Wednesday, 29 October 2014

Can we make more sustainable clothing choices?

I was dismayed to read recently of the extent of plastic pollution due to microfibres that come off our clothes when we wash them. Depending on how sewage is disposed of these fibres will get into the sea or our agricultural soils. Ecologist Mark Browne has found that 85% of the human made material on the shoreline consists of microfibers of nylon and acrylic, almost certainly from clothes [1]. However, some synthetics are biodegradable and when other aspects of sustainability such as carbon emissions or water use are considered synthetics are often a good choice. In practice there are a lot of factors and our behaviour, in particular how we wash and dry our clothes, how often we do this, how long we keep them and how we dispose of them when we have finished with them all make a big difference.

The carbon footprint of our clothes is 0.6 tonnes/person/year

According to WRAP, we spend about £44 billion/year on clothing (£720/person), and the global carbon footprint comes to 38 million tonnes of CO2e, (0.6 tonnes/person) [2]. Quite a lot of this happens abroad but, for comparison, this is about 5% of the average Brit’s UK carbon footprint. If we are to reduce our carbon emissions by 80% we can’t ignore this bit.

The carbon footprint of our clothes through the whole lifecycle has been estimated by WRAP. The table below shows the overall impact of each phase [3].

Phase% of carbon emissions footprint
Fibre production (eg. growing)15%
Other manufacturing stages60%
Distribution and retail6%
Laundry in use26%
End of life (disposal or recycling)-7%


The field to wardrobe phases come to about 80% of the carbon footprint. We could reduce this either by improving efficiency or by making our clothes last longer. However laundry is also important. Overall synthetic fibres are often better than natural ones for two main reasons: they tend to last longer and take less energy in washing and drying. They are lighter and absorb less water in washing which means less energy both in washing and in drying.

Making our clothes last 10% longer saves 8% of carbon emissions

WRAP estimates that manufacturers could reduced carbon emissions by 4% across the supply chain by improving their processes and another 8% by increasing durability so clothes last 10% longer.

WRAP surveyed nearly 16,000 people about their habits related to clothing. They found we value durability above fashion when buying clothes – but well below ‘value for money’. Most people said that if more durable clothes were more expensive they would not be able to buy them without a higher income too. However, 32% of respondents said they would be interested in a ‘durability index’ to help them make decisions on this.

Synthetic clothes are often more durable than natural ones. One study of hotel sheets found that the potential lifetime of polyester cotton sheets was twice that of pure cotton [4]. However, we don’t always wait until clothes are worn out before we discard them (or leave them to languish in a cupboard). WRAP’s survey found that 57% of us have clothes that no longer fit us and 36% have clothes that we don’t like any more. However only 18% have clothes we don’t use because they are out of fashion, so there must be lots of other reasons why we fall out of love with our clothes. Also 16% had clothes in need or repair.

This suggests even without buying more durable clothes we could extend their life:

  • By passing them on to someone else (e.g. a charity shop or a clothes swap party) when they don’t fit us any more or if we don’t like them any more.
  • By repairing them when they need it. Most of us can sew on a button but only half can darn or patch a hole and only a quarter of us can fix a zip. It isn’t that hard though, and I bet most of us know someone who can - you could swap a favour with them.


Incidentally, Against Breast Cancer is currently running a campaign for bra recycling. Every tonne of bras raises £1000. So this might be a good time to tidy that particular drawer.

Choice of material makes a difference - and where it was manufactured

You might think that there must be big differences in carbon emissions between different types of material – and you would be right. From WRAP’s analysis, per ton of material produced, wool is twice as bad as polyester and acrylic isn't much better whereas cotton and polyamide are in between. However, because a lot of the emissions are due to manufacturing it makes a lot of difference where the material is produced. China’s electricity has more carbon emissions than ours, so material made in China has more carbon emissions [3].

I was intrigued to find a life cycle analysis of an organic cotton T-shirt that proudly announced 90% of the carbon emissions from manufacturing were saved by using renewable energy. There was no mention of savings from the organic method to grow the cotton, so presumably there weren’t any [5].

Some synthetics are biodegradable - but which ones?

We don't have to forgo the durability of synthetics in order to avoid plastics pollution because some synthetics are biodegradable. For example rayon, modal and lyocell are all made from natural cellulose and are biodegradable. The cellulose usually comes from wood pulp or bamboo and it is chemically dissolved to make the new fibre so these materials are sometimes called semi-synthetic. Lyocell is sometimes branded Tencel, so that is another one. Also, some types of polyamide and polyesters are biodegradable even though they are derived from fossil fuel. There are doubtless others. I find this very confusing and I would like to see a label for biodegradable fabrics.

