Silk has long been considered an elegant, prized material across the world. It may still be a lavish material but the question we want to know is if silk is sustainable.
The origins of the silk industry go back over two thousands years ago to imperial China. Silk quickly made a name for itself as being one of the most sought-after materials for creating ultra-soft clothing and accessories.
With the world wanting access to silk, the Silk Road was created connecting the Far East to the West around 130 BCE. This continued to be a main trading route through to the 20th century.
The quality of silk fabrics is undeniable, but one important question still stands – is silk sustainable?
Here we answer all the most common questions you might have about silk, from the way it’s made today to its environmental and ethical impacts.
What is silk?
Silk is a natural, animal-derived fibre known for its strength, and durability. Silk is produced by insects, mainly silkworms but it can also be created by beetles and even honey bees.
Fibroin is the main protein that makes up the structure of this soft fibre.
It’s exactly this protein that gives silk fabrics its strength — high-end textiles aside, the stiffness and extensibility of fibroin are prized even in the biomedical field!
While there are many different species of silkworms producing silk fibres, the large majority of silk textiles on the market are derived from the cocoon of the domesticated Bombyx mori, whose silk is known for its signature softness.
How is silk made?
Most commonly, silk fibres are created by silkworms as they make their cocoon. It’s here where the insects remain until they’re ready to complete their metamorphosis into moths.
Once the larvae are in their cocoons, the silk fibres are harvested by boiling the structure in hot water and unravelling the cocoon’s threads.
This is an extremely careful and labour-intensive process, as unravelling the threads too quickly might damage the fibres. Slowly, every single thread is reeled into longer threads, wound on a reel, and finally washed so that the gum that kept all the threads together can dissolve.
This is when the dyeing process begins. After bleaching and drying the fibre, the silk is immersed in a dye bath to soak the desired colour in.
Finally, the threads are spun and woven with the help of machines that, in many ways, still resemble the classic spinning wheel you might picture when you think about traditional silk production.
China is the biggest producer of Silk, followed by India, Uzbekistan, Brazil and Iran.
Is silk vegan?
As you might already have guessed by now, no, silk is not a vegan-friendly material.
Much like with wool, suede, and leather, making silk requires the use (and in the eyes of vegans, the exploitation) of animal labour and animal bodies.
On top of keeping the species domesticated to continue harvesting the precious silk threads, the boiling process also ends up killing the silkworm larvae inside of their cocoons.
But this doesn’t necessarily mean that silk is completely out of reach for vegans.
Vegan silk, a cruelty-free alternative to traditional silk, skips the boiling process by allowing the larvae to come out and transform into silkmoths before harvesting the discarded cocoon.
However, as the insects are still kept in captivity for their whole life in order to keep the industry running, not many vegans see this new cruelty-free silk as fully vegan!
Is silk a sustainable fabric?
With the controversial vegan question out of the way, let’s get to an even more challenging one: Is silk sustainable?
In many ways, silk is more sustainable than textiles like conventional cotton and leather. This is because in its raw form, silk doesn’t require many fertilisers or pesticides to produce.
In fact, the mulberry trees used to feed the silkworm larvae can easily be grown organically, needing a lot less water than cotton crops as well as a lot less polluting pesticides and fertilisers. Look out for any certified organic products which are certainly more sustainable.
The problem with silk begins during the transformation from raw material to fabric.
According to the Higg Materials Sustainability Index (MSI), silk ranks higher than almost all other fibres when it comes to the environmental impact from raw material to finished product. Even worse than the likes of polyester and rayon. Not a good sign for the silk sustainability.
This is due to a number of factors, including the use of bleach, wasteful dye baths, excess water use and high energy usage (and, in turn, fossil fuel usage). It’s thought that it requires 1,000 tonnes of fresh water to create 1 tonne of silk.
High energy use seems to have the most negative environmental impact, resulting in some of the heaviest contributions to global warming in the textile industry.
Air conditioning and humidity control are the main culprits behind silk’s intensive energy use. Silk farms need to be kept at a certain level of humidity and temperature to guarantee each silkworm does its job. As most silk today is produced in hot countries in South Asia, a lot of energy is required to keep each farm at a stable temperature and humidity level.
On top of that, the drying process that follows the cocoon boiling also uses massive quantities of steam, further contributing to fossil fuel use.
On the more positive side, there is zero waste to silk production. Everything is used, re-used or integrated back into the local economy.
Is silk a biodegradable and compostable material?
While silk’s high energy usage leaves behind a heavy environmental footprint, the same cannot be said for its discarded materials.
On top of being, at least in its raw form, a renewable resource, silk is long-lasting and biodegradable. This makes for a better alternative to textiles like polyester and nylon.
Silk is made from natural fibres, which means it’s also a compostable material like 100% cotton and wool.
But before you go putting your silk in the compost pile, you should first make sure it’s been dyed with natural dyes, as the use of synthetic dyes can hinder the biodegradability of the fibre!
So, is silk bad for the environment or not?
So, what conclusion can we draw from this? Is silk sustainable or in any way eco-friendly?
Looking at the data, it seems that silk suffers from many of the same issues that conventional cotton does, minus the sky-high water usage.
It is a renewable, biodegradable, natural fibre with a lot of potential to be made more environmentally friendly by switching up energy-intensive and polluting processes. But at the same time, the high energy usage associated with silk makes it the top contributor to climbing greenhouse gas emissions, with little chance of improvement without fundamentally changing how silk is made.
You also have to factor in the use of an inordinate amount of insects who get boiled before they even reach their main lifestage. This may not bother most people but it’s not the most Earth friendly activity is it?
While they might not be silky-smooth, materials like linen, Tencel, or even organic raw cotton make for a more sustainable alternative to all silk products. If you do have any silk products, your best bet is to try and keep them for as long as possible.
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