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It’s a basic question faced by millions of shoppers every day: paper or plastic? Making the best choice for the environment, however, is less simple.
Last November Californians approved Proposition 67, which upheld a 2014 ban on the issuing of single-use plastic bags in grocery and drug stores. As a result, shops were able to continue charging customers around a dime for reusable plastic or paper bags. The ban seems effective because it should lead to a reduction in plastic waste. More importantly, the extra charge aims to incentivize people to bring their own reusable bags to the store. But let’s face it, many shoppers still forget, which brings us back to that darn choice we often have to make at the checkout line.
So, which option is better?
Plastic bags were first used in the 1970s as an environmentally friendly alternative to paper. The logic was that less paper leads to less felled trees. Even better, the material used in making plastic bags, polyethylene, comes from ethane, a byproduct of natural gas extraction and a major contributor to global warming (when it’s not being frozen and used to make handy shopping bags).
The production of paper, by contrast, exacts a heavy toll on the environment. Resource-wise, apart from the trees that are lost, the entire logging process involves the use of heavy machinery that run on fossil fuels. That’s not to mention the massive amount of water required to turn pulp into paper, at a ratio of one part pulp to 400 parts water.
On that information alone, choosing plastic over paper would seem the obvious choice. But that would mean ignoring the other half of a grocery bag’s life: recycling.
“The whole point is we have to think of this in terms of the entire life cycle of our products,” Rachel Harvey, a sustainability program manager at UC Irvine and an activist who helped banish plastic bags from much of Hawaii, said, in an interview with the Orange County Register. “The recycling bin is the last stop on their chain. We want people to be more intentional on the front end of the chain.”
Harvey’s point aside, most shoppers who opt for paper likely do so due to the simple fact that paper easily decomposes. On this point, these consumers are not wrong. While it generally takes paper about a month to decompose, plastic, by contrast, only tends to break down, on average, after 20 years. Plastic is one of the world’s worst litter culprits, spreading itself far and wide, often at the great expense of wild animals and birds, particularly sea-dwellers who end up ingesting the ubiquitous marine trash.
That said, even though paper breaks down easier, it requires far more energy to recycle. For starters, paper weighs a great deal more than plastic does, resulting in tons more weight that must be processed by municipalities, and by association, a much greater expenditure of greenhouse emissions.
Taking both production and recycling into account, it becomes difficult to choose a clear winner between paper and plastic. So over the years, a number of governments have turned to the scientific method to find an answer.
In 2005, the Scottish government released a report comparing the environmental impacts of plastic and paper bags. Based on two years of inquiries involving interviews with experts and governments who had conducted similar research around the world, the government found that overall, paper tended to have “a more adverse impact than a plastic bag for most of the environmental issues considered.”
The U.K. Environment Agency, a governmental research group, conducted a similar inquiry around the same time period. Its report was a life cycle assessment comparing the environmental impacts of a variety of grocery bags. From extensive research, some of the study’s key findings concluded that:
- Single-use plastic bags outperformed all alternatives, even reusable ones, on environmental performance.
- Plastic bags have a much lower global warming potential.
- “The environmental impact of all types of bag is dominated by the resource use and production stages. Transport, secondary packaging and end-of-life management generally have minimal influence on their performance.”
- “Whatever type of bag is used, the key to reducing the impacts is to reuse it as many times as possible.”
Eric Masanet, a lead researcher in the Energy and Resource Systems Analysis Laboratory at Northwestern University reiterated these scientific findings in an article on Ecomyths Busted, saying that, “the science shows that moving from plastic to paper is not necessarily ‘greener’.”
So does Prop 67 help the environment at all? In short, yes—and no. Given California’s long coastline, a decrease in plastic litter that would otherwise end up in the ocean is an extremely positive outcome. But in order to be truly comprehensive about environmental awareness, an effective policy needs to take into account the considerable impact of paper bags. A fine example is that of Austin, Texas, where both paper and single-use plastic bags are banned. Quoted in an article on the Guardian, Reuseit.com explained that when “faced with the question of paper or plastic, the answer should always be neither.”
If you’d prefer to hear this advice more melodically, Australian comedian Tim Minchin immortalized in song this one simple piece of advice: “Take your canvas bag, take your canvas bag, take your canvas bag to the supermarket.” (As long as you make sure to use that canvas bag at least 131 times.)