the sac blog

SAC Responds to Leather Industry Concerns Over Higg MSI

October 15, 2020

The Sustainable Apparel Coalition believes that active engagement with all interested stakeholders across the value chain is not only beneficial, it is essential to achieving our vision of transforming business for exponential impact. 

We recently received a letter from a coalition of leather industry representatives expressing concerns about the Higg MSI impact score for leather. As part of our commitment to engagement, we welcomed the opportunity to respond to the group’s concerns. The comments below are reflective of our response, the full text of which is available here.


The Sustainable Apparel Coalition (SAC) is committed to driving exponential improvement for the apparel industry through collective action. Through the Higg Index suite of tools, made available on the platform, the SAC is developing and implementing science-based tools and best practices with our 250-plus members to track and measure social and environmental performance.

Transparency is paramount to the work of the SAC, as is our steadfast commitment to collaboration and multi-stakeholder engagement. We welcome an open dialogue with industry partners, such as the International Council of Tanners and others, to ensure that our tools and methodologies reflect the most current peer-reviewed science. One of our key goals is to provide the tools and data necessary to help Higg Index users to identify and improve the sustainability performance of all types of fibers and materials.

The fundamental purpose of the Higg Materials Sustainability Index (Higg MSI) is to support apparel, footwear, and home textile designers and developers in making more sustainable material choices, leveraging independently-verified data and insights and providing insights across the range of environmental impacts associated with materials production. All background life cycle impact assessment data in the Higg MSI comes from ISO-compliant studies and commercial databases, primarily the GaBi database by Sphera.

The Higg MSI data is updated twice a year to include new and updated data submissions to reflect best-available information. We are not planning to suspend the score for leather at this time but continue to work on plans  to improve the tools over time; something we’ve been committed to from the outset.  We know there is always more work to be done. To ensure the highest accuracy of Higg MSI data, the SAC regularly engages with industry partners and invites them to submit new and updated LCA data.

Below are some of the questions the SAC has been asked about the Higg MSI methodology:


Q: What steps are you taking to integrate up-to-date data to represent the current status of the leather supply chain? 

SAC has been in discussion with the Leather Working Group (LWG) to identify credible data sources that can be used to update this information (such as: livestock rearing practices and economic allocation factors) and that can be maintained for annual updates. We welcome data sources that can be used to update the time representativeness of the current cow hide datasets.


Q: How are you reflecting the varying impacts of the different farming methods used in the rest of the world, outside of the U.S. and Brazil?

SAC agrees that it would be beneficial to have more geographical coverage to reflect farming methods in different regions.  We are in dialogue with the LWG to identify potential sources of information that would enable expanded coverage accordingly.


Q: The lifespan of a typical beef animal is usually between 12 and 36 months, although the Higg MSI current assumes a five-year lifespan. Will you take steps to address this issue? 

The Higg MSI relies on external data and contains several options for cow hides that are built from US and Brazilian cattle models. The dataset for Brazilian cattle, reflecting pasture-raised Brazil cattle, does currently assume that the lifespan of the cattle is 5 years. We have already identified this as an assumption that we will be requesting Sphera update for this data set.


Q: Will the Higg MSI take into consideration types of leather produced, e.g. splitting of hides into grain leather and suedes? 

Given the Higg MSI displays all materials in “per kg” impacts, there are no impact differences from the splitting of hides. Splitting leather increases the surface area of the actual leather product, and the result of this would be reflected in the Higg Product Module (a new tool that enables a shift from looking at material impacts only to total product life cycle impacts).


Q: Do the multiplication factors artificially distort the Eutrophication and Resource Depletion scores for all natural fibres in the Higg MSI, including leather, compared to synthetic materials? 

This is an incorrect interpretation of the Higg MSI normalization approach. We would encourage closer review of the tool’s methodology document. The Higg MSI uses a “reference system” approach to normalization. What this means is that we’ve calculated the global material production impacts for the apparel and footwear industries and compare the results to this context. Notably, this is the same type of approach that the European Commission’s Product Environmental Footprint normalization methodology uses, albeit for global production as the reference system. In the Higg MSI, 10 points represents the impacts of an average apparel/footwear material for each impact category.


Q: Can you provide more insight into the methodology for the impact of Chemistry assessment in the Higg MSI?

The Chemistry methodology is provided in the Higg MSI methodology document. While it is true that the impact method used is not a standard quantitative LCIA method, the semi-quantitative approach developed and approved by the SAC Chemistry Task Team and Product Advisory Council was done to reduce the differences in scores between different materials. This recognizes that in many instances, chemical inventories and flows in LCAs are incomplete. If the USEtox chemistry LCIA methodology was directly applied, the difference between leather, natural fibers, and synthetic fibers would be orders of magnitude larger than they are in the current version of the Higg MSI.


Q: Why does the climate impact not take account of advancements in climate studies and in particular, GWP*?

The Higg MSI uses the IPCC 2013 GWP100a global warming potential (GWP) LCIA impact methodology. This is the most broadly accepted and up-to-date method to measure greenhouse gas emissions. The emission factors are developed and updated by the International Panel on Climate Change (IPCC) climate scientists, with the current emission factors coming from the most recent report, the fifth assessment report (AR5).  It is also the methodology recommended by the GHG Protocol and the majority of accounting standards. The IPCC 2013 GWP100a methodology already acknowledges that there is a small difference between the emission factors for biogenic methane and fossil methane and that is included (28 vs 30).


Q: Why does the Higg MSI use cradle-to-factory gate and not recognise the use and end-of-life phases of a product? 

The Higg MSI is a cradle-to-gate assessment to help brands and manufacturers understand the environmental impacts and hotspots related to the production of different materials. It does not replace other sourcing considerations, nor does it claim to. Commercial considerations such as quality and price already have wide scale methods available for standardized comparability (ex. ISO, ASTM, AATCC standards) and the Higg MSI is meant to fulfill this for environmental considerations. The Higg MSI is additive to other commercial considerations, it does not replace them. The Higg MSI is only one tool in the Higg Index suite of tools and with the recent launch of the Higg Product Module (PM) we expect to see brands and manufacturers extending their environmental considerations through the product lifecycle, moving towards products as the unit of comparison rather than materials, given the variability around the ways materials can be used. The second edition of the Higg PM, launching next year, will include consideration of use and end-of-life, including material and product quality, repairability, and the use phase. As has always been the case in terms of evolution of these industry tools, we welcome further conversation and contribution of relevant data on how to include the aspects of durability and repairability of leather into the Higg PM assessment framework.