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The pros and cons of reusable bags

Updated: Aug 4, 2023

Habits make you feel comfortable, psychologists say: it’s what you know; it’s what you’re familiar with; it’s what you’re used to doing. But they don't always serve your best interests or, on a broader scale, that of the planet.

Habits are hard to break because they are deeply wired into our brains by constant repetition, according to neuroscientists. In general, changing your behaviour requires constant work, attention, practice, patience and persistence. As the Chinese philosopher Lao Tzu famously said: “Watch your thoughts, they become your words; watch your words, they become your actions; watch your actions, they become your habits; watch your habits, they become your character; watch your character, it becomes your destiny.

Plastic bags were invented in the late 1960s, but only became widely used in stores in the 1970s. In the 1990s, scientists identified the negative environmental implications of the surge in plastic production. By the early 2000s, public awareness of the issue had grown due to the devastation the use of single-use plastic was wreaking on the planet.

Rarely recyclable, plastic can take up to 1 000 years to biodegrade. The Wall Street Journal estimated that Americans use and dispose of 100 billion plastic bags each year and the Environment Protection Agency found that less than 5 percent are recycled. At least 14 million tons of plastic end up in the ocean every year, and plastic makes up 80% of all marine debris found from surface waters to deep-sea sediments. By 2040, it will be around 29 million tons a year if nothing changes.

Not only does plastic kill at least 100 000 marine animals each year, but it’s also probably killing humans too. New studies suggest that a quarter of the 10 000 chemicals identified in consumer plastic products are toxic to humans, and we are directly consuming these chemicals in the form of microplastics.

Research shows that human exposure to microplastics could lead to oxidative stress, DNA damage, and inflammation, among other health problems (“Effect of Microplastic on the Human Health”, written by Ahmad K Jassim and published in March). Particularly when inflammation becomes chronic, this can pave the way to very serious health problems.


Woman holding paper shopping bags

The term “reusable” can often imply something great for the planet. But just because a bag is reusable doesn’t mean its materials are eco-conscious. Photo: Pexels


What’s the difference between reusable and eco bags?

Some places around the world have banned single-use plastics because of the harm they inflict on the environment. However, in some cities where those bans have been implemented, corporations have opted to offer reusable plastic grocery bags instead.

While they are better than single-use plastic, they’re only better if people really re-use them… over and over.

Plus, the term “reusable” can often imply something great for the planet. But, just because a bag is reusable doesn’t mean its materials are eco-conscious. Check for canvas grocery bags made from environmentally friendly and sustainable materials before you buy.

An eco-friendly shopping bag will help you live the lifestyle of the 3Rs: reduce, reuse and recycle, says the United States Environmental Protection Agency, among many institutions.

  • Reduce: Reduces waste from disposable store packaging and cuts down fossil fuel usage and greenhouse gases required for the ongoing production of single-use disposable bags.

  • Reuse: Lowers the burden on natural resources because you can use the same bag for multiple purposes, over and over again.

  • Recycle: Helps build a better planet through environmentally sustainable and recyclable materials.

Unintended consequences

Reusable water bottles, metal straws, biodegradable utensils, and canvas grocery bags are now readily available on the market. While more than 2 million plastic bags are still being manufactured every minute, the greener alternative, reusable bags, is having unintended consequences. Bag hoards are creating fresh environmental problems, with reusable bags having a much higher carbon footprint than thin plastic bags, campaigners say.

The thing with habits is that after weaning yourself off one habit considered detrimental to your health, you end up replacing it with another, which while better, still calls for mindfulness in its execution. Many of us are drowning in reusable bags - cloth totes or thicker, more durable plastic bags.

In New Jersey, 2022’s ban on single-use plastic and paper bags has meant grocery delivery services have switched to heavy-duty bags, CNN reported. Their customers complain of a glut of reusable, heavy-duty bags that they don’t know what to do with. The key is to faithfully reuse them and dispose of them carefully so they don’t end up as pollution.

Data from Alameda County in California, released by its Waste Management Authority, which did not include 2020 data due to Covid restrictions on reusable bags and supply chain paper bag issues, shows that the use of single-use plastic has steadily increased.



