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Nov 04, 2024

Plastic, Paper or Cotton: Which Shopping Bag is Best? – State of the Planet

Renée Cho On March 1, New York State instituted its plastic bag ban, joining seven other states in an attempt to lessen litter, garbage in landfills, ocean pollution, and harm to marine life. March 1

Renée Cho

On March 1, New York State instituted its plastic bag ban, joining seven other states in an attempt to lessen litter, garbage in landfills, ocean pollution, and harm to marine life. March 1 was also the day that New York acknowledged its first coronavirus case. And despite the fact that California was the first state to ban plastic bags in 2014, San Francisco has reversed its plastic bag ban because of the coronavirus, outlawing the use of reusable shopping bags, which are capable of spreading viral and bacterial diseases. New Hampshire, Massachusetts, Oregon and Maine have also banned reusable bags or delayed their plastic bag bans for now as have a number of cities.

Given the concerns pulling us in different directions—our health, the environment, climate change—what’s an environmentally responsible, health-conscious shopper to do? Let’s compare the main bag choices—plastic, paper and cotton—to try to answer that question.

Life Cycle Analysis

To understand the full spectrum of impacts and benefits of a particular bag, we need to analyze its life cycle. A life cycle analysis (LCA) 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.

In any LCA, the total environmental impact also depends on how efficient each process is, and how many protective environmental measures are implemented at every stage. Energy use is also subject to variables such as the source of raw materials, the location of manufacturing and processing, how long a product is used and the final disposal method.

Life cycle studies done in Europe and North America have determined that, overall, plastic bags are better for the environment than paper or reusable bags unless the latter are used many times. Most, however, did not consider the problem of litter, which we know is a major drawback of plastic bags.

Plastic bags

Plastic bags were invented in 1967, but only became widely used in stores in the 1970s. The most commonly found thin plastic shopping bags given out at cash registers are usually made of high-density polyethylene (HDPE), but some are made of low-density polyethylene plastic (LDPE).

The energy embodied in plastic bags comes initially from the mining of the raw materials needed to make them—natural gas and petroleum—whose extraction requires a lot of energy. The raw materials must then be refined, which requires yet more energy. Once at a processing facility, the raw materials are treated and undergo polymerization to create the building blocks of plastic. These tiny granules of polyethylene resin can be mixed with recycled polyethylene chips. They are then transported by truck, train or ship to facilities where, under high heat, an extruder shapes the plastic into a thin film. The film is flattened, then cut into pieces. Next, it is sent to manufacturers to be made into bags. The plastic bags are then packaged and transported around the world to vendors. While polyethylene can be reprocessed and used to make new plastic bags, most plastic bags are only used once or twice before they end up being incinerated or discarded in landfills. The Wall Street Journal estimated that Americans use and dispose of 100 billion plastic bags each year; and the EPA found that less than five percent are recycled.

A 2014 study done for the Progressive Bag Alliance, which represents the U.S. plastic bag manufacturing and recycling industry, compared grocery bags made from polyethylene (HDPE), compostable plastic, and paper with 30 percent recycled fibers. It found that the HDPE bags ultimately used less fuel and water, and produced less greenhouse gas gases, acid rain emissions, and solid waste than the other two. The study, which did not consider litter, was peer-reviewed by Michael Overcash, then a professor of chemical engineering at North Carolina State University. Because the carrying capacity of a plastic and a paper bag are not the same, the study used the carrying capacity of 1,000 paper bags as its baseline and compared their impacts to the impacts of 1,500 plastic bags. The plastic bags used 14.9kg of fossil fuels for manufacturing compared to 23.2kg for paper bags. Plastic bags produced 7kg of municipal solid waste compared to 33.9kg for paper, and greenhouse gas emissions were equivalent to 0.04 tons of CO2 compared to paper’s 0.08 tons. Plastic bags used 58 gallons of fresh water, while paper used 1,004 gallons. Energy use totaled 763 megajoules for plastic, and 2,622 megajoules for paper.

Sulfur dioxide, a type of sulfur oxide, and nitrogen oxide emitted from coal-fired power plants that produce the energy for processing bags contribute to acid rain. The plastic bag produced 50.5 grams of sulfur oxides compared to 579 grams for the paper bag; and 45.4 grams of nitrogen oxides, compared to 264 grams for paper.

A 2011 U.K. study compared bags made of HDPE, LDPE, non-woven polypropylene, a biopolymer made from a starch polyester, paper and cotton. It assessed the impacts in nine categories: global warming potential, depletion of resources such as fossil fuels, acidification, eutrophication, human toxicity, fresh water toxicity, marine toxicity, terrestrial toxicity and smog creation. It found that HDPE bags had the lowest environmental impacts of the lightweight bags in eight of the nine categories because it was the lightest bag of the group.

