Eco-friendly FabricsThis is a featured page

Perhaps surprising to many, textiles have a relatively high carbon footprint (see below for an explanation of what this means). The US government puts the textile industry at 5th place in importance in its carbon footprint, right after primary metals, nonmetallic mineral products, petroleum and chemicals! In the developing world, the carbon footprint of textiles is even higher! Furthermore, the textile industry is the Number One industrial polluter of fresh water on the planet! As a result, the consciencious world citizen, seeking to lower his or her ecological footprint (see below), will naturally seek to invest more heavily in fabrics and garments with smaller environmental impact.

Do-it-yourself (DIY) sewers need good information about what is an eco-friendly fabric and what is not, as there is a certain amount of confusion over this. Also, issues of social justice and fair trade cross-cut with issues of sustainability - we would prefer to buy fabrics (and garments) produced by people who have been paid a decent wage for their work. And, of course, the notion and question of a fabric or garment's carbon and/or ecological footprint is increasingly becoming of interest.

Three elements form the basis for classification of eco-friendly fabrics today :
(1) Sustainability : does the fabric result from easily regenerated core materials?
(2) Resource Use : how much land and resources are required to harvest the material and turn them into usable fabric?
(3) Processing : how many toxic chemicals are used or generated during the process of growing and treating the harvested material to generate fabric?

The ecological footprint (EF) measures how quickly we are using the Earth's resources. The EF can be measured either in global hectares (gha), global hectares per person (gha per capita), or can be converted to the number of Earths used per renewable Earth - as of 2005, our global ecological footprint was 1,3 (i.e. we are using Earth's resources 1,3 times faster than the Earth can replenish itself). If a North American lifestyle at today's level were to be maintained by everyone, our global ecological footprint would be 5,0!

The carbon footprint (CF), a separate measure, represents the production of greenhouse gases (i.e. carbon dioxide) from pollution, and is measured in kilograms, pounds or tonnes of carbon. However, the carbon footprint may be converted to the amount of land or sea area needed to store the emitted carbon, and hence can be directly compared to the ecological footprint. Viewed in this way, the carbon footprint contributes roughly half the current ecological footprint, and therefore efforts to reduce our carbon footprint will lead naturally to a reduction in the ecological footprint as well.

Energy expenditure is also sometimes used as a metric, although it is really only a small part of the story. Synthetic and artificial fibres require relatively high energy expenditure to produce (100-200 MegaJoules per kilogram of fiber), cotton and wool are moderate (50-60 MegaJoules per kilogram) while the production of hemp (2 MJ per fiber kg) and flax (10 MJ per fiber kg) requires minute amounts of energy in comparison. This low energy production is part of the reason that hemp is often singled out as a particularly eco-friendly fabric - however, there are other considerations (see below) that make hemp less than perfect as a fabric choice. Note that, by comparison, one gallon of car fuel contains 130 MJ of energy. Organic cotton production also typically requires less energy than conventional production (15 MJ/kg compared to 55 MJ/kg). Nylon requires 250 MJ per fiber kg, while rayon is on the border between natural and synthetic fibres in terms of energy uptake (100 MJ/kg). (NB. Most of the numbers used here and below come from a single study : “Ecological Footprint and Water Analysis of Cotton, Hemp and Polyester”, by Cherrett et al, of the Stockholm Environment Institute. There is a dearth of good studies in this area!)

Detailed and complete measurements of different fabric fibers using standardized metrics has barely begun, and hence reliable comparisons are still difficult to perform and present.

