Fiber fiber fiber! From conventional cotton to polyester to nylon, the (unsustainable) options in the current fashion market are endless. Manufacturing clothing from these fabrics require tons of resources to cultivate and process. However, these fibers are cheap grow and can generate large quantities of clothing. But, what about sustainable fibers?
The Status Quo
Let’s begin by taking a closer look at a typical cotton t-shirt to see its true impact at the fibre stage and how it compares to sustainable fibers. To keep things simple, we’ll be focusing on two main components: emissions/energy and water usage.
Emissions and Energy:
The total energy use in cotton production is based on the multiple energy inputs of machinery, fertilizers, and pesticides. Emissions is closely linked to energy as emissions is primarily from energy usage in production and farm machinery, and losses to the atmosphere from fertilizer and pesticide usage on the soil.
Conventional cotton is typically irrigated rather than rain fed, employing multiple channels to transport water and feed the crops. This turns out to be an energy-intensive process, requiring about 19.4 kWh per kg of cotton harvested. On top of this, cotton comes in third place globally in terms of the amount of pesticide used and fourth place in terms of fertilizer used, following corn, soybeans, and wheat.
Conventionally grown cotton also used $3.3 billion worth of pesticides in 2014 and accounted for 5.7% of all plant protection chemicals sold that year. The use of these chemicals coupled with the sheer scale of global cotton production creates staggering numbers by generating 220 million metric tons of carbon dioxide per year.
It won’t be news to you that conventional cotton is a water-intensive crop, as statistics such as 2700 litres of water needed to produce one t-shirt, have been shared widely for years now. In our blog on fast fashion last month, we discussed how the water required to produce one cotton t-shirt is equivalent to the amount of water that an average person drinks in 2.5 years.
What makes the cotton water crisis even more critical is the amount of virtual water consumed. Virtual water is essentially the hidden cost of a product, a sum of all the water used in the agricultural to the manufacturing process to the use to the waste created. It is the indirect usage of water through the lifecycle of a product. And because it is ‘hidden’ (i.e. we cannot visually see how much water it takes), we can easily turn our heads away and pay no mind to it.
On top of this, the concept of virtual water and cotton production disproportionately affects developing countries. For example: India is one of the largest suppliers of cotton globally, ranking in third (13.8%) behind China (26.1%) and United States (14.2%). Through the virtual water calculations, it suggests that producing 1kg of cotton in India consumes 22,500 litres of water. That’s water that cannot be used for anything else as it has evaporated or is too contaminated to be reused.
It is estimated that in 2013, India produced more than 7.5 million bales of cotton and exported 38,000 billion litres of virtual water. This water was not used for anything else besides cotton production and if conserved, it would be able to meet the needs of 85% of India’s population (1.1 billion people) for an entire year.
In most parts of the world, 1 kg of cotton only requires 10,000 litres. However, India’s larger water footprint is due to inefficiency in water use and high rates of pollution. Cotton is also grown in drier regions of the country and governments have subsidized costs of the electric pumps, placing no limits on the volume of groundwater extracted. This has created an overall high level of water consumption nationally as the country’s groundwater and surface-water resources are rapidly depleting.
With all these issues, the environmental footprint of your average cotton t-shirt looks like this:
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The Sustainable Fiber Alternatives:
Luckily, over the last few years, we have seen a spike in the use of sustainable fibers globally as fashion brands and consumers have become more mindful of the impact that their fabric selection has. Sustainable fibers made from organic cotton, hemp, and bamboo all use reduced levels of resources to manufacture and create less waste overall.
Making the switch to sustainable fibers is a low hanging fruit for greening your supply chain. While other sustainable changes (i.e. manufacturing processes, changing facilities, and transportation) might be harder to integrate, switching to sustainable fabrics actually has a smaller effect on other portions of the supply chain. Companies can simply ask their fabric manufacturers to switch to a sustainable version of the fibers, instead of using a conventional one. Plus, the benefits of switching to sustainable fibers in improving other parts of the supply chain can be seen in mere months.
To make our #GreenestTee, we are going to look at emissions/energy use and water use in the fiber stage, and use organic cotton as an example to illustrate this impact.