Building a new set of consumer behaviour

In terms of bag choice, Steve Cohen, director of the Research Program on Sustainability Policy and Management at the Earth Institute, told the Columbia Climate School website that it’s very hard to predict whether plastic, paper or cloth bags are the best in terms of net energy or carbon because they all use carbon. “But once a product that’s made of fossil fuels, like a plastic bag, hits the waste stream, it’s there forever,” he said. “That’s the biggest problem with the plastic.”

Cohen believes that the important issue isn’t so much the specific environmental impact of the packaging you use, however, but what it is doing to your behaviour pattern.

“What’s key is to get people conscious of packaging and to start thinking about closing the loop from production to consumption,” he said.

“We’re trying to build a set of consumer behaviours that are environmentally conscious, so I wouldn’t just look narrowly at the specific environmental impact of the form of packaging. I would be thinking more about what it is teaching people about being conscious of how their goods are moving around and being packed and disposed of.”

The answer to what’s the greenest replacement for a single-use plastic bag isn’t straightforward, but the advice boils down to this: Reuse whatever bags you have at home, as many times as you can.


Bulldozer on a landfill with plastic bags

If we are striving towards a sustainable future with less of the buy-and-throw (away) mentality, then the single-use bag is not very consistent with that way of living. Photo: CSIR


Why breaking free from plastic is difficult for consumers

On the Rachel Carson Council website (Rachel Carson is regarded to be one of the top green campaigners of all time. The US scientist's 1962 book, Silent Spring, is credited by many with kick-starting the modern environmental movement with her account of the damage caused by the unrestrained industrial use of pesticides), Audrey Magnuson wrote: "Fossil fuel and petrochemical companies have been hard at work convincing the public that the plastic pollution crisis can be fixed by individual actions like beach clean-ups and using overpriced metal straws… It is big corporations that are to blame for the crisis we find ourselves in.

"They have used plastic to inject fossil fuels into nearly every aspect of daily life to the point where consumers can’t reasonably break free. We need strong federal laws that enforce corporate responsibility for plastic waste and protect human and environmental health. We must stop the production of needless consumer plastic before it can become waste that poisons our environment for centuries to come."

A report produced for the United Nations Environmental Programme (UNEP) in 2020 found a thick and durable polypropylene (PP) bag (they often have a woven feel) must be used an estimated 10 to 20 times compared to one single-use plastic bag, while a slimmer but still reusable polyethene (PE) bag five to 10 times.

“There will always be cases where we forget our (reusable) bags at home. We should try not to do that but when we do, we need to buy a bag. And if we then have already too many durable bags at home, it would be better from a climate perspective, at least, to buy a single-use paper or plastic bag,” said Tomas Ekvall, one of the authors of the UNEP report and adjunct professor at the Chalmers University of Technology in Sweden.

However, he stressed that the single-use plastic bag epitomised throwaway culture and that alone was perhaps a reason to avoid their use.

“If we are striving towards a sustainable future with less of the buy-and-throw (away) mentality, then the single-use bag is not very consistent with that way of living. So in that sense, it might be reasonable to try to avoid it, even though it’s not specifically an environmental benefit from that choice.”

The throwaway culture began as early as the 1950s. In August of 1955, LIFE magazine featured a short article called “Throwaway Living”. It was accompanied by a large, black and white photograph of an American family joyously hurling a symphony of Styrofoam, paper, and plastic plates, cups, straws, utensils, napkins, and serving trays into the air, Magnusson reported.

"The piece emphasised the luxury of this throwaway life for housewives who could now shortcut their kitchen cleaning routine. 'Use it, then toss it, and it takes care of itself!' This happy fifties family captures the reckless abandon with which companies have pushed a pervasive, plastic American culture. As a direct result we’ve plasticised our environment nearly to the point of no return," she wrote.


Stylish woman with canvas shopping bag.

