The 2006 United Nations Food and Agriculture Organization report, Livestock’s Long Shadow, released in April of 2008, claimed that 18 percent of global greenhouse gases are caused by animal agriculture. The Center for Consumer Freedom helped to clarify this claim.
Buried in the report is the information that deforestation-mainly in the Amazon Rainforest-is included in that figure. Without it, livestock’s contribution falls to less than 12 percent.
But even 12 percent still sounded a bit high. In April 2008, the U.S. Environmental Protection Agency (EPA) released a report, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2006, detailing a complete accounting of global-warming-related emissions in the United States and where they come from. This report said that 6 percent of total U.S. greenhouse gas emissions is from all of agricultural, not just meat production.
It gets more interesting still. The EPA separates out the various kinds of agricultural emissions into two categories, one that relates to raising animals for food and the other for non-animal related agriculture (like; grain production). The result: greenhouse gas sources directly related to livestock production in the United States only accounts for 2.58 percent of the total.
2.58 percent is a far cry from 18 percent.
From the EPA's Inventory of U.S. Greenhouse Gas Emissions and Sinks.