Climate change and the textile industry

15 10 2014

Time sure flies doesn’t it?  I’ve been promising to reiterate the effects the textile industry has on climate change, so I’m re-posting a blog post we published in 2013:

In considering fabric for your sofa, let’s be altruistic and look at the impact textile production has on global climate change. (I only use the term altruistic because many of us don’t equate climate change with our own lives, though there have been several interesting studies of just how the changes will impact us directly,like the one in USA Today that explains that wet regions will be wetter, causing flash flooding; dry regions will get drier, resulting in drought. And … a heat wave that used to occur once every 100 years now happens every five years (1)).

Although most of the current focus on lightening our carbon footprint revolves around transportation and heating issues, the modest little fabric all around you turns out to be from an industry with a gigantic carbon footprint. The textile industry, according to the U.S. Energy Information Administration, is the 5th largest contributor to CO2 emissions in the United States, after primary metals, nonmetallic mineral products, petroleum and chemicals.[2] And the U.S. textile industry is small potatoes when compared with some other countries I could mention.

The textile industry is huge, and it is a huge producer of greenhouse gasses (GHG’s). Today’s textile industry is one of the largest sources of greenhouse gasses  on Earth, due to this huge size.[3] In 2008, annual global textile production was estimated at 60 billion kilograms (KG) of fabric. The estimated energy and water needed to produce that amount of fabric boggles the mind:

  • 1,074 billion kWh of electricity or 132 million metric tons of coal and
  • between 6 – 9 trillion liters of water[4]

Fabrics are the elephant in the room. They’re all around us but no one is thinking about them. We simply overlook fabrics, maybe because they are almost always used as a component in a final product that seems rather innocuous: sheets, blankets, sofas, curtains, and of course clothing. Textiles, including clothing, accounted for about one ton of the 19.8 tons of total CO2 emissions produced by each person in the U.S. in 2006. [5] By contrast, a person in Haiti produced a total of only 0.21 tons of total carbon emissions in 2006.[6]
Your textile choices do make a difference, so it’s vitally important to look beyond thread counts, color and abrasion results.
How do you evaluate the carbon footprint in any fabric? Look at the “embodied energy’ in the fabric – that is, all of the energy used at each step of the process needed to create that fabric. Not an easy thing to do! To estimate the embodied energy in any fabric it’s necessary to add the energy required in two separate fabric production steps:

  1. Find out what the fabric is made from, because the type of fiber tells you a lot about the energy needed to make the fibers used in the yarn. The carbon footprint of various fibers varies a lot, so start with the energy required to produce the fiber.
  2. Next, add the energy used to weave those yarns into fabric. Once any material becomes a “yarn” or “filament”, the amount of energy and conversion process to weave that yarn into a textile is pretty consistent, whether the yarn is wool, cotton, or synthetic.[7)

Let’s look at #1 first: the energy needed to make the fibers and create the yarn. For ease of comparison we’ll divide the fiber types into “natural” (from plants, animals and less commonly, minerals) and “synthetic” (man made):

For natural fibers you must look at field preparation, planting and field operations (mechanized irrigation, weed control, pest control and fertilizers (manure vs. synthetic chemicals)), harvesting and yields. Synthetic fertilizer use is a major component of the high cost of conventional agriculture: making just one ton of nitrogen fertilizer emits nearly 7 tons of CO2 equivalent greenhouse gases.
For synthetics, a crucial fact is that the fibers are made from fossil fuels. Very high amounts of energy are used in extracting the oil from the ground as well as in the production of the polymers.
A study done by the Stockholm Environment Institute on behalf of the BioRegional Development Group concludes that the energy used (and therefore the CO2 emitted) to create 1 ton of spun fiber is much higher for synthetics than for hemp or cotton:

KG of CO2 emissions per ton of spun fiber:
crop cultivation fiber production TOTAL
polyester USA 0 9.52 9.52
cotton, conventional, USA 4.2 1.7 5.9
hemp, conventional 1.9 2.15 4.05
cotton, organic, India 2 1.8 3.8
cotton, organic, USA 0.9 1.45 2.35

 

