Approximately nine million dairy cows, 90 million beef cattle, 60 million swine and billions of poultry in the U.S. produce more than 100 times more organic waste (and nutrients) than humans; but where human waste makes its way to a septic tank or sewage treatment plant, livestock waste/ manure is usually spread untreated on the ground for its fertilizer value, where much of it runs off. USEPA calls nutrient runoff one of the greatest water quality problems in the U.S. today; in many watersheds, runoff from livestock manure is among the largest sources. Today, the industry is under fire globally for its impacts on climate change. In California, US EPA is considering how to regulate ammonia emissions from cattle due to their impact on PM2.5 and nitrates. The industry and it’s impacts on water quality and climate change are under scrutiny by regulatory agencies, advocacy groups, institutional investors and its consumers.
Climate Change
- Impacts come from both enteric fermentation and manure waste and handling
- Methane and nitrous oxide (N2O) are the primary carbon-equivalent sources
- Livestock account for 4.2% of U.S. greenhouse gas emissions (USEPA) and 14.5% globally (UNFAO)
- Climate change impact is a very large focus of anti-livestock advocacy groups and industry competitors
Nutrients/ Runoff
- Livestock production is one of the largest sources of excess nutrients (nitrogen & phosphorus) in many major U.S. watersheds
- Highly mobile and volatile N from ammonia (from animal waste) becomes airborne and deposits N elsewhere. It is difficult and expensive to control (UNEP: What is Nitrogen Pollution?; NOAA website)
- N&P fuel harmful algae blooms (HABs – EPA website) in fresh, estuary and coastal salt waters that are increasingly toxic
- HABs lead to dead zones in the Gulf of Mexico, Chesapeake Bay, and other large waterbodies (NOAA National Ocean Service website)
- Nitrates from manure leach down to contaminate groundwater (EPA website)
- Ammonia from livestock waste contributes to the formation of PM2.5 – small inhalable particulate matter that poses a significant health risk – especially in dry western climates
- Increasing P concentrations in agricultural soils reduce productivity
- Successful (and large) nuisance odor lawsuits are on the rise
- Studies show increased pathogen levels near waste spray fields and that those pathogens demonstrate antibiotic resistance
- Pathogens in manure used as fertilizer lead to foodborne illnesses