How Sustainable Are Denim Fabrics? A Life-Cycle Analysis

By
Quynh Nguyen

Read Time:26 Minutes

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Your wardrobe likely contains more than just one but several clothing items made with denim fabric. It is the material of the ubiquitous jeans and much more. Yet the cotton fibers that make up the majority of denim fabrics are notorious for polluting production, exploitation, and even modern-day slavery. So, we had to ask: How sustainable are denim fabrics?

The sustainability of denim fabrics ranges from unsustainable (with conventional cotton as the base) to sustainable (with recycled and organic cotton). In addition, traditional finishing methods for denim fabrics are highly polluting, though new techniques can be more sustainable.

In this article, we’ll walk you through the life-cycle of denim fabrics used for clothes and household items. Then, we evaluate its sustainability, potential, and shortfalls. And in the end, we’ll show you tips for buying sustainable products made with denim fabrics.

Here’s How We Assessed the Sustainability of Denim Fabrics

Conventional denim fabrics are made with 100% cotton. The more-recently-invented and increasingly-popular stretchy types of denim are, however, often a blend of cotton with artificial materials like polyester, lyocell (occasionally known as TENCEL), and spandex (also known as Lycra).

The sustainability of denim fabrics depends largely on the type of fiber(s) used and the manufacturing practices that give the denim material its iconic look and feel.

“Sustainable: The ability to be maintained at a certain rate or level | Avoidance of the depletion of natural resources in order to maintain an ecological balance”
Oxford Dictionary

To understand the sustainability of denim fabrics, we must assess their life-cycle and each stage’s sustainability. This life-cycle assessment (LCA) is a method to evaluate the environmental impacts of products and materials. Over the years, companies have strategically used LCA to research and create more sustainable products. So, let’s have a look at the LCA of cotton fabrics!

In this article, we’ll use the cradle-to-grave perspective of the LCA, examining the five stages of the life-cycle of clothes and household items made with denim fabrics. When applicable, we also look at cradle-to-gate assessments.

The life-cycle stages of denim fabrics	Each stage’s sustainability
Sourcing of denim fabrics	Sourcing conventional cotton fiber is mostly unsustainable because the cotton crop is water-thirsty and vulnerable to various pests. Also, the widespread monoculture in cotton cultivation depletes the soil and necessitates synthetic fertilizer in many growing regions. However, sourcing organic cotton reduces greenhouse gas emissions from producing and using synthetic fertilizers and pesticides while avoiding polluting water and soil. Sourcing recycled cotton requires far fewer resources, including water and energy used to grow and harvest new cotton plants. Also, it prevents additional textile waste.
Manufacturing of denim fabrics	Manufacturing conventional denim fabrics is generally not very sustainable. Denim production typically involves many synthetic chemicals, which could cause severe water pollution if the effluent is not treated properly. Also, denim manufacturing is energy-intensive. High energy usage could have serious knock-on ecological impacts if manufacturing relies heavily on fossil fuels.
Transporting of denim fabrics	The transportation of denim fabrics is generally unsustainable. It might have a significant carbon footprint because of the emissions associated with transporting vehicles. Denim fabrics typically travel from fields (where denim plants are grown) to fiber and fabric factories, then sorting centers, shops, and consumer’s houses before going to recycling centers or landfill.
Usage of denim fabrics	The usage of denim fabrics tends to be less sustainable because of the relatively high energy consumption for washing, drying, and ironing. However, the environmental impacts of the usage stage can be reduced with changes in how denim clothes are laundered.
End-of-life of denim fabrics	The end-of-life stage for pure cotton denim fabrics is generally sustainable because these are reusable, biodegradable, and compostable.

Overall, we can say that denim fabrics are on a spectrum from fairly sustainable (made with recycled and/or organic cotton with sustainable manufacturing practices) to reasonably unsustainable (made with conventional cotton and synthetic fibers).

However, the actual environmental impact of a particular product, be it a pair of jeans or a denim jacket, depends on more specific factors, including:

the sourcing/growing of cotton fibers and other fibers if used
the dyeing and finishing practices
the type of energy used in manufacturing and usage
the distance and mode of transportation

Let’s dive deeper into each life-cycle stage and find out how you can buy denim fabrics more sustainably.

How Sustainable Is the Sourcing of Cotton Fibers for Denim Fabrics

Sourcing conventional cotton fiber is mostly unsustainable because the cotton crop is water-thirsty and vulnerable to various pests. Also, the widespread monoculture in cotton cultivation depletes the soil and necessitates synthetic fertilizer in many growing regions.

