Sustainability has been a big trend buzzword the last few years, and there are many definitions of sustainability with regards to economic, social and environmental fields. Here I would like to focus on the environmental field: how eco-friendly is knitting? I am thinking of four main areas: the sustainability of the growing/production of the material, the process to turn the material into fibre, the dying process, and the use of the fibre. The last one is an easy one, hand-knitting requires no energy other than human labour. So it's sustainable on that front. But the materials are a bit more tricky. There are of course numerous materials that make fibres, animal fibres, natural fibres and man-made fibres. I'm going to rule out man-made fibres here. Synthetic fibres are created from petroleum, creating a higher dependence on oil, at a time when we are running out.
When I started knitting I thought that as long as I bought yarn that was not man-made, it was sustainable. Wrong. I can't really go into detail here about every single type of fibre, but here are a few points and links to further information.
One of the most used fibres in the world is cotton. Particularly in summer this is a very popular fibre for clothing, accessories, bags, towels, etc. http://www.ecofashionworld.com/EcoFashion-Pulse/HOW-THIRSTY-IS-YOUR-TSHIRT.html contains a very good article about the pros and cons of cotton and discusses the water usage and the use of pesticides and fertilisers. AND... it points out an issue I had never even considered: a garment's lifecycle impact: the sum of environmental impacts caused by a product's existence. Washing and drying uses a lot of energy and water.
http://organicclothing.blogs.com/my_weblog/ is another website that is entirely dedicated organic, natural and sustainable clothing and contains lots of information on a large variety of fibres and other materials. Bamboo for example, has in recent years been hailed a the new sustainable fibre, and indeed it is a very sustainable plant to grow. But the process to turn the bamboo into fibres uses huge amounts of chemicals renders it very unsustainable.
Another way to go would be to use recycled yarns. Etsy shop ThoughtfulRoseSupply sells yarn obtained from unwanted sweaters. She points out the following:
"Did you know--soaring US demand for cashmere has devastated parts of China's landscape? Overgrazing by cashmere-producing goats has led to the "desertification" of formerly rich grasslands. If you want to help reduce demand, enjoy the luxury of cashmere in a more eco-friendly (and wallet-friendly) way, by buying recycled yarn instead of new."
Gridjunky, who's creations I highly admire for their graphic textures, also mainly uses recycled yarns. So hit the charity shops (in the UK) or (in the US) thrift stores or go through your wardrobe and ask your friends for their unwanted sweaters, or if you want to save the time to carefully unravel and wash the recycled yarns, find shops such as ThoughtfulRoseSupply who've done the hard work for you!