Paper vs. Plastic Showdown

There’s a new sheriff in town—and plastic shopping bags are taking the heat. With Chicago the latest city to jump on the bandwagon of 160+ other U.S. cities (and potentially the whole of California) in outlawing plastic bags, it’s simple to assume that easy-to-recycle paper bags are the greener choice. But as the dust settles on the paper-plastic showdown, a closer look reveals the paper bag has its holes, too.

The key to understanding the good, bad, and eco-ugly of both options—and therefore making the best decision as a consumer—explains Northwestern University’s Eric Masanet, PhD, is to consider the impact of each part of the product’s life cycle from cradle to grave. “The science shows that moving from plastic to paper is not necessarily ‘greener,'” he says. Instead, it may simply shift the environmental impact from decreasing litter to increasing resource use and greenhouse gas emissions.

To really go green, he suggests committing to reusable bags, even if made from plastic. To understand why, let’s wrangle in the three main categories of impact in answering the once-inescapable checkout question, “Paper or plastic?”

Impact Category 1: Home on the Production Range

Before a plastic bag can become litter, or a paper bag can be recycled, someone’s gotta actually make the thing first, by extracting raw materials like trees and natural gas, then processing said materials in a complex system that requires resources like water and energy.

Paper bags are born in places like this riverside Maine paper mill. (Alexis Horatius)
Paper bags are born in places like this riverside Maine paper mill. (Alexis Horatius)

Trees can seem like a more benign source material than natural gas or oil. But converting hard wood into paper requires a resource-heavy pulping process, which the UK’s Environment Agency determined in its life cycle analysis (LCA) to be “significantly worse” than plastic in terms of its impact on human health and eco-toxicity (that’s LCA speak for stress on an ecosystem).

“Paper manufacturing is a highly energy-intensive process,” states the EPA’s summary of the paper industry’s environmental impact. It requires large amounts of water, energy, and chemicals, and can emit toxic and hazardous chemicals into air and water. The nation’s paper industry also generates more than 12 million tons of solid waste a year.

None of this is to say that plastic production is not also resource-heavy; it is. But, according to Masanet and an LCA expert from the University of Oregon, plastic bag production creates less greenhouse gas and uses less water and chemicals than paper.

Category 2: The Distribution Frontier

America runs on trucks…and often, so do our bags. Paper bags are five to seven times heavier than plastic, and therefore require more trucks to carry them. It’s a simple point: Heavier loads mean more trucks, which also means more air pollution.

Though this is one area where plastic gets more efficiency points, it’s important to remember it’s just one trade-off in a much more complex equation, which leads us to…

Category 3: A Million Ways Bags “Die” in the West

You don’t need to be a cowardly farmer battling a notorious gun-slinger (as Seth MacFarlane does in his latest fun flick) to know that how and where we go is kind of a big deal. The “grave” of a paper or plastic bag can mean very different things.

Go team recycling!
Three cheers for the ease of paper recycling! (D. Simmons)

Paper bags are easy to recycle, and, even if left as litter, can disintegrate so fast they won’t necessarily accumulate in the environment the way abandoned plastic bags will. Plastic litter, on the other hand, can have serious consequences, from clogging storm drains to dramatically altering ocean habitats.

But there’s another angle to consider. Because they’re stronger than paper, plastic bags have a much higher potential for reuse. A study cited in the UK LCA report cited above estimated that 76 percent of plastic shopping bags were reused at least once, often as trash bags or dog-poop bags for which we would otherwise buy new plastic bags.

Paper bag reuse is also possible to some extent, but…let’s be real: you’re not likely to want to pick up after your dog with paper, double bagged or not. The potential for reuse (and consequently reduced demand for new material) does play a role in the product’s entire life cycle impact.

Desperado for Some Conclusions

So who wins? Each industry can point to something good about their product and something bad about the other. The plastic bag scores points in resource efficiency in terms of transport and reuse. Paper gets ’em for being made with renewable material, easy recyclability and relatively short breakdown time. Masanet cautions against calling winners or losers, suggesting instead that we look at the whole picture and try to minimize the impacts that most concern you and that are most important in your area.

The upshot of plastic bag restrictions is that they could decrease the amount of plastic litter that clogs our waterways and landfills, and even make a little dent in our dependence on fossil fuel (at least the portion used to make plastic). But in terms of legislation, perhaps the most effective policy would be that which targets both paper and plastic single-use bags, like in Austin, Texas.

“It’s not black or white between paper and plastic,” concludes Masanet. And yet, one simple alternative does stand out…

Last Man Standing: Your Trusty Reusable Bag

Compared with both paper and plastic single-use bags, reusable bags are “an environmental slam dunk—if you reuse them,” says Masanet.

OGT-BYOBSurprisingly, he recommends choosing bags made with plastic over cotton, because cotton has an “enormous environmental footprint” of water, energy, and fertilizer and pesticide use. Plus, the thin recycled plastic options fit better in your purse/murse for those last-minute shopping trips.

The UK EPA report backs him up on this point, finding that reusable plastic bags only need to be reused 4-11 times, and cotton bags a whopping 131 times, to ensure they have lower global warming potential than the ultra-lightweight, single-use plastic bag.

Paper or plastic? If you still live in a place where this question is even possible, repeat after us: Neither, thanks.

Myth Outcome: Myth Busted

Paper is not necessarily greener than plastic—when you look at the full cradle-to-grave impact of both paper and plastic, you see both have significant impact on the environment. In other words, partner, it’s basically a draw. Let’s cancel the duel and ride off into the sunset—reusable bags in hand, of course.

One Green Thing

Bring reusable bags to the store to avoid the need for single-use paper or plastic altogether. If you need to buy a bag, opt for durable recycled plastic options over cotton, unless you plan to reuse the cotton bags hundreds of times.

// Widgets

One comment

  1. EcoMyth did not consider the need to greatly reduce the use of all fossil fuel based products. They only looked at the energy needed to produce paper vs plastic bags.

    They should have considered the more significant impacts of using oil (e.g., climate change and lung diseases), taking oil out of the ground (e.g., spills in drinking water like Kalamazoo River and lake Michigan, destruction of the Gulf of Mexico and Exxon Valdez) and impacts/costs of using our military, bribery and political power to control oil coming from other nations.

    These political actions will continue even if we outlawed plastic bags, but we need to begin making policies that loudly proclaim that all fossil fuel based products are extremely dangerous. I prefer renewable paper containers made from grass and other quick growing plants that are ecololically sustainable.


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