However, sourcing organic cotton reduces greenhouse gas emissions from producing and using synthetic fertilizers and pesticides while avoiding polluting water and soil.

Sourcing recycled cotton requires far fewer resources, including water and energy used to grow and harvest new cotton plants. Also, it prevents additional textile waste.

What Raw Materials Are Used for Denim Fabrics

Conventional denim fabrics are made with 100% cotton fibers. On the other hand, modern stretch denim fabrics could contain a small percentage of spandex which contributes to the stretching property, and/or other synthetic materials like polyester and lyocell.

The following section will focus on the environmental impacts of sourcing cotton fibers – the natural cellulose fibers extracted from cotton seeds, as cotton fibers are the sole or the major raw materials for denim fabrics.

(The environmental impacts of other synthetic fibers used in denim fabrics can be found in reference links at the end of the next section.)

How Do the Raw Materials Sourced for Cotton Fabrics Impact the Environment

The main raw materials for denim fabrics come from cotton plants – a water-thirsty and high-input crop. Thus, sourcing cotton fibers is mostly unsustainable, even though the cotton plant has carbon sequestration potential and is, in principle, a renewable resource.

Growing Cotton Plants Has Very High Water Footprint

Cotton is a thirsty crop:

The global average water footprint for cultivating and ginning (i.e., separating the cotton fibers from the seeds) is 2,235 m³(for 1,000 kg of cotton fibers).
82% of this water volume (2,235m³) is for irrigation.
In comparison, fiber crops such as flax (for linen) or bamboo don’t require irrigation (only rainwater).

Diluting pesticides is another source of water consumption at this stage.

According to a life-cycle assessment of Levi’s denim jeans, the water consumption associated with the fiber stage for a pair of jeans averaged 2,565 liters. The fiber stage accounts for 68% of the total water footprint of Levi’s^® 501^® jeans.

Pesticides Used in Growing Conventional Cotton Contaminates Soil and Groundwater

Cotton plants are vulnerable to various pests, including insects, worms, fungi, and bacteria. Specifically, several hundred species of insects attack cotton crops.

Because of the need to control the damage caused by pests, conventional cotton farmers use a disproportionate amount of chemical pesticides.

According to a 1999 report from WWF, the percentage of the world’s pesticides used for cotton crops averaged 11%. At the same time, cotton acreage amounts to only 2.4% of the world’s arable land. Meaning that cotton was responsible for nearly five times as much pesticide usage as their acreage amounts would indicate.

Worldwide, almost one-in-four insecticides is used in cotton cultivation.

Three out of 10 most acutely hazardous insecticides are reported as commonly used chemicals in cotton cultivation.

Using chemical and synthetic pesticides in cotton cultivation is widespread and harmful. It threatens:

the quality of the soil
the quality of fresh and groundwater
the health of biodiversity within the fields and in the surrounding areas
the health of farm workers and nearby populations

However, there are pest-controlling alternatives, including methods that produce much more sustainable cotton fibers.

One alternative way to deal with cotton’s pest challenges is genetic modification of the cotton seeds to be pest-resistant. For example, genetically modified “Bt cotton” seeds produce proteins that fend off pink bollworms and consequently help to reduce the immediate need for pesticides.

On the other hand, organic cotton farmers rely on natural measures to combat their pest challenges, such as:

Employ crop rotation to increase plant’s health and natural pest resistance and avoid the same pests coming back every year for their favorite source of food
Maintain biological balance by using natural enemies to keep a check on pests
Use pest-capturing traps
Use mico-organisms to target pests

These natural measures are much more environmentally friendly than synthetic pesticides as they improve the cotton plant’s health and the cotton field’s biodiversity while avoiding soil and water pollution.

Unfortunately, organic cotton currently makes up less than 1% of global cotton.

Cotton Fields Tend to Require A Lot of Fertilizer Due to Soil Degradation

The common monoculture practices in cotton cultivation deplete nutrients in the soil, resulting in fertilizers being necessary. When conventional cotton farmers use chemical-based fertilizers, it leads to two main environmental impacts:

Possible disruptions in the ecosystem and biodiversity loss due to freshwater contamination from run-off fertilizer
Greenhouse gas emissions as a result of synthetic fertilizer production and usage

Possible disruptions in the ecosystem and biodiversity loss due to freshwater contamination from run-off fertilizer

Fertilizer run-off from cotton fields contaminated rivers, lakes, and wetlands. Even though fertilizer is not directly toxic to organisms living in freshwater bodies the way pesticides are, fertilizer run-off could alter the nutrient system, affecting the balance of the ecosystem.

