We’ve already put together guides about some of the most eco friendly fibres and fabrics, and the least eco friendly fibres and fabrics.
In the guide below, we look at how silk sustainable, eco friendly and animal friendly silk might be across different measures.
Summary – Is Silk Sustainable, Eco Friendly & Cruelty Free For Fibres, Fabrics & Textiles?
Sustainability & Eco Friendliness
– Potential Benefits
Is a natural fibre
Mulberry trees may absorb carbon, and produce oxygen
Most parts of the mulberry tree (used for mulberry leaves to feed silkworms) can be utilised in some way
Mulberry trees might be able to be grown with little to no pesticides, herbicides and fertilizer
Mulberry tree plantations, silk farms, and silk production facilities might involve lesser negative land and soil health and degradation issues compared to fibre crops that require regular or heavy planting, tilling, harvesting, and replanting.
Mulberry trees might be able to use land fibre crops cannot
Silk fibre and fabric may use chemicals for treatment and finishing, but growing mulberry trees, and silkworm farming and cocoon harvesting might not use as many chemicals as other fibres at early stages of production
– Potential Drawbacks
Silk still uses chemicals to clean and dye silk
– Questionable Factors
treehugger.com indicates that ‘[silk] production has a larger environmental impact than other natural fibres [and synthetic fabrics]’. Although it’s difficult to tell across what metrics treehugger.com is referring to it being worse, and specifically how it’s worse
One sustainability index, the HIGG index, rates silk as having one of the worst environmental impacts of any fibre. It’s worth noting though that the HIGG index currently only assesses the manufacturing/supply and production chain stages, and only assesses environmental impact according to a limited range of sustainability measures. ecocult.com points out some of the potential limitations of the current HIGG index assessment, and the challenges of data collection for sustainability assessments in general
It might be unclear how much water silk production uses compared to other fibres. Some sources indicate the mulberry trees used in silk production are water hungry, and silk production uses water too. Other sources indicate that silk uses less water than several other fibres. As one example, it’s worth asking if silk needs as much water as more water hungry/irrigation hungry cottons.
It might be unclear what silk’s carbon footprint is individually, and what it is compared to other fibres. Mulberry trees may absorb carbon and expel oxygen, but this should be offset against carbon emissions at the silkworm farming and fibre production phases. Some sources indicate that silk’s carbon footprint isn’t small given it’s sizeable energy footprint. Does silk have a higher carbon footprint than synthtic fibres for example that involve extraction, refining, polymerization and other stages?
It might be unclear how much energy silk production uses compared to other fibres. Some sources indicate that silk farms, and also harvesting cocoons take a lot of energy. Energy usage might be silk’s largest component of it’s environmental footprint. But how much? And, how much more than other energy intensive fibres?
Animal Cruelty Considerations
Conventional silk production has involved the boiling/dissolving/steaming (and sometimes gassing) of silkworms, in order to obtain silk threads.
Although silkworms are intentionally killed before they can eat through their cocoons, there’s some evidence which suggests that silkworms don’t suffer pain in this process
Some individual silk producers may opt to protect silkworms against disease, and opt not to use growth hormones on their silkworms
However, there are alternatives to traditional silk production that either prioritise animal welfare, or don’t use silkworms in the production of silk
What is worth noting is that the alternatives to conventional silk may present tradeoffs of new benefits, but also new drawbacks.
For example, some raise the point hat Peace silk is more expensive, the silk isn’t as refined, and the moths used only survive for a few days (and therefore the higher price isn’t)
So, alternatives to conventional silk may not be a perfect solution
In some countries, there have ben reported child labor and working conditions concerns in the past for silk production
Silk is one of the lesser produced and lesser consumed fibres as a share of all fibres at this point in time
Although silk production is smaller than many other fibres, silk is worth more per unit of weight than some other fibres, and silk production may be more expensive in some ways than some other fibres which have a lower production cost
Silk production still employs millions of people globally, even in rural areas
Peace Silk can be more costly in production than traditional methods of silk production where silkworms are boiled
What About The Eco Friendliness & Sustainability Of Other Fibres & Fabrics?
We’ve put together guides about some of the most eco friendly fibres and fabrics, and the least eco friendly fibres and fabrics.
These guides may provide further insight on how silk compares to other fibres too.
Other Factors That Might Impact The Sustainability Or Eco Friendliness Of Fibres
This guide outlines some more of the factors that contribute to how sustainable and eco friendly different fibres and fabrics might be.
*This Guide Is A Generalisation Only
The different variables in silk production can all impact the final sustainability and animal friendly footprint of silk.
This is especially true between different producers, and between the developed and developing world countries.
