Greenhouse Gas Emissions From The Dairy Sector
According to this report from the United Nations Food and Agricultural Organization (FAO), the dairy sector accounts for about 4% of global anthropogenic greenhouse gas emissions (GHG). This estimate includes emissions associated with the production, processing, and transportation of dairy products, as well as those related to meat production associated with animals originating from the dairy system.
Emissions originating from the production, processing, and transportation of dairy animal systems account for about 2.7% of global anthropogenic greenhouse gas (GHG) emissions. The global average GHG emissions per kilogram of dairy products is 2.4 kg of carbon dioxide equivalents. The other 1.3% comes from animals from the dairy industry slaughtered for meat.
In 2007, the dairy sector released approximately two billion metric tons of carbon dioxide equivalents, 1.3 billion attributed to milk, 151 million to meat from culled dairy animals, and 490 million from calves from the dairy sector raised for meat.
Methane contributes the most significantly to the GHG impact of milk; methane is associated with about 52% of total GHG emissions in developing and developed countries. Nitrous oxide emissions account for 27% in developed countries and 38% in developing countries, while carbon dioxide accounts for 21% in developed countries and 10% in developing countries.
http://www.fao.org/docrep/012/k7930e/k7930e00.pdf