But because they are light and easily blown around, plastic bags are difficult to dispose of properly. They litter streets and trees, and wash into the ocean where they entangle and are consumed by marine life. They are rarely recyclable and can take 20 to 1,000 years to break up into pieces. Over time, sun and heat do break plastics into smaller and smaller pieces, forming microplastics under five millimeters long. These have been found everywhere—in the guts of marine animals and in waterways and on beaches around the world. So while these life cycle studies have not considered litter as an impact, the world recognizes that the omnipresence and persistence of plastic waste is an enormous environmental problem.

In terms of bag choice, Steve Cohen, director of the Research Program on Sustainability Policy and Management at the Earth Institute, said 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.”

Which is not to say that plastic has no value. In this time of coronavirus, most of the personal protective equipment is made of plastic. “That’s what you should be using it for,” said Cohen, “But the idea that you need it to carry around your grapefruits is kind of silly. It’s unnecessary.”

Non-woven polypropylene cloth-like plastic totes that are often given away free as publicity are stronger and more durable than HDPE and LDPE plastic bags, and thus can be used multiple times.

They are made from polypropylene polymers derived from fossil fuels, and can include recycled material. The polymers are spun into threads then pressed together between heated rollers to produce a fabric that feels similar to canvas. According to a California State University, Chico study, if comparing one-time use, the non-woven polypropylene bags use considerably more non-renewable energy and fresh water than single-use plastic bags. Moreover, they are not biodegradable and need to be washed to avoid contamination—COVID-19 has been found to survive on polypropylene for three days.

Paper bags

Paper bags are made from a renewable resource and are biodegradable. In the U.S., over 10 billion paper bags are consumed each year, requiring the felling of 14 million trees.

Once the trees are cut down, the logs are moved to a mill where they can wait up to three years until they dry out. Once ready, bark is stripped off and the wood is chipped into one-inch cubes that are subjected to high heat and pressure. They are then mixed with limestone and sulfurous acid until the combination becomes pulp. The pulp is washed with fresh water and bleach then pressed into paper, which is cut, printed, packaged and shipped. As a result of the heavy use of toxic chemicals in the process, 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 pulp, which can add to 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 growth of algae and depletion of oxygen.

A Danish study comparing LDPE, 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. One estimate maintained that it would take seven trucks to transport the same number of paper bags as can be transported by a single truck full of plastic bags. Their bulk also takes up more space in inventories and landfills.

The extent of impacts from paper bags, however, depends on whether the forest is sustainably managed and also on the environmental measures used in the paper processing plant.

Cotton totes

Cotton bags are made from a renewable resource and are biodegradable. They are also strong and durable so they can be reused multiple times.

Cotton first needs to be harvested, then cotton bolls go through the ginning process, which separates the cotton from stems and leaves. Only 33 percent of the harvested cotton is usable. The cotton is then baled and shipped to cotton mills to be fluffed up, cleaned, flattened and spun. The cotton threads are woven into fabric, which then undergoes a chemical washing process and bleaching, after which it can also be dyed and printed. Spinning, weaving and other manufacturing processes are energy intensive. Washing, bleaching, dyeing, printing and other processes use large amounts of water and electricity.

The Danish and U.K. studies and several others found that cotton totes have the worst environmental impacts of all bags. Cotton requires land, huge quantities of water, and chemical fertilizers and pesticides to grow. The use and production of fertilizer contribute significantly to eutrophication. Harvesting, processing, and transporting cotton to market all require large amounts of energy; and since cotton totes are heavy and bulky, they cost more to ship. In addition, they are difficult to recycle since textile recycling in the U.S. is limited—only 15.2 percent of all textiles were recycled in 2017. As a result, a cotton bag needs to be used 7,100 times to equal the environmental profile of a plastic bag.

Bags made from organic cotton, grown without pesticides, fare even worse environmentally. Because organic cotton yields are 30 percent less than conventional cotton, they need 30 percent more water and land to produce the same amount as conventional cotton. Organic cotton bags need to be used 20,000 times to equal the environmental impact of plastic bags.

Today, another critical factor to consider is that cotton and other reusable shopping bags can carry bacteria and transfer it from home to grocery carts and checkouts and back again. One study of reusable bags discovered that they were rarely washed and as a result, bacteria were found in almost all the bags studied, with 12 percent containing E. coli. While most reusable bags are made of polypropylene, upon which COVID-19 has been shown to survive three days, so far there are no scientific findings about how long the coronavirus can survive on clothing or textiles. However, in a 2005 study of the SARS virus, another coronavirus, it survived on cotton for five minutes to one hour depending on the amount of exposure.

