Paper Vs. Plastic Bags: What is the greener option?

Many people may not care what their shopping bags are made of, but as an eco-conscious person, you know there are many differences between paper vs plastic bags. So, you choose the paper bag on your weekly supermarket trip. But are they truly more environmentally friendly than plastic ones? Or is there a better third contender–reusable bags? 

There's no straight answer, but a critical life cycle analysis highlighting the environmental impact of each material can clarify things.

TABLE OF CONTENTS:

Raw material consumption

Here, we consider the type and amount of raw materials consumed by plastic and paper bags. Raw material extraction accounts for a significant portion of a product's environmental impact.

Paper bags

Paper requires forests to be cut down. Every year, the paper industry cuts down an estimated 4 to 8 billion trees. 

Trees are renewable natural resources, but the bad news is that many logging companies do not care to replace lost trees. Some loggers evade responsibility even in countries with reforestation policies because of lax monitoring and consequences.  

Trees lock in atmospheric carbon and are crucial to climate change control. Losing trees contributes to about 20% of annual CO2e. Deforestation also removes wildlife habitat, contributing to species endangerment.

Marketers use words like 'natural,' 'green,' and 'eco-friendly' to convince consumers that paper bags contain only organic materials. However, papermaking requires many chemicals, some of which are toxic pollutants.

Plastic bags

They make the thin plastic bags at the supermarket using high-density polyethylene (HDPE). Other types of plastic bags exist, some much sturdier or lighter than HDPE, but they are all from fossil fuels–natural gas and oil.

It takes 12 million barrels of oil yearly to satisfy the paper demand in the U.S. alone. Unfortunately, almost all that oil ends up in landfills. Fossil fuels are not renewable, and the lack of adequate conservation measures is alarming. Researchers predict the world will run out of oil and gas by 2060.

On a positive note, several studies claim plastic bags consume only about 6% of the water required to produce paper ones. A UK paper bag manufacturer claims to use only one gallon of water for a single bag.

The carbon footprint of manufacturing

How much energy is required to produce your preferred shopping bag? How much carbon emissions and toxic waste does the manufacturing process release? 

Paper bags

The production process is the most carbon-intensive aspect of a paper bag's life cycle. The machines processing pulp into paper require energy, which manufacturers usually get from nonrenewable energy sources. A study estimated that one paper bag requires four times as much energy as a plastic bag. A 2021 estimate put the CO2e of one paper bag at 86g.

Several researchers agree that paper often requires more toxic chemicals compared to plastic. Paper manufacturing uses chemicals like chlorine, limestone, EDCs, PBTs, heavy metals, and sulfur. These chemicals leach into the environment, polluting air and water.  

Pollutants from the paper industry can cause skin irritation, respiratory diseases, chronic disorders, harmful genetic mutations in marine life, and reproductive damage in humans and wildlife.

Plastic bags 

Drilling for oil is the most carbon-intensive aspect of plastic manufacturing. Extracting and transporting fossil fuel to factories within the U.S. emits 12.5 to 13.5 million metric tons of CO2e. Further processing releases an additional 184.3 to 213 million metric tons of greenhouse gas emissions.

On the positive side, plastic bag production consumes much less energy than paper bag production. A comparative study found that 1000 paper bags require 1,219 megajoules, while the same amount of plastic bags consumes only 457 megajoules. However, the low energy advantage is limited. HDPE bags consume less energy; however, plastic products with high initial energy input are more recyclable.

As the demand for plastic continues to soar, so will its impact on climate change. Plastic GHG emissions and particulate matter pollution have steadily increased due to plastic production growth in coal-dependent economies.

Reuse potential

The number of times we reuse shopping bags can reduce our carbon footprint. They design most shopping bags for single use, but consumers can reuse them for various purposes.

Paper bags 

We need to reuse paper bags at least three to 43 times to have a carbon footprint comparable to single-use plastic bags.

Reusing a paper bag is nearly impossible. Unlike plastic bags, paper bags tear easily, get wet in the rain, and are not stain-resistant. Sometimes, they don't even last one use. 

A paper bag would require some extra support, usually in the form of a plastic lining, to increase its reuse potential. However, lining paper bags with plastic creates a new set of problems. Plastic-lined paper bags are not readily biodegradable and won't work in compost. Additionally, recycling them is nearly impossible.

As a last resort, consumers can upcycle paper bags into gift wrappers, writing sheets, envelopes, decor, paper mache crafts, etc. While upcycling paper is excellent, it requires time that many folks can't spare.

Plastic bags 

A plastic bag has a higher carrying capacity than a paper bag because they make it using a more durable material. Non-woven polypropylene and polyethylene bags need to be used at least thirty-seven times to reduce their carbon footprint to that of single-use plastic bags.

Most plastic bags, even single-use plastic bags, can be used twice. Flimsy ones make great trash bags, and sturdy ones work as carrier bags. You can reuse one plastic bag for many different purposes.

Unfortunately, most people don't reuse plastic bags. It's more accessible and cheap for them to get a new one whenever the need arises. Even introducing so-called heavy-duty reusable plastic bags doesn't encourage reuse.

