Last autumn’s revision of the Higg Index included new figures for leather, showing a substantially reduced environmental impact. Cascale also worked with 13 cotton industry bodies, following years of disparate figures, as data becomes ever more important to brands.

How can brands justify the choices they make when it comes to selecting materials and suppliers? It is not possible to make these decisions solely on cost as responsible business practices become more prevalent and incoming regulations such as the European Union’s (EU) Corporate Sustainability Reporting Directive and Green Claims Directive will require companies to be transparent about their choices. 

To analyse materials, more than 40,000 businesses use the Higg Materials Sustainability Index (MSI), a cradle-to-gate assessment tool that calculates environmental impacts and is operated by Cascale (formerly called the Sustainable Apparel Coalition, with the index hosted by Worldly). For each material, the MSI provides scores, taking into account the energy, water and chemicals used, as well as waste generation and water pollution. Environmental impact is measured  for global warming, nutrient pollution, water scarcity, abiotic resource depletion, use of fossil fuels and chemistry.

But trying to compare these materials, with a myriad of variables, is difficult, and there have been cries – particularly from natural fibres producers – that comparing certain data sets creates an unfair picture. This has partly been because natural fibres such as leather, wool and cotton are often assigned high carbon footprint figures because of the resources needed to grow or collect the fibres, and also because the figures stop at the gate (manufacturing). This means that the material’s durability – which some claim is the most important sustainability metric – is not considered. Other factors, such as microplastic migration and synthetic fibres’ inability to degrade, are also not represented, for instance in the European Union’s Product Environmental Footprint.

Over the years, the Higg Index has been criticised by several associations, including leather and wool industry representatives and in 2022 by the Norwegian Consumer Authority, which recommended its users stop backing claims with Higg data. In response, Higg temporarily suspended the MSI and commissioned a third-party review. Consultants at KPMG said it needed to improve the quality of data and add warnings to avoid inappropriate comparisons.

In the background, work was already under way to update the data attributed to cotton. Thirteen associations – including Better Cotton, Cotton Council International, Cotton Incorporated, National Cotton Council of America, Organic Cotton Accelerator and the US Cotton Trust Protocol – gathered online, initially monthly, as part of the Cotton Expert Team. Over three years, they worked to build a blueprint for cotton data. This included defining lifecycle assessment (LCA) data source requirements, modelling approaches and data-use best-practices, as well as addressing gaps or considerations outside LCA data. The task was to agree on the data needed, define a common template, the assumptions underlying the model, and the intended and allowed use cases. They also discussed the common figures existing in the literature.

Change of heart

For many years, associations have shied away from producing collaborative figures, so, what was the impetus for the change of heart? For Better Cotton, under which about 20% of the world’s cotton is grown, it was partly because pooling resources on LCAs meant money could be used elsewhere. “The opportunity to share LCA data as a united industry group has allowed us to continue targeting investment in our field-level programmes rather than channelling these funds towards Better Cotton’s own LCAs,” Miguel Gomez-Escolar Viejo, Better Cotton’s head of monitoring, evaluation and learning, tells us.

Better Cotton is a non-profit, multi-stakeholder governance group that promotes better standards in cotton farming across 22 countries. More than 2.1 million farmers have a licence to sell their cotton as Better Cotton and the network has more than 2,700 members. Miguel Gomez-Escolar Viejo notes a global LCA for Better Cotton could not capture the regional nuances, but however, country-level LCAs could link the data to physically sourced cotton and further incentivise brands to invest in improvements. “What is exciting about this new LCA is the sheer amount of data we have used,” he adds. “Data has been collected from over 60,000 farmers. Using all our farm-level data is a truly exciting way to better reflect reality and lay the foundations for targeted farmer support that helps tackle their environmental footprint.”

For the US Cotton Trust Protocol, which launched in 2020 and covers more than 2 million acres, data is key and updating the current sets was a key driver for collaborating. “Our shared goal is to enhance the depth and quality of data within the Higg MSI methodology and results,” Daren Abney, CEO of the Protocol, tells Footwearbiz. “Other than data from Australia, Better Cotton in India and the US Cotton Trust Protocol, as of today, other datasets are old and of poor quality – with some dating as far back as 2007. As such, this collaboration is crucial for improving the accuracy and representation of future assessments, ultimately benefiting the entire cotton industry.”

Geographic nuances

So, what has changed? The updated dataset incorporates more recent information for the US, Australia and India and is more likely to reflect differences between geographies. The modelling, data collection methods and the year of data collection are different, and variations will also arise in some of the metrics. However, specific differences in results depend on the impact category being considered. Mr Abney points out that harmonisation always comes with a set of limiting assumptions. “Differences in data between the Higg MSI and data reported directly by the Trust Protocol can arise from variations in methodologies, scope, background data and data collection periods,” he says, but adds that overall, it can identify areas for improvement and drive positive change. 

