Human consumption of meat and dairy products is a major driver of climate change. Greenhouse gas (GHG) emissions associated with their production are estimated to account for over 14.5 percent of the global total. This is more than the emissions produced from powering all the world’s road vehicles, trains, ships and aeroplanes combined. It is considerably more than the emissions produced by the world’s largest national economy, the United States. New technologies and changes in livestock production practices offer important means to reduce livestock emissions, but on their own cannot deliver the reductions needed to limit the rise in global temperatures to two degrees Celsius.