A bag’s environmental footprint depends on a plethora of factors: how it was made, what materials were used, how far it was transported and much more. But the few thorough studies on the subject do offer some takeaways.
Paper bags tend to require more energy to produce than plastic ones. A 2011 study by Britain’s Environment Agency concluded that you’d have to reuse a paper bag three times to bring its global warming impact in line with that of a plastic bag used just once.
A 2018 study by Denmark’s Environmental Protection Agency found that plastic bags made from low-density polyethylene, a versatile and widely used form of plastic, have the smallest environmental footprint of eight types of grocery bags, including paper ones.
What about discarded bags? According to the British study, what happens to a bag at the end of its life contributes very little to its global warming impact. But from a broader environmental perspective, the question is still worth thinking about.
Only about 10 per cent of plastic bags in the US gets recycled. The recycling rate for the category that includes paper bags is significantly higher at 43 per cent.
This means that most paper and plastic bags wind up in a landfill. In landfills, paper bags produce methane and carbon dioxide, both potent greenhouse gases, as they break down. A plastic bag produces neither but when plastic escapes into the environment, it can degrade into microplastics that sometimes last for centuries.
Samantha MacBride, an expert on urban waste at Baruch College of the City University of New York, US, stressed another consideration for consumers to keep in mind: the use of plastic bags perpetuates the fossil fuel industry. “That system needs to retract if we’re going to have a future,” she said.
Takeaway on Totes
Reusable totes have surged in popularity as a way to reduce single-use bags. But those good intentions have backfired in some ways as branded totes have become ubiquitous swag at conferences, company events and with certain retailers.
If a household accumulates more totes than it could ever use, that defeats the purpose of reducing overall consumption. It also means a bigger environmental footprint, since sturdier bags require more resources and materials to produce compared to single-use ones.
The British study found that a cotton bag would have to be reused 131 times to reach the carbon footprint of just one single-use plastic bag. The Danish study put that figure at 149 times. This is because of the land, water and fertiliser required to grow cotton, the energy needed to process cotton into yarn and the fact that most cotton bags are shipped from China or India.
MacBride recommended seeking out reusable bags made in your country from sustainable fibres like hemp or bamboo. Or, even better, from used fabric scraps.
Bottom Line
Whatever your bag is made of, experts agree that reusing it as many times as possible is key to bringing down its environmental footprint.
This is where paper bags fall down, said Steven Cohen, an environmental policy expert at Columbia University, US, because they are the least durable option. If you’re diligent about reuse, then sturdy totes are probably the best bet, especially ones made from recycled material. Just don’t accumulate dozens of them.
Michael Overcash, a chemical engineer and CEO of the Environmental Genome Initiative, a nonprofit group that evaluates the environmental footprints of products, cited a 2020 study in which he and colleagues compared the global warming potential of 20 products and found that reusable ones were consistently better than single-use ones. The same conclusion should apply to bags, he said.
“If you reuse a cotton bag a hundred times, it might get dirty-looking, and you might want to wash it, but that means 100 paper or plastic bags didn’t have to be made,” Overcash said. “The maths is simple.”
NYTNS