Which bag is better for the environ­ment, paper or plastic?

However, the other side claims that plastic bags are better than paper because they weigh so much less per bag that the gasoline and diesel burned to move them around (from the factory where they’re made to the stores where they’re used to your car taking your groceries home) save so much in emissions of carbon dioxide that they more than make up for the oil used to make the plastic. In addition, the production of paper bags generates 70 percent more air pollutants and 50 times more water pollutants than does the production of plas­tic bags because four times as much energy is needed to produce paper bags, and 85 times as

much is needed to recycle them. Okay, then plastic bags must be better.

Unfortunately, both sides are correct.

But how can this be? One has to be better than the other, right?

This is one of the problems with sustainability. The issues are so complex and interconnected that even the experts are having difficulty com­ing to conclusions. Customers simply want to know which is the better product to buy. Most are, overwhelmingly, interested in buying products that support their values. However, we can’t give them the information they desire because we don’t yet know it ourselves.

There may be an even better answer, though. How about no bag? Or a re­usable bag?

While some communities, such as the city of San Francisco, have begun to ban plastic bags, there’s no consensus among experts as to which is better. The ones who care most

about greenhouse gases contributing to global climate change promote the use of plastic bags simply because their weight is so much less than if we were to add up the miles traveled from manufacturing to store to your car to your home, the resulting fuel and emissions saved alone is drastic over paper bags. In contrast, those promoting paper bags point to paper be­ing biodegradable and sourced from a renew­able resource (trees). However, this is true only if the trees felled to make the bags come from well-managed forests and are actually replaced and cared for until adulthood. Likewise, bio­degrading waste is preferable to static waste, but people should know that almost nothing degrades in a landfill since it isn’t permeated by water, sunlight, and insects and bacteria that could break down the trash.

The answer isn’t easy. In fact, it’s probably a tie. If the paper bags are composted correctly and not put in a landfill, then they may be a better proposition—especially if they’re reused as many times as possible. However, most bags aren’t composted. So plastic bags, even though

it seems less intuitive, may be the better op­tion in the short run, especially as we move to reduce global levels of greenhouse gasses, like carbon dioxide.

There may be an even better answer, though. How about no bag? Or a reusable bag? Many times, stores automatically put purchases in bags, even when they’re not needed (such as when there’s only one item, or when customers already have another bag with them, or when the product itself comes in protective packag­ing—like an orange). Convenience is impor­tant but watching a grocery line for even a few minutes will show the amount of waste in bags that are used unnecessarily.

Dematerialization (see Chapter 5) teaches us that the less we use, the better. So, no bag is of­ten the best answer. This highlights one of the first principles we can rely on for progress: less is often better. However, less is a tricky word. This principle isn’t saying that we should do with less (functionality), but use less material

to deliver the same—or even better—perfor­mance. That’s the true meaning of less is more.

For a moment, consider another question: “Which is better for the environment, a paper cup or a ceramic mug?”

Finding the point at which one solution is bet­ter than another is difficult, especially when it relies on reuse. We can illustrate this with another example. At what point does it make more sense to reuse a ceramic or glass mug than constantly to use paper cups, once each?

Some would answer the ceramic mug, be­cause it can be reused, whereas the paper cup is thrown away after (usually) one use. But ceramic is notoriously energy intensive to cre­ate (particularly the firing process). Mugs and glasses require a lot of energy in their creation—much more than a single paper cup.* In order to make a fair comparison, we need to measure all sorts of factors, such as how much hot water and soap is used to wash the mugs in between use. Fortunately, someone’s already done this for us, as shown in the following

table.** The important factor here is number of uses. It would take 70 uses of the ceramic mug to offset the water, energy, and materials used in the production of paper cups. So, for a single use, the paper cup is far better. In fact, for up to 69 uses, the paper cups (all 69 of them) would be better for the environment. But, at the 71st use of a ceramic mug (and everything after that), it would be better for the environ­ment. This requires us, then, to assess where and how drink containers are used. Perhaps, for temporary, transient uses (like on an air­plane or for take-out), paper is better after all. However, wherever possible, if mugs can be reused (as in offices, homes, restaurants, and so on), they are better still.

Paper Cup

Ceramic Mug


1 use

71 uses

37 uses

* Glass is less energy intensive and much more recyclable than ceramic.

** “Paper Versus Polystyrene: A Complex Choice.” Science 251:504-505. Hocking, M. B. 1991

The lesson here is that, in order to determine which solution has less impact, we have to take into account how often it is used. Any demate­rialization of an existing product may introduce issues that can only be accounted for by ad­dressing repetitive use.

Other, similar, examples include disposable diapers versus reusable cloth diapers, and so on.

My mother (and probably yours as well) cares about the environment and wants to make good decisions when she purchases and uses things. However, like most people, she has neither the time nor the interest in becoming an expert in all of these disciplines just to make decisions in the grocery store. Nor does she have access to the data necessary to make bet­ter choices. This creates an important problem: if experts can’t agree or determine, absolutely, which choices are better, how can we expect the rest of us to?

The only answer is that designers and develop­ers, who are in a position to make evaluations

based on privileged data and decisions based on deeper understandings, need to help by em­ploying their skills at every possible step of the process. This is, perhaps, the most important contribution we can make in the world, but it’s often unsung.

Updated: September 26, 2015 — 9:50 pm