Traditional "natural" fabrics


Cotton : Although potentially an eco-friendly fabric, current cotton production is highly unfriendly to the environment. Today 22% of insecticides used globally are used on cotton crops. Growing enough cotton for a single t-shirt requires 260 gallons of water. Also, bleaching and dyeing create and use toxic chemicals. Some fabric stores now carry "organic cotton" fabrics which consist of cotton fibers derived from certified and strictly regulated organic farming systems. The regulations for organic farming abolish the use of synthetic pesticides and fertilizers as well as of genetically modified organims. The consumer should be wary, however, of products labelled as "organic cotton", as the certification of organic cotton covers solely the cultivation and no other steps of the textile chain. Environmental certification methods for fabrics are still under development but a number are now in use - products that are "green" certified (such as via the GOTS standard) are hence more sure than ones that are not certified. In addition, it has been reported that a new "coloured cotton" variegar which grows naturally in shades of green and brown has been developed based on a traditional Aztec plant - this would presumably require less dyeing during processing.
Wool : There are ecological considerations to be respected even in the production of wool. Sheep must be managed appropriately - they can graze plants to destruction and their manure may enter the water supply if the flocks are mismanaged. The production of cashmere wool is particularly plagued by such problems, as almost all cashmere comes from relatively small region of the world where the land has reportedly been overgrazed. Factory-farmed sheep, as with other factory-farmed animals, have miserable lives with little consideration for the animals. The process of scouring wool, and then bleaching and dyeing it may also use toxic chemicals. Responsible manufacturers, however, have several choices for surmounting these difficulties.
Silk : Silk is lusterless, stiff and harsh until it is scoured, removing the outer gelatinous layer of matter from the silk filament. The most common chemical used for scouring is dry cleaning fluid (perchloroethylene), a potential carcinogen. Unfortunately, this fluid tends to escape into the water table during the processing in many parts of the world.
Linen : Bast fibres, including flax (linen), hemp, ramie and abaca, need little fertilizer or other attention, aside from water, to grow. However, they do require a process called "retting" to separate the fibre from the stalk, and this process can be decidedly non eco-friendly. Chemical retting requires toxic chemicals as well as lots of water. Water retting consists of soaking the stalks in water - however, this process introduces a lot of acid into the water and if the latter is untreated, it can harm the environment when released. Most current practice of water retting makes no effort to filter the water. Dew retting involves leaving the stalks out to be broken down by the action of sun and rainwater. It is the most environmentally safe process, albeit at a higher cost.
Hemp : Although a naturally occuring fabric that grows rapidly and densely and has attracted a great deal of attention as a potentially "green" fabric. Hemp, however, is actually quite stiff and requires a lot of processing (usually using chemicals) to soften it up for use in fabrics (see discussion above on retting for linen).
Leather : Leather has a huge carbon footprint, even when one takes into account that it contributes only a small fraction to the total value of a cow (7% compared to the meat value of the animal). Cows generate methane, one of the worst greenhouse gases. In addition, the processing used to produce leather (i.e. "tanning") uses highly toxic chemicals. As a result, although usually considered "natural", leather is a product with an unusually high ecological footprint. This is one of the reasons that much footwear has a high ecological footprint - when synthetic fibres are not used, leather usually is, keeping their ecological footprint high regardless of what goes into their fabrication.

Contemporary "natural" fabrics

Bamboo : Bamboo is a fast-growing grass-like plant whose fibres can now be processed to generate fabric yarns. It is also a natural antibacterial product and the fabric created from bamboo "wicks" moisture away from the skin, making a fabric that is unusually comfortable to wear. The resultant cloth is also biodegradable - in fact, it tends to wear out rather quickly. Bamboo can be transformed into yarn by chemical or via mechanical processing - the latter is much more environmentally friendly, albeit substantially more costly. Not all bamboo that arrives from China (where most bamboo fibre is harvested) has been mechanically processed. In addition, chemical fertilizers are sometimes used to enhance growth (even though bamboo is such a fast-growing plant it is often considered to be a pest!). Green certification, when it arrives for bamboo, will be a boon for straightening out these issues.
Soy silk : Soy silk is made from the by-products generated by the tofu-making process. Liquefied proteins are extruded and spun into fibres using the engineering developed for artificial petroleum-based fibres but using a natural and renewable raw material instead. The high protein content of soy silk fibres means these fibres absorb natural dyes easily and hence lend themselves to taking up color.
Ingeo™ Corn : Developed by Dow Chemicals, this fibre is nonetheless extracted from the starch and sugars of corn. The resulting fibres can be spun into a yarn. However, on the down side, the fibre is extracted from genetically-engineered corn, banned in several countries.

Semi-natural fabrics

Rayon (viscose)
: Rayon is a cellulose-base fibre made from wood chips. The process used to convert woodchips into usable fibres requires the heavy use of toxic chemicals. Hence despite its reputation as being somewhat "green", rayon is not particularly eco-friendly. However, it produces a yarn and fabrics that breathe much better than do most synthetic fibres made from petroleum by-products.

