Environmental impacts of animal agriculture
Animal agriculture, in particular meat production, can cause pollution, greenhouse gas emissions, biodiversity loss, disease, and significant consumption of land, food, and water.
Cows, sheep, and other ruminants digest their food by enteric fermentation, and their burps are the main source of methane emissions from land use, land-use change, and forestry.
[18][19] Major corporations purchase land in different developing nations in Latin America and Asia to support large-scale production of animal feed crops, mainly corn and soybeans.
This practice reduces the amount of land available for growing crops that are fit for human consumption in these countries, putting the local population at risk of food security.
[23] Examples of waste roughages include straw from barley and wheat crops (edible especially to large-ruminant breeding stock when on maintenance diets),[24][25][26] and corn stover.
[39] However, according to FAO, grazing livestock in drylands “removes vegetation, including dry and flammable plants, and mobilizes stored biomass through depositions, which is partly transferred to the soil, improving fertility.
[40] The use of ever increasing amounts of land for meat production and livestock rearing instead of plants and grains for human diets is, according to sociologist David Nibert, "a leading cause of malnutrition, hunger, and famine around the world.
[43] A particularly important North American example of depletion is the High Plains (Ogallala) Aquifer, which underlies about 174,000 square miles in parts of eight states of the USA and supplies 30 percent of the groundwater withdrawn for irrigation there.
This type of production chain produces byproducts; endotoxin, hydrogen sulfide, ammonia, and particulate matter (PM), such as dust,[61][62] all of which can negatively impact human respiratory health.
Air pollutants from these operations have caused acute physical symptoms, such as respiratory illnesses, wheezing, increased breath rate, and irritation of the eyes and nose.
[71] Despite the wealth of environmental consequences listed above, local US governments tend to support the harmful practices of the animal production industry due to its strong economic benefits.
[100] As conditions vary a lot[101] the IPCC would like these taken into account when estimating methane emissions, in other words countries where cattle are significant should use Tier 3 methods in their national greenhouse gas inventories.
One study found that shifting compositions of current feeds, production areas, and informed land restoration could enable greenhouse gas emissions reductions of 34–85% annually (612–1,506 megatons CO2 equivalent per year) without increasing costs or changing diets.
[114][115][116] The principal mitigation strategies identified for reduction of agricultural nitrous oxide emissions are avoiding over-application of nitrogen fertilizers and adopting suitable manure management practices.
[119] Methane belching from cattle might be reduced by intensification of farming,[120] selective breeding,[103] immunization against the many methanogens,[103] rumen defaunation (killing the bacteria-killing protozoa),[121] diet modification (e.g. seaweed fortification),[122] decreased antibiotic use,[123] and grazing management.
[127] A more controversial suggestion, advocated by George Monbiot in the documentary "Apocalypse Cow", is to stop farming cattle completely, however farmers often have political power so might be able to resist such a big change.
[139] A 2017 meta-study of the scientific literature estimated that the total global soil carbon sequestration potential from grazing management ranges from 0.3–0.8 gigatons CO2eq per year, which is equivalent to 4–11% of total global livestock emissions, but that "Expansion or intensification in the grazing sector as an approach to sequestering more carbon would lead to substantial increases in methane, nitrous oxide and land use change-induced CO2 emissions".
[143] Another peer-reviewed paper found that if current pastureland was restored to its former state as wild grasslands, shrublands, and sparse savannas without livestock this could store an estimated 15.2–59.9 gigatons additional carbon.
[146] Additionally, in the Piedmont region of the US, well-managed grazing of livestock on previously eroded soil resulted in high rates of beneficial carbon and nitrogen sequestration compared to non-grazed grass.
Small ruminants, such as sheep and goats, can control some invasive or noxious weeds (such as spotted knapweed, tansy ragwort, leafy spurge, yellow starthistle, tall larkspur, etc.)
[174] The biologists Rodolfo Dirzo, Gerardo Ceballos, and Paul R. Ehrlich write in an opinion piece for Philosophical Transactions of the Royal Society B that reductions in meat consumption "can translate not only into less heat, but also more space for biodiversity."
[177][178] Livestock management options for riparian protection include salt and mineral placement, limiting seasonal access, use of alternative water sources, provision of "hardened" stream crossings, herding, and fencing.
[179][180] In the Eastern United States, a 1997 study found that waste release from pork farms has also been shown to cause large-scale eutrophication of bodies of water, including the Mississippi River and Atlantic Ocean (Palmquist, et al., 1997).
[181] In North Carolina, where the study was done, measures have since been taken to reduce the risk of accidental discharges from manure lagoons, and since then there has been evidence of improved environmental management in US hog production.
[182] In Central-Eastern Argentina, a 2017 study found large quantities of metal pollutants (chromium, copper, arsenic and lead) in their freshwater streams, disrupting the aquatic biota.
[198] Bacterial diseases are a leading cause of death and a future without effective antibiotics would fundamentally change the way modern human as well as veterinary medicine is practised.
[8] In June 2023, the European Commission's Scientific Advice Mechanism published a review of all available evidence and accompanying policy recommendations to promote sustainable food consumption and reducing meat intake.
So we should consider ways to unburden the consumer and make sustainable, healthy food an easy and affordable choice.The production of cattle has a significant environmental impact, whether measured in terms of methane emissions, land use, consumption of water, discharge of pollutants, or eutrophication of waterways.
Significant numbers of dairy, as well as beef cattle, are confined in concentrated animal feeding operations (CAFOs), defined as "new and existing operations which stable or confine and feed or maintain for a total of 45 days or more in any 12-month period more than the number of animals specified"[255] where "[c]rops, vegetation, forage growth, or post-harvest residues are not sustained in the normal growing season over any portion of the lot or facility.
[262] While research suggests some of these impacts can be mitigated by developing wastewater treatment systems[261] and planting cover crops in larger setback zones,[263] the Union of Concerned Scientists released a report in 2008 concluding that CAFOs are generally unsustainable and externalize costs.