The table above only gives results for polyester; other synthetics have more of an impact: acrylic is 30% more energy intensive in its production than polyester [8] and nylon is even higher than that.
Not only is the quantity of GHG emissions of concern regarding synthetics, so too are the kinds of gasses produced during production of synthetic fibers. Nylon, for example, creates emissions of N2O, which is 300 times more damaging than CO2 [9] and which, because of its long life (120 years) can reach the upper atmosphere and deplete the layer of stratospheric ozone, which is an important filter of UV radiation. In fact, during the 1990s, N2O emissions from a single nylon plant in the UK were thought to have a global warming impact equivalent to more than 3% of the UK’s entire CO2 emissions.[10] A study done for the New Zealand Merino Wool Association shows how much less total energy is required for the production of natural fibers than synthetics:

 

Embodied Energy used in production of various fibers:
Energy use in MJ per KG of fiber:
flax fibre (MAT) 10
cotton 55
wool 63
Viscose 100
Polypropylene 115
Polyester 125
acrylic 175
Nylon 250
SOURCE: “LCA: New Zealand Merino Wool Total Energy Use”, Barber and Pellow, http://www.tech.plym.ac.uk/sme/mats324/mats324A9%20NFETE.htm

Natural fibers, in addition to having a smaller carbon footprint in the production of the spun fiber, have many additional benefits:

  • being able to be degraded by micro-organisms and composted (improving soil structure); in this way the fixed CO2 in the fiber will be released and the cycle closed. Synthetics do not decompose: in landfills they release heavy metals and other additives into soil and groundwater. Recycling requires costly separation, while incineration produces pollutants – in the case of high density polyethylene, 3 tons of CO2 emissions are produced for ever 1 ton of material burnt.[11] Left in the environment, synthetic fibers contribute, for example, to the estimated 640,000 tons of abandoned fishing nets in the world’s oceans.
  • sequestering carbon. Sequestering carbon is the process through which CO2 from the atmosphere is absorbed by plants through photosynthesis and stored as carbon in biomass (leaves, stems, branches, roots, etc.) and soils. Jute, for example, absorbs 2.4 tons of carbon per ton of dry fiber.[12]

Substituting organic fibers for conventionally grown fibers is not just a little better – but lots better in all respects:

  • uses less energy for production, emits fewer greenhouse gases and supports organic farming (which has myriad environmental, social and health benefits).  A study published by Innovations Agronomiques (2009) found that 43% fewer GHGs are emitted per unit area under organic agriculture than under conventional agriculture.[13] A study done by Dr. David Pimentel of Cornell University found that organic farming systems used just 63% of the energy required by conventional farming systems, largely because of the massive amounts of energy requirements needed to synthesize nitrogen fertilizers. Further it was found in controlled long term trials that organic farming adds between 100-400kg of carbon per hectare to the soil each year, compared to non-organic farming. When this stored carbon is included in the carbon footprint, it reduces the total GHG even further.[14] The key lies in the handling of organic matter (OM): because soil organic matter is primarily carbon, increases in soil OM levels will be directly correlated with carbon sequestration. While conventional farming typically depletes soil OM, organic farming builds it through the use of composted animal manures and cover crops

Taking it one step further beyond the energy inputs we’re looking at, which help to mitigate climate change, organic farming helps to ensure other environmental and social goals:

  • eliminates the use of synthetic fertilizers, pesticides and genetically modified organisims (GMOs) which is an improvement in human health and agrobiodiversity
  • conserves water (making the soil more friable so rainwater is absorbed better – lessening irrigation requirements and erosion)
  • ensures sustained biodiversity
  • and compared to forests, agricultural soils may be a more secure sink for atmospheric carbon, since they are not vulnerable to logging and wildfire.

Organic agriculture is an undervalued and underestimated climate change tool that could be one of the most powerful strategies in the fight against global warming, according to Paul Hepperly, Rodale Institute Research Manager. The Rodale Institute Farming Systems Trial (FST) soil carbon data (which covers 30 years) provides convincing evidence that improved global terrestrial stewardship–specifically including regenerative organic agricultural practices–can be the most effective currently available strategy for mitigating CO2 emissions.

