Paper Bag or Plastic Bag: Why the Real Question Is How We Use Them

The narrator does not downplay the damage done by plastic. He describes it as a scourge for marine, terrestrial and human life. According to him, plastic is now present throughout the entire water cycle, and it literally "rains" plastic all over the planet. It is found in the air, water, soil and food, and even in human blood, livers, kidneys and brains.

When we think about the pollution caused by a plastic bag, he explains, we mostly think about its end of life: the bag left on a riverbank after a picnic. That is indeed plastic's major weakness compared with paper. But it is only part of the problem, because even before it reaches the natural environment, the bag has already generated a large share of its environmental impact.

For the polyethylene in a plastic bag, the narrator describes the steps: extracting oil, distilling it and sending it to a steam cracker, a kind of enormous furnace that reaches 800°C, to obtain ethylene. The ethylene is then polymerized, meaning its molecules are chemically rearranged, before being turned into powder or pellets. These pellets are then melted, extruded and blown. Every step requires a great deal of energy and generates pollution.

Paper is no simpler. The raw material is trees: they are cut down, the wood is transported, then reduced to chips and then to pulp. This pulp is chemically treated to remove impurities and make it stronger, then spread over large screens and dried on cylinders. The sheets are then wound into reels, cut, folded and glued to form the bags. Here too, every step consumes energy and pollutes. The narrator cites a figure: the paper industry reportedly discharges 126 billion cubic meters of wastewater every year, or 40% of the world's industrial wastewater.

One of the characters then suggests simply comparing the impact of a kilo of paper and a kilo of plastic. The narrator rejects this method. For a comparison to be meaningful, the object has to be measured against its function. A bag's function is to carry groceries from the store to your home. Yet for the same volume (he takes the example of 14 liters), it generally takes much more paper than plastic.

The narrator acknowledges paper's advantages: it relies on renewable resources and causes fewer problems at the end of its life. But, he insists, renewable does not mean zero impact. According to him, since a paper bag requires six times more material to be strong enough, most indicators show that its impact during production is far greater than that of a disposable plastic bag. He suggests, for example, that it could consume up to three times more water and emit 80 to 90% more greenhouse gases.

Should we conclude that we should throw everything out and go back to plastic? The narrator says no. For him, the question must shift to use: the real issue is not so much the material as the human tendency to throw everything away. A paper bag gets used once and thrown away because it has torn. A plastic bag also gets used once and thrown away, simply out of habit.

He then passes critical judgment on public policy. The ban on single-use plastic bags in France and Germany was hailed as a victory for the environment and, according to him, as a windfall for a paper industry that was not in great shape. But above all, he argues, it reveals policymakers' lack of big-picture thinking: replacing disposable plastic with equally disposable paper is, in his view, not the best idea.

Taking the entire life cycle into account and measuring materials against the service they provide, the narrator asserts that a good old plastic shopping bag becomes less impactful, after a few reuses, than a disposable bag, whatever its material. To decide between paper and plastic in terms of reuse, the most relevant criterion is durability. And on that point, according to him, paper is rarely able to carry groceries over the long term.

The characters then think they have found the answer: the tote bag, stylish and reusable. The narrator calls for rigor and examines its full life cycle. The material is cotton, and growing it involves water consumption, land use and pesticide use. Organic cotton is not the norm, he adds, and when it is produced, it is rarely to make tote bags.

His figures illustrate the scale of the problem. To offset the carbon footprint of a tote bag compared with that of a disposable plastic bag, it would have to be reused more than 150 times. On other indicators, such as water resource depletion, the number of reuses required could reach 5,000. In practical terms, for someone who goes grocery shopping three times a week, the same tote bag would have to be used for around thirty years to offset its impact on water. And if "disposable" plastic bags were reused three or four times, that period would rise to 90 to 120 years.

The narrator highlights one last problem: tote bags have become promotional giveaways that brands hand out to appear on as many shoulders as possible. They end up piled by the dozen in closets. Unless they are passed down from generation to generation, he says, it will be hard to ever make up for their impact.

To conclude, the narrator sums up the landscape: plastic pollutes, paper pollutes and tears, and cotton is sturdy but has a very high impact. He also mentions hybrid materials meant to imitate paper that turn out to be impossible to recycle. His general principle: the impact-free product does not exist, and the environmental relevance of a material always depends on the function it is asked to perform.

Everything therefore depends, according to him, on technical choices and the uses they lead to. A bag's design is quickly constrained by the laws of physics. Use, on the other hand, is negotiable, because it rests on societal choices that go far beyond the question of shopping bags. His final recommendation: reuse every reusable bag you already own as many times as possible.

The video ends with a return to the checkout. This time the two shoppers have a shopping bag and have even replaced meat with plant-based protein. But the cashier immediately asks them whether they want their receipt printed or sent by email. The dilemma begins again.