Rising populations and incomes are expected to double the global demand for meat and milk from 229 to 465 million tonnes and 580 to 1043 million tonnes, respectively, by 2050. This will almost double the amount of greenhouse gases produced by livestock, dwarfing attempts to cut emissions elsewhere. Apart from all of us turning to a vegetarian diet, can anything be done to reduce greenhouse gas emissions from livestock?

Cows, sheep and goats may seem like innocent victims of humanity's appetite for meat, but when it comes to climate change they have a dark secret. Forget cars, planes or even power stations, some of the world's worst greenhouse gas emitters wander idly across rolling pastures chewing the cud, oblivious to the fact that their continuous belching (and to a lesser degree, farting) is warming the planet.

Take New Zealand, where 34.2 million sheep, 9.7 million cattle, 1.4 million deer and 155,000 goats emit 48 per cent of the country's greenhouse gases in the form of methane and nitrous oxide. Worldwide, livestock burps are responsible for 18 per cent of greenhouse gas emissions - more than produced from all forms of transport combined.

This article from New Scientist magazine issue 2687 is controversial  but thought provoking.