Free plastic carrier bags will disappear from Australia’s two largest supermarkets in 2018. There are many arguments for and against this change, as it is important to look at the all environmental impacts of their alternatives. Dr Carol Kilcullen-Lawrence writes.
Free plastic carrier bags are often referred to as single use; however, this doesn’t take into account their downstream use as bin liners for example. Studies show that, in South Australia when this change occurred, sales of bags for refuse massively increased. In many cases, these bin liners are heavier than carrier bags, so more plastic reaches landfill. Additionally, if light-weight supermarket bags are replaced with thicker bags that customers pay a small fee for, while these are designed to be reusable for a while, if they eventually end up as bin liners the negative environmental impact is even greater.
In Europe they have taken some steps to avoid this use of the sturdier bags for refuse, by describing them as a ‘Bag for Life’ so when they are no longer suitable for carrying groceries, they can be returned to the supermarket for recycling and replaced with a new one free of charge. It’s important to point out however that the colourful branding with supermarket logos etc. provides another negative environmental impact compared to plain light- weight bags.
Many would be surprised at the findings when sustainability of different carrier bags is assessed throughout their full lifecycle. A common reaction is to assume paper bags have the lowest environmental impact. In fact, although studies vary, all agree that paper bags have higher or equal environmental impact (depending upon which specific impact is being measured) as light- weight plastic bags and fabric reusable bags. Paper is only more favourable if measuring eutrophication, as manufacturing and recycling paper carrier bags has a lower impact on our waterways in terms of release of nutrients. In considering other types of environmental impact, resource use, energy and greenhouse gas production, the most favourable carrier bags are light-weight plastic and reusable fabric bags.
Looking more closely at reusable fabric bags, focus clearly needs to shift to how many times they are actually reused. To ensure their impact remains the most favourable they must be reused at least 100 times, with some analysis claiming this can be as high as 175 times. This varies depending on their actual composition, be it PP, PET, cotton or hemp and the like. Many are not sturdy enough to last the distance, in terms of stitching etc. Some customers also raise concerns about hygiene and no studies have taken into account the impacts of regularly washing bags.
While not as numerous as supermarket bags, it would be good to see investigations into other types of free shopping bags at retail outlets. The formats of these are wide and variable – high quality, heavy- weight, paper and plastic – many with elaborate ribbon and cord handles so that when customers recycle them, they are unlikely to deconstruct them into separate components that are compatible with recycling together.
Many DIY stores are giving customers access to cardboard packaging that their goods have been delivered to the store in. This was popular for groceries in many parts of the world years ago. While this could be acceptable to many customers, space is premium in supermarkets and this may not fit with the in-store image large chains want to portray.
Once light-weight carrier bags are gone, will the focus shift to the smaller light-weight grocery bags used for customers to select their own loose produce? Increasingly, there are options emerging to buy fabric reusable versions of these and in reality they could themselves be reused several times as they are not subject to the stresses put on carrier bags.
There are so many factors that come into play when assessing which carrier bags are truly best for the environment. An Australia-wide approach is more likely to achieve the best outcome, rather than individual states and supermarket chains making random decisions. Light-weight plastic carrier bags are not necessarily the worst environmental option, so perhaps the focus needs to move to offering customers effective ways to recycle them. Essentially, their composition is almost identical to many soft plastics used to package all types of products used in the home, and courier bags from online shopping. We shouldn’t accept that these are destined for landfill. Light-weight plastic carrier bags can be diverted into schemes that are emerging for such household waste.