Recycled fabrics

Fortrel EcoSpun™ : This is a polyester fibre made from recycled plastic bottles. It is generally made into fleece. Fortrel provides a useful alternative to making new petroleum-based fibres, and the fleece produced is valued from its warmth and durability. However, it is a bit of a stretch to call this fabric "eco-friendly" or "green" - rather, it is another by-product of petroleum production, albeit further removed from the main production process for synthetic fibres.

Non-ecological, non-renewable fabrics

Polyester : A petroleum-based by-product, polyester has a carbon footprint much higher than any other fabric, making this one of the worst possible fabrics to use, despite its popularity and low off-the-shelf price.
Nylon : Nylon is petroleum-based by-product with a particularly poor record for environmental impact due to several toxic by-products generated when making this fabric.
Lycra-spandex : Spandex (and Lycra) is a polyurthethane product, and hence another petroleum by-product. It necessarily has a high carbon footprint and a correspondingly high ecological footprint. Spandex is widely used as a fibre supplement to introduce stretch into a fabric which would otherwise have little stretch. If you must buy stretch fabrics, go for ones with as small a percentage of spandex as possible.

The following table showcases some of the differences found in footprint between polyester (and other synthetic fibers, which are generally worse), conventional fabrics such as cotton and so-called organic fibres such as organic cotton and hemp. It is the relative numbers that are important, here, more than their absolute values.

Fibre source Carbon Footprint
weight per tonne
(crop growth)
Carbon Footprint
weight per tonne
(fiber production)
Carbon Footprint
weight per tonne
(total)
Additional Relative Ecological Footprint
(hectares/tonne fiber)
Polyester - 9,5 kg (20,9 lbs) 9,5 kg (20,9 lbs) 1,7 - 2,2 ha/tonne fiber
Conventional cotton 4,2 kg (9,3 lbs) 1,7 kg (3,7 lbs) 5,9 kg (13,0 lbs) 2,2 - 3,6 ha/tonne fiber
Organic cotton (US) 0,9 kg (2,0 lbs) 1,5 kg (3,3 lbs) 2,4 kg (5,3 lbs) ?
Organic cotton (India) 2,0 kg (4,4 lbs) 1,8 kg (4,0 lbs) 3,8 kg (8,4 lbs) ?
Conventional hemp 1,9 kg (4,2 lbs) 2,2 kg (4,8 lbs) 4,1 kg (9,0 lbs) 1,5 - 2,0 ha/tonne fiber

Most other artiicial or synthetic fibers have considerably higher carbon footprints (acrylic is 30% higher, nylon even more so, and nylon production produces nitrogen dioxide (N2O) which is 300 times more toxic than carbon dioxide!).

In a recent Australian study, clothing was found to be the largest single contributor to the ecological footprint of a large city (Melbourne), corresponding to some 14,5% of the total ecological footprint. Motor vehicle transportation represented a distant 1,5% in comparison (however, overall use of cars in Melbourne is about 20%, compared to the US average of 50%). Combined with other processed fabric fibres (2,6%), textile products such as curtains, tarpaulins and tampons (together representing 2,7%) and with footwear (1,6%), more than one fifth of the city's ecological footprint resulted from choices in clothing, footwear and fabrics.

Summary

To summarize, no fabric fibre has a perfect environmental record. The safest way to proceed is to choose fabrics that have been environmentally certified using one or more of the emerging certification standards. Staying clear of synthetic fibres is generally better from an ecological standpoint, particularly petroleum based fibres. Although flax and hemp and such products are potentially good choices, if they lack certification they are not necessarily appropriate.

Other ways to reduce the carbon footprint of fabrics includes making clothes oneself (this saves on contributing to energy costs, chemical dyes or other by-products of the fabric industry, but does not change the chemicals used in creating the fibre or the fabric), and, particularly, changing one's habits in how clothes are cleaned. Studies show that each load of laundry that passes through a dryer generates a carbon footprint of 2 kg. Changing to concentrated liquid detergents and cooler wash temperatures also lowers the carbon footprint substantially, from a maximum of 0,9 to about 0,6 kg per load of wash (not counting the drying cycle).

Clothes and fabrics are found to be significant contributors to our individual carbon footprint, and hence making choices in this area has potentially a relatively large impact on reducing our carbon and ecological footprint. Furthermore, buying certified green products puts pressure on the textile industry to change its environmentally destructive practices and thereby ensure an additional reduction in our ecological footprint.



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