Bamboo viscose vs cotton: which is more sustainable?
Sustainability has become a buzzword in the fashion industry. More and more brands are marketing the materials their products are made from as clean, green solutions. Two common fabrics that vie for the title of the most sustainable material are cotton and bamboo viscose.
However, in the discussion of bamboo viscose vs cotton, what is the difference between the fabrics? Which is more sustainable and which one should we be using to build a green tomorrow?
The making of bamboo and cotton
The best place to start in seeing who wins the bamboo viscose vs cotton contest is at the beginning. To better understand these fabrics, we need to know how they are made.
Making bamboo viscose fabric
Bamboo viscose is a semi-synthetic fabric. Although it has natural materials at its origin it undergoes chemical treatment in its manufacturing process.
The production process begins by harvesting mature stems of bamboo. The bamboo stems are then cut into chips, washed and treated with chemicals, such as sodium hydroxide, to be broken down into a pulp.
The bamboo fibre pulp is be treated and manufactured to be turned into a fibre, which is treated again with chemicals. The resulting material can be spun into yarn and weaved into fabric that can be made into clothing.
Bamboo lyocell production (and what is bamboo lyocell fabric?)
Also entering the fabric market more recently is bamboo lyocell. Similar to bamboo viscose, lyocell still requires chemical processing to be turned into a fabric. However, lyocell is produced in a closed-loop system (meaning that chemicals and water are reused), greatly reducing the risk of environmental contamination from toxic chemicals.
Cotton, meanwhile, starts life as the fluffy fibre in cotton seed pods. Once harvested cotton undergoes the ginning process where the cotton fibre is separated from seed pods. Any dirt, stems or other unneeded materials are also removed. This creates cotton fibres that can be cleaned and then turned into yarn that goes on to be woven into fabric.
Sustainability: bamboo viscose vs cotton
So now we know how they´re made, let´s compare how environmentally friendly the two are.
1. Is bamboo viscose eco-friendly?
Bamboo comes with a range of environmental advantages and disadvantages and exploring these helps to give an overview of the sustainability of the fabric.
Advantage: pesticide and fertiliser free
The bamboo plant doesn’t require chemical fertilisers or pesticides. The use of fertiliser and pesticides can contaminate soil and waterways leading to loss of biodiversity. They can also pose a significant risk to human health and can remain prevalent in the environment decades after use. So, the fact that bamboo crops don’t require pesticides or fertilisers is a big point in their favour.
Advantage: efficient to grow
The growing and harvesting of this crop is so efficient that, due to the plant’s root network, crops don’t even need to be replanted after harvesting but will simply start growing again. This, in and of itself, makes it an inherently renewable resource. It also grows incredibly quickly, able to grow almost three feet a day.
Advantage: less water needed
When it comes to the actual growing of the crop, most people point to bamboo as a sustainable option. Bamboo only requires a fraction of the water that cotton does and comes with the added advantage that the crop can reshoot without having to be replanted.
Advantage: no microplastic shedding
Whilst this is the same for cotton, the fact that bamboo is natural also makes it a better option than microplastic shedding polyesters.
Disadvantage: harmful chemicals
The making stage is where bamboo viscose’s sustainable streak does falter. Although the raw material is very sustainable, turning it into fabric is a chemically intensive process. The chemicals used in the viscose process are incredibly potent, including those such as carbon disulphide and sodium hydroxide, commonly known as lye. These harsh chemicals can go on to pollute waterways and soil and pose a significant risk to human health.
Chemicals such as sodium hydroxide, are highly corrosive and can contribute to environmental problems such as increased water salinity. Making a bad situation worse, only half of the chemical waste produced in making viscose fabrics can be recaptured and reused.
However, while only 50% of bamboo’s hazardous waste can be recaptured, these chemicals can still be processed through wet processing facilities. This avoids chemical dumping and does make the whole process a little more environmentally friendly.
In recent years, companies like BAM have started to lead the way in making this process more environmentally friendly.
Disadvantage: lack of transparency
Another problem that bamboo runs into is the fact that there isn’t a lot of information out there about bamboo suppliers. This lack of information could potentially hide a whole host of environmental and human rights transgressions.
While the magnitude of the cotton sector does pose a similar problem, many organic cotton supply chains have certifications (such as GOTS) that require a greater level of transparency.
Some brands, such as BAM, have put in the work themselves to trace supply chains back to the growers. Overall though, bamboo needs far more transparency in the industry.
To learn more about BAM’s approach check out our interview with the brand’s Sustainability and Technical Manager Merryn Chilcott.
Disadvantage: land clearing
Allegations of land clearing are another potential disadvantage for bamboo. Reports have emerged of forests being cleared for bamboo plantations, offering a major blow to the eco-friendly claims of the crop.
2. Is cotton eco-friendly?
Bamboo may be a mixed bag when it comes to sustainability, but when looking at cotton vs bamboo viscose, does cotton score any better?