The cotton tote has become a cheap status symbol for anyone — brands and individuals — wanting to eschew plastic and show off their green credentials. Photo: Pexels


Spotlight on the canvas bag alternative

One of the most popular eco-friendly moves is using canvas bags as an alternative to plastic bags. Bags made from canvas fabric were once hailed to be the solution to reduce the trash and pollution caused by single-use plastic bags.

Canvas bags are considered eco-friendly because they are made from natural materials like cotton and linen. They are also a more sustainable option because they can be used multiple times, much more than the usual plastic bag’s capacity.

When the bags get dirty or have holes, people can rewash or patch them up to look new again. Once they are too worn out and thrown out, they will eventually decompose.

Some experts believe that the whole process of producing the canvas fabric is what makes it a not-so-environmentally friendly option. They are green in principle, but how they are produced and how people use them does not fit many people’s definition of “eco-friendly.”

Cotton is a resource-intensive crop that requires lots of water and uses a substantial amount of pesticides and fertilisers, which introduce nitrates to land and waterways and result in the creation of nitrous oxide, a greenhouse gas. This means its environmental footprint is bigger than many people appreciate.

According to the UNEP report, a cotton bag needs to be used 50 to 150 times to have less impact on the climate compared with one single-use plastic bag.

A 2018 Danish Environmental Protection Agency report suggested that a cotton bag should be used at least 7 100 times to offset its environmental impact when compared to a classic supermarket plastic bag that’s reused once as a trash bag and then incinerated. (If that cotton is organic, the figure is 20 000 times, with the report assuming a lower yield but the same input of raw materials.)

That report looked at 15 different environmental indicators, including climate change, ozone depletion, air pollution, water use and land use. However, when focused solely on cotton’s climate impact, it suggested that a cotton tote would need to be reused at least 52 times — in line with the UNEP report.

The Danish report is what’s known as a Life Cycle Assessment (LCA), a set of methods scientists use to assess the environmental costs associated with a product over its entire life span. The UNEP report reviewed 10 Life Cycle Assessments produced in a number of different countries since 2010. However, Ekvall said that such an approach often relied on assumptions and simplifications; and the results often varied a lot.

A life cycle analysis looks at how much energy is used and how many environmental impacts a product is responsible for at every stage of its life, from cradle to grave. This includes extracting the raw materials, refining them, manufacturing the product, packaging it for shipment, transporting and distributing it, its use and possible reuse, recycling and final disposal.



“It is a problem that the LCA results are seemingly easy to understand, but it takes an expert to understand how the results were calculated and why they are different,” he said.

He said it’s better to view LCAs as “a rule of thumb” rather than a hard-and-fast guide. Plus, they don’t take into account hard-to-measure factors like microplastics, the impact of which on human and animal health isn’t yet fully understood, and marine litter. How, for instance, do you quantify a dead whale with 40kg worth of plastic bags in its gut?

It’s also important to note that plastic bags are responsible for a significant share of litter, but play a very small role in the climate crisis when compared with other products and commodities, the UNEP report said. As such, it’s perhaps far more important to think about what you’re putting in your shopping bag and simply consume less.

Enck, who has used the same cotton tote bag for 20 years, agreed. “I think we shouldn’t let the LCA take our common sense away from us. Single-use plastic has enormous environmental damage.”

A canvas bag indeed has imperfections, just like how people see the downsides of using bamboo straws or metal straws instead of plastic straws. Still, canvas bags also have their good points that the world can benefit from. If you can commit to using them until they are worn out, then you make the most out of the resources made to produce them.

The good news is that manufacturers and producers are not stopping until they find the most desirable way to create a better choice than what the world currently has. There are already some existing initiatives that aim to turn cotton into an actual eco-friendly canvas fabric. One example is how the Better Cotton Initiative partnered with retailers to help cotton farmers make their crops more eco-friendly while reducing their resources in production.


Woman with many paper shopping bags.

Paper bags are made of durable paper, which can carry more weight than a thin single-use plastic bag. Photo: Pexels


Papering up the cracks

Paper bags have been part of trade and commerce for more than centuries. They are made from a renewable resource and are biodegradable. In the US, over 10 billion paper bags are consumed each year, requiring the felling of 14 million trees, the Columbia Climate School reported.

