Life Cycle Assessment

What’s My T-shirt Have to do With it?

By: Leo Wiegman

“Cradle to grave designs dominate modern manufacturing” architect Bill McDonough and chemist Michael Braungart,(2002) Cradle to Cradle: Remaking the Way We Make Things. www.mbdc.com

T-shirts are arguably the most popular and common clothing item on Planet Earth.

Life cycle assessment—often abbreviated as LCA and also termed “life cycle analysis,” “cradle to grave,” or “material flow analysis”—is the study and valuation of the environmental impacts of a specific product or service made necessary by its existence.

A product system, or life cycle, can begin with extracting raw materials from natural resources and generating the energy needed to produce the goods. Materials and energy are integral to production, packaging, distribution, use, maintenance, and eventually recycling, reuse, recovery or final disposal.

The US EPA National Risk Management Research Laboratory has a more detailed definition that you can read here.

In the case of a T-shirt, the life cycle stages involve a wide variety of impacts including fertilizer and vehicle fuel used to grow cotton, water to irrigate the crop, dyes and water used to manufacture the fabric, fuel and other energy used to transport and distribute the t-shirt, as well as bleaches and detergents used by the end user to wash the shirt.

In other words, we should study and quantify both the process of how a product is created and the impact of using and disposing of the product itself.

The International Organisation for Standardisation (ISO), in particular, provides ‘principles and framework’ in ISO 14040 and ‘requirements and guidelines’ in ISO 14044 that are voluntary for its 165 member nations.

Environmental management standards in many industry sectors are beginning to require such life cycle assessment, or to stress the benefits of voluntary compliance.

The main goals of life cycle thinking are to reduce a product’s resource use and emissions to the environment as well as improve its socio-economic performance throughout its life cycle.

Such thinking creates links between the economic, social and environmental dimensions within an organization and throughout its entire value chain.

Now that we have the technical stuff out of the way, what about the T-shirt?

What would a life cycle analysis for my T-shirt look like?

The cycle below shows the kinds of resources required in the making and use of the t-shirt.

(Source: Figure adapted from Remmen A, Jensen AA, Frydendal J (2007) Life Cycle Management: A Business Guide to Sustainability. UNEP Life Cycle Initiative  in Division of Technology, Industry and Economics, eds Valdivia S, Sonnemann G, de Leeuw B).

A product system, or life cycle can begin with extracting raw materials from natural resources in the ground and generating energy. Materials and energy are then part of production, packaging, distribution, use, maintenance, and eventually recycling, reuse, recovery or final disposal. In the case of a simple T-shirt, the stages involve a wide variety of impacts from fertilizer used to grow the cotton, to dies and water used to manufacture the shirt, to bleaches and detergents used by the owner to wash the shirt.  

Let’s zoom in to read the label on this shirt, chosen because it was black and would photograph best. Leaving aside the brand name and size, it says, “100% cotton.” No polymers died making this shirt—except maybe for the thread used to stitch it together.

Does it take much water to grow a non-food crop like cotton? I don’t know but in a detailed study from 2016 on the life cycle of cotton fiber and fabric from Cotton Inc., the industry’s trade association, they address this issue directly; “[W]hile 50% of the water for cotton in the world is derived from rainfall, a majority of the irrigation water used is transpired by the plant and leaves the watershed from where it was taken.”

In 2005, UNESCO’s Institute for Water Education published “The Water Footprint of Cotton Consumption” offering a different, more scientific viewpoint from a decade earlier: “Although the chain from cotton growth to final product can take several distinct steps, there are two major stages: the agricultural stage (cotton production at field level) and the industrial stage (processing of seed cotton into final cotton products).”

The top two cotton producing nations in the world are China (25% of world’s production) and the USA (18%). About half of cotton is grown using irrigation, often in dry regions where water is scarce to begin with, such as India, Pakistan and Uzbekistan.

We happen to have plenty of water in the northeastern United States. We often overlook the water footprint of our lifestyle choices.

Next the label says, “Made in Vietnam.” That’s interesting, because cotton is not a crop grown in Vietnam. According to the USDA, Vietnam imports somewhere between 5 to 7 million bales of cotton per year.

Next, the label offers laundry guidance, “MACHINE WASH WARM WITH LIKE COLORS.” Warm water washing is more energy intensive than cold water washing. Aha!

The 2016 Cotton Inc. study suggests cold water is better: “Use phase impact reduction can be made through the change of laundering behavior by switching from machine drying to line drying, using cold wash water with appropriate detergents, and using higher efficiency washing machines.”

Let’s give a little shout out to Duluth Trader. Their T-shirts are the longest lasting I have ever owned. Maybe they will consider suggesting a cold water wash works just great.

Tip: When we replaced our washing machine, we added a PureWash water ionizer. It ionizes the cold water entering the washing machine. This greatly reduces the detergent needed and lets us wash virtually everything in cold water. And that saves money while producing cleaner laundry! No bleach needed!

Here I am replacing the desiccant cartridge that provides ions. The cartridges last about a year before they change color and need replacement.

I ignore the rest of the instructions on the t-shirt label: NON-CHLORINE BLEACH ONLY, TUMBLE DRY LOW, REMOVE PROMPTLY, WARM IRON IF NEEDED. Who irons T-shirts?! 

When we focus on how to better manage the life cycle impacts of the goods or services our organizations provide, we find opportunities in every direction. From how we procure the raw materials to how we market the end products.



(Source: Figure adapted from Remmen A, Jensen AA, Frydendal J (2007) Life Cycle Management: A Business Guide to Sustainability. UNEP Life Cycle Initiative  in Division of Technology, Industry and Economics, eds Valdivia S, Sonnemann G, de Leeuw B).

All functions in an organization play an important role in life cycle management. The figure shows examples of how different departments in an organization can contribute to the overall life cycle management program.  The T-shirt ideas here are merely illustrative and only the tip of the iceberg of all the life cycle opportunities that could be examined and connected to each other.

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