Risks of cotton farming

Environmental risks

Cotton is mostly grown in monoculture and is a very pesticide-intensive crop. Although it is only grown on 2.5 % of the world’s agricultural land, it consumes 16 % of all the insecticides used worldwide. These pesticides are washed out of soils, and pollute rivers and groundwater.
Pests often develop resistance to pesticides that are used on a continuous basis. Furthermore, the chemicals eliminate not only pests but also their natural enemies. This interference with the ecosystem considerably reduces biodiversity and can result in pests that were previously not so important (secondary pests) becoming a major problem. 
If cotton is cultivated intensively, it requires large amounts of water for irrigation. This causes soil salinisation, particularly in dry areas and hence a degradation of soil fertility. The diversion of entire rivers into huge irrigation channels in Central Asia has led to the gradual drying-up of the Aral Lake, one of the largest inland waters in the world. It is estimated that 60% of irrigation water in Central and Southern Asia is lost before reaching cotton fields because of poor infrastructure (PAN UK, 2006). 
Cotton production also contributes to climate change. Industrial fertilizers are produced using considerable quantities of finite energy sources (1.5% of the world’s annual energy consumption), releasing large amounts of carbon dioxide. Furthermore, the excessive application of nitrates to agricultural land leads to their being transformed into nitrous oxide (“laughing gas”), a greenhouse gas that is 300 times more destructive than CO2 in terms of global warming. Finally, soils are important carbon sinks. Soil degradation seriously reduces their carbon sequestration capacity, thereby contributing to the greenhouse effect.
Lake Aral, 1989 to 2003
Further reading: 
“My sustainable T-Shirt”, Pan UK  
Socio-economic risks 
Conventional cotton production has a series of social and economic risks, especially for small farmers in developing countries. Many small farmers in the South fall ill or die due to a lack of adequate equipment and knowledge about how to handle pesticides properly. Medical costs and an inability to work are a severe economic burden on affected families. 
The excessive use of chemical fertilizers and pesticides in monoculture causes soil degradation, reducing its nutrient and water retention capacity. As a consequence, farmers face declining yields and have to increase production inputs. The resistance of some pests and the appearance of secondary pests only add to the problem.
To pay for the increasing costs of farm input, small farmers are obliged to borrow from banks or cotton buyers. However, a farmer’s income from his cotton harvest is often lower than the cost of the inputs due to low crop yields and market prices, driving more and more farmers into debt.
As cotton is a cash crop, cotton farmers are highly dependent on volatile world markets. Growing only cotton reduces families’ food security, particularly in regions with unstable climatic conditions, since in bad years they are unlikely to have enough money to buy food.
Links:         “From the plant to the T-Shirt”
                  “My sustainable T-Shirt” (Pan UK)
                  Secondary pests on Bt cotton in India