Production & Consumption Of Silk
Silk is one of the lesser produced and lesser consumed fibres worldwide at the moment.
China is the leading producer of silk.
Consumption Of Silk
Silk makes up a very small proportion of global fibre use, at 0.24%
Production As A Share Of All Fibres
We don’t have the specific production numbers of silk fibre right now.
What we have done however is outlined the production shares of natural fibres compared to other fibres in this guide.
Polyester and cotton are the most commonly produced fibres at this point in time.
Top Producing Countries
China overwhelmingly dominates [silk] production, producing nearly six times as much silk as India, its nearest rival in terms of volume.
Cruelty To Animals (Silkworms) In The Silk Industry
Conventional silk production traditionally uses silkworms for the cocoons they provide.
Some forms of silk production do involve forms of cruelty/slaughter for silkworms.
Other forms of silk production take the welfare of the silkworms into consideration, although they can be more costly or time intensive to produce.
Potential Cruelty Issues
Extracting raw silk starts by cultivating the silkworms on mulberry leaves.
Once the worms start pupating in their cocoons, these are dissolved in boiling water in order for individual long fibres to be extracted and fed into the spinning reel.
From ecocult.com: [… different silk producers may or may not protect silkworms against disease with disinfectant or sterilization practices, or use hormones on silkworms]
Potential Protection Of Silkworms During Production
There is a form of making silk called Peace Silk, where silkworms are allowed to hatch out their cocoons, but it may be more costly and takes more time.
Certified organic silk, wild silk, and Fair Trade silk may also protect the welfare of silkworms.
We list some other types of silk at the bottom of this guide that may have animal welfare benefits.
Usage Of Mulberry Tree Material
Mulberry trees used for mulberry leaves to feed silkworms might be well utilised.
From ecocult.com: [… the mulberry tree components such as fruit, wood, foliage and so on are all used in some way after the growth of the trees]
How Much Water Does Silk Use?
Water is used for silk production to:
– Grow mulberry trees
– Boil or steam cocoons and silkworms
– Clean the silk of sericin just before the yarn or even woven fabric stage
– And, for general silk fibre production
According to several sources, silk may use a lot of water if mulberry trees are water hungry (particularly for irrigated water), and if the production stage uses a lot of water
Other sources indicate that although silk can use a reasonable amount of water, it doesn’t use as much water as several other fibres.
So it may not be clear how much water silk uses in comparison to other fibres.
From treehugger.com: ‘silk production uses a lot of water [because the mulberry tree is a thirsty tree] and large volumes of water are necessary for several steps in the silk processing chain’
‘Textile Exchange disagrees with HIGG’s assertion that silk production requires a lot of fresh water’.
[Although silk production can use a reasonable amount of water, is uses less water than viscose, rayon, lyocell, modal, TENCEL and other fibres]
onlinelibrary.wiley.com has some more specific data on the water footprint of silk production at both the farming stage, and the fibre processing stage.
They also identify the blue water footprint and grey water footprint of silk.
Carbon Footprint Of Silk
Mulberry trees may provide a carbon sink and also produce oxygen.
However, silkworm farming and silk fibre production may have a carbon footprint.
Some sources indicate that silk has a higher carbon footprint compared to other fibres, but, it may not be clear of silk’s carbon footprint when carbon sequestration is taken into account.
From ecocult.com: [… the energy used in silk production may contribute to climate change, if there are equivalent emissions from this energy used.]
Energy Footprint Of Silk
Silk may use a lot of energy to manage/control air temperature and air humidity on silk farms, and also to harvest cocoons.
One source says this is where majority of silk’s environmental impact is done.
Another source says that silk production might improve it’s sustainability if it can use mulberry wood material as a source of bioenergy instead of using fossil fuels.
treehugger.com: ‘… silk production uses a lot of energy for [maintaining controlled temperatures on silk farms, and harvesting cocoons with hot water and hot air]’
From ecocult.com: [… silk does most of it’s environmental damage with the energy it uses for air conditioning and humidity control on silk farms (related to the climates of the countries that mostly produce silk), as well as steam or hot air for cocoons after harvesting]
Potential Sustainability Improvements With Energy Use
From ecocult.com: [these activities could become more sustainable by burning mulberry wood]
How Much Pesticide & Fertilizer Does Silk Use
Mulberry trees might be able to be grown with little to no pesticides, herbicides and fertiliser.
From ecocult.com: [… the mulberry trees that silk production requires don’t use pesticides.]
Silk, Soil Health, & Land Degradation
There might be few negative soil and land health and degradation concerns for silk compared to fibre crops that require heavy tilling, harvesting, and sowing, and also synthetic fibres that require mining/extraction of petrochemicals.