Cascale (which did not respond to interview requests) said the new cotton LCA methodology offers  “unprecedented accuracy and consistency”. “This new methodology provides businesses with reliable data to make informed sourcing and sustainability decisions,” it added.

However, the cotton associations warn against comparison. “Sharing Better Cotton-specific LCA data may have several positive and negative impacts that we are currently evaluating,” explains Gomez-Escolar Viejo. “We understand the initial desire is for users to compare the data sets from different regions and programmes, or against conventional cotton production. However,  these are not valid comparisons and they can lead to inaccurate conclusions that do not support the industry in working towards the collective environmental footprint reduction of cotton production. 

“For one, this data should not be used for sourcing strategies since LCAs are only telling part of the story of cotton, and do not cover or reflect any social or economic impacts, weather variability or seasonal differences, among other factors. For example, an LCA reflecting a year in which extreme weather events led to lower yields would reflect differently to an LCA covering a year in which there were no such events, without creating space to explain the impact external variables had.”

The LCA data for India is the first set of figures within this model, and it cannot be compared with any previous data sets. Better Cotton will update data from the same regions at regular intervals, which will make these data sets comparable and show change and improvements over time.

“Previously we took the position that we were not in favour of publishing a global Better Cotton LCA, since it would not reflect regional nuances, challenges and priorities,” adds Mr Gomez-Escolar Viejo. “However, if the only use case for this dataset would be to account for Scope 3 greenhouse gas emissions, a global Better Cotton figure could be useful and considered the ‘best available data’. Cotton production emissions datasets seem to be a requirement from brands since they are increasingly under legislative pressure to substantiate their sustainability reporting with data. It is important to remember that good data used poorly would be akin to using inaccurate data.”

With cotton being the world’s second-most used fibre, according to the Textile Exchange at 22% of global usage (although this is half that of polyester, at 54%), the need to grow and buy responsibly is pressing. The Higg MSI will be updated bi-annually and cotton programmes will, in the future, be able to add data directly to the index. Eventually, users will be able to select specific cotton programmes and regions, said Cascale, adding the cotton Member Expert Team (MET) has inspired new workstreams, including a textile wet processing MET. “In the future, other fibres may come forward for a data overhaul,” it added.

Leather turnaround

Other fibres did come forward for data overhaul – last autumn, the figures for leather on the Higg MSI were substantially reduced.

In 2020, several leather industry bodies requested that Cascale suspend leather’s MSI score due to “inappropriate methodologies” and “out-of-date, unrepresentative, inaccurate and incomplete data” that had led to leather being burdened with a disproportionately high score. “This has led to a negative perception of leather that does not reflect its sustainable, circular nature,” said Dr Kerry Senior, then-secretary of the International Council of Tanners. “On the basis of the current Higg score, manufacturers are deselecting leather in favour of fossil fuel-derived, unsustainable synthetic products,” he said at the time. Cascale did not suspend the score, but opened consultations.

Although it was not announced by Cascale, last October consultancy Spin360, multi-stakeholder initiative The Leather Working Group (LWG) and promotion body Leather Naturally announced new figures for bovine leather had been adopted by the MSI, on the back of a joint body of work that included data from 45 manufacturing facilities across 18 countries and evaluated 92 leather products. It also encompassed information from the footwear, automotive, leathergoods and upholstery sectors. From this, the values were revised, with reductions across every Higg MSI category – global warming potential, eutrophication, water scarcity, abiotic depletion and chemistry.

“While anyone can submit a new dataset to the Higg MSI that is attributable to their company, our aim was to update the global default value for leather,” Debbie Burton, director of communications at Leather Working Group, tells Footwearbiz. “Ultimately, the size of the dataset at 92 specific leather articles, as well as the geographical and technical representativeness of the dataset, were the main attributes of this work for the sector and for Cascale, providing more accurate data for a global average.”

The new dataset, included in the October 2024 update of the MSI, resulted in the environmental impacts of bovine leather being between 55% and 67% lower than the previous MSI value. The global warming potential, which previously showed an impact of 36.8 points on the scale, has been reduced by 60% to 14.6 points. 

 “While the Higg index clearly advises users not to compare different materials (for example, leather versus cotton) and instead encourages comparisons within the same material category (eg, chrome-tanned versus glutaraldehyde-tanned leather), the practice of cross-material comparison remains,” states Leather Naturally. “Consequently, it was crucial to provide design and sourcing teams with the most reliable and comprehensive data available. Although there is still room for improvement, this dataset offers a clearer and more accurate picture than ever before.”

“This is a significant step forward,” concludes Spin360 CEO Federico Brugnoli, “as an important player has recognised that LCA primary data, obtained with verified methodologies, can have a positive global impact for the leather industry.” 

The Air Jordan Mid Subway is made with water-resistant leathers for durability. Designers and sourcing professionals will be able to make more informed decisions about leather when using the Higg suite of tools.
Credit: Nike

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