For example, excess nutrients (nitrogen and phosphorus) in rivers and lakes lead to an explosive growth of algae.

As algae consume oxygen and block sunlight from underwater plants, their bloom results in dead zones in the water (fishes and other species being killed off).
Also, some harmful algae produce extremely dangerous toxins that can make people and animals sick or even die.

Greenhouse gas emissions as a result of synthetic fertilizer production and usage

Synthetic fertilizer accounts for the largest share of greenhouse gas emissions during cultivating and ginning (i.e., separating the cotton fibers from the seeds), according to a life-cycle inventory of cotton fiber and fabric.

Specifically, GHG emissions from the decomposition of fertilizer in the field accumulate to about 500 kg CO₂ -eq for every 1,000kg of cotton fiber, representing 35% of the total emissions (1,428 kg CO₂-eq) of this stage.

On top of that, fertilizer production contributes an extra 27% of the total GHG emissions.

Other sources of carbon dioxide emissions during this stage include irrigation, ginning, and tractor operations (for sowing, spraying, weeding, and harvesting).

Carbon Sequestration During Cultivation Has Positive Global Warming Impact

As cotton plants grow, they absorb CO₂ from the atmosphere while releasing oxygen. During their lifespan of around 150 to 180 days, cotton plants act as a carbon sink, taking greenhouse gasses out of the atmosphere and helping to mitigate the climate crisis.

On a global average, cotton cultivation absorbs more carbon dioxide than the GHG emissions from cultivating activities and required materials (including synthetic fertilizer and pesticides).

Specifically, cultivating and ginning 1,000 kg of cotton fiber has a negative carbon footprint of -112 kg CO₂-eq, thanks to the 1,540 kg CO₂-eq sequestered and stored in the cotton plants during this stage, according to a global life-cycle inventory of cotton fiber and cotton fabric.

In brief, carbon sequestration during this growing stage of cotton’s life-cycle lowers the total carbon footprint and global warming impact of cotton fibers and fabrics. However, this stage is water, fertilizer, and pesticide-intensive, resulting in major environmental impacts, including:

Water consumption
The health of the soil, water, and ecosystems affected by pesticide use
Eutrophication potential (due to nitrogen and phosphorus from fertilizer building up and disrupting the ecosystems)
Field emissions (GHGs) associated with fertilizer, irrigation, and ginning

It is important to note that not all cotton fibers are made equally (bad). Though conventional cotton is ranked class E – the least sustainable fiber class, recycled cotton fiber belongs to class A – the most sustainable fiber class, according to Common Objective’s Made-By Environmental Benchmark for Fibres.

Here are various forms of cotton fabrics in the general order from the most sustainable (at the top) to the least sustainable (at the bottom):

Recycled cotton: mechanically recycled from pre- or post-consumer waste
Organic cotton: grown without synthetic fertilizer and pesticides
In-transition cotton: moving away from unsustainable practices to more sustainable ones. This group of cotton fabrics includes:
1. In-conversion cotton
2. Better Cotton Initiative (BCI) cotton
3. Cleaner Cotton™
4. Fair Trade cotton
5. Naturally colored cotton
Conventional cotton

Where Are the Raw Materials for Cotton Fabrics Usually Sourced From

The various species of cotton are native to most subtropical parts of the world. The cotton plant has also been domesticated and grown in many parts of the world. There are cotton crops in over 80 countries. Following are countries among the top producers of cotton fibers:

India
China
Pakistan
Brazil
Uzbekistan
Turkey
Turkmenistan
Burkina Faso
The US

The most critical environmental challenges in cotton-growing countries, as we will discuss in detail below, are the results of high water demand and excessive use of chemicals in cotton cultivation.

There Is High Water Stress in Cotton-Growing Regions

Many of the major cotton fiber producers are countries under high water stress. They include India, China, India, Pakistan, Turkey, and the US.

Cotton’s high demand for water exacerbates the water crisis as its cultivation draws out groundwater and uses up surface water resources:

For example, 97% of the water from the Indus River (Pakistan’s main water source) is used to irrigate cotton fields.
Cotton crops are also associated with the drying out of the Aral Sea basin in Central Asia – once the world’s fourth-largest lake.

