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Life cycle assessment (LCA) explained

February 4, 2022
Data & transparency

Learn everything you need to know about Life cycle assessment (LCA) in our 3-part LCA blog series. In this series, you will learn the fundamentals about life cycle assessment (LCA), such as what is an LCA, how it works and the benefits of life cycle analysis as well as the challenges in LCA studies. In addition, our senior LCA analyst Dr. Karpagam Subramanian, PhD in Environmental and Social Sustainability, will share her knowledge and experience of working with brands like PANGAIA, thredUP and BAM Bamboo Clothing, on LCA studies, including her expert tips on how to do a product life cycle assessment.

Increasingly, European regulators are looking into environmental claims in the fashion industry. In late 2021, the Dutch Consumer and Market Authority (ACM) started investigating several brands with misleading claims about sustainability in the apparel sector. Earlier this year, the UK Competition and Markets Authority (CMA) officially announced that a review of environmental claims in the fashion retail sector is in motion. The Danish Consumer Ombudsman authority has recently published guidelines on the use of environmental claims for businesses and brands engaged in green communication. Any sustainability claims companies make must be based on a life cycle analysis data.

However, an apparel product’ life cycle is rather complicated as it involves many phases such as fiber and yarn production, textile manufacturing (weaving, sewing and dyeing), assembly, packaging, transportation and distribution, consumer use, disposal and recycling. Every step of the entire value chain has an environmental impact. In the words of Dr. Kannan Muthu, world renowned Life Cycle Assessment specialist, at Green Story we believe that the “only way for brands to claim a product is sustainable, is to perform a robust LCA, otherwise it will be regarded as greenwashing”. Our Know Your Impact solution has helped 150+ brands gain accurate life cycle analysis data of their products and visualize their environmental impact with credible, verifiable and relatable metrics. To date, we have analyzed more than 2,000 supply chains in the fashion space across 35 countries.

Life cycle assessment (LCA), which is also called environmental LCA, is an internationally accepted and widely used methodology for evaluating the environmental impact of a product. It allows objective and scientific evaluation of the resource requirements of a product and its potential impact on the environment during every phase of its lifecycle.

Before diving into the world of LCA, it is important to have an understanding of the different life cycle stages a product goes through in fashion. This also gives you an overview of the supply chains involved in an LCA study as they are closely connected. The supply chains in fashion refer to the process of tracing each step of the apparel manufacturing process, from raw material sourcing, to the factories where suppliers process these materials into garments; and the distribution network by which the final products are delivered to consumers.

What does a product life cycle typically look like in fashion?

  • Fiber Production. This process covers the extraction and processing of fibers. It includes all sub-processes such as the cultivation of crops, scutching, degumming, ginning etc., depending on the type of fiber.
  • Yarn Manufacture. This includes the spinning of yarn of either filament or staple fibers. It includes all related processes such as carding, combing, roving and spinning for natural/cellulosic fibers and wet spinning processes for synthetic fibers.
  • Fabric Manufacture. This process covers the knitting and weaving of yarn into fabric and considers all sub-processes of sizing and warping, sanforizing, and compacting.
  • Dyeing and Finishing. This includes the scouring, bleaching, dyeing, and fabric finishing processes and sub-processes such as water softening processing and wastewater treatments.
  • Assembly. Covers the cutting and sewing of fabric into apparel products. It includes steam and ironing of clothes before packaging.
  • Distribution. This process considers the transportation from the assembly location to warehouse/store and from warehouse/store to end-users.
  • End of life. Involves the collection and management of apparel products at the end of their useful life (reuse, recycling, incineration and landfilling).

What is an LCA exactly?

LCA is an analytical tool to quantify the energy consumed, materials used and emissions to air, water and soil from a product throughout its life cycle, i.e. cradle to grave, covering raw material acquisition, production and assembly, transportation, to product use, reuse, recycle and disposal by documenting the inputs (material and energy flows) and outputs (emissions to air, water, soil and solid waste) and aggregating the environmental impacts resulting from the consumption and emissions.

When zooming in on the lifespan of garments, there is no doubt that the production of garments has a significant impact on resource availability and the environment. The production of raw materials, the extraction of energy as well as the manufacturing of textiles release greenhouse gas to the air (i.e., CO2 and methane), Nitrogen and Phosphorus to the water, and chemicals and pesticides to the land. Life cycle assessment (LCA) is an important scientific tool that can help to understand the complexity of apparel’s environmental burdens and provide an accurate assessment of its potential environmental impact. It provides a holistic approach that incorporates upstream activities in the supply chain and downstream processes after manufacturing.