To be safe, wash reusable bags in warm or hot water after shopping, which can reduce the bacteria by 99.9 percent and kill COVID-19. Only use the bags for groceries and ideally, put meats into a separate bag since meat juices left in bags can enable bacteria to grow quickly. Don’t leave reusable bags in the car because when it gets hot, bags become an ideal place for bacteria to grow.

The final outcome

Generally speaking, bags that are intended to last longer are made of heavier materials, so they use more resources in production and therefore have greater environmental impacts. To equal the relatively low global warming impact of plastic bags, paper and cotton bags need to be used many times; however, it’s unlikely that either could survive long enough to be reused enough times to equal the plastic bag’s lower impact.

Ultimately, the single use of any bag is the worst possible choice. The key to reducing your environmental impact is to use whatever bags you have around the house as many times and in as many ways as possible. It’s understandable if, during this time of COVID-19, you’ve reverted to plastic bags to protect yourself and are probably discarding them after a one-time use. But when the risk of COVID-19 abates, remember to try to use whatever bag you choose as many times as possible. HDPE or LDPE bags can be used to store food, line wastebaskets, pick up dog poop, pack lunches, pad packages, stash wet umbrellas and in many more ways.

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 behavior 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 behaviors 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.”

*Editor’s note, 10/19/22: A previous version of this story incorrectly stated that paper bags create 70 times more air pollution. We have corrected the sentence and we regret the error.

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Thank you for the review, I found it very enlightening. Sometimes it’s hard to make a real and fair comparison of the environmental impact of substitute products without proper information.

this kinda helps

Thank you for detailed information.But … if we include the non-biodegradability of plastic into the LCA and the social cost of litter and introduction of plastic micro-particles into the food chain, which packaging material is then the most environmentally friendly?

Interesting study and valuable insights, but I agree with the micro-plastic insight which can’t be ignored when we look at the amount of plastic waste harming our waterways. Furthermore, plastic bags are often doubled for strength, so comparing a cotton bag to one plastic bag isn’t the reality. The cotton bag shown looks like it could hold at least two typical plastic bags full of groceries, possibly three. If we do the math we might learn that the bag would have to last 7 to 11 years depending on how many times one shops a week. It might be interesting to study what other durable materials such as a lighter synthetic fiber bag might do for the narrative of the study. However, the microplastic issue and its impact on our food chain might be more of the problem, as well as textile recycling is easier to do than regular plastic bag recycling (impacts of behavior)

I second these concerns

But this is more an issue of people not seperating plastics in garbage and failure to properly recycle, and the failure of currently existing garbage/waste system that somehow allows bags to even reach the oceans and waterways in the first place. This is a human behaviour issue of litter and failure to properly reduce, reuse, recycle. Plastic bags aren’t the bigger problem. The issue should be consuming less stuff, less plastic packaging vs plastic bags, better waste system to avoid plastics in ocean, and recycle the plastics to other bags.

This is an interesting article. By comparing plastic vs paper vs cotton bags, cotton bags should be used since it reduce the global warming which is an impact of using plastic and paper bags. And based on the factors that given in this article, cotton bags are more eco friendly and can be used multiple times. Recently, I happened to read a blog on “Benefits of buying eco friendly cotton bags”. Kindly check: https://www.earthsafe.in/benefits-of-buying-eco-friendly-cotton-bags/

Have you read the article? Cotton bags were shown to be the least eco-friendly. If you really want to help the environment, reuse plastic bags, it is not that hard.

Thanks for the useful information. Do you have a comparative analysis that is more recent than the 2007 Washington Post article quoted in this article. I have been finding several references that come to similar conclusions (i.e. virgin paper is immediately horrible in its impact and plastic is horrible forever) but it would be good to see an article that references a peer reviewed LCA comparison. It would also be helpful to look at different kinds of paper (e.g. how does virgin paper compare to recycled or paper made with agricultural residues like wheat straw left after the grain harvest).

Single use plastic is actually the best as you need to use any other type of bag 50+ times to equal the amount of damage in production through to recycling, if any country recycles instead of burning or burying like Malaysia after the carbon footprint of sending it there.

Are you sure about the figures, Renée ?14 billion trees a year means 42 per American, just for paper bags.This seems a lot…

10 million trees for 14 billion bags, that’s 1 tree for 1400 bags, sounds legit. But only 365 million Americans, each would have to take 4 bags per year, that sounds excessive when less than 20% do the shopping, even less choose paper.

You should know better than to reference a study put out by the PLASTIC BAG MANUFACTURING sector. For shame.

What do you think, paper or cloth bag is good?

Hi, what type of bag should I use?

