• Because nitrous oxide [released by nitrate-fertilised soil] is 296 times stronger than CO₂ at global warming and methane [cow farts] is about 26 times as potent as CO₂, the combined greenhouse effect of our livestock worldwide is greater than the sum total of all the cars, trains, busses, trucks, ships, airplanes and jets.

    "Threshold: The Progressive Plan to Pull America Back from the Brink". Book by Thom Hartmann, p.22, July 23, 2009.