As a result of the heavy use of toxic chemicals in the processing, paper is responsible for 70 percent more air pollution and 50 times more water pollution than plastic bag production according to a Washington Post analysis, resulting in more toxicity to humans and the environment than HDPE bags. And while 66 percent of paper and paperboard are recycled, the recycling process requires additional chemicals to remove the ink and return the paper to a pulp, which can add to the paper’s environmental impact.

A 2005 Scottish study also found that paper bags scored more poorly than plastic on water consumption, atmospheric acidification and the eutrophication of water bodies, which can lead to the growth of algae and depletion of oxygen.

A Danish study comparing LDPE (low-density polyethene plastic), polypropylene, bleached and unbleached paper, and cotton bags, and a few others, found that LDPE bags had the lowest environmental impact. Unbleached paper bags were found to equal the LDPE bags in terms of global warming potential. But the environmental impacts of bleached paper were considerably higher than those of unbleached paper — a bleached paper bag would need to be reused 43 times to equal the LDPE’s environmental impact.

A portion of paper bags’ environmental impact results from their being six to 10 times heavier than plastic bags, so transporting and distributing them requires more fuel and costs more.

Due to their weight, though, durable paper bags can withstand more pressure or weight than plastic bags. Being sturdier than plastic bags, they provide a wider space for more items because of their rectangular structure. The sturdiness also allows them to be carried without being worried that the content would be dropped.

You can iron them to make the paper bags look good again before reusing them. Used plastic bags are usually badly wrinkled, and you can’t do anything about it. Paper bags also present less of a suffocation risk to young children or animals.


Rubbish bin overloaded with plastic.

A CSIR study showed that ‘biodegradable’ doesn’t necessarily mean better – at least not for carrier bags. Photo: CSIR


CSIR research reveals best reusable bag option

In 2020, the Council for Scientific and Industrial Research (CSIR) released the findings of a life cycle sustainability assessment (LCSA) of grocery carrier bags in South Africa. LCSA is a useful tool that unpacks the environmental, social and economic impacts of a product throughout its life cycle.

The study showed that reusable plastic carrier bags are the best option in South Africa, as they have a substantially lower environmental impact compared to single-use bags – provided that consumers do actually reuse them.

Funded by the Department of Science and Innovation (DSI), the study provided an objective scientific assessment to inform the government, producers, retailers and consumers about the environmental and socio-economic impacts of different types of carrier bags.

“The results of this research are important in evidencing how we manage single-use plastics in South Africa” noted Dr Henry Roman, director of Environmental Services and Technologies at the DSI. “Although single-use plastics provide many benefits, there are also many avoidable plastic products that negatively impact our environment. Developing capability in LCSA allows us to make informed decisions on the most appropriate material for product design.”

The study assessed 16 types of carrier bags made from a range of different materials. It included the standard, single-use plastic shopping bags that most people are accustomed to, which are made from high-density polyethylene (HDPE), with varying levels of recycled content and a thickness of 24 microns. It also included a number of reusable and biodegradable alternatives.

Twenty-one environmental and socio-economic indicators were used to assess each bag. This included 18 indicators that are typically used in environmental life cycle assessment (LCA) studies (such as water use, land use, global warming, etc.).

The team also developed a new indicator to account for the impacts of plastic pollution, which is currently missing from most LCA methods. In addition, two key socio-economic indicators (impacts on employment and affordability for consumers) were added, which are also missing from most LCA studies.

According to the findings, the best-performing bag overall is the reusable plastic bag – also made from HDPE – but thicker and stronger (70 microns) than the standard 24-micron single-use bag. This bag is currently sold at one of South Africa’s major grocery supermarket groups for R3 per bag, with a 50c discount on grocery shopping each time it is reused.

The other reusable bags – made from other types of plastics, such as polyester (recycled PET) and polypropylene – also perform well.

While single-use bags rank lower, the best performing among them is the standard 24-micron HDPE plastic bag with 100% recycled content. Among the 24-micron HDPE bags, the higher the recycled content, the better the overall performance of the bag.

