Environmental impact

Agriculture may often cause environmental problems because it changes natural environments and produces harmful by-products. Some of the negative effects are:

* Loss of biodiversity
* Surplus of nitrogen and phosphorus in rivers and lakes
* Detrimental effects of herbicides, fungicides, insecticides, and other biocides
* Conversion of natural ecosystems of all types into arable land
* Consolidation of diverse biomass into a few species
* Soil erosion
* Deforestation
* Depletion of minerals in the soil
* Particulate matter, including ammonia and ammonium off-gassing from animal waste contributing to air pollution
* Air pollution from farm equipment powered by fossil fuels
* Weed Science - feral plants and animals
* Odor from agricultural waste
* Soil salination
* Water crisis

According to the United Nations, the livestock sector (primarily cows, chickens, and pigs) emerges as one of the top two or three most significant contributors to our most serious environmental problems, at every scale from local to global. Livestock production occupies 70% of all land used for agriculture, or 30% of the land surface of the planet.It is one of the largest sources of greenhouse gases—responsible for 18% of the world's greenhouse gas emissions as measured in CO2 equivalents. By comparison, all transportation emits 13.5% of the CO2. It produces 65% of human-related nitrous oxide (which has 296 times the global warming potential of CO2) and 37% of all human-induced methane (which is 23 times as warming as CO2). It also generates 64% of the ammonia, which contributes to acid rain and acidification of ecosystems.