By Malee Oot October 14, 2013
Greenhouse gas (GHG) emissions associated with livestock could be reduced by as much as 30% according to a new report from the United Nations Food and Agriculture Organization (FAO). Livestock account for 14.5% of all GHG generated by human activity. Globally, the major culprit is cattle, responsible for 65% of total emissions from the livestock sector.
The bulk of emissions associated with livestock are generated by animal feed and processing, making up nearly 45%. But, GHGs released during the digestion process, called enteric fermentation, are also significant, especially from cattle. The breakdown of animal manure generates about 10% of livestock related emissions, primarily because of the release of nitrous oxide, a GHG with a global warming potential (GWP) 300 times that of carbon dioxide.
According to the United Nation’s Food and Agriculture Organization’s report "Tackling Climate Change Through Livestock: A global assessment of emissions and mitigation opportunities," the greatest potential for cutting emissions from livestock comes from focusing on animal feed and improving herd efficiency.
Improved feeding techniques could drastically reduce methane generated during digestion processes and cut nitrous oxide emissions released as manure decomposes. In the United States, almost all meat comes from factory farms, termed Concentrated Animal Feeding Operations (CAFOs), the largest 2% of facilities now contain over 40% of all U.S. livestock. Factory farmed cattle are raised to pack on weight quickly, and fed an energy intensive grain based diet.
[Science magazine recently reported that trenbolone, widely used in the US for fattening cattle, is actually not degrading in the environment as thought - but instead recombining zombie-like in the dark, and possibly disrupting our aquatic ecosystems.]
In the United States, half of all harvested crop land—149 million acres, is planted with grains exclusively for animal feed. Chemical and energy-intensive inputs like synthetic fertilizers and pesticides contribute substantially to livestock associated GHG emissions. Producing animal feed accounts for 53% of emissions associated with poultry production and 23% created by beef production.
Grass-fed beef is a point of contention among environmentalists, particularly climate practitioners. The Environmental Working Group (EWG), a national environmental health advocacy organization, recommends grass-fed. The longer life of pasture feed animals allows for greater methane and nitrous oxide emissions, but some studies suggest well managed grazing lands can efficiently sequester carbon. And grass-fed beef typically involves less energy intensive inputs.
However, grass-fed cattle operations, being less intensive, tend to occupy a larger footprint, even if it is a more ecologically balanced one. but narrowly-focused and unrestrained profit-motives place no value on ecological balance or future sustainability. According to the U.N. report "Livestock’s Long Shadow," livestock utilize 30% of the earth’s total land area, including 33% of arable land globally. Oftentimes, animals are not grazed on marginal land, and forests are often cleared to create pasture for livestock. In the Amazon, nearly 70% of land previously forested has been converted for grazing.
Only 3% of beef in the U.S. market is grass-fed. Given America’s strong appetite for red meat, a shift to lower-intensity grass-fed beef anytime in the near future seems unrealistic. Globally, increasing incomes in developing countries are also creating a greater demand for livestock-based products. Scientists are urging those who can afford meat substitutes to substantially cut back on meat consumption. Mark Sutton, lead author of the United Nations Environment Programme (UNEP) report "Our Nutrient World: The challenges to produce more food and energy with less pollution," created the term ‘demitarian,’and has urged meat eaters in the Europe and the U.S. to cut meat consumption in half.