The title is a rhetorical question – it is I believe a truth universally acknowledged, that there is no such thing as “most sustainable” when it comes to textiles. (Sorry, is my play on Jane Austen words just dodgy?).
Failing having an all-out winner on the most sustainable textiles, we could think about groups of textiles. There is any number of ways of classifying them. One of the most obvious would be natural fibres vs. synthetics. Personally, I’ve never been able to form a convincing argument to myself that natural fibres are definitively more sustainable (you can read the goods and bads here, and the microplastic issue which I wrote about here). This issue cropped up again for me during a Fashion Revolution event in London this year where there was a question from the audience to the panel around whether synthetics should be banned.
My ears especially pricked up when Dr Mark Sumner (fashion, retail and sustainability lecturer at the School of Design at the University of Leeds) answered with a discussion on how some Life Cycle Assessments (LCAs) showed that polyester can be more “sustainable” than cotton. I caught up with him separately to chat more about this.

Life cycle assessment – what is it all about?
Life cycle assessment (LCA) involves the evaluation of some aspects – often the environmental aspects – of a product system through all stages of its life cycle.
Source – European Environment Agency
Seeing that an LCA does what it says on the tin, you would expect that LCAs should be a reliable point of comparison for fibre sustainability. But as usual, it’s not that simple…
Why are LCAs challenging?
Conducting LCAs requires adherence to a set of British or European standards. But this doesn’t mean there isn’t variation in the different parameters used to measure sustainability. According to Mark, you could analyse a bunch of different LCAs and come up with different conclusions depending on which studies you choose. Some of the challenges:
1. Is your data independent?
In this day and age where our lives are all about data, data, data, the story is no different for LCAs. But it is challenging to find independent data. Mark tells me there have been quite a few LCAs conducted around cotton. But whilst some data might come from academics, the stakeholders involved the LCAs might be also be engaged in the production of cotton. And therefore they may look at things with a slightly different lens.
2. Is your data granular enough?
Another challenge data granularity. Continuing with the cotton example, the water footprint of cotton produced in India maybe 3-4 times higher than the cotton from Australia. So just looking at the headline outputs of the elements of an LCA isn’t going to be enough.
3. Consumers are not all created equal
Assumptions made about consumers is one of the big variables. Most LCAs look at how much environmental impact there is per wear or wash, but how on earth do you get that accurate? What one consumer does can be the complete opposite of another. Mark has few clothes and wears them to death over a number of years. In contrast, his niece is 19 and only interested in wearing each of her garments a few times. And then there’s me (and maybe you?) somewhere in between. I don’t consider myself to have an “excessive” amount of clothing, but stuff does enter the wardrobe on a reasonably regular basis (though there is much that gets stored away and taken out again depending on the season).

Why bother with LCAs and fibre sustainability indexes then?
Philosophically speaking, LCAs and fibre sustainability are important for the fashion industry. There needs to be some kind of baseline to work with, and independent studies are probably the most truthful data that can be accessed.
But as you’ll have gathered from above, LCAs and fibre sustainability indexes (e.g. Higg) are complicated. Also, whilst transparency is important, the next question is that even if all the available data was interrogated, what do you then do with the information? How does it influence decision making?
An example of doing something with the information might be consumer transparency. We could have labels on garments to tell consumers the level of “green-ness” of a garment. But that assumes a level playing field with everyone using the same standards and symbols.
As an aside – whether consumers would understand the labelling or care about it is an entirely different matter. A blog post on that is coming your way soon!
Back to the #fashionquestiontime question – what is more sustainable, polyester or cotton?
According to Mark, if a garment is being worn until it completely wears out, then polyester is the best. It has a long life span and is more durable than cotton. But there are known issues with it being derived from non-renewable sources. And there is a disposal problem as well as a microfibre problem.
At this moment, you have to decide what’s important to you. If you’re worried about chemicals and pesticides and social impact then think about cotton. If you’re more concerned about fossil fuels, then think about polyester.
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So there you go, another person who says that trying to be “sustainable” really depends on interpretation and what matters to the individual. As ever, there’s no right answer – except using less and consuming less!
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5 comments
Very interesting to read, thanks!
I missed seeing this article when first published. Great read, and I think about the different groups of textiles creating a different set of sustainability issues too. I just tore a much loved RTW polyester shirt at the seams while handling an active baby – it makes me think, “completely wearing out a garment” may sometimes have more to do with its construction than the strength/resilience of the fabric itself perhaps? So many things are cheaply made these days (RTW), and sometimes even when home sewn, I don’t want to discard old threads and use them, but later found them terribly brittle/tear-prone 🙁
I think it could be both fabric and construction quality. Even at home I certianly notice the difference between cheap and expensive overlocker threads. Having said that I need to wash a lot before anything actually falls apart!