154 Zinc Over 60 per cent of the more than 14 million tons of zinc produced each year go to protecting steel from rust and corrosion through galvanising. Emissions of zinc from human activity amounts to around a million metric tons per year, although the International Zinc Association says: “By comparison, annual anthropogenic emissions of zinc are estimated to be only 10 per cent of that from natural sources.” Natural fibres It seems logical that natural fibres such as cotton, bamboo, wool and silk should be more sustainable than synthetic ones, although some of these have damaging impacts on the environment. Cotton crops, for example, require a great deal of water and pesticides. Bamboo Because it grows fast, does not require fertilisation and regenerates quickly, bamboo is popular and considered to be sustainable. However, methods of harvesting can be damaging to the environment and there is evidence of land clearing to plant it. Cotton Organic cotton from non-GM seeds is the most sustainable type. However, cotton is very waterintensive to grow. Some cotton farmers are adopting regenerative approaches to address impacts on soil, carbon capture and biodiversity. PRODUCTS AND MATER I ALS Sustainable Materials Management Source: US Environment Protection Agency, Sustainable Materials Management
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