How kangaroo burgers could save the planet

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. Methane accounts for the bulk of ruminant green house gas emissions, one tonne of the gas has 25 times the global warming potential of the equivalent amount of carbon dioxide.