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Wool industry completes world’s first peer-reviewed textile fibre cradle-to-grave Lifecycle Assessment (LCA) study

Pitch #1: Wool industry completes world’s first textile fibre cradle-to-grave Lifecycle Assessment (LCA) study taken to peer-reviewed publication.

Key messages:

  1. The world’s first peer-reviewed textile fibre cradle-to-grave LCA study has now been published in The International Journal of Life Cycle Assessment. Titled Environmental impacts associated with the production, use, and end-of-life of a woollen garment, this study brings together 10 years of Woolmark-funded research.
  2. Garment users have the ability to influence the environmental impact of their clothing.
  3. To date, published wool LCA studies have investigated the farm stage and the early stages of wool processing. This study however takes into account all life stages of a garment, including the use phase and end-of-life.

What the study says:

This study brings together the past decade of The Woolmark Company's eco-credentials research across all life stages, from the farm to end-of-life and contributes to Woolmark's strategy of positioning wool as a leading and forward-looking industry, carefully stewarding the environment.

To date, there have been limited life cycle assessment (LCA) studies on the environmental impacts of the full supply chain including the use phase of garments, with the majority of LCA studies focusing on a segment of the supply chain. This study aimed to address this knowledge gap via a cradle-to-grave LCA of a woollen garment.

What the study found was that the number of times a garment is worn is the most influential factor in determining garment impacts. This indicates consumers who are aware of wool’s attributes have the largest power to influence the sustainability of their wool garments by maximising the active garment lifespan and therefore reducing overall impacts.

What did the study measure?

This study investigated greenhouse gas emissions, fossil fuel energy and water stress associated with the production, use and end-of-life of a lightweight woollen sweater, together with inventory results for freshwater consumption and land occupation. Primary datasets were used for the wool production and wool processing stages, while primary datasets relating to consumer garment use were supplemented with literature data. Impacts were calculated and reported per garment wear event.

Wool’s long life:

Consumers, or garment users, were found to have a significant role in determining the period of time that garments remain in active use, which is the most influential factor governing environmental impacts. Quality clothing in use for longer periods needs to be replaced less often, reducing the need for new resources to manufacture replacement clothing.


Pitch #2: Consumers hold the power to influence clothing’s sustainability, study finds

Key messages:

  1. The sustainability of clothing is strongly influenced by the number of times it is worn and how long it is kept in active use.
  2. Garment use (and reuse) is the most influential factor determining the impact of wool garments, so extending garment lifespans offers the highest potential for environmental gains.

How often clothes are worn is the most influential factor in determining environmental impacts from clothing, according to the world’s first peer-reviewed textile fibre cradle-to-grave LCA study.

What garment was tested?

The garment was a unisex, lightweight woollen sweater containing 300grams of fine Merino wool, with a micron of less than 20.

One garment wear included an average of 0.2 washing and drying cycles and was 0.92% of the total life of the garment. The full garment life was 109 wears.

What was the length of the use phase?

The use phase was defined as the total number of times a garment was worn by a first and subsequent owner of the garment. The average number of lifetime wears for the first user was 79 wears - the average of male and female users was sourced from a wardrobe survey of 1111 consumers from China, Germany, Japan, the UK and USA.

The second use phase (reuse) was treated as an extension in the number of lifetime wears, with a single washing process included between the first and second user. The rate of garments donated for reuse was 76.1% from the consumer survey data.

It was assumed that the second use phase was half the length of the first, averaging 39.5 wears. For comparison, the study also modelled impacts with the maximum reported garment wear life in the survey data which was 400 wears.

Why is garment lifespan important?

The purpose of clothing is to be worn and the more often it is worn over its lifetime, the more completely it fulfils its purpose. Consequently, this study calculated the lifetime impacts of the garment per single wearing event. Unsurprisingly, the duration of garment lifetime was found to be the most influential factor determining the impact of woollen garments. In the present study, the total number of wears was estimated to be 109. However, if this garment was disposed of after only one season, or 15 uses, this would result in a 5.8- to 6.8-fold increase in environmental impacts and resource use. Conversely, increasing garment lifetime (provided the garment remains in active use) reduced environmental impacts.

The survey completed for this study showed woollen sweaters in consumer wardrobes had been purchased between <1 year and up to >30 years ago, and some survey respondents reported garments had been used for >200 times and were expected to be used for a further 200 or more times. Increasing the total number of wears to 400 reduced environmental impacts by 49 to 68%, indicating substantial improvements are possible if a garment’s lifetime is extended.


Pitch #3: Why fashion urgently needs to upgrade its eco rating tools

Key message:

A review of a leading environmental impact rating tool for apparel finds that unless improvements are made, weaknesses in the underlying science could lead to misleading ratings, potentially guiding well-intentioned consumers to less sustainable products.

What do textile lifecycle assessment tools do?

Lifecycle assessment tools measure the impact of textile on the environment over all life stages, from raw material production through processing, manufacture, distribution, use, recycling and ultimately disposal.

LCA is a young science which is still evolving and environmental ratings agencies such as the Sustainable Apparel Coalition (SAC) do not yet account for all life stages in their environmental rating index, known as the HIGG material sustainability index (MSI).

The MSI is increasingly being adopted by industry but this LCA tool only currently accounts for the front-end of the supply chain, up to the retail outlet. Without including key environmental impact stages such as the use phase and garment end-of-life in the MSI, comparisons between fibre types are not meaningful. If not addressed, these inconsistencies could guide well-intentioned consumers towards less sustainable fibre choices.

“Several significant environmental impacts and processes are excluded from the MSI including the use phase, recyclability, biodegradability, renewability of resource used, microfibres, abiotic resource depletion (minerals) and abiotic bioaccumulation,” said Dr Steve Wiedemann of Integrity AG & Environment. Until addressed, these omissions limit the scientific robustness of the MSI and could lead to less sustainable fibre choices, which may compromise the SAC’s goal of promoting a sustainable apparel industry.

Key findings:

The EU is taking the lead on LCA methodologies and its Product Environmental Footprint (PEF) program considers potential environmental impacts across a range of products, including Apparel and Footwear.

The Woolmark Company has been, and continues to be, an active contributor to the environmental assessment processes undertaken by organisations such as the Sustainable Apparel Coalition. The wool industry funds much-needed research to help develop a robust and scientifically defendable methodology for environmental assessment of the textile industry. The wool industry has a seat at the table at key technical forums in the EU to drive responsible change in the fashion industry so the environmental footprint of garments can be correctly assessed. Such assessments are vital for identifying the environmental hotspots where our efforts need to be focused to further reduce the footprint of wool clothing.

Supporting documents:

Merino wool does not contribute to the global microplastics problem
Read more about wool's environmental footprint