This is a serious problem for countries where cotton cultivation is widespread, as water scarcity is considered one of the top 10 challenges the world may face in the coming years.

There Is High Water Pollution in Cotton-Growing Regions

According to the WWF, water pollution caused by cotton cultivation (and its water demand) severely impacts major ecosystems such as the Aral Sea in Central Asia, the Indus Delta in Pakistan, and the Murray Darling River in Australia.

The Widespread Use of Genetically Modified Cotton Seeds Causes Biodiversity

Cotton is one of the world’s top three genetically modified crops, along with corn and soy. When cotton seeds are genetically modified to resist pests and herbicides, the direct need for synthetic pesticides and herbicides is reduced, lessening the negative impacts of using these chemicals.

However, this practice has social and environmental impacts in the long run in countries with high-adoption rates, such as India.

Most prominently, extensive use of GMOs leads to the loss of biodiversity. Some genetically modified seeds focus on selective pests attacking the cotton plants, but not all harmful species. The exclusive use of one strain of GM seeds reduces biodiversity and makes the cotton vulnerable to other types of pests.

There are also allegations regarding the need to buy new genetically modified seeds every year dictated by patent laws and the suicide of more than 270,000 Indian cotton farmers forced into a cycle of unmanageable debt.

Related: Are you interested to learn more about the environmental impact of synthetic fibers used in denim fabrics? Check it out in the following articles:

According to a life-cycle assessment of Levi’s^® 501^® denim jeans, the (fiber) sourcing stage has the largest shares in the whole life-cycle in several environmental impact categories. Specifically,

The fiber sourcing stage accounts for 78% of the life-cycle’s land occupation
The fiber sourcing stage accounts for 68% of the life-cycle’s water consumption
The fiber sourcing stage accounts for 37% of the life-cycle’s eutrophication

The carbon emission of fiber sourcing averages 2.9 kg CO₂-eq for a pair of Levi’s^® 501^® jeans, according to the same life-cycle assessment.

How Sustainable Is the Manufacturing of Denim Fabrics

Manufacturing conventional denim fabrics is generally not very sustainable. Denim production typically involves many synthetic chemicals, which could cause severe water pollution if the effluent is not treated properly. Also, denim manufacturing is energy-intensive. High energy usage could have serious knock-on ecological impacts if manufacturing relies heavily on fossil fuels.

How Sustainably Is Denim Fabrics Generally Manufactured

Cotton-based denim fabrics are made with natural cellulose fibers extracted from cotton seeds (or so-called cotton bolls). Once separated, cotton fibers are processed and woven into yarns subject to a series of finishing treatments.

The typical manufacturing process of denim fabrics, such as in blue jeans, includes these specific steps:

Produce cotton fibers: The cellulose fibers are extracted from cotton bolls via the following steps:
- Defoliate plants with matured cotton bolls, often by machines with chemical spraying
- Separate the fibers from the seed – the ginning process.
- At this point, the fibers are called slivers.
Produce cotton yarns: The cotton slivers are joined, pulled, twisted, and stretched to form yarn.
Dye the long, vertical threads with indigo dyes: Cotton yarns are often dyed in (chemically) synthesized indigo before being woven into denim fabrics. Only the long vertical threads, referred to as warp, are dyed. (The shorter horizontal threads – called the weft – are left undyed.)
Slash the dyed yarn: The dyed yarns (warp) are coated with a starchy substance to improve their strength and stiffness.
Weave the denim fabric: the dyed long vertical warp and the undyed short horizontal weft are woven on a large mechanical loon.
Finishing treatment: A series of finishing treatments are applied to the woven denim fabrics, including:
- Resizing (or sanforized): denim fabrics are pre-washed to prevent substantial shrinking at the consumer’s house.
- Stone washing: denim fabrics are washed together with pumice stones in large washing machines to give a faded, worn-out look to the fabric
- Bleaching: denim fabrics are decolored (locally) for a certain designed look, such as with the whisker effect.
- Sand blasting: denim fabrics are blasted with sand to create faded areas.

Let’s now deep dive into a few key sustainable issues of this life-cycle stage:

Manufacturing Is One of The Two Main Contributors to Denim Fabrics’ Life-Cycle Carbon Emissions and Global Warming Impact

Here is an example: manufacturing a pair of Levi’s^® 501^®denim jeans accounts for 40% of cradle-to-grave GHG emissions, according to a life-cycle assessment of Levi’s^® 501^® jeans.