In general, biodegradable plastic and paper carrier bags perform poorly overall (except in terms of plastic pollution), due mainly to their land and water use impacts, the CSIR said. Biodegradable bags (particularly those made from a combination of imported polybutylene adipate terephthalate (PBAT) and starch) only outperform the conventional 24-micron (single-use) HDPE bags if the latter has a recycled content of 50 percent or less.

While reusable carrier bags perform better overall, the single-use bags are best from an employment perspective. In particular, single-use paper bags perform well in terms of job creation, followed by 24-micron HDPE bags with 100% recycled content.

“This study shows that ‘biodegradable’ doesn’t necessarily mean better – at least not for carrier bags,” said Anton Nahman, a principal environmental economist at the CSIR, who led the research team.

“Taking into account environmental and socio-economic impacts across the full product life cycle – from resource extraction, through production and use to end of life – the best-performing bags are all made from conventional plastics. In particular, the reusable ones are best – but only if they are actually reused, as many times as possible.”

“While this study shows that reusable bags are the best option for South Africa, if retailers and consumers want to use single-use bags now in the interim, then the 100% or 75% recycled content 24 micron HDPE bags are the next best solution. Increasing the recycled content of products will also help to create a demand and a market for waste plastic, typically collected by informal waste reclaimers, helping to improve their livelihoods during a difficult time, further compounded by the very low oil prices,” noted Professor Linda Godfrey, manager of the CSIR Waste Research Development and Innovation Roadmap Implementation Unit.

With LCSA capability now existing within South Africa and the CSIR, Dr Douglas Trotter, manager of the Sustainable Ecosystems Area of business for the CSIR, said: “We hope that brand owners will use this tool to inform the choice of products that they put into the South African market, to ensure that they have the best overall environmental, social and economic performance. Sustainable product design is a critical part of South Africa’s transition to a more circular economy.”




NATURECODE.ORG VIEW ON REUSABLE BAGS

Everyone is told to utilise reusable bags, but does anyone really know much about them? There is misinformation, and frankly just not enough information out there about reusable grocery bags, so we’re here to set the record straight. So, are reusable bags really better for the environment? The short answer is yes, but there are other factors to consider, including manufacturing costs, product lifespan, and time spent in actual use. Let’s discuss how you can actually measure that, though, because every manufacturer has different practices when it comes to actually producing plastic bags. Spoiler alert: none of them are good.

Why plastic bags are bad

So let’s dissect them so we can first understand how bad plastic bags are for the environment, then discuss the excellent benefits of switching to reusable items like multi-use bags. One trillion plastic bags are created every year. That’s a global figure.

A lot of fuel has to go into producing these bags, which adds more to the environmental damage we’re causing. Then it costs fuel to distribute those bags. Plastic bags bleed polypropylene and BPAs into the soil, which in turn ruins the soil, and then washes into streams, rivers, and other bodies of water that lead to the ocean. It all comes back to the ocean.

Longer lifespan, repurposing major benefits

But what if we all switched to reusable shopping bags instead? There are still manufacturing and distribution costs, but in an ideal world, we would eventually require far fewer reusable bags to be created than their plastic counterparts.

Reusable bags have a very long lifespan, especially if you take care of them properly, which is why they’re such an excellent option. On top of that, reusable bags can be retired for other purposes once they’re tattered and no longer viable for groceries.

Provided that you use them enough, reusable bags are better for the environment, just not at first. If you purchase reusable bags — which cost more energy to produce than the equivalent number of plastic bags — you need to actually use them frequently, and for a long period of time for them to be worthwhile.

So reusable bags technically cost more to manufacture when they’re in the factory (if you’re comparing them to the cost of producing a single plastic shopping bag), but don’t cost as much to gather materials for. Most reusable bags have a cotton blend construction, and cotton farming costs less than mining and gathering oils that are used in plastic.

Cotton is also biodegradable, so even if you don’t get as many uses as you’d like out of it, at least it won’t hang around for a millennium. Everyone would like to believe that just buying reusable bags is the answer, but there’s a little more that goes into it than that.

How many times do you need to use a reusable bag for it to matter?

