Climate change can be curbed by changing the diet of livestock, whose feed crops, farting, belching and manure contribute a fifth of the planet’s greenhouse gas emissions, a new study said yesterday.

The study by the International Livestock Research Institute (ILRI) said livestock risk growing as global demand for meat and milk surges and recommended simple steps to curb livestock-related greenhouse gas emissions.

It recommended using more nutritious pasture grasses, supplementing diets with crop residues, restoring degraded grazing lands and adopting more productive breeds, among other simple measures for tropical countries.

ILRI noted that in Latin America, switching cows from natural grasslands to pastures sown with a more nutritious grass called Brachiaria can increase daily milk production and weight gain by up to three fold.

“Even if only about 30 per cent of livestock owners in the region switch from natural grass to Brachiaria... that alone could reduce carbon dioxide emissions by about 30 million tons per year,” said ILRI’s Philip Thornton.

“Livestock enterprises contribute about 18 per cent of the world’s greenhouse gases, largely through deforestation to make room for livestock grazing and feed crops, the methane ruminant animals give off, and the nitrous oxide emitted by manure,” the study pointed out.

The scientists said the burden of changing livestock production practices would largely be on half a billion of the poorer farmers in tropical countries.

“It would be a useful incentive if these farmers were allowed to sell the reductions they achieve as credits on global carbon markets,” Mr Thornton said.

He estimated that at $20 per ton – the current rate of carbon on the European Climate Exchange – poor livestock keepers in tropical countries could generate about $1.3 billion each year in carbon revenues.