What's the best alternative to a single-use plastic bag? It depends
Eco-conscious shoppers should consider the full life cycle of whatever they use, experts say
Ottawa recently announced it will phase out some single-use plastics by 2025, but finding sustainable alternatives is trickier than you might think.
The ban, which targets six categories of plastics, is part of an effort by the Liberal government to achieve zero plastic waste by 2030. A study commissioned by Environment and Climate Change Canada showed that, in 2016, Canadians threw away three million tonnes of plastic waste, only nine per cent of which was ultimately recycled. The rest ended up in landfills, waste-to-energy facilities or the environment, where it can harm wildlife while taking hundreds of years to break down.
One of the single-use items on the banned list is the plastic checkout bag that many Canadians use for groceries and other kinds of shopping. Up to 15 billion plastic checkout bags are used every year in the country, according to government data.
They're also one of the major sources of plastic litter found on shorelines. In 2021, almost 17,000 plastic bags were collected during community cleanups.
Even before the federal government's move, some jurisdictions including P.E.I., Nova Scotia and a number of B.C. communities had already banned single-use plastic bags. Some major retailers such as Sobeys and Walmart have also stopped offering them.
The majority of Canadians are shifting away from single-use plastic bags, too. In a 2019 survey, 96 per cent of respondents said they used their own bags or containers when grocery shopping, though only 47 per cent of those said they always did so.
Examining the full life cycle
The challenge for eco-conscious shoppers is that alternatives to single-use plastic bags also leave an environmental footprint.
A 2020 study by the UN Environment Program analyzed the findings of seven life cycle assessments (LCAs) on shopping bags published since 2010. An LCA assesses the environmental impacts of a product or services from, essentially, cradle to grave. This includes:
- Raw material extraction.
- Logistics and distribution.
The study found the environmental ranking of bags varies depending on which criteria you consider. For example, one type of bag may score well in cutting down on litter but be a poor option when it comes to water and land use to make it.
The number of times a reusable bag is used is also crucial, the study found. On the lower end, a paper bag needs to be used four to eight times to have less impact on the climate than a single-use plastic bag. Meanwhile, a cotton bag needs to be used 50 to 150 times to be environmentally superior, according to the study.
Given the impacts from all life cycle stages, one of the best options for shoppers would to skip the bag altogether whenever possible, said Tony Walker, an associate professor of environmental studies at Dalhousie University in Halifax.
"Reducing consumption of anything and everything is key because everything requires resources and energy to produce," said Walker, who advised the federal government on its Zero Plastic Waste Agenda and Oceans Plastics Charter.
If you do need a plastic bag alternative, here's a closer look at the pros and cons of some common options.
The cotton bag has greater environmental impacts than other types of bags during production due to the high amount of energy required to grow, irrigate and fertilize the cotton.
However, its durability lends itself to hundreds, even thousands, of uses, which makes it an environmentally friendly alternative, says Walker.
As well, cotton bags are made from a renewable resource and are degradable at end of life, though the 2020 UN study notes it matters how it is disposed. Waste incineration for cotton bags is climate neutral and therefore a better option than landfilling, where the study says degradation of the cotton releases methane, a greenhouse gas that contributes to global warming.
Paper bags have a few things going for them: they can decompose easily, they can be put in compost bins depending on your jurisdiction and they can be recycled as paper, says Walker.
However, like cotton, they demand quite a bit of energy to produce. They also require forestry products as raw materials and take more fuel to transport than other, lighter materials.
Another major drawback of paper is its low durability.
"It kind of keeps us stuck in this single-use model," said Sarah King, head of Greenpeace Canada's oceans and plastics campaign. "I definitely encourage folks to think of what they already have and how they can incorporate that into their routine."
Reusable plastic bag or bin
Some retailers offer reusable bags made of plastic materials, including low-density polyethylene (LDPE), polypropylene (PP), polyethylene terephthalate (PET) and polyester. Others offer reusable plastic bins that shoppers can carry their items in.
Loblaws, which introduced a plastic-bag fee in 2007, has made both options available to customers. In response to a query from CBC News, the company said their black reusable President's Choice bag is 99 per cent PET fibre made from post-consumer recycled plastic, while their green plastic bins are made from high-density polyethylene.
Walker said a reusable bag having recycled content "is a fantastic thing, better than it going to waste."
But, "it is still made from a fossil fuel product, and so it would have to be disposed of very carefully at the end of life," he said.
These bags are often marketed as eco-friendly owing to an ability to break down into harmless material faster than conventional plastics.
But Walker says very few are actually 100 per cent "bio-based" — that is, derived from biological sources such as plants or algae — and instead may contain up to 25 per cent petroleum products, requiring specific conditions to break down at end of life in waste management or recycling facilities.
Indeed, a U.K. study published in 2019 tested the deterioration of biodegradable, oxo-biodegradable (containing additives for quicker breakdown), compostable and conventional plastic bags in four environments: the sea, soil, open air and controlled laboratory conditions. After three years, none of the bags showed any substantial deterioration across all of the environments.
Even when biodegradable bags degrade, unless they are 100 per cent bio-based, they risk leaking microplastic pollution into the environment, Walker said.
And there's another big caveat even for bags that are 100 per cent bio-based.
"You might be obtaining plant-based material that otherwise would have been land given over to food production — so that could cause food shortages in parts of the world with food insecurity — or it could have been virgin forest that was cut down to make this material," Walker said.
"So it's not the panacea."
Consumers can drive change
Consumers have a lot of power to influence manufacturers and retailers to improve on some of these "first gen" alternatives, says one business expert.
"It's up to us as consumers to nudge this along with our own behaviour," said Barry Cross, an assistant professor and distinguished faculty fellow of operations strategy at the Smith School of Business at Queen's University in Kingston, Ont.
Cross also cited the potential role of some of the larger fast food and retail organizations like Lululemon, who have "the size and the reach to be able to influence some of those packaging developers and some of the innovation associated with coming up with new alternatives."
But is it enough? By the federal government's own estimates, the six categories of banned products only made up about three per cent of the total amount of plastic waste Canada created in 2019.
That will make it difficult for Canada to reach to goal of zero plastic waste by 2030, says Greenpeace Canada's King.
"Unless they add more items to the ban list, unless they actually set overall plastic production reduction targets and also invest in a transition to truly zero-waste systems that are centred on reuse, there's no way they will ever meet their 2030 goal," she said.
However, all three experts CBC News spoke to agreed the ban on plastic bags and the other five categories of single-use plastic is a positive thing, especially when it comes to changing the mindset around waste and pollution.
"This is low-hanging fruit — these items, many of us can easily do without," said Walker. "If we can do without those, then it will help the government and consumers start to think more carefully about the plastics that we use, especially single-use plastics that we can do without.
"So yeah, whilst it might be on paper only a small step forward, a step forward by any means is better than no action at all."