It can take more than 20,000 litres of water to produce 1kg of cotton; equivalent to a single T-shirt and pair of jeans. 73% of global cotton harvest comes from irrigated land (as documented in the WWF report The Impact of Cotton on Freshwater Resources and Ecosystems).
Agriculture is the largest source of pollution in most countries. 2.4% of the world’s crop land is planted with cotton and yet it accounts for 24% and 11% of the global sales of insecticide and pesticides respectively. Unsafe use of agricultural chemicals has severe health impacts on workers in the field and on ecosystems that receive excess doses that run-off from farms.
The use of genetically-modified (GM) cotton varieties (read our Modified Jeans feature) has increased remarkably in recent years reaching 20% (67.7 million ha) of the global crop area in 2002. Several of the major cotton-producing countries cultivate a significant percentage of their cotton fields with GM varieties that are resistant to some insect pests and/or tolerant of certain herbicides.
River Basin impacts
Unsustainable cotton farming, with massive inputs of water and pesticides, has already been responsible for the destruction of large-scale ecosystems such as the Aral Sea in central Asia and the deteriorating health and livelihoods of people living there. Cotton is also one of the most 'thirsty' crops in several large River Basins (see report Agricultural Water Use and River Basin Conservation) including the Indus River in Pakistan, the Murray-Darling Basin in Australia, and the Rio Grande in United States and Mexico.