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Lately not a day goes by without yet another report on the environmental harm caused by apparel and textiles, along with a host of recommendations for changes by industry, policymakers and shoppers. Consistent across most of these articles is that, compared to synthetic or man-made materials, natural fibres make a disproportionate contribution to negative environmental impacts. But how reliable is the information underpinning these assessments? Beverley Henry reports.

A critical look at the evidence underpinning apparel sustainability rankings reveals serious shortfalls. Many are inconsistent with the international standards that guide best practice for assessment of the environmental performance of a product. This is not to say that any rankings are intentionally misleading, but to highlight the risk of perverse outcomes when methods and data are incorrectly applied, and when the limitations on current tools are not taken into account. Consequently, there is a real risk that recommendations inadvertently lead to more, not less, environmental harm.

Sustainability assessment is a relatively new science.  It is complex, especially where the value chain is long and products are diverse. Rules to ensure a ‘level playing field’ are set out in guidelines for Life Cycle Assessment (LCA) by the International Organization of Standardization (ISO). ISO 14040:2006 and 14044:2006 provide broad guidance for quantifying environmental impacts of a product from cradle-to-grave. Importantly, in 2017 ISO provided clearer guidance on using an LCA approach for comparative assertions and for communicating a ‘Footprint’ (a single score across one or few impacts). LCA is the most holistic system currently available, but it is still evolving. It is not a perfect tool and there are many dimensions of sustainability not captured in LCA.

Is a level playing field possible across fibres?
LCA does provide a basis for a ‘level playing field’ across equivalent products, but only if applied correctly.  In practice, some data are frequently missing or of poor quality, and the assumptions or simplifications that are made because of this affect results and potentially bias comparisons.  Simplifications such as not including the full life cycle or counting only a few environmental impact categories risk making the field no longer level. There is evidence that in apparel sustainability assessments, natural fibres such as wool are particularly disadvantaged.  

The full life cycle
Each stage of the life cycle of a garment from extraction of raw materials to final disposal affects the environment in some way. Which stage dominates differs depending on the impact, type of apparel and material. Taking climate change as an example, over half of the full life cycle impact of wool garment commonly occurs at the raw material stage, while for polyester raw material may represent less than 10%.  Clearly, comparison at the fibre stage cannot give an accurate ranking for garments of different materials.  

Often overlooked in apparel LCA studies is the consumer use phase. However, Levi Strauss’s  2013 LCA showed that over the full life of denim jeans, consumer care (washing, drying etc) represented 37% of climate change and 23% of water consumption impacts. Additionally, a paper by Consumption Research Norway (SIFO) showed significant variations in consumer care across garments of different materials. Woollen garments were found to be washed less frequently than cotton and at lower temperatures using a gentler cycle, with less tumble drying than the average for all laundry.
Only by including these differences can comparisons across fibres reflect differences in sustainability. Investment in acquiring reliable data over the great diversity in home laundry practices is, therefore, an essential, if difficult, task.  

Analysis also showed that wool clothing commonly has a longer service life  than equivalent items of alternative fibres, reducing ‘production burden’ per wear or per garment. Along with end-of-life biodegradability, this is another important factor in sustainability.

Environmental impacts:
To avoid trade-offs between impacts, ISO requires all categories of significance to be counted in publicly available comparisons. For issues such as microplastic pollution, where reliable indicators and quantification methods are not yet available, this limitation should be acknowledged. Where possible the risk of trade-offs should be identified. For example, moving to replace cotton with polyester in apparel may reduce water consumption and land use at the fibre production stage, but increase harm to marine and freshwater ecosystems and potentially human health due to microfibres.   

The three issues discussed as barriers to creating a level playing field for apparel sustainability assessment are data problems, methodology development, and incorrect application of tools such as LCA. Investments across the industry are improving data coverage and quality. Examples for wool include a new LCA study by The New Zealand Merino Company and an AWI survey to build on data and understanding of use phase. Continuing to report results and data and engage with organisations including the Sustainable Apparel Coalition will improve the quality of apparel sustainability assessments. Technical experts globally are working on new and improved impact methods and while expertise in correctly applying these methods is growing across the industry, vigilance is needed to ensure that not even unconscious bias undoes good progress towards a level playing field in this complex area.  

Dr Beverley Henry is an Adjunct Associate Professor at Queensland University of Technology, Australia, and a consultant with more than 30 years’ experience in research on environmental, sustainability and LCA issues.  


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