A comparative delve into the Higg Material Sustainability Index (MSI) methodology versus Green Story's LCA study

The blog series by Dr Subramanian Senthilkannan Muthu, PhD in Environmental Life Cycle Assessment is divided into three parts. In this third and final part, Dr. Muthu critiques the HIGG MSI and how this methodology differs from that adapted by Green Story.

HIGG MATERIAL SUSTAINABILITY INDEX

There are many possible methods and guidelines for measuring environmental performance, whether of products or organizations such as ISO 14040/44 standards, Product Environmental Footprint Category Rule (PEFCR) guidance, International Reference Life Cycle Data System (ILCD) Handbook.

Sustainable Apparel Coalition developed the Higg Material Sustainability Index (MSI) methodology to guide the environmental impact assessment of different materials. However, Higg MSI methodology has been under question for its methodological flaws. The methodological choices are based on the practical issues categorized below.

1. Guidance for comparative analysis and public disclosure

The Higg Index website and tool clearly encourage users to compare products, and therefore promote comparisons using a public platform. However, there are specific requirements to make comparative assertions for public disclosures. On the contrary, Green Story instead baseline the analyzed supply chain to estimate the marginal impacts or savings and also follows the requirement by ISO 14044 (section 5.3) to make any comparative assertions.

2. Choice of system boundaries and functional unit

The Higg MSI applies a cradle-to-gate system boundary compassing two out of four major lifecycle stages, without use phase and end-of-life. There has been no documented consideration and justification of this exclusion in the Higg MSI system, which is required as per ISO 14044, (section 4.2.3.3.1).

Green Story uses a flexible approach for system boundaries based on scope including cradle-to-gate, cradle-to-grave, and cradle- to-cradle systems. For screening LCAs, a simple explanation is provided in the LCA report regarding the exclusion of the use phase and end-of-life.

3. Choice of LCA methods and handling multi-functionality

LCA study may be conducted using either attributional (aLCA) or consequential (cLCA) methods. The choice of appropriate methods has been covered in the ILCD, and should avoid inconsistencies regarding the LCA method and allocation method. The Higg MSI method have not given prescriptive guidance regarding use of
aLCA or cLCA methods and do not give prescriptive guidance with respect to methods for handling multi-functionality, which leaves a degree of ambiguity in the Higg MSI and potential inconsistencies in the underlying datasets and results.

Whereas Green Story uses consistent methods for LCA studies with a clear description of the LCA method and any allocation applied in the report.

4. Data quality, transparency and handling of uncertainty

The Higg MSI database was found to rely heavily on three source documents: van der Velden et al. for yarn formation and preparation, Cotton Incorporated for colourisation and the Koç and Kaplan study for textile formation. These data points seem to be have been applied for multiple fibre types, resulting in a high
proportion of the resulting Higg MSI score relying on generalized data in the textile manufacturing processes. The heavy reliance on generalized data from a limited number of studies may not be representative of global textile manufacturing trends and has the effect of reducing the representativeness of the results for different
fabrics, and inherently reducing variability between fabric types because of the standardization of underlying datasets.

Additionally, Higg MSI contains no uncertainty analysis. It is therefore unclear whether apparent differences between fabric types are statistically valid.

Green Story uses the most representative data for the material and process and encourages the use of primary data. Secondary data is collected from Gabi 10.6.1 database, Ecoinvent 3.8 database, and the relevant literature. Primary data that is collected from suppliers is benchmarked and validated by textile experts before modeling. All the sources of datasets are mentioned transparently in the final LCA report. The uncertainty analysis is included in the comprehensive LCAs conducted at Green Story meant for public
disclosures.

5. Exclusion of important impact categories, LCIA methods and
coverage of non-LCA assessed issues

As per ISO 14040, comparative product assessment using LCA should employ a sufficiently comprehensive set of category indicators to be used for the decision-making process. The T-shirt PEFCR identifies acidification, climate change, resource use, respiratory inorganics, water scarcity, freshwater eutrophication and marine eutrophication as the most relevant impact categories for T-shirts. The Higg MSI currently reports impacts from a subset of LCA impact categories, namely global warming, eutrophication, water scarcity and abiotic resource depletion (fossil fuels). In addition to this, a qualitative assessment of impacts from chemicals is included. The outcome of comparing fabrics on a small subset of indicators is arguably insufficient to meet the comprehensiveness requirement of the standard.

Green Story reports and interprets a comprehensive list of indicators as included in EF 3.0, ReCiPe, TRACI, CML methodologies for comprehensive LCAs.

6. Weighting and normalization

The Higg MSI method involves a normalization and weighting process to aggregate impacts into a single score. Weighting has a significant impact on the Higg MSI score and the use of weighting values could result in unintended environmental outcomes and burden shifting when different fabrics are compared, Whereas

Green Story only assesses and reports the characterized results based on widely used methodologies such as ReCiPe, EF 3.0, TRACi, CML.

HOW DOES GREEN STORY HELP FASHION BRANDS?

Green Story’s work is aligned towards helping brands to trace their supply chains, identify their potential footprints, and devise strategies to reduce the environmental footprint of their products and organization as well.

Green Story via comprehensive LCAs helps brands to connect with their suppliers and provide visibility deeper into the supply chain.

In addition to analyzing the best possible representative LCA’s, Green Story provides numerous ad-hoc services to brands for their sustainability journey. These include but are not limited to:

• Achieving carbon neutrality through offsets
• Dissemination through webinars
• Training & knowledge transfer 
• Carbon footprint assessment
• Assessment of material circularity
• Impact reduction plans

LETTING CONSUMERS DRIVE THE CHANGE

With the world developing economically, more and more industries are flourishing, providing individuals with a wide range of choices and facilities. People are benefiting from industrial developments, but another side of the coin is that these industries are causing concern for the environment. With consumers knowing the environmental impacts and having the choice, more and more players will make a shift towards environmental-friendly practices, use materials that are grown organically or recycled, and invest in technologies that are less energy intensive and have less emissions. 

Watch our webinar

In this webinar we discuss the use and misuse of data in fashion's sustainability claims and the role of Life Cycle Assessment (LCA) plays in measuring the environmental impact of fashion. with Dr Subramanian Senthilkannan Muthu, PhD, Chief Sustainability Officer Green Story, and Katina Boutis, Director of Sustainability Everlane.

About Dr. Subramanian Senthilkannan (Kannan) Muthu, Ph.D.

Green Story is committed to sustainability through scientific means and correct procedures. The LCA and other sustainability initiatives at Green Story are led by renowned textile and LCA specialist, Dr. Kannan Muthu (Chief Sustainability Officer, Green Story). Please reach out to him at kannan.muthu@greenstory.ca.

Prior to Green Story, he led the Environmental Services Division-Asia of SGS and was head of Sustainability of SgT Group. With a PhD in Environmental Life Cycle Assessment in Textiles and Clothing, Dr. Muthu is a Textile Technologist and has published 140 scientific books and 100 research articles. He has over 12 years of experience in environmental and chemical sustainability and has worked with hundreds of factories and international leading brands’ supply chains. His body of work makes him one of the most respected and widely quoted figures in the field of LCA.