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How the Higg Index is heroing plastic
and condemning natural fibers.
The Higg Index is a transparency program developed by an alliance of global brands called the Sustainable Apparel Coalition (SAC) to compare the environmental impact of different materials.

Transparency is a critical step to transform the industry through accountability. The premise of the Higg Index is important, necessary and urgent. Yet it is completely flawed.

The aim of the Higg Index is to ward consumers from brands giving a false impression of their environmental impact or presumed benefits. To that end, the European Green Deal is considering using the Higg Materials Sustainability Index (MSI) data to influence its “Substantiating Green Claims” legislation and Product Environmental Footprint (PEF) tool, a Life Cycle Assessment (LCA) based method to quantify the relevant environmental impacts of products.

However, an article in the New York Times posted on June 12th, 2022, has heavily criticised the Higg Index and the methodologies used. It also addresses the problematic governance of the SAC whose members include most of the largest fast fashion houses who use large amounts of polyester and other petrochemical fibres. An article in The Intercept on June 3rd, 2022, has also highlighted the repeated criticism by analysts of the Higg MSI for using dubious data to promote polyester as the most sustainable fabric available. The use of the Higg data by brands to market their “positive environmental impact” on clothing labels has also been declared illegal by the Norwegian Consumer Authority on the basis of greenwashing. It concluded that the data was misleading to consumers and the claims unsubstantiated. Off the back of this H&M has suspended its use of product labelling tool. 

Today more than ever, understanding the flaws of the Higg Index methodology is imperative. Veronica Bates Kassatly, a fashion industry independent analyst and critic of the industry’s sustainability claims, says the widespread adoption of the Higg Index tool to support sustainability claims risks “taking the industry backwards”.

The Higg Materials Sustainability Index is pushing global apparel brands away from natural fibres and towards polyester which are based on petrochemicals. This despite synthetic fibres being a major contributor to microplastic pollution and contributing 35% to the total amount of microplastic ocean waste.

According to the index, wool has a total MSI impact of 81 per kg and silk, another natural material, of 1,086 per kg — while fast fashion favourite, polyester, has a total impact of only 36 per kg. These ratings are coming under fire from independent experts as well as representatives from natural-fibre industries. As these ratings are based on flawed methodologies, incomplete data sets and select criteria.

The huge risk here is that this becomes a justification for the increased use of polyester and other synthetic fibres, rather than more sustainable natural fibres. So what is the reason the Higg index is so flawed?
"According to the Higg Index, wool has a total MSI impact of 81 per kg, while fast fashion favourite, polyester, has a total impact of 36 per kg."
1. The Higgs Index only calculates cradle to gate impact.

This means it measures the impact of a material from resource extraction (cradle) to the factory gate. It does not consider the full life cycle of each material, with post-purchase impact and end of life impact not taken into account. This is massively problematic. In the case of synthetic fibres, micro-plastics shed with every wash and enter our hydric resources. The toxic impact of materials treated with Fluorocarbons (PFCs) is also not considered — a long chain chemical used to make textile water repellent. PFCs slowly leach from the fabrics and gradually find their way into the water system. Over time, they bioaccumulate in the environment and enter the food chain, with the potential to cause health problems for both wildlife and people.

The material’s water consumption and CO2 emission during a garment’s lifespan, and waste pollution at the end of a garment’s lifetime are also not considered. This impact occurs downstream in fabric use and disposal.  As a counter to this, wool is 100% biodegradable, incredibly long-lasting and does not require to be washed as often as synthetic materials thanks to its incredible antibacterial properties. Its lifetime, cradle to grave impact (from resource extraction to manufacturing, transportation, product use, and ultimately, disposal) is significantly lower than that of polyester.

We are not saying the Higgs index is lying. We are saying it is telling an incomplete, skewed version of real impact.
2. The Higg MSI data and methodology is intransparent.

The Higg MSI collates secondary data from life-cycle analyses performed in the industry. A lot of this research seems to be funded by trade associations or large fashion brands that may have a vested interest in synthetic fibres. And the large majority of the data is not publicly accessible nor peer-reviewed.

In addition, the SAC doesn’t disclose the methodology to calculate the scores or the concrete data used in each score. The SAC also repeatedly seems to have been reluctant to disclose information on this. By way of example, when the SAC recently increased the score of silk from 681 to 1,086 and decreased the score of polyester from 44 to 36, it offered no explanation about the rationale behind this.

In such a critical tool such as this, it seems imperative to aim for maximum transparency in the calculation methodology and data sourcing to help fashion industry participants and consumers to make informed decisions.
"It only measure the impact of a material from resource extraction (cradle) to the factory gate. It does not take into account the full life cycle of each material. The post-purchase and end of life impact of the item of clothes is not being taken into account."
3. The Higg Index makes no distinction in how the materials were sourced and ignores social impact.

The data on the environmental impact of Silk, the worst-rated material on the MSI, was drawn from a 2014 study of 100 silk farmers who rely on irrigation in a single state in India. The lead researcher from this study, Miguel F. Astudillo, told the New York Times, as reported in their article “How plastic giants recast plastic as good for the planet” that the study was not representative of the global industry and was unaware it was being used by the index.  The same unfair approach was also taken when measuring the impact of polyester. This was calculated using data on European polyester production, yet 93% of polyester is produced in Asia, where manufacturing, energy standards and environmental laws for the disposal of chemical waste are very different compared to EU standards and vary wildly between nations.

Where and how the raw materials are sourced has a huge amount of impact on the final figures.

In 2019 Veronica Bates contacted the Sustainable Apparel Coalition enquiring on whether the Higg intended to amend its score for organic cotton, as a significant percentage is sourced from Xinjiang, and discovered to be tainted with prison, child and forced labour. The reply she received, as she reports in her article “Was it plastic all along”, was “The Higg MSI does not measure social impacts, nor does it claim to.” What this fundamentally means is that whether the material was sourced from the world’s most over-farmed land by the world’s most exploited farmers or by a farm that adopts regenerative farming practices and pays its people above minimum wage makes absolutely no difference in the way the index rates it’s environmental sustainability.  Environmental sustainability cannot exist without the safeguarding of human rights. The two are intrinsically tied.
This lack of nuance to the data is glaringly apparent in its treatment of wool.

If the Higg MSI data was used to influence the European “Substantiating Green Claims” legislation, no distinction would be made between the wool we source from regenerative farms and the wool the Sustainable Apparel Coalition examined for its Index. Regardless of the fact our farms are able to naturally sequester -14kg CO2 per kg of wool produced. We also worked with an independent third-party, Carbon Footprint Ltd. to calculate and verify the negative carbon profile of all our knitwear via an unbiased Product Life Cycle Assessment (available here) from cradle-to-grave that aligns with the Carbon Neutral protocol.

In May 2019 the International Wool Textile Organization (IWTO) called for the inclusion of full product life-cycle impacts in the Higg Materials Sustainability Index. In June 2021 the Sustainable Apparel Coalition launched the Higg Product Module, which assesses the environmental impacts of a completed product. Once again this only calculates cradle-to-gate impacts, with a promise that upcoming releases will calculate the impact of a product's full lifecycle (cradle-to-grave) therefore also accounting for consumer impacts and end of life disposal. Until then, unfortunately, polyester and fossil fuels that are found in 65% of all garments will continue to be heroes, rather than villains.

Once again, the fashion industry has to change. But let’s use the right tools and the right data to move the industry forwards. Not backwards.

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