Pest problems have increased, however. The great environmentalist John Muir once called sheep 'four-legged' locusts such is their contribution to environmental degradation. Sheep dips are a serious source of water pollution as well. Much rayon production is from eucalyptus plantations, trees which outside their native areas are environmental disasters, particularly linked to nutrient depletion and the lowering of water tables. Synthetic fibres consume 23,000 barrels of oil every day.
All polyester used in the UK is imported.
Silk pupa feel pain but are gassed or killed in boiling water or acid. Alternatives to silk include alginate fibres from seaweed, ardil from peanuts and vicara from maize. Each year it is estimated that 24 million coyotes, foxes, racoons, lynxes, rabbits, bobcats, muskrats, sables, opossums and other animals find themselves snared in steel-jawed leg traps. Fur is also comes from factory-farmed animals. Overall, some 44 million animals are killed each year for their furs.