At the fiber level it is clear that synthetics have a much bigger footprint than does any natural fiber, including wool or conventionally produced cotton. So in terms of the carbon footprint at the fiber level, any natural fiber beats any synthetic – at this point in time. Best of all is an organic natural fiber.
And next let’s look at #2, the energy needed to weave those yarns into fabric.
There is no dramatic difference in the amount of energy needed to weave fibers into fabric depending on fiber type.[15] The processing is generally the same whether the fiber is nylon, cotton, hemp, wool or polyester: thermal energy required per meter of cloth is 4,500-5,500 Kcal and electrical energy required per meter of cloth is 0.45-0.55 kwh. [16] This translates into huge quantities of fossil fuels – both to create energy directly needed to power the mills, produce heat and steam, and power air conditioners, as well as indirectly to create the many chemicals used in production. In addition, the textile industry has one of the lowest efficiencies in energy utilization because it is largely antiquated.

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(1) http://www.usatoday.com/story/news/nation/2013/02/28/climate-change-remaking-america/1917169/
(2) Source: Energy Information Administration, Form EIA:848, “2002 Manufacturing Energy Consumption Survey,” Form EIA-810, “Monthly Refinery Report” (for 2002) and Documentatioin for Emissions of Greenhouse Gases in the United States 2003 (May 2005). http://www.eia.doe.gov/emeu/aer/txt/ptb1204.html
(3) Dev, Vivek, “Carbon Footprint of Textiles”, April 3, 2009, http://www.domain-b.com/environment/20090403_carbon_footprint.html
(4) Rupp, Jurg, “Ecology and Economy in Textile Finishing”, Textile World, Nov/Dec 2008
(5) Rose, Coral, “CO2 Comes Out of the Closet”, GreenBiz.com, September 24, 2007
(6) U.S. Energy Information Administration, “International Energy Annual 2006”, posted Dec 8, 2008.
(7) Many discussions of energy used to produce fabrics or final products made from fabrics (such as clothing) take the “use” phase of the article into consideration when evaluating the carbon footprint. The argument goes that laundering the blouse (or whatever) adds considerably to the final energy tally for natural fibers, while synthetics don’t need as much water to wash nor as many launderings. We do not take this component into consideration because
. it applies only to clothing; even sheets aren’t washed as often as clothing while upholstery is seldom cleaned.
. is biodegradeable detergent used?
. Is the washing machine used a new low water machine? Is the water treated by a municipal facility?
. Synthetics begin to smell if not treated with antimicrobials, raising the energy score.
Indeed, it’s important to evaluate the sponsors of any published studies, because the studies done which evaluate the energy used to manufacture fabrics are often sponsored by organizations which might have an interest in the outcome. Additionally, the data varies quite a bit so we have adopted the values which seem to be agreed upon by most studies.
(8) Ibid.
(9) “Tesco carbon footprint study confirms organic farming is energy efficient, but excludes key climate benefit of organic farming, soil carbon”, Prism Webcast News, April 30, 2008, http://prismwebcastnews.com/2008/04/30/tesco-carbon-footprint-study-confirms-organic-farming%E2%80%99s-energy-efficiency-but-excludes-key-climate-benefit-of-organic-farming-%E2%80%93-soil-carbon/
(10) Fletcher, Kate, Sustainable Fashion and Textiles, Earthscan, 2008, Page 13
(11) “Why Natural Fibers”, FAO, 2009: http://www.naturalfibres2009.org/en/iynf/sustainable.html
(12) Ibid.
(13) Aubert, C. et al., (2009) Organic farming and climate change: major conclusions of the Clermont-Ferrand seminar (2008) [Agriculture biologique et changement climatique : principales conclusions du colloque de Clermont-Ferrand (2008)]. Carrefours de l’Innovation Agronomique 4. Online at
(14) International Trade Centre UNCTAD/WTO and Research Institute of Organic Agriculture (FiBL); Organic Farming and Climate Change; Geneva: ITC, 2007.
(15) 24th session of the FAO Committee on Commodity Problems IGG on Hard Fibers of the United Nations
(16) “Improving profits with energy-efficiency enhancements”, December 2008, Journal for Asia on Textile and Apparel, http://textile.2456.com/eng/epub/n_details.asp?epubiid=4&id=3296

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Bamboo and the FTC

19 08 2009

Bamboo-background

“Bamboo” fabric has taken the world by storm – people love its luxurious softness, smooth hand and gentle drape,  and they also seem to love its eco credentials (as touted by those selling the fabric).

