Intensive farming
Environmental impact

Industrial agriculture uses huge amounts of water, energy, and industrial chemicals, increasing pollution in the arable land, usable water, and atmosphere. Herbicides, insecticides, and fertilizers accumulate in ground and surface waters. Industrial agricultural practices are one of the main drivers of global warming, accounting for 14–28% of net greenhouse gas emissions.

Many of the negative effects of industrial agriculture may emerge at some distance from fields and farms. Nitrogen compounds from the Midwest, for example, travel down the Mississippi to degrade coastal fisheries in the Gulf of Mexico, causing so-called oceanic dead zones.

Many wild plant and animal species have become extinct on a regional or national scale, and the functioning of agro-ecosystems has been profoundly altered. Agricultural intensification includes a variety of factors, including the loss of landscape elements, increased farm and field sizes, and increase usage of insecticides and herbicides. The large scale of insecticides and herbicides lead to the rapid developing resistance among pests renders herbicides and insecticides increasingly ineffective. Agrochemicals have may be involved in colony collapse disorder, in which the individual members of bee colonies disappear. (Agricultural production is highly dependent on bees to pollinate many varieties of fruits and vegetables.)

Intensive farming creates conditions for parasite growth and transmission that are vastly different from what parasites encounter in natural host populations, potentially altering selection on a variety of traits such as life-history traits and virulence. Some recent epidemic outbreaks have highlighted the association with intensive agricultural farming practices. For example the infectious salmon anaemia (ISA) virus is causing significant economic loss for salmon farms. The ISA virus is an orthomyxovirus with two distinct clades, one European and one North American, that diverged before 1900 (Krossøy et al. 2001). This divergence suggests that an ancestral form of the virus was present in wild salmonids prior to the introduction of cage-cultured salmonids. As the virus spread from vertical transmission (parent to offspring).

Intensive monoculture increases the risk of failures due to pests, adverse weather and disease.
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