High carbon emissions are the result of primary energy demand from fossil sources. Denim manufacturing is energy-intensive. High direct energy usage is associated with the following activities:

Forming the yarn and weaving the fabric
Cutting and sewing the garment
Washing the garment

However, more sustainable denim manufacturing processes that save energy are available. Some examples include:

Using enzymes instead of actual pumice stones in the stone-washing step
Using lasers in the bleaching step to achieve the whisker effects instead of using harsh chemicals

Manufacturing Conventional Denim Fabrics Uses Toxic Chemicals With High Risks of Water Pollution

Conventional denim manufacturers use many chemicals, especially in the dyeing and other finishing processes. Some of these substances are harsh chemicals with potential health risks.

Here are some examples of chemicals used in various steps in denim manufacturing and their potential harms:

The process of coloring cotton yarns with synthetic indigo dyes involves many toxic chemicals. Aniline – a feedstock for indigo synthesis – is derived from benzene, a toxic chemical. Other toxic chemicals used in the indigo synthesis are formaldehyde, hydrogen cyanide, sodium amide, and alkalis.
Converting water-insoluble indigo dyes into a soluble form uses caustic soda (or sodium hydroxide) and sodium hydrosulfite. Caustic soda can cause damage to the skin and eyes. As pigments often don’t absorb into the yarns fully, leading to chemical residues being released into the water stream, causing turbidity and ecological disruption in addition to being poisonous, carcinogenic, or mutagenic.
Heavy metals (lead, chromium, cadmium, copper, and nickel) are commonly found in indigo dyes. Their toxicity affects multiple organs in the body: the kidney, the nervous, vascular, and immune systems, and the skin. Additionally, they can cause congenital disabilities and cancer.
Sodium carbonate is often used in the desizing step while finishing denim fabric. If sodium carbonate enters water bodies, it can increase the alkalinity of the water, harming marine life.
Potassium Permanganate (PP) is an oxidizing agent often used to lighten a specific area and create whisker effects on denim. This chemical can irritate and burn the skin and eyes on direct contact.
The bleaching process typically uses a strong oxidative bleaching agent like sodium hypochlorite (NaOCl). This is a highly irritating chemical that has the potential to cause significant chemical burns to the people who work with it. Also, the residues from treatment using NaOCI can affect the lungs and creates many other acute respiratory distress syndromes, threatening living beings and the ecosystem.

For every kilogram of denim, the manufacturing process releases between 40 and 65 liters of effluent. The wastewater will contaminate surface and groundwater sources without proper treatment.

However, more sustainable denim manufacturing processes that sidestep the harshest chemicals are available, including:

Replacing the conventional synthetic indigo dyes
- bio-based indigo dyes
- waterless indigo dyeing using supercritical carbon dioxide
Replacing the traditional dyeing methods with
- digital spraying
- foam dyeing
- dope dyeing
- sCO₂ dyeing
Replacing the harsh chemicals in conventional bleaching with the use of ozone and laser-assisted bleaching

Where Are Denim Fabrics Usually Manufactured

India, the US, and China are the three largest denim producers worldwide.

One of the main sustainability issues with producing velvet fabrics in these countries is the dependency on fossil fuels for energy generation. Only 9.31% of the primary energy in India comes from renewable sources. The renewable energy shares in the US and China are higher (10.66% and 14.95%, respectively), yet they are relatively low, especially compared with some European countries, such as Spain (22.34%) or Germany (19.45%).

Using renewable energy (solar, wind, hydroelectric, geothermal, and biomass) reduces carbon emissions at this stage.

How Sustainable Is the Transportation of Denim Fabrics

The transportation of denim fabrics is generally unsustainable. It might have a significant carbon footprint because of the emissions associated with transporting vehicles. Denim fabrics typically travel from fields (where denim plants are grown) to fiber and fabric factories, then sorting centers, shops, and consumer’s houses before going to recycling centers or landfill.

In the life-cycle of denim clothes, transportation typically occurs as below:

From fields where cotton is grown to the cotton fiber and denim fabric manufacturing location(s)
From the denim clothing manufacturing location to sorting centers/physical shops
From sorting centers/physical shops to the consumer’s house
From the consumer’s home to the centers for recycling/ disposing

Traveling Distances of Denim Fabrics Vary Depending on the Supply Chain

It is not uncommon for denim fabrics to have their supply chain spreading globally, meaning that crop cultivation, fiber production, fabric spinning, and clothes manufacturing might happen in various towns, countries, or even continents.