It’s easy to tout bamboo (the plant) as eco friendly, because it is a wonderfully beneficial plant and just might be the world’s most sustainable resource: It’s the fastest growing grass and can grow up to a yard or more per day.  Growing bamboo improves soil quality and helps rebuild eroded soil. The extensive root system of bamboo holds soil together, prevents soil erosion, and retains water in the watershed. It doesn’t require replanting after harvest because its vast root network continually sprouts new shoots, all the while pulling in sunlight and greenhouse gases while converting them to new growth.  All this without the use of tractors or other machinery using petroleum, and without pesticides or fertilizers.

Bamboo (the plant) produces a huge biomass, both above and below ground.  One study found bamboo produces 14 tons of wood per acre, as against 8 for loblolly pine[1]; planted in large groves, it can store four times the CO2 as a stand of trees of similar size, and it releases 35% more oxygen.[2] Currently there are no known genetically modified organism (GMO) variants of bamboo.

But though bamboo the plant can be terrifically sustainable and beneficial, bamboo the fabric can raise environmental and health concerns – but like many issues on the green front, the answer is not black and white.  Some bamboo fiber can be green and some is not – and some green bamboo fiber can be woven conventionally and dyed with dyestuffs that contain lead, mercury, or other heavy metals, mutagenic chemicals that change our DNA or endocrine disruptors which affect our hormone balance.  And the factory using these chemicals probably did not treat their effluent before returning it to our waterways.

The Federal Trade Commission has finally acted to restrict some of the more outrageous claims being made about textiles, bamboo fabric specifically:  they have charged four sellers of clothing and other textile products with deceptive labeling and advertising.  Their intention is to demonstrate that unsubstantiated green claims in the clothing and other textile related product categories will not be tolerated.  And believe me, that’s a GREAT thing, because claims are being made for “green” textiles of every stripe – often stretching the “green” issue to the limit.   But to categorically say bamboo fabric is NOT green is to overstep in the opposite direction.   There is some naturally retted bamboo (processed like flax or hemp) on the market though it’s still hard to find.  The process used to turn bamboo into a fiber which is used almost exclusively today, the viscose process, can also be eco friendly if the manufacturer makes the effort to capture emissions and treat effluent.   We have to stop and take the time to evaluate claims.

Let’s give it a go.

“Rayon” is the generic name for any man-made fiber made from cellulose  – man in this case applies a chemical process to transform the cellulose.  It’s usually used with cellulose found in very hard and woody plants, such as wood or bamboo, although it can also be made from algae or other types of cellulose.   Cellulose is a carbohydrate and the chief component in the walls of plants.  There are several chemical and manufacturing techniques to make rayon, but the most common method is the viscose process.  In the viscose process, cellulose is treated with caustic soda (aka: sodium hydroxide) and carbon disulfide, converting it into a gold liquid about the color and consistency of honey, called viscose.  Viscose is forced through fine holes, called a spinerette, directly into a chemical bath where it hardens into fine strands.  When washed and bleached these strands become rayon yarn.  Most rayon made today uses this viscose process, which dates to the early 1900s.


RayonDiagram

Viscose is known as a “regenerated cellulose” fiber – in other words, it is reconstituted from cellulose.  Other regenerated cellulosic fibers include lyocell, Tencel®, modal and MicroModal – these are all made from wood.  Although the viscose process of making rayon from wood or cotton has been around for a long time, it wasn’t until 2003 that a method was devised for using bamboo for this process.(3)

The reason the viscose process is thought to be detrimental to the environment is based on the process chemicals used.  Though sodium hydroxide is routinely used in the processing of organic cotton, and is approved by the Global Organic Textile Standard (GOTS), carbon disulfide can cause nervous system damage with chronic exposure.  And that “chemical bath” to harden the threads?  Sulfuric acid.  These chemicals do not remain as a residue on the fibers – the proof of this is that almost all of the viscose produced can be (and often is) Oeko Tex certified (which certifies that the finished fiber has been tested for any chemicals which may be harmful to a person’s health and contains no trace of these chemicals.)

The problem comes in disposing of these process chemicals:  the sodium hydroxide (though not harmful to humans) is nevertheless harmful to the environment if dumped into our rivers as untreated effluent.  Same with carbon disulfide and, certainly, sulfuric acid.  Oeko Tex certifies only the final product, i.e.,the fibers or the fabric.  They do not look at the production process, which can be devastating.  The production could be done in a closed loop process, capturing and reclaiming all the chemicals used during manufacture, but this is seldom done.