Advantage: natural and biodegradable
Cotton is a natural fabric, so this means that it can biodegrade. With waste a major problem in the fashion industry, the fact that cotton biodegrades is incredibly positive. It takes between one week and five months for the average cotton fabric to decompose. In comparison, bamboo fabric takes a year or more to biodegrade.
For more on which fabrics are biodegradable, see our article Styles that don´t last forever: which fabrics are biodegradable.
Advantage: a bigger sector
The size of the industry provides more choice for companies, meaning they have greater options to choose suppliers that fit with their company ethics. It also means a variety of industry specific certifications.
When looking for sustainable materials one of the key factors to look out for is certifications. While there are some sustainability certifications that relate to bamboo, the sheer size of the cotton industry means that there are more certifying bodies tailor made for it. Certifications such as the Better Cotton Initiative and Cotton made in Africa (CmiA) exist solely for the cotton sector.
Disadvantage: a thirsty crop
One of cotton’s main drawbacks is the amount of water needed to grow the cotton plant. It takes 2,700 litres of water to create just one cotton t-shirt. When considering that the textile industry is responsible for 4% of freshwater use worldwide, those cotton t-shirts start to add up. Water use from cotton production is so problematic that it is one of the leading factors in the drying of the Aral Sea.
Disadvantage: a dirty and dangerous crop
Also impacting cotton’s sustainable credentials is its insecticide use. Conventionally grown cotton is a major polluter, using 16% of the world’s insecticides. This extensive use of insecticides impacts the health of ecosystems and communities and can contaminate water and soil.
However, organic cotton evens this score a little, and while bamboo doesn’t require pesticides to grow it doesn’t mean that all farmers don’t use them.
When compared to conventional cotton though, well-managed bamboo crops, overall come out as the more sustainable option.
Conventionally farmed cotton also comes with a litany of human rights issues. Everything from slavery to child labour has been reported in the sector. To learn more about the human impact of cotton check out our article about cotton farmers.
The organic exception
It’s important to note that organic cotton, grown without the use of insecticides and with greater transparency doesn’t have the same impact as regular cotton on its local ecosystems. While it is still a thirsty crop, its lack of insecticide and pesticide use makes it drastically better for biodiversity. And its transparency makes it better for human rights.
Fabric properties: bamboo viscose vs cotton
As we’ve seen, both cotton and bamboo viscose have a lot of points in their favour and both also have some core sustainable drawbacks. For a fabric to be a solution in the fashion industry, it also needs to be practical to use. So when it comes to comparing these two fabrics its important to also look at their properties.
1. Properties of bamboo
The naturally versatile properties of bamboo viscose make it popular for a wide variety of uses. It can be found in everything from shirts and dresses to underwear and socks. The fabric is famous for its soft, silky texture and has an elegant drape.
Bamboo fabric is often grown without the use of pesticides and is soft against the skin. The fabric is also a wonderful insulator, this makes it great for trans-seasonal clothing, while its moisture wicking properties (meaning it absorbs moisture and moves it away from the skin), make it ideal for sportswear.
However, it isn’t all good news for bamboo clothing. The fabric is prone the shrinkage and can pill more easily than other textiles.
2. Properties of cotton
One of the most widely used natural fabrics, cotton has been popular throughout much of fashion’s history. It’s highly versatile and is used in almost every facet of the industry from luxury formal wear to basics and underwear and is a big player in markets such as the bedding industry.
When farmed organically it can be great for those with sensitive skin. Cotton also scores points for its durability and moisture absorption qualities, with the fabric able to absorb one fifth of its weight in water before feeling wet.
However, much like bamboo, cotton does have some key drawbacks, one of these is shrinkage. While it takes to dye well initially cotton clothing is also known to fade over time.
Bamboo viscose vs cotton: Is bamboo viscose more breathable than cotton?
Being natural fabrics, both bamboo and cotton are breathable. While there is debate over which is the most breathable, the thermoregulating properties of bamboo do make it especially popular for hot weather clothing.
Sustainable and practical? The overall verdict
Both bamboo viscose and cotton offer a range of properties that make them incredibly useful in the fashion sector.
When it comes to sustainability, although there are some key areas that bamboo viscose could improve upon to make it even more eco-friendly, when compared to conventional cotton, it is the more sustainable option.
When compared to organic cotton, bamboo sourced from well-managed farms and processed without chemical dumping, is relatively comparable in how sustainable it is.
When brands, such as BAM, are proactive in their approach to trace supply chains and ensure ethical practices every step of the way, it only makes bamboo even more sustainable.
A sustainable fabric
There are a lot of fabrics out there claiming to be sustainable, and while there are some issues with bamboo viscose, overall the answer to the question is bamboo viscose eco-friendly, is yes. Organic cotton and bamboo viscose offer good options in building a modern fashion sector and every sustainable fabric choice helps to create a sustainable future.