Here are some scenarios for transporting denim fabrics:

Farmers grow cotton in Australia to be sourced and transported to a denim manufacturer in China. Final pieces of denim clothes are then shipped to Europe to sell to consumers.
Cotton fibers are harvested from fields in India and transported to Brazil for denim fabric production. Denim clothes are then sold to the US market.
Manufacturers in the US source cotton fibers from crops grown in the US and turn them into denim fabrics and clothes locally before selling them to US consumers.
US manufacturers source cotton fibers in the US and send the fibers to fabric factories in Mexico and then to clothing factories in Egypt. The final denim clothes are sent back to retail shops in the US.

You can reduce the transporting carbon footprint by choosing denim fabrics that travel a shorter distance from the fields and are made closer to your home.

The Carbon Footprint of Transporting Denim Fabrics Depends Largely on the Vehicle of Transportation

During its life-cycle, a piece of denim clothing can be transported using various types of vehicles, including:

Large container ships
Planes
Freight trains
Long-distance trucks
Short-distance delivering vans

And these various types of transportation vehicles have different carbon footprint impacts:

Large container ships are generally the most carbon-efficient option for the international transportation of goods, while planes are the heaviest carbon emitter.
Large container ships emit, per unit of weight and distance, half as much carbon dioxide as a train and one-fifth and one-fiftieth as much as a truck and a plane (respectively).
Deliveries made by planes – for example, to fulfill fast shipping options for clothing – are the mode of transportation with the highest carbon footprint.

For example, you as a consumer can choose not to pick the fast delivery option when ordering denim clothes to reduce the carbon footprint of your denim items.

How Sustainable Is the Usage of Denim Fabrics

The usage of denim fabrics tends to be less sustainable because of the relatively high energy consumption for washing, drying, and ironing. However, the environmental impacts of the usage stage can be reduced with changes in how denim clothes are laundered.

As an example, a pair of Levi’s^® 501^® denim jeans has a total carbon footprint of 33.4 kg CO₂-eq, in which 12.5 kg CO₂-eq is the share of the usage phase (which equals 37% of the total CO₂ footprint).

This example demonstrates that usage is one major contributor to the environmental impacts of denim fabric.

The carbon emissions of the usage stage are associated with electricity to run washing machines, drying machines, and irons.

If fossil fuels are the main sources of energy at a user’s home, high energy consumption will result in an elevated carbon footprint.

Modifying laundering behaviors, however, would reduce the environmental impacts. Possible changes include:

Wash clothes less often (The Raw Jeans movement emphasizes delaying washing denim jeans for as long as possible)
Switch to line drying instead of using tumble driers
Do cold washes with appropriate detergents
Use energy-efficient washing machines

A life-cycle assessment reports 29% and 33% reductions in carbon emissions when cold washes replace warm washes and when efficient washing machines replace conventional washing machines, respectively, in one year of usage.

The same assessment also shows that the climate change impact of one-year usage is half when drying denim jeans on the line instead of inside a drier.

How Sustainable Is the End-of-Life of Denim Fabrics

The end-of-life stage for pure cotton denim fabric is generally sustainable because it is reusable, biodegradable, and compostable.

If denim fabrics are made with 100% cotton fiber, their biodegradability is the same as their base material, cotton. There are three main options for cotton-based denim fabrics:

Composting
Incineration
Landfilling

Depending on the conditions, it can take one week to five months for pure, untreated cotton fabrics to decompose.

However, it is important to note that the biodegradability changes for denim fabrics dyed with chemical indigos and/or containing plastic-based synthetic fibers like spandex and polyester.

How Circular Are Products Made of Denim Fabrics

In the textile industry, a circular economy is designed to keep products and materials in use for as long as possible, especially through reusing and recycling. It also covers regenerating natural systems that support the industry and reducing polluted waste released into such systems.

“The circular economy is a systems solution framework that tackles global challenges like climate change, biodiversity loss, waste, and pollution.”
Ellen MacArthur Foundation

As a whole, the textile industry is almost linear: 97% of the input is new resource.

It is possible to recycle the cotton content in denim fabrics mechanically, physically, and chemically.

Mechanically recycling cotton results in cotton fibers with shorter lengths, which makes it, in principle, not possible to make denim fibers truly circular, arguably. The majority of recycled cotton is claimed mechanically.
The physical recycling of denim uses denim as feedstock for blends of regenerated cellulose fibers like lyocell or viscose.
Chemical recycling of denim breaks down the fabrics with acids or enzymes and creates new materials, which are more like rayon.

