Cotton is one of the most widely grown crops in the world and one of the most devastating to the environment. Around 25% of all insecticide sales are used on crops on non-organic cotton farms. The run off from these farms have destroyed ecosystems such as those in the Aral Sea and is having a serious impact on water supplies in many parts of the world including the Murray-Darling basin in Australia.
Using chemical pesticides on crops kills beneficial organisms in the soil which leads to soil degradation which in turn leads to the need to add chemical fertilisers. The use of pesticides also leads to more pests as they become resistant to these chemicals. Farming a single crop such as cotton leads to less wildlife, especially birds, which again results in more pests. Farms which continue to use these chemicals will become unsustainable in the future.
Farmers who have gone back to producing crops without the use of pesticides have ultimately produced bigger crops and have seen a fairly rapid return of bird wildlife which has controlled the number of insects attacking their crops. Companion planting has also reduced pests as well as improving soil condition and water pollution.
Some of the most dangerous chemicals which are used to grow cotton have been banned in the developed world but are being sold by the US, Japan, and Europe to developing nations. These insecticides and pesticides have resulted in serious health problems for farm workers, especially in the developing world, including cancer and respiratory problems.
Pesticides used on cotton crops are also found in the food we eat. Cotton seeds are fed to cattle and cotton seed oil is used in the processing of some foods such as potato chips and biscuits.