Recyclability and recycling rate

Recycling helps reduce virgin raw materials and energy consumption and lowers overall environmental impact. However, current recycling practices leave much to be desired.

Paper bags 

Paper is widely recyclable–we can recycle almost any kind of paper. It's far easier to access curbside recycling for paper bags than plastic bags. In a 2018 EPA report, paper waste had a recycling rate of 68%–the highest compared to other solid wastes.

Recycling paper reduces and weakens the fibers. After about four cycles, the fibers become unusable and get lost as sludge. Manufacturers often mix virgin and recycled pulp to ensure adequate quality, but many manufacturers opt for virgin materials immediately.

The paper recycling process can be chemically intensive. A study found that recycled paper contained more chemicals, such as solvents, biocides, and flame retardants, compared to virgin products. Much of those chemicals enter the environment via fumes and untreated wastewater.

Plastic bags

Recycled plastic produces 42% less carbon emissions than conventional plastic production. With proper safety measures, gas fumes from recycling won't be much of a problem.

Plastic bags are recyclable; however, the recycling rate could be more impressive. We have recycled less than 10% of the seven billion tonnes of plastic waste generated globally.

Plastic bags are among the least recycled plastic products. In most cases, you can't recycle a plastic bag using standard curbside recycling. You'll have to locate special recycling centers or programs, and it's too much effort for most folks.

Recycling plastic bags is challenging. The lightweight bags easily get caught in machinery, cause sorting issues, and cost more than they're worth.

End-of-life impact

Whether single-use, reused, virgin, or recycled, we discard our shopping bags sooner or later—the environmental impact of these discarded bags on their materials and disposal methods.

Paper bags

Paper bags end up in the trash quickly, mainly because they are not durable enough for reuse. According to the EPA, paper is the largest component of municipal solid waste.

Under the right circumstances, a paper bag will decompose within six months, turning into organic soil nutrients. However, biodegradation is slower in a landfill due to the anaerobic environment. Slow biodegradation causes methane emissions, which have serious climate change consequences.

The best way to dispose of paper bags is composting, but only some can or want to do that. 

Another safe option is incineration. Burning paper for energy is relatively safe as the CO2 emitted is part of the natural carbon cycle. However, paper often contains chemicals that release toxic fumes and other air pollutants.

Plastic bags

The world consumes more than one to five trillion plastic bags yearly, according to various estimates. They design half of all plastic produced worldwide for single use, and even those meant for reuse sometimes end up in the trash after one use.

Plastic waste has a bigger environmental impact compared to paper. Plastic bags are not biodegradable, so they remain in the landfill for a long time before breaking down into microplastics.

Plastic bags contribute majorly to litter on land and in water bodies. They clog drains and are generally an eyesore. In their whole or microplastic form, plastic bags endanger marine animals and find their way up the food chain. 

There's no perfect way to discard a plastic bag. In landfills, it releases methane and ethylene, greenhouse gases. Burning plastic for energy releases toxic fumes and particulate matter. Recycling is the most eco-friendly option available for now.

Are reusable bags the solution?

They design reusable bags to offer durability so consumers can use them enough times to offset their carbon costs. Non-woven PP, Recycled PET, cotton, jute, linen, hemp, and polyester are some common reusable bag materials.

The environmental impact of reusable bags depends on how they are produced and used. The emphasis is on "usage" because improper use will cause reusable bags to have a far greater impact than single-use bags.

Cotton bags, a popular option, carry a high manufacturing carbon footprint. Growing cotton is water and chemical-intensive. Manufacturers use dye, bleach, and other chemical treatments to process cotton yarn. Producing one cotton bag requires many times as much energy as a plastic bag.

A comparative study found that cotton bags required 7,100 reuses (20,000 for organic cotton) to be more or equal to the impact of plastic and paper bags. Other cloth bags, like hemp and jute, have a lower manufacturing CO2 footprint. However, they still need to be reused a few times. 

Reusing is easy, right?

Breaking the habit of linear consumption is easier said than done. People often forget their reusable bags at home and buy more bags whenever they shop.

Cloth bags get dirty and need regular washing. Some people don't want to commit to such chores; instead, they just get a new shopping bag.

Even if we make reusable shopping bags from compostable plastic or natural fiber with low energy and zero pollution, the materials will go to waste if people don't reuse them.

Some local authorities have banned single-use plastic bags to encourage more people to reuse their reusable bags. Supermarkets that stopped giving out free reusable bags and increased the price of new bags have also had positive results.

Paper vs. Plastic Bags: The verdict

The plastic-paper debate has gone on forever, and reusable cloth bags have even entered the mix. All these bags have their merits and demerits.

Plastic bags can be environmentally friendly if made from only recycled materials, disposed of through sustainable waste management, and recycled properly. 

The most eco-friendly paper bag is made entirely from recycled material, used at least a couple of times, and composted or recycled rather than landfilled or incinerated.

Cotton bags are initially energy-intensive, but their unrivaled durability offsets the cost. With proper maintenance, they can last more than ten years.

The best way to reduce the carbon footprint of your shopping bags is to use any and every bag responsibly. Now that you know more about the environmental impact of each type of shopping bag, which one wins for you?