Some households do three times as much washing as others (per person)

I was surprised that WRAP found the laundry stage was only 26% of the total footprint. Other studies (including my book) report in-use emissions as high as 50% to 80% of the total. However, WRAP have convinced me because they have used a top-down estimate of laundry energy based on average use of washing machines and tumble dryers. This takes account of the fact that we have already adopted many energy saving habits, such as not using the tumble dryer if we can avoid it because it uses so much energy (and often isn’t good for the clothes either).

Of course, WRAP based this on average use of washing machines, tumble dryers and ironing but in practice, our behaviour varies enormously. Using data from the Household Energy Study [7] I find that annual washing machine energy use per person varies by a factor of three even among ‘moderate’ households - ignoring the top and bottom 20%. Some people wash their things a lot more often than others.

WRAP had a question in their survey asking whether we tend to wear clothes more than once before washing them. Not surprisingly, underwear was rarely worn more than once (only 10% wore them more than once). However, even with jeans and trousers, 35% of people said they usually washed them after just one wear. Well perhaps they work on a building site or otherwise get very messy. I certainly don’t. In fact this is one area where natural fibres win over synthetics for me – they stay nice smelling for longer so I don’t have to wash them as often.

By WRAP calculations we each wash in total about 409 kg/year. That is more than 1 kg/person/day. However, that includes bed linen as well as clothes.

For those of us who do our laundry at home, minimising our washing saves us money on our energy bills as well as reducing the impact of our clothes. We can save here by:

  • Only wash clothes when they need it.
  • Wait for a full load.
  • Sort clothes so you can use a low temperature wash most of the time.
  • Avoid using the tumble dryer – wait for a sunny day and dry outside if you can.
  • If you have to use the tumble dryer, separate clothes that need a lot of drying so you can dry the others for a shorter time.


Even your holey socks can be useful as rags

As I have already pointed out, if your clothes no longer fit or you don’t like them any more then you can pass them on to someone else. But what if they really are worn out, irreparable or indelibly stained? What should you do with them then? About 30% of our clothes end up in landfill but this is a waste because even rags have value. Absorbent materials are useful as wiping clothes in industry (costing around £1/kg to buy). Other material can be shredded and used for stuffing furniture, sound insulation, carpet padding and so on [8] [9]. So even your old and holey socks are worth putting in the recycling bin.

There are things we can do now but it would be easier to make better choices if we had more information

I haven’t covered all the environmental impacts of clothing because I am mainly interested in the carbon emissions. From this point of view, synthetics are usually better because they are more durable – and most of the carbon emissions are from the production phases so long lifetime is important. However I am also concerned about pollution from plastics, and many synthetics leak plastic fibres into the environment when we wash them. This is very bad.

There are some things we can do to make our clothing more sustainable even if we do stick to natural fibres.

  • Take advantage of natural fibres ability to shrug off odours so we wash them less.
  • Take care of them and mend them when they need fixing.
  • Pass them on to others when we have done with them, if they are still wearable.
  • Recycle them as rags when they are finished with.

It would be easier to make better buying choices for our clothing if we had more information. For example it would be good if the label included a mark for biodegradability and perhaps an index for durability.

[1] Inside the lonely fight against the biggest environmental problem you’ve never heard of (Guardian) 27/Oct/2014
http://www.theguardian.com/sustainable-business/2014/oct/27/toxic-plastic-synthetic-microscopic-oceans-microbeads-microfibers-food-chain

[2] Valuing our clothes: the evidence base (WRAP) July 2012
http://www.wrap.org.uk/sites/files/wrap/10.7.12%20VOC-%20FINAL.pdf

[3] A Carbon Footprint for UK Clothing and Opportunities for Savings [WRAP] July 2012
http://www.wrap.org.uk/sites/files/wrap/Appendix%20IV%20-%20Carbon%20footprint%20report.pdf

[4] E. M. Kalliala and P. NOusiainen (1999) Environmental profile of cotton and polyester cotton fabrics (AUTEX Research Journal)
http://autexrj.com/cms/zalaczone_pliki/2b.pdf

[5] The carbon footprint of a cotton T-shirt (Continental Clothing) 2009
http://files.continentalclothing.com/press/LCA%20Executive%20Summary.doc

[6] Eco Fiber or Fraud? Are Rayon, Modal and Tencel Envirinmental Friends of Foes (Natural Life Magazine) http://www.naturallifemagazine.com/0908/ecofiber_or_fraud.htm

[7] Household Electricty Survey 2 (DECC) (June 2013)
https://www.gov.uk/government/publications/household-electricity-survey--2

[8] Holey socks, not in the trash (Bay State Textiles)
http://www.baystatetextiles.com/holey-socks.htm

[9] Cleaning Rags and Cloths (Galleon Supplies)
http://www.galleonsupplies.co.uk/products.asp?cat=Cleaning+Rags+%26+Cloths



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