Emissions and Energy:
Compared to its conventional cotton counterpart, it is estimated that the production of organically grown cotton saves 288.7 million kilowatts of energy per year, which is enough to power 30,000 homes for a year. Switching to organic cotton can also save 92.5 million kg of CO2 emissions per year, which is equivalent to taking nearly 20,000 cars off the road for a year.
This decrease in emissions and energy can be due to the lack of pesticide use, insecticides, and fungicides used in the organic farming and cultivating processes. The Global Organic Textile Standard (GOTS) prohibits the use of toxic inputs in processing organic apparel and textiles. Thus, by cultivating GOTS certified organic cotton plants, there can be seen 70% decrease in the acidification of land & water.
What’s important to note is that organic cotton is a water-intensive crop because it grows in warm climates.To add, the average organic yield of organic cotton is about 25% lower than a conventional cotton. However, organic cotton requires significant less amounts of water to manufacture one t-shirt because of natural crop treatments (from 2120 liters to 182 liters). These treatments also allow for the soil to retain significantly more water and thus, the crops need much less irrigation.
Compared to conventional cotton, switching to organic cotton fibres can have the following impact in our #GreenestTee:
Next, let’s try creating a t-shirt from Tencel™ Lyocell (Tencel). Invented by Lenzing AG in Germany 40 years ago, Tencel is the brand name of lyocell. It is made from the pulp of trees and is comparable to rayon fiber.
Emissions and Energy:
The biggest pro of Tencel is that it was created with sustainability in mind. Thus, it has high resource efficiency, low waste, and minimal overall impact. Almost 80% of the harvesting of Tencel is done by hand, which diminishes the need for heavy machinery and added emissions. On top of this, Lenzing focuses on harvesting from new growth, certified, and controlled forests, removing the need to further destroy old growth forests.
When harvesting the pulp from Eucalyptus trees, Tencel uses a non-toxic solvent called amine oxide. This is key as 99.5% of the non-toxic chemicals gets recycled and no new waste is created or enters the ecosystem.
Producing Tencel is a closed-loop process, meaning it is incredibly water efficient and is able to capture, recycle, and reuse of 99% of water and solvents. The natural and managed forests also only use rainwater to grow and thus, no irrigation or extra machinery is required. Tencel also requires less land to field, with only a half acre of forestland can produce enough eucalyptus leaves without the need for pesticide or irrigation.
By creating a t-shirt made from Tencel, compared to conventional cotton, here’s the change in impact of our #GreenestTee:
Next, let’s try creating a t-shirt from Recycled PET (rPET), a plastic resin and a form of polyester. Essentially, this is a synthetic fabric, made from recycled polyester. Polyester currently dominates fiber types, making up 49% of the total production globally. Thus, rPET is a great sustainable alternative as it does not require the same energy-intensive processes as virgin polyester does. However, we would be remiss to not call out the issue of micro-fibre pollution from rPET and any such synthetic clothing as they are not biodegradable.
Emissions and Energy:
Since rPET is recycled, it bypasses the oil extraction required to make virgin polyester. Thus, this reduces the CO2 emissions of rPET in comparison to virgin polyester and thus, is a great alternative. However, since rPET is still synthetic, it requires mechanical processes of breaking down the materials and dyeing the fabric, releasing more emissions than the natural fabrics we discussed above.
One of the most important benefits of using rPET is that it provides a solution to the plastic problem as it prevents the need of raw material extraction. Five PET bottles can be taken from a landfill and recreated into a t-shirt.
The production of rPET saves significant amounts of water by avoiding virgin polyester production: 35% to be precise. By recycling these plastics, this also helps decrease the amount of plastic waste that enters landfills and reduces the number of toxic chemicals entering into the Earth.
By creating our #GreenestTee from rPET, as compared to cotton, this is the impact:
Conclusion: What is the most sustainable fiber?
As we can see from the discussions above, sustainable alternatives from fabrics such as organic cotton, tencel, and rPET help to reduce emissions and water significantly as compared to a traditional conventional cotton t-shirt. So which one do we pick?
There are a lot of other sustainable fabrics we didn’t look into for the blog, but you can find a comparison of the 8 greenest ones in our Green Fabric Guide. For now it looks like organic cotton is going to be our pick at the fiber stage. What are your thoughts?
Interested in other sustainable fabric options? We’ve written two free ebooks on it! Check out our Fantastic Fibres and Green Fabrics Guides for in-depth info on the most popular and up-and-coming sustainable fibres!