A senior UN official and co-author of a UN report detailing this problem, Henning Steinfeld, said “livestock are one of the most significant contributors to today’s most serious environmental problems”. 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% if 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. Livestock expansion is cited as key factor driving deforestation, in the Amazon basin 70% of previously forested areas are now occupied by pastures and the remainder used for feed crops. Through deforestation and land degradation, livestock is also driving reductions in biodiversity.
LAND TRANSFORMATION AND DEGRADATION
Land transformation, the use of land to yield goods and services, is the most substantial way humans alter the Earth’s ecosystems, and is considered the driving force in the loss of biodiversity. Estimates of the amount of land transformed by humans vary for 39-50%. Land degradation, the long-term decline in ecosystem function and productivity, is estimated to be occurring on 24% of land worldwide. With cropland over-represented. The UN-FAO report cites land management as the driving factor behind degradation and reports that 1.5 billion people rely upon the degrading land. Degradation can be deforestation, desertification, soil erosion, mineral depletion, or chemical degradation (acidification and salinization).
Eutrophication, excessive nutrients in aquatic ecosystems resulting in algae blooms and anoxia, leads to fish kills, loss of biodiversity, and renders water unfit for drinking and other industrial uses. Excessive fertilization and manure application to cropland, as well as high livestock stocking densities cause nutrient (mainly nitrogen and phosphorus) runoff and leaching from agricultural land. These nutrients are major nonpoint pollutants contributing to eutrophication of aquatic ecosystems.