And then of course there is the weaving of these viscose fibers into fabric – if done conventionally, the environmental burden is devastating (in terms of chemical and water use) and the fabric itself probably contains many chemicals known to be harmful to our health.

What is the FTC saying in their charge of deceptive advertising?  The unsubstantiated green claims they take issue with are:

  • The claim that the products are manufactured using an environmentally friendly process.
    • As I explained above, the claims may or may not be true.  Certainly the standard viscose production process is definitely NOT environmentally friendly, but some manufacturers use new closed loop systems, treat and/or recycle wastewater and capture emissions.  Tencel® certainly advertises its environmentally friendly production processes, based on closed loop systems, and a new non-toxic solvent (amine oxide) which, they say,  is 99.9% recycled.  Tencel® brand takes great pains to differentiate itself from viscose (saying that it is different because it’s based on solvents, but  I cannot find what they really mean by this as it seems to me they’re just using different chemicals.)  In the lyocell/Tencel process, the wood pulp is dissolved in N-Methylmorpholine N-oxide, then pushed thru spinneets to form individual fibers.  Although there is little by-product, the process uses a lot of energy and the solvent used is a by-product of gasoline production.
  • The claim that these products retain natural antimicrobial properties of the bamboo plant.
    • There has been little research done on viscose made from bamboo.  However, many studies have been done by Lenzing Group, which produces Tencel®.  One study sponsored by Lenzing found that “bacterial growth on textiles made from cellulosic fibers as compared to synthetic fibers showed lower bacterial growth”.[4] Of course, many claims assert that bamboo’s “natural antimicrobial properties” are retained by the viscose fibers.  However, could  it be possible that the exceptional water absorption ability of cellulosic fibers retards bacterial growth, as Tencel® claims?
  • The claim that they are biodegradable.
    • Ohio State University’s Consumer and Textile Sciences fact sheet on lyocell says it is “biodegradeable and recyclable”[5] and Tencel® also makes that claim – as seen in many advertisements about products made from this fiber. Is the bamboo viscose not as biodegradeable and/or recyclable as lyocell and Tencel®, both very similar fibers to bamboo viscose?  What is the inherent difference that would preclude the degredation of one and not the other?

The FTC says that “bamboo is not a generic fiber”.  Their reasoning is that the products are advertised as being made of “bamboo” when they should be saying the products are made of “rayon” or “rayon from bamboo”:

  • The differences between lyocell, Tencel, modal and viscose gets WAY technical; I think it’s sufficient here to note that they are all known by their fiber or brand names, rather than the cellulose source used in production.  For example, rayon is derived from wood pulp – and the kind of wood used can vary from beech, pine, spruce and hemlock to Eucalyptus – it’s not known as “lyocell rayon from beech” or “Tencel rayon from beech trees” as the FTC is requiring for “rayon from bamboo”. MicroModal, another regenerated cellulosic fiber, is even classified as “cotton” for importation by U.S. Customs.(6)

I guess I’m glad they’ve finally drawn a line in the sand.  Something is always better than nothing.  But I’m disappointed that they’re focusing on the fiber and ignoring the processing, because the processing is both a huge environmental burden (if done conventionally) and potentially very harmful to us and our kids.  So why stop with the fiber?  The Global Organic Textile Standard (GOTS) addresses these issues.  If manufacturers were forced (by the market or by federal regulations) to have third party certifications in place, we’d all be healthier and the ecosystem would have a better chance.  Perhaps the FTC could spend some effort spreading the word about GOTS and what exactly a GOTS certified fabric is  and why it’s better than a fabric (non certified) made with a GOTS certified – or organic – fiber.


[1]Raver, Ann, “A Cane the World Can Lean On”, New York Times, July 5, 2007

[2] Janssen, Jules A., Technical University Eindhoven, 2000

[3] US patent 7313906 by Xiangqi Zhou, Zheng Liu, Liming Liu and Hao Geng

[4] http://www.lenzing.com/fe/media/I_22-30_FIRGO_The_Functional_Properties_of_TENCEL.pdf

[5] http://ohioline.osu.edu/hyg-fact/5000/5572.html

[6] http://www.askandyaboutclothes.com/forum/archive/index.php?t-49815.html