The sustainability of an item of clothing is measured over the whole lifecycle of the garment; from how it’s made and what it’s made from, to how often it’s worn and washed, and finally what happens after it’s no longer wanted. This is often called cradle to grave analysis.
Sustainability of clothing is a hot topic at the moment, with many clothing brands producing sustainable collections, or claiming to be sustainable but without saying how they are being sustainable. Unfortunately, many brands are not sustainable and instead use it as a marketing ploy to get people to buy their clothes, otherwise known as ‘greenwashing’. Changing Markets report ‘Synthetics Anonymous’ found that out of the companies they researched who made claims about sustainability, 59% made claims that flouted the UK Market and Competition Authority’s green-claims guidance .
Below are some points to take into consideration when assessing whether an item of clothing is sustainable or not…
How it’s made/what it’s made from
Different materials are used to make fabric. The most common fabrics you will come across are wool (from sheep), cotton (from the cotton plant) and polyester (a synthetic plastic fibre made from crude oil). Each one has different environmental concerns and has a different impact on the environment when it is made. For example, cotton is grown in hot countries but needs a lot of water to grow—up to 10,000 litres of water for just one pair of jeans, which is about 10 years’ worth of drinking water for one person . Most cotton is also grown using pesticides, which can cause health problems for the workers and damage the natural environment where it’s being grown .
Polyester is a plastic fibre, so releases a lot of carbon dioxide when it is made—one polyester shirt produces about 5.5kg of carbon dioxide versus a cotton shirt which produces 2.1kg . The dyes, bleaches and chemical processes used to colour our clothes also have a big environmental impact when hazardous chemicals are released into the water supply .
Many fashion brands use polyester in their clothes, and in an attempt to be more environmentally friendly they use recycled polyester. Unfortunately, this doesn’t mean that they are recycling old clothes to make new clothes; in fact, recycled polyester (or rPET) is made from plastic bottles. There are a few highly debated issues [6,7] when it comes to using rPET in clothing; though it saves you from having to use new crude oil, unless it’s made from sea plastic (plastic pollution removed from the sea) it is technically classed as “downcycling”, where a material loses quality through the recycling process and cannot be easily recycled in its new form. Because recycled polyester is often mixed with other fibres to make clothes, it can’t be recycled in the future to make clothes again (more on that later). When clear plastic drinking bottles are used to make rPET, they can actually be made back into plastic bottles again without downcycling to the same extent , so can have a much longer life through their many iterations before going to landfill or being downcycled.
How often it’s worn and washed
The way we treat our clothes once we’ve bought them also plays into how sustainable they are. By buying an item of clothing and using it for as long as possible, we reduce its carbon footprint—using a garment for nine months longer could reduce its environmental impact by 20–30% .
Buying a higher quality item also means it will last longer as it will be better made and therefore more durable. Unfortunately, a lot of the clothes sold in the UK are classified as ‘fast fashion’.
Fast fashion is when clothes are made quickly in high volumes to copy catwalk and celebrity trends and are sold at a cheap price. Because fast fashion items are made quickly, they are often made of low quality, cheap materials, with low durability. Unfortunately, they are often also made by workers who are being exploited and not paid living wages, to keep the price as low as possible for the consumer . Fast fashion clothes are seen as disposable and are often thrown away in landfill when they aren’t trendy or desirable anymore—it is estimated that more than half of fast fashion produced is disposed of in less than a year . Their low durability means they also don’t last as long when you wear them, meaning they have a much shorter life even if they are still desirable. They are most likely to be made of polyester.
Repairing clothing when they start to wear out is a great way to improve the sustainability of an item by helping it to last longer. Whether it’s patching a hole in your jeans or replacing a broken zip, there are lots of ways to mend your clothes and care for them—you can find loads of free resources online that can help you repair your clothes and make them last longer .
Another way of improving the sustainability of your clothes is to not wash them as much, and to wash them on a lower heat . This can be especially important for synthetic fabrics, like polyester, that shed microplastics into the water every time they are washed—each cycle of a washing machine can release more than 700,000 plastic fibres into the environment . You can help prevent most of these microplastics from polluting water by using a filtering bag when you wash your clothes .
What happens when it’s no longer wanted?
