Methane, global warming and meat production

The most important non-CO2 greenhouse gas is methane, and the number one source of methane worldwide is animal agriculture.
Methane is responsible for nearly as much global warming as all other non-CO2 greenhouse gases put together

Animal agriculture produces more than 100 million tons of methane a year.
A good way to reduce global warming in our lifetimes is to reduce or eliminate our consumption of animal products.

http://earthsave.org/globalwarming.htm