LCA is not the same as “footprinting.” Although the two terms are sometimes used interchangeably, footprinting is a subset of LCA that only takes into account a single metric (Deloitte Consulting LLP, 2012). For example, carbon footprint, water footprint, energy demand are subsets of LCA. Increasingly, LCA-based carbon foot printing has become popular, especially when being evaluated for environmental policies focusing on global warming issues.

There are two international standards when it comes to LCA standardization. The International Standards Organization (ISO) created principles and framework (ISO 14040) and requirements and guidelines (ISO 14044) for conducting LCA studies. According to ISO 14040, the general methodological framework for LCA has four stages: the goal and scope of the LCA, life cycle inventory (LCI), life cycle impact assessment (LCIA) and interpretation of results.

1. Goal and scope of your LCA

Defining the goal and scope is the first step in an LCA study. Here, it is important to understand the purpose and the intended application of your LCA study, as well as defining what product and how much of the product will be analyzed. This is called a functional unit in LCA studies. A functional unit is a quantified description of the function of a product that serves as the reference basis for all calculations regarding impact assessment . It is necessary to ensure the comparability of results. For example, in comparative LCA, 1 kilogram of finished garment made from organic cotton is evaluated against the same functional unit of product made from conventional cotton.

Besides defining the product to be assessed, you need to determine the scope of the product life cycle, which is known as system boundaries in LCA studies. Where does the life cycle end in the given product’s lifespan? It can be from cradle to gate, which ends before the use stage. Or, it can be from cradle to grave, which is the end of life, when an apparel is at disposal of wastes. A defined product system is essential to data collection at stage 2, life cycle inventory.

Finally, you need to define the environmental impact categories or performance indicators in order to understand your LCI results. Impact category examples include global warming potential (e.g. GHG gas emissions), primary energy demand from renewable and non-renewable resources (e.g. fossil fuel), blue water consumption, etc. Global Warming Potential (GWP), Primary Energy Demand (PED) and Blue Water consumption (Water) are commonly used as impact indicators in LCA studies. The combination of these three categories builds a holistic perspective of the primary impacts on nature and the environment.

2. Life cycle inventory (LCI)

The second stage of an LCA study is life cycle inventory, where the data to quantify your product’s resource use and emissions gets compiled. LCI provides an inventory of the energy and material flows taken from and released to the environment. For example, material, water and energy are your product’s input, and final product, by-products, and all the releases to air, land, and water are your product’s output. Only activities inside your product system (as defined in stage 1, the goal and scope of the LCA) are considered for collecting the environmental input and output data.

Life cycle inventory is considered the most time-consuming phase in an LCA. Here, your production processes and supply chains are being mapped out and evaluated. Due to the high volume of product variety in fashion, the supply chain structure is very complex. Usually, brands work with production partners and manufacturing suppliers to gather first-hand data (as known as primary data) for the fabric types used in clothing products. When primary data is unavailable, secondary data from LCI databases such as GaBi and Ecoinvent can help fill in the data gaps for the needs of data collection. The level of accuracy and the quality of your data collection can significantly influence your LCA analysis and results.

3. Life cycle impact assessment (LCIA)

Following LCI, a life cycle impact assessment (LCIA) is the third step of the LCA method. Here, you will get a quantitative assessment of the environmental impact of your product by assigning your LCI results to the predefined set of impact indicators. For example, CO2 gases emitted in the life cycle of the studied product are calculated and then related to the functional units. Global Warming Potential (GWP) is measured in CO2 equivalents.

Typically, impact categories are evaluated with the specific category indicators as the following:

  • Climate change, kg CO2 equivalent
  • Water depletion, m3
  • Fossil depletion, kg oil equivalent
  • Terrestrial acidification, kg sulfur dioxide (SO2) equivalent
  • Freshwater eutrophication, kg phosphorus (P) equivalent

4. Life cycle Interpretation

Life cycle interpretation is a combination of all the four stages of LCA. It reviews, quantifies and evaluates the results of LCI and LCIA, giving you valuable insights into product design, production process and downstream activities. It can contribute to making informed decisions to minimize and mitigate environmental impacts or to improve the long-term sustainability of your product and your supply chains.

According to ISO 14044, life cycle interpretation comprises the following elements: i) an identification of the significant issues based on the results of the LCI and LCIA phases of LCA; ii) an evaluation that considers completeness, sensitivity and consistency checks; iii) conclusions, limitations, and recommendations. This means that careful interpretation of results can help to improve the quality of the outcome, i.e. your decision-making process for sourcing or design. However, when making external claims, it is important to communicate your LCA results in a fair, complete, and accurate manner.

In the next LCA blog, we will be discussing the benefits as well as the limitations of life cycle assessment. In addition, we will share our thoughts on the best approach to interpreting, communicating and reporting LCA results. Stay tuned!