Blue Jeans Go Green™ is an example of circular denim jeans, using recycled denim made from sustainably sourced cotton fibers.

According to a life-cycle assessment of Levi’s® 501® denim jeans, all the life-cycle stages from the cradle to the grave have environmental impacts as follows:

A pair of Levi’s^® 501^® denim jeans has a life-cycle climate change impact of 33.4 CO₂ -eq
A pair of Levi’s^® 501^® denim jeans has a life-cycle water consumption of 3,781 liters
A pair of Levi’s^® 501^® denim jeans has a life-cycle eutrophication impact of 48.9 PO₄ -eq
A pair of Levi’s^® 501^® denim jeans has a life-cycle abiotic depletion of 29.1 mg SB -eq

Other notable results from this life-cycle assessment are:

In the life-cycle of denim fabrics, manufacturing and usage are the main contributors to environmental impacts
Denim has a high impact on water usage and water contamination, mainly due to the cotton cultivation and manufacturing stages.

How Can You Buy Denim Fabrics More Sustainably

The key to sustainably buying denim products is to check on relevant environmental and original certifications.

Certifications for denim fabrics made with recycled fibers:

Recycled Claim Standard (RCS): The Textile Exchange RCS was originally developed as an international, voluntary standard that sets requirements for third-party certification of Recycled input and chain of custody.
The Global Recycled Standard (GRS): The Global Recycled Standard (GRS) is an international, voluntary, full product standard that sets requirements for third-party certification of Recycled Content, chain of custody, social and environmental practices, and chemical restrictions. It can be used for any product with more than 20% recycled material.

Certifications for denim fabrics made with organic fibers:

USDA ORGANIC: This certificate is applied to growing the crop (raw material), ensuring natural agricultural products are produced that can be certified as “organic.”
Global Organic Textile Standard (GOTS): A globally-recognized certification system that ensures a certain threshold of organic content has been met. It covers manufacturing, packaging, labeling, transportation, and distribution (but not what happens in the fields where crops are grown).
USDA Certified Biobased Product: The USDA BioPreferred® Certification is a voluntary certification offered by the United States Department of Agriculture. The certificate identifies products made from plants or other renewable materials.

Certifications for denim fabrics made with in-transition cotton:

Better Denim Initiative (BCI ) Denim: BCI certifies denim according to The Better Denim Standard System, a holistic approach to sustainable denim production that covers all three pillars of sustainability: environmental, social, and economic.
Cleaner Denim™: Cleaner Denim™ eliminates the 13 most toxic chemicals used in conventional denim cultivation in California, reducing toxicity in our air, soil, and watersheds.
Fairtrade International: A Fair Trade certification includes social, economic, and environmental standards that apply to the full supply chain from the farmers and workers to the traders and companies bringing the final product to market.
Fair For Life: Fair for Life certifies every step of production instead of the finished product. It prioritizes transparency in business at all levels.

Certifications for all forms of denim fabrics:

STeP by OEKO-TEX®: STeP by OEKO-TEX® is an independent certification system for brands, retailers, and manufacturers from the textile and leather industry. It communicates organizational environmental measures, including reducing carbon footprint and water usage.
OEKO-TEX^®: OEKO-TEX^® labels aim to ensure that products pose no risk to human health (i.e. containing banned chemicals).

Some certifications are signaling brands’ efforts toward lowered environmental impacts and a circular economy are:

B Corp Certification: The label B Corp is a certification reserved for for-profit companies. Certified holders are assessed on their social and environmental impacts.
Cradle2Cradle certification: Cradle2Cradle provides a standardized approach to material circularity. It assesses whether products have been suitably designed and made with the circular economy in mind covering five critical categories: material health, material reuse, renewable energy and carbon management, water stewardship, and social fairness.

Where to Buy Sustainable Denim Fabrics

As we have established throughout the life-cycle assessment, not all denim clothes are made equally: denim fabrics made with recycled and/or organic cotton are fairly sustainable. In contrast, conventional denim fabrics can be highly unsustainable.

