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Paper, plastic or cotton: which carrier bag is the least harmful?

Bag of bags plastic cotton organic-cotton carry environmental impact waste pollution co2 climate change

Who doesn’t have a bag full of bags? Ours contains 23 plastic grocery bags, three big plastic shopper bags, a plastic cooling bag, two reusable nylon bags, three see-through plastic bags, and 17 cotton bags. It turns out that the six organic cotton bags we use daily are the main contributors to the environmental footprint (CO2 and water usage) of our bag of bags. This made us ask ourselves how sustainable our choice really was. Answering that question was not as easy as we thought – it depends on many different factors, some of which we will break down in this post.

What made us swap plastic for cotton in the first place?

Almost all of our plastic bags were bought when we were not thinking about sustainability or conscious shopping. Most of them have not been used for two years and have just been chilling inside our bag of bags. Only 6 out of 17 cotton bags we have bought ourselves. These are the ones we have been using extensively for our daily grocery shopping for the past two years. The rest of the tote bags have been collected during fairs or were gifted to us. We occasionally use one or two, but the rest remain unused because they are unpractical in size or have prints or logo’s that we do not find appealing.

Clever marketing convinced us that the only way to be an eco-friendly shopper is by buying organic cotton carriers – so we did. We stopped using the plastic bags we already owned because it felt like plastic was getting a bad reputation. Many of them break after only one or two uses and eventually end up in a landfill or in the ocean, where they endanger aquatic life. Even though some of them are made from biodegradable plastics, they still linger in landfill and ocean water for decades or even centuries. A precise heat, acidity, and bacterial culture are required to allow for proper degradation – something landfill and ocean water cannot provide.

Swapping from plastic to paper was not practical in our eyes. We have lived in the United States for a short while, and that is where we experienced some of the discomforts of using paper bags first-hand. They tear easily and are completely useless when they absorbed even the tiniest bit of water. Yes, they are often compostable and recycled easily, but heavily rely on new resources and are treated with many chemicals. Unless coated with acrylate, recycled paper fibres are often too short and weak to be used for carrier bags. Thus, millions of trees need to be felled for the global paper bag market. The USA alone consumes about 10 billion paper bags annually, which requires roughly 14 million trees.

This meant that the only thing that would work for us was going with reusable shopping bags – preferable ones that are fully biodegradable and durable. We did not want to use plastic and went with cotton. In the end, we chose to buy organic cotton because we did not like the idea of going with a pesticide-intensive crop. Like conventional cotton, organic cotton requires a lot of land and consumes a lot of water, making this type of bag not necessarily environmentally friendly. On average, the yield of organic cotton is roughly 25% lower than that of conventional cotton, making it even worse in terms of CO2 and water usage. However, cotton is fully compostable and is, therefore, the least harmful carrier for aquatic life.

What is the environmental footprint of these bags exactly?

According to a recent lifecycle analysis from the Danish Environmental Protection Agency, our bag of bags has a total environmental footprint of 140 kilograms of CO2 and 860 litres of water, corresponding to 5 months of daily phone charging and a 45-minute shower. It turns out that the six organic cotton bags we use daily are the main culprits. Together, they are responsible for 63% of the total CO2 emissions and 71% of the total water consumption. All of our plastic bags together are only responsible for 6% of the total CO2 emissions and less than 1% of the total water consumption, precisely why many studies state that these types of bags carry the lowest environmental toll.

Even though plastic bags rely on resources such as petroleum, they result in less carbon emission, water consumption and less harmful by-products than their paper and cotton brothers and sisters. Many studies showed that when plastic bags are being used as trash bag afterwards, they carry an even lower environmental toll. According to the Danish lifecycle analysis, organic cotton bags require 149 uses every time the same plastic bag is used to provide the same environmental performance (CO2 and water usage only) as the plastic ones.

When other indicators such as human toxicity, terrestrial and marine acidification & eutrophication, and resource depletion are also taken into the equation, organic cotton bags come out way worse. This is mainly caused by the high impact of cotton on freshwater eutrophication. Considering this, organic cotton bags require up to 3800 uses every time a plastic bag is used. But… all in perspective. When placed in context, an average 225 grams steak has a 22x higher impact on freshwater eutrophication than a single organic cotton bag. That steak only lasts 30 minutes tops; that carrier can last many years. If you had asked me, I would have preferred to skip a steak once to compensate for 22 cotton bags that will last a lifetime, are compostable and do not choke aquatic life when they end up in marine environments.

What is the real problem with carrier bags?

Many articles misquote lifecycle analyses or do not adequately place the numbers in context, leaving many confused people on the web wondering which type of bag they should choose. This choice may become more accessible when we leave the production process entirely out of the picture.

We live in a world filled with stuff in this day and age, and carrier bags are part of this. Originally, cotton bags were presented as the most environmentally friendly option because they have high durability and can be used repeatedly without breaking down as plastic does. Businesses liked the environmentally friendly vibe of the bags, turned them into fashion items, or used them as a marketing channel, resulting in mindless consumerism.

Conventional cotton bags can be produced relatively cheap and are easily printed with slogans or logos. Many companies started giving them away during conferences or at events, turning people in walking billboards, exactly how we got our hands on 11 cotton bags with prints that we don’t use. With cotton bags available for free everywhere, they have become an unending product like plastic bags are. Just like in our bag of bags, plastic is being replaced by cotton.

Swapping a cotton bag for a plastic one can still be relatively sustainable and be less polluting than plastic. But this is only the case if we just had a couple of them that are reused until they can no longer carry our groceries. Accepting a new tote bag at every stand you visit is not sustainable – neither is gifting them to others.  

The solution is quite simple, use what you already have and upcycle them when their end is near. Old tote bags are the perfect material to patch up clothes; for example, our ugly tote bags will be sacrificed for this purpose. If you buy a new bag, buy one that lasts – be it plastic or cotton. We would still pick organic cotton above plastic. What do you prefer?

Elise & Joy

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