10 million trees for 14 billion bags, that’s 1 tree for 1400 bags, sounds legit. But only 365 million Americans, each would have to take 4 bags per year, that sounds excessive when less than 20% do the shopping, even less choose paper.

you should use paper because that’s what the article said was best or maybe just reuse plastic bags it is not hard

Is recommending the use of plastic bags derived from petroleum socially responsible when the other options exist and all people would need to do during COVID is bag their own groceries using re-usable bags …?

Just came across this article as the family was arguing over which is the most environmentally unfriendly bag. Life-cycle studies don’t only talk of sea life (nor should it!). We try to carry our groceries from the store when possible (a jacket has surprisingly many pockets!) 🙂

i am doing research and am finding overall that plastic is better than paper.

no it is not. plastic is worst because it harms our earth. It usually takes 400 to 1000 years to decompose

Currently, everywhere around the world paper used for making bags have shifted from virgin grade to 80% recycle paper which has reduced carbon footprint, energy consumption, deforestation etc making paper bags as best among the 3.

When reading the Washington Post source, I saw a difference in figures. If it is a mistake on my end, I apologize, but I am currently seeing that on the source, it says, “…70 percent more air and 50 times more water than production of plastic bags.” This is a far cry from the 70 times more air pollution, and once again, I would like to apologize if I’m wrong, just want to point out an error I found in a fact of yours.

Thanks for letting us know, we have fixed the error.

Someone paraphrased a single part of your discussion on Facebook to me, because I happen to like using cloth bags. But they failed to put the whole point of this article. Super glad I found this article.

Why do people do this this is are only chace to live on this earth then we dead

i hate paper bags i become ill from the fumes they are made from allergens such as old newspaper and magazines many people are sickened by them

If you use a plastic bag to make an eco-friendly bag, it will be twice as eco-friendly.

Thank you for providing a fresh perspective and challenge the prevailing narrative of villainizing Plastic. However, this does not absolve us from the responsibility of proper waste management and recycling practices. By embracing recycling initiatives, supporting innovations, and raising awareness about the importance of responsible usage, we can ensure that plastic bags continue to serve as a viable and eco-friendly option in our modern lives.

I just read an article which talked about how very little plastic is recycled here in the US, like 20%. China long ago stopped taking our trash.That seems like a place to start since it takes hundreds or thousand of years to breakdown?Bamboo for paper sounds like a possibility but it needs to use fewer chemicals to produce.Just how does the plastic end up in our rivers and oceans?There are reusable ziplock bags avaiable for those who can afford them.But what about tras can bags?

non of the bags are good for shopping because they have their own disadvantages.

Although, not addressed in the article, I’ve been using the same backpack for grocery shopping for over a decade. I’d love to see backpacks in the list of comparisons. I also use the same bagpack for camping and travelling.

Bagpacks have drawbacks too as I’m guilty of only washing mine a few times a year. (However when I buy meat or produce, I place them in plastic clear bags you find in the produce and meat departments in Northern Ontario). As I become older (early 40s women), I find that a bagpack doesn’t match my outfits. Also many stores in Canada assume you are a theif if you use a bagpack and demand thag you leave your bagpack at the front entrance. Therefore you also need a purse for your id, any emergency medication, wallet, phone etc.

I believe in freedom and it’s best for all of you to come up with the best solutions for your climate and lifestyle. I live in Northern Ontario, Canada and I don’t own a vehicle. I walk 1-3km to and from the grocery store in all sorts of weather from minus 30 to plus 30 degrees Celsius. So that’s another reason why a backpack is convenient for me.

I appreciate articles like this because it helps me make better decisions. Thanks for sharing this article and keep up the good work.

that is alot of history and it is out of topic

It was okay you got a bit out of topic

Good Blog!!! Well Explained about the topic… Very useful

paper is best

i thank paper is better who is with me on this There has been a lot of talk about switching from plastic bags to paper bags. While paper bags are biodegradable and can be recycled, they also have their downsides. Paper bags require more energy and resources to manufacture and transport than plastic bags, which can result in a larger carbon footprint. Additionally, paper bags are not as durable as plastic bags and can tear easily, which may not be ideal for carrying heavy items. However, if used responsibly and recycled properly, paper bags can be a more eco-friendly alternative to plastic bags. Ultimately, the choice between paper and plastic bags comes down to personal preference and the specific situation.

So still no one can agree and there’s no clear advice about what to do. So people will continue understandably to be confused and nothing will move forward. I don’t have any plastic bags lying around and avoid getting them with shopping because we were all told to avoid them. but now paper is bad and cotton is bad and I have no plastic bags. so I really have no idea what is the best solution.

Very helpful but, there is the fact that all bags will have disadvantages.

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