About 56 times. The average cotton shopping bag weighs about 45 grams when empty, and a plastic shopping bag weighs about 5.5 grams (the thin and transparent polypropylene kind). If you use a cotton bag 46 times, you’re justifying the weight of the material versus the weight of plastic that would have been used. That’s basically what you need to break even.

Manufacturing one cotton bag is more energy-efficient than manufacturing 46 plastic bags, and that’s great for air pollution, but the end goal is to prevent those 46 pieces of plastic from entering landfills and our oceans. There are over five trillion pieces of plastic currently littering the ocean, and a hefty percentage of those are plastic bags.

As defined by a Danish study in 2018, any cotton grocery bag should be used 7100 times for it to truly be positive for the environment. When the United States researched a similar point, they defined a much lower number for the full lifetime of a cotton grocery bag.

Why? Because American consumers are apparently more likely to forget their reusable bags and end up using plastics anyway, which negates the point of buying reusable bags in the first place. That means that instead of taking yourself out of the plastic bag pollution equation, those people are occasionally dipping their toes back in the water for short bursts of time and using plastic anyway.

Forty-six uses to break even, and as many uses as you can possibly get out of the bags afterwards — that’s how you make reusable bag purchases worth your time.

Are reusable bags better than plastic?

Yes, they’re better for the environment, and could actually bring down the supply and demand of single-use plastic bags in the future. Plastic bags can take a millennium to degrade in nature, at which point it will have poised the soil and nearby water sources, but reusable bags don’t.

Well, most of them don’t. Some reusable bags are made out of PVC, which is one of the most toxic forms of plastic that there is. The mindset many people have is, “Well, I’m not going to throw it out, so it doesn’t matter,” but nothing could be farther from the truth. Reusable bags are meant to have an end to their life cycle. Purchasing them with the intent of never throwing them out is unreasonable.

The handles will eventually undergo enough stress and break, holes might form, and there are just a lot of things that could go wrong.

If you are going to throw out a reusable bag (after years of continuous use), then it makes sense for it to be biodegradable. The biodegradable definition states the product will break down after an allotted time, which is great!

So most reusable bags are better than plastic bags. There’s an upfront environmental cost of manufacturing and distribution, but after that point you decide how much of an impact will be made on the environment. If you can use a few bags for your weekly grocery shopping, and care for them enough to last for five years, you’ll be able to stop over 2 000 plastic bags, about 11kg, of plastic out of landfills and oceans.

Why is cotton a great material for grocery bags?

Cotton is less expensive to produce, and less costly to the environment during manufacturing. The best part about cotton is that it is biodegradable, so when you eventually wear through your reusable bags you’ll be able to throw them out without making a black mark on the earth.

Cotton comes from nature, and breaks down within a year or two after it’s been reintroduced to the earth, making it fully biodegradable. If the cotton bags in question don’t contain harsh or chemical dyes (there are excellent natural dyes that don’t harm the earth), then microorganisms will have absolutely no trouble breaking down the cotton.

When you compare those facts to plastic, it’s a no-brainer. Plastic can take a millennium to break down, or at the very least, around 450 years for thin plastic bottles.

Plastic actually shares one fact with cotton: they’re both made of polymers, but two different types. Synthetic polymers, which are in plastic, are laboratory-made and cannot be found in nature. Their simple, though powerful molecular composition makes them extremely difficult to break down through natural means.

Microorganisms have little to no effect on synthetic polymers. The only thing that can break them down is UV light from the sun, and that’s provided that discarded plastic actually has direct sunlight to degrade in. Then you have naturally occurring polymers, which are found in cotton, wool, and leather. These still have a similar molecular structure but are biodegradable.

You can have a cotton or canvas backpack for 30 years and have it look like new, or a leather jacket for a century and still retain that bit of lustre. The difference is that when they are introduced to natural microorganisms found in soil and nature, they will break down without harming any part of nature. In short, cotton breaks down quickly without leaving negative effects on the earth.


* I'm Not Plastic's vision is to encourage people to embrace an authentic lifestyle, in which single-use plastic and food waste are eliminated.




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