Mulberry trees may be grown on sustainably managed plantations, or regular plantations, depending on the producer.
Also, silkworms are usually bred not on land, but in a box and then moved to gauze – essentially it can be done in commercial silkworm facilities.
Land Use Of Silk
Mulberry trees might be sustainable in the fact that they can use land fibre crops can’t.
From ecocult.com: ‘… the mulberry trees that silk production requires use marginal land that other fibre crops and plants wouldn’t make use of.
The Yield & Efficiency Of Silk
Some yield and efficiency data on silkworms and mulberry leaves to produce silk is …
Silkworms To Produce Silk
The amount of usable silk in each cocoon is small, and about 2500 silkworms are required to produce a pound of raw silk (texeresilk.com)
It takes about 5000 silkworms to make a pure silk kimono (wikipedia.org)
Mulberry Leaves To Produce Silk
To produce 1 kg of silk, 104 kg of mulberry leaves must be eaten by 3000 silkworms (wikipedia.org)
How Many Chemicals Does Silk Use?
Silk might not use as much chemical input as a fibre like conventional cotton for example, or polyester.
Silk uses chemicals at the fibre processing and finished fabric stages.
Farming mulberry trees and silkworm farms may not use as much chemicals as fibre crops that use pesticides, fertilizers, and other chemicals.
And fibres like viscose may use more chemicals at the fibre production stage.
treehugger.com indicates that silk uses chemicals to ‘clean and dye silk’
Fro ecocult.com: [silk is sometimes treated with metallic salts to make it heavier or more lustrous, and this could impact toxicity of the silk, or create more toxic waste water at the production stage. But, the main potential for chemical use is during dyeing and finishing, as is the case for other fabrics.]
Biodegradability & Recyclability Of Silk
In it’s natural form, silk is biodegradable and recyclable.
If it’s been treated with synthetic chemicals or combined with synthetic fibres in a fabric though, it may not be.
Impact Of Silk On The Environment, Humans & Human Health, & Animals & Wildlife
Some assessments of the environmental impact of silk put silk near the top of the list for least eco friendly fibres, albeit assessed on a narrow criteria.
But, when you consider that other fibres might deal with heavier amounts of pesticides, fertilizers, processing chemicals, etc – silk may not be as environmentally destructive overall in comparison to other fibres.
Humans & Human Health
treehugger.com indicates that there ‘[may be issues with child labor, and safe working conditions in some countries in the world]’
But, apart from that, it might not have any more issues than any other other fibre.
Wildlife & Animals
Obviously there’s an impact on silkworms.
Approximately 2500 silkworms die to make 1 pound of raw silk, according to multiple sources.
Practical Benefits Of Silk As A Fibre
In this guide, we outline the traits and practical benefits of some different common fibres.
There’s an FAO.org resource referenced in that guide, along with other resources, that point out some of the potential practical benefits of silk as a fibre.
Economic Impact Of Silk
Value Of Silk Industry
[The size and share of the silk market was close to 21.45 billion USD by revenue at the end of 2021]
[It’s expected to grow annually into the future to 28.71 billion by 2026]
treehugger.com indicates that [silk production employs millions of people in both China and India, and sericulture can employ people in rural areas’
Cost Of Production
ecocult.com indicates (paraphrased) that some companies may substitute silk with synthetic and semi synthetic fibres to save money. This brings into question the cost of production of silk
[Silk production needs limited funds for manufacturing, but it is labor concentrated, and the prices of raw silk are high]
[The high prices of raw silk restrain the global silk market]
General Benefit Of Natural Fibres
One source indicates that natural fibres provide a number of potential economic and practical benefits.
More Information About Mulberry Trees & Leaves
The White Mulberry Tree is the one with the leaves usually used to feed silkworms.
Read more about it here:
The Essential Guide To Mulberry (permaculturenews.org)
Alternatives To Regular Silk
Some alternatives to regular/conventional silk can include:
Vegan silk (plant based silk)
Certified organic silk
Fair trade silk
Synthetic spider silk
Each of these types of silk have either different features, or different tradeoffs to conventional silk.
eluxemagazine.com outlines some features of pace, spider and art silk:
Peace silk, or Ahimsa silk [involves] silk worms [hatching] from their silk cocoon naturally.
This silk can have different capabilities … because the silk fibres are now shorter compared to if the egg was in tact
Spider silk – made from yeast, water, and sugar
Art silk – made from bamboo ‘silk’ in a chemical manufacturing process
Note though that Peace silk may increase the price of the final product, and may still involve a difficult life for the silk worms involved in the production (craftsmanship.net)