As more and more retailers pledge to replace plastic bags for paper ones, you could be forgiven for believing that we are becoming more environmentally friendly. But is replacing plastic bags really a good thing? Not necessarily, according to the Environment Agency.
Research shows that it takes more than four times as much energy to manufacture a paper bag as it does to manufacture a plastic one. Whereas plastic bags are produced from the waste products of oil refining, paper bags require forests to be cut down to be produced. Whether or not the wood comes from responsibly managed forests, the manufacturing process produces a higher concentration of toxic chemicals compared with making single-use plastic bags. Paper bags also weigh more than plastic which means transportation requires more energy, thereby adding to their carbon footprint.
Fans of the paper bag claim that an increase in paper bag use will result in more trees being planted. This will help to offset the climate change impact, as trees lock up carbon from the atmosphere. Plus, paper bags are more widely recyclable and will decompose much more quickly than plastic so are therefore less likely to be a source of litter or pose a threat to wildlife.
The Environment Agency did a study, examining a range of bags made from different materials to find out how many times they need to be reused in order to have a lower global warming potential than a conventional single-use plastic bag. They found that paper bags needed to be reused at least 3 times which is only one less than a plastic bag for life. Given the low durability of paper it is unlikely that a paper bag would survive at multiple trips to the supermarket particularly if they get wet.
Cotton bags are the most durable and will have a much longer life. However, due to the high amount of energy used to produce and fertilise cotton yarn, each bag would need to be reused a staggering 131 times.
It seems that there is no such thing as an environmentally friendly bag. The key to reducing the negative impact of any carrier bag, regardless of what it is made of is to reuse them as much as possible. Remembering to take your bags with you when you go shopping and ensuring that end of life bags are properly disposed of will have a much greater impact than choosing to use paper, plastic or cotton.