For sustainably-made denim, you want to look for the following:

Denim fabrics made with recycled cotton
Denim fabrics made with organic cotton
Denim fabrics made with in-transition cotton
Denim fabrics made stretchy with lyocell (instead of spandex)
Denim fabrics use more sustainable dyes (such as bio-based indigo) and more environmentally friendly dyeing methods (such as foam dyeing)

If you search for sustainable denim manufacturers, make sure they are transparent about the following:

Usage and treatment of chemicals like fertilizer, pesticides, dyes, etc.
Water usage efficiency
Water treatment
Energy efficiency
The share of renewable energy at manufacturing locations

Here we compile for you a list of some sustainable brands selling low-impact, sustainable denim fabrics(in alphabetic order):

Why Is It Important to Buy Products Made of More Sustainable Fabrics

It is important to buy products made of more sustainable fabrics because a sustainable textile industry has a lower carbon footprint, helps save natural resources, and is better for forests, animals, and humans.

Buying Sustainable Fabrics Reduces Your Carbon Footprint

The production of clothing and footwear is estimated to contribute 10% of global greenhouse gas emissions – more than all international flights and shipping combined. If the fashion industry were a country, it would be the fourth largest emitter of carbon dioxide.

One way to reduce the carbon footprint of the clothes you buy is to opt for sustainable fabrics. Sustainable fabrics, which are often made with natural or recycled fibers, have relatively low carbon footprints compared to petroleum-based fabrics. For example, organic cotton made in the US has a carbon footprint of 2.35 kg CO₂ (per ton of spun fiber) – a quarter of polyester’s carbon footprint.

Buying Sustainable Fabrics Reduces the Demand For Natural Resources and Waste Management

The textile industry uses water and land to grow cotton and other fibers. It is estimated that 79 billion cubic meters of water were used for the sector worldwide in 2015. For example, producing a single cotton t-shirt requires as much water as one person drinks for 2.5 years (2,700 liters of fresh water).

Worse yet, the textile economy is vastly more linear than circular: the largest amount of resources used in clothes ended up in landfill (instead of being recycled to remake clothes). According to a report by the Ellen Macarthur Foundation,

Less than 3% of materials used in the textile economy in 2015 came from recycled sources.
In other words, more than 97% of resources used in making clothes are extracted new.

When clothing items are disposed of within a short period of time – under a year in the case of half of the fast fashion clothes – the natural systems that provide raw materials for fabrics don’t have enough time to recover and regenerate, which could lead to ecological breakdown.

Sustainable fabrics are made with less water and emissions while lasting longer:

Because they are durable, you don’t need to buy new clothes too often.
Thus, you help reduce the pressure to extract more resources for making new items.

Similarly, making and consuming sustainable fabrics made with recycled materials reduces the demand for virgin materials while helping tackle waste management.

Buying Sustainable Fabrics Encourages the Sustainable Management of Forests

Sustainable plant-based fabrics are made with raw materials from forests and plantations that are sustainably managed, such as complying with FSC standards.

When you buy sustainable plant-based fabrics, you discourage unsustainable forestry practices like illegal logging. You can help reduce deforestation, biodiversity loss, and the effect of climate change.

Buying Sustainable Fabrics Encourages Fairer Treatment of Animals

The fashion industry is rife with animal mistreatment when it comes to making animal-based fabrics like cashmere or leather. Every year, billions of animals suffer and die for clothing and accessories.

Buying sustainable vegan alternatives can help to reduce the pressure on raising more and more animals to meet the demand for animal-based fabrics while sacrificing their well-being and lives.

Suppose you have to buy fabrics made with, for example, leather or wool; make sure you only choose brands committed to cruelty-free products. In that case, you help advocate better treatments for animals raised within the textile industry.

Using Sustainable Fabrics Encourages Fairer Treatment of Textile Workers

Recent statistics from UNICEF estimated as many as 170 million child laborers worldwide, many of whom were engaged in some form of work in the textile industry. They don’t get paid minimum wages and often work long hours.

When you buy sustainable fabrics from brands transparent about the working conditions at their factories, you discourage the use of child labor and help promote better working conditions for textile workers.

Final Thoughts

Conventional denim fabrics are generally not a very sustainable material, even though they are made with natural cellulose fibers from cotton plants – a renewable resource.

Cultivating cotton requires a lot of water. Also, synthetic chemicals in conventional cotton farming harm the environment, workers, and users.

However, recycled cotton and organic cotton are sustainable materials for making more environmentally friendly denim fabrics. The environmental impacts of some in-transition cotton are also significantly less than those of conventional cotton.

To make it even more sustainable when buying denim fabrics:

Buy second-hand when possible.
While using denim products, maximize the number of wear between washes, and keep the items as long as possible.
At the end of denim products, upcycle the material to extend its usage and arrange for it to be recycled or properly disposed of.