A lot has been said about the sustainability of different fibers, and silk has been getting a bad reputation in the last years with large companies like ASOS banning silk from their collections under pressure from organizations like PETA. The ease with which fashion companies have removed silk from the collection, immediately had me thinking that that would be an easy way to replace silk with cheap, shiny and very environmentally unfriendly replacements like polyester.
We have to distinguish between ethical (is it ok to wear animal based materials), and sustainable (is silk better or worse than other fibers?). What we choose to wear, buy, or eat, is ultimately a personal choice. It is worth mentioning, though, that practically any product comes with its own set of ethical tradeoffs.
Some facts and numbers
Silk is a natural protein fiber produced by the larvae of the silk moth.
There are more than 500 species of wild silkworms in the world.
Silk is the only natural filament fiber.
A filament from one cocoon can measure 600-900 meters.
Silk production is less than 0.2% of the global fiber market.
Silk can either be reeled or spun, depending on the way the silkworm leaves the cocoon.
Silk is divided in two types; domestic (mulberry) and wild silk (mugs, tassar, eri).
The silk industry has traditionally always been an agro-based cottage industry in many countries, and in these counties, this sericulture is an important part of local culture.
Worldwide more than 600.000 tons of silk is produced per year.
China produces more than 60 % of the world's silk per year, with over 400.000 tons of production per year. Most of this silk is industrial and not part of a cottage industry. Work conditions and production processes in this industry are infamously vague and it is very hard to get real numbers.
India comes second with around 160.000 tons of yearly production, most of which is wild grafted peace silk.
Uzbekistan is the third-largest producer of silk, with around 18.000 tons of production per year.
Countries with large traditional silk sericulture are:
China
India
In total there are over 25 countries that still produce silk as a real part of their economy. (source)
In Madagascar a silk project has been set up to protect the rainforest, other countries like Rwanda also explore silk as a possible export crop that can stimulate local economy,
Sericulture as a solid way of employment.
In India, silk sericulture is practiced in over sixty thousand villages. Just in the state of Karnataka alone, more than nineteen thousand villages raise silkworms for the silk industry. This business is providing employment to roughly 6 million people in those rural areas of India that otherwise do not have many economical opportunities. It is calculated that the silk production from the cultivation of mulberry trees to the weaving process on just one acre of land, creates as many as 1000 days of employment.
In most other silk-producing countries the situation is similar: sericulture creates low-stake (minimal investments) employment in rural areas that are otherwise not endowed with many employment opportunities. Moreso: a high percentage of the people working in sericulture is female, and this is helping women become players in the decision-making process. Taking that away will cause a large gap in income and status that is not easily filled with any alternative.
Is silk eco-friendly?
The answer is: it depends. Large industrial silk production is not eco-friendly at all. It uses tons of water (for growing the mulberry trees, reeling, and for degumming) and energy (Keeping controlled temperatures, heating the water used for reeling and cleaning, and hot air to dry filaments and fabrics).
This is not the case in the cottage industry, here the worms grow in the open air, and they eat what is available. Mulberry trees are grown in areas that are otherwise not suitable for crop growing. The silk processing in this cottage sericulture is notoriously low-tech and does not even use any energy in most of the steps. There is no reeling in water (the silk is spun) and the spinning and weaving are done manually.
Water use
If we look at the water-use in the silk industry these are the rough numbers:
To produce just one conventional cotton shirt (approximately 140 grams) requires approximately 3000 liters of water.
The water footprint of one handwoven silk shirt is 376 liters.
An organic linen shirt is your best option when it comes to water footprint: 33 liters of water on average for one shirt.
Environmental Pollution
No doubt that when it comes to pollution, silk is one of the most environmentally sound options available. No pesticides are used on the mulberry trees, which we surely can not say about the cotton industry. Silk is a circular and zero-waste fabric. It is a renewable resource, it is completely biodegradable, and the production process uses less chemicals, and energy than many other fibers.
The biggest pollution takes place during the degumming and bleaching stage of production. The use of sulphur dioxide, sodium hydrosulphite, and sodium or zinc sulphoxylate formaldehyde is in itself not the biggest issue, but the uneducated use of it without proper protective gear, and the uncontrolled disposal of waste water is.
For comparison: cotton growing typically use many hazardous pesticides like aldicarb, phorate, methamidophos and endosulfan. In cotton processing we see the use of ammonium sulfate, hydrochloric acid, benzidine, and oxalic acid.
Linen is traditionally touted as the most environmentally friendly fiber. But the current blast in linen use, makes that more producers are using fertilizers and irrigation to speed up the growing process, and strong alkali to reduce retting times. My children would say: 'this is why we can't have nice things'.
Labour issues
there have beentanks about the silk industry and labour circumstances, but here is my but: there are labour circumstance issues in the entire fashion industry (Bangladesh sweat shops anyone?). The only way to avoid it is by buying fair trade, GOTS etc and working with suppliers whom you know are responsible. When you are buying industrial, cheap mill silk from China, you must know that there have been short-cuts somewhere along the production line.
What are the alternatives to silk?
During the late 19th century, viscose/rayon was developed as a silk substitute. This man-made cellulose fiber is produced from wood pulp. While this sounds attractive, you should now that viscose processing is one of the most polluting industries in the world because it requires highly toxic chemicals and the regenerative-ability of the wood source is doubtful.
Banana silk, lotus silk, rose silk etc, are all new buzzwords for the same viscose process made from different sources. If it is not certified with OEKO tex or GOTS there is absolutely no traceability.
Polyester leaks microplastics into the water and it is not biodegradable. Factories producing polyester without wastewater treatment systems can release dangerous materials like antimony, cobalt, manganese salts, and sodium bromide into water streams.
Choosing your silk:
For me personally, silk is my most beloved fabric together with linen. It is durable, feels amazing and it is a joy to dye and print with. To make sure am getting the best silk that also leaves me with a clear conscience, I prefer handwoven silks from solid, reliable sources, with a fair-trade label. If they are unbleached or half bleached it is even better.
I highly recommend the handwoven matka silk, silk noil and bulbul silks you can find here.