While the
greenhouse gas footprint
of the production
of other foods, compared to sources such as livestock, is highly dependent on a number
of factors, production
of livestock currently accounts for about 30 %
of the U.S.
total emissions
of methane.316, 320,325,326 This
amount of methane can be reduced somewhat by recovery methods such as the use
of biogas digesters, but future changes
in dietary practices, including those motivated by considerations other than climate change mitigation, could also have an effect on the
amount of methane emitted to the
atmosphere.327