A British supermarket chain is raising the price of its reusable plastic bags as a test and introducing a paper version. Paper bags will be available in only eight Morrisons stores as part of a two-month experience. The network said the reduction of plastic was the main environmental concern of its customers.
Paper bags remain popular in the United States, but they fell into disuse in UK supermarkets in the 1970s, since plastic was seen as a more durable material.
But are paper bags more environmentally friendly than plastic bags?
Before you answer, you need to know:
- How much energy is used to make the bag?
- How durable is it? (That is, how often can it be reused?)
- How easy is it to recycle it?
- How quickly does it decompose if it is thrown away?
‘Four times more energy’
In 2011 a research paper produced by the Northern Ireland Assembly found that “four times more energy is needed to make a paper bag than to make a plastic bag.”
Unlike plastic bags (which the report says are produced from refuse from petroleum refining products), paper requires that forests be cut down. The manufacturing process, according to the survey, also produces a higher concentration of toxic chemicals compared to the manufacture of disposable plastic bags.
Paper bags also weigh more than plastic: this means that transport requires more effort, increasing their carbon footprint, the study adds.
According to the Morrisons supermarket chain, the material used to make your paper bags will be 100% from forests that are managed responsibly.
And you have to consider that if new forests are grown to replace lost trees, this will help offset the impact of climate change because trees store carbon from the atmosphere.
Durability X Impact
In 2006, the Environment Agency (EA) examined a variety of bags made from different materials to find out how many times they would need to be reused to have a contribution to global warming that a single use plastic bag.
The study found that paper bags needed to be reused at least three times, one less than durable plastic bags (which needed to be used four times).
At the other end of the spectrum, EA found that cotton bags required the greatest number of reuses, 131. This is due to the high amount of energy used to produce and enrich cotton yarn.
But even if a paper bag requires the least number of reuses, there is a practical consideration: will it last long enough to survive three trips to the supermarket?
Paper bags are not as durable as reusable plastic bags, and are more likely to tear, especially if they are wet.
In its conclusion, the British government agency says that “it is unlikely that the paper bag can be regularly reused in the required number of times due to its low durability.”
The Morrisons network insists there is no reason why its paper bag can not be reused as often as plastic, although this depends on how the bag is handled by the customer.
Cotton bags, although using more carbon in their manufacture, are the most durable and will have a much longer life.
Despite its low durability, one advantage of paper is that it decomposes much faster than plastic and therefore is less likely to be a source of litter and represents a risk to wildlife.
Paper is also more widely recyclable, while plastic bags can take between 400 and 1,000 years to decompose.
Which is better, after all?
Paper bags require a slightly smaller number of uses than reusable plastic ones to have become more environmentally friendly than disposable plastic bags.
On the other hand, paper bags are less durable than other types. Therefore, if customers have to replace their bags more often, they will cause greater environmental damage.
In addition to all these variables, the key to reducing the impact of all bags – no matter what they are made – is to reuse them as much as possible, says Margaret Bates, a professor of sustainable waste management at the University of Northampton in England.
Many people forget to take their reusable bags on weekly trips to the grocery store and end up having to buy more in the box, he says.
This will have a much greater environmental impact compared to the choice between paper, plastic or cotton.