Advocacy groups often blame livestock production for greenhouse gas emissions, where in fact livestock is a very small contributor according to a recent report by Frank Mitloehner, professor and air quality specialist at the University of California-Davis.

Livestock production accounts for 4.2% of all GHG emissions, far from the 18% to 51% range that is often cited by various advocates. In fact, transportation accounts for 27% of GHG emissions and energy production accounts for 31%. Breaking down the 4.2% Environmental Protection Agency figure for livestock by species, shows the following contributors: beef cattle, 2.2%; dairy cattle, 1.3%; swine, 0.47%; poultry, 0.08%; sheep, 0.03%; goats, 0.01% and other (horses, etc.), 0.04%.

According to Mitloehner, if all Americans practiced Meatless Mondays U.S. GHG emissions would be reduced by 0.6%.