It’s important to think about what happens at the end of a garment’s life as this will also affect its sustainability. If your clothes are in a good condition, you might want to donate them to a charity shop, however only 1–3% of clothes sorted at Oxfam’s Wastesaver facility end up going back into shops in the UK . Around 35% of them go to Oxfam’s partners in Senegal to be sold, but the majority are in too poor condition to be resold so are sent for recycling. Sorting textiles is done by hand and takes a long time and a skilled workforce to separate good from poor quality items, and to separate it by fibre content for recycling , so it is an expensive process.
Less than 1% of clothing that is recycled actually becomes clothing again . Most clothing is shredded and downcycled into things like stuffing for mattresses, car upholstery and insulation.
If you choose to put your used clothing in the bin, it will either be buried in a landfill or burnt. Around 300,000 tonnes of clothes are burnt or buried in landfill in the UK each year, with 20% going to landfill and 80% being burnt  (that’s the equivalent of a pile of clothes 30 times heavier than the Eiffel tower). Unlike a normal compost heap, landfills don’t allow any air to circulate, so clothes take a very long time to break down—synthetic fabrics can take hundreds of years to break down . Burning waste in incinerators also has a negative effect on the environment.
Why are so few used clothes recycled back into clothes? When an item can be recycled back into its original form, or re-enter the raw material stream, it is called cradle-to-cradle production (i.e. it doesn’t reach the ‘grave’ at the end of its life; instead, it’s born again). At the moment, virgin materials are still cheaper than recycled materials—it’s cheaper to grow brand new cotton rather than recycling old cotton, so there isn’t a commercial drive to use recycled materials. However, many manufacturers can now understand the environmental benefit of recycling materials, so there is lots of research going into it.
When clothes are made out of just one type of fibre they can be recycled fairly easily, but the technology is still quite expensive. Waste cotton garments can be shredded and pulped up  or transformed using chemicals  to make a new recycled type of natural cellulose (used in viscose, a synthetic fibre made of natural materials) to reduce the amount of trees, raw cotton and oil used in fabric production. Garment-to-garment manufacturing unravels clothes or similar colours thread by thread, cleans and re-spins the threads and then weaves or knits them into new garments. The H&M Foundation and the Hong Kong Research Institute of Textiles and Apparel are testing this out in Hong Kong . [The scarf currently on display in the Textiles Gallery Conversation Space was made using garment-to-garment manufacturing]
In most garments, however, different types of fibres are mixed together; for example, skinny jeans are cotton with a bit of elastane (a synthetic elastic fibre) mixed in to help them stretch. Natural fibres, like cotton and wool, are recycled using different processes to synthetic fabrics like polyester, so when you mix natural and synthetic fibres together, they become almost impossible to separate for recycling. Polyester clothing is much harder to recycle as it degrades significantly each time you make it into something else. This is why most polyester clothing is downcycled into the mattress stuffing, car upholstery and insulation we mentioned earlier. However, scientists are trying to work out other ways of recycling polyester clothing without it degrading—chemicals can be used for fibre recycling on a small scale, and there are even tests to separate polyester from mixed fibre clothing using fungi .
So how can we make our clothing more sustainable?
You can also repair the clothes you do have to make them last longer. Learning some basic sewing to fix a broken hem, or ironing on a patch to cover a hole in your trousers can give your clothes a new lease of life. If a garment is a bit trickier to fix you might find that you have friends, relatives or neighbours who can help you fix the item, or you could take it to a local tailor or seamstress. There are also lots of online tutorials to help you build your skills to fix more complicated problems with your clothes or refashion them into something new!
If you are buying new clothes, try to buy clothes made from natural fabrics or recycled polyester, to decrease the impact those clothes have on the planet. If you need to declutter some clothes, think about selling them or donating them to charity. And if your old clothes aren’t in good enough condition to sell or donate, find out where you can recycle fabric near you—fabric is recycled at most of Greater Manchester’s Recycling Centres.
And finally, the biggest thing you can do is to buy fewer new clothes. The fewer new clothes we buy, the fewer new clothes are made, so the less damage it does to the environment. Thankfully, second-hand clothes shopping is now very popular and clothing trends often come round every few years so there are lots of good second-hand clothes available—it might even help you save money too.
Find out more about sustainability in the textiles industry at the Science and Industry Museum in the Textiles Gallery, including our temporary exhibition in the Conversation Space. You can also read our accompanying post on the history of sustainability in the textiles industry.