable bags are most environmentally friendly if they're 100% cotton, because production of the starch-polyester blends often found in some reusable tote bags has significantly higher climate impacts than cotton production.
Taylor told NPR that the best thing we can do as individuals is to keep reusing the same grocery bags we have over and over—no matter their material. She also noted that banning plastic bags isn't the best way to reduce waste, and advises imposing a fee instead.
A study conducted by Taylor and a colleague at the University of California at Berkeley found that imposing small fees for plastic grocery bags is just as effective as banning them entirely, and allows those who repurpose plastic grocery bags for their trash cans or for disposing pet waste some flexibility.
Three states currently have bans on plastic bags—Hawaii, California, and New York—and many cities and counties have implemented some sort of regulation to ban or tax them in the last decade. Taylor advises extending our focus to regulating the use of paper bags as well and doing our part to reuse the bags we currently own whenever possible.