Pardonnez-moi! The cows that supply French dairy group Danone with milk burp a lot: 4mn tonnes of methane a year. If Danone can cut that by 30 per cent, as it has promised to do, it should genuinely make a significant contribution to climate goals — and improve animal husbandry while at it.
Methane’s impact on global warming has only recently come under the spotlight. The gas — emitted by wetlands, cattle and fossil fuels — does not last as long as CO₂ in the atmosphere. But whilst it is up there, it traps a lot more heat.
Over 100 years, its global warming potential is 27 times that of CO₂, according to the IPCC. That means that the 580mn tonnes of methane the IEA estimates are released a year have the same impact as 15.6 giga tonnes of CO₂, or about a quarter of the global total.
However, methane’s short-term potency — a staggering 81 times over 20 years — is more relevant. That is because climate has tipping points. If permanently frozen ground thaws, it will emit more methane and put the 1.5C degrees global warming target even further out of our reach.
Where should we focus our efforts? Oil and gas companies are an obvious target. But the biggest man-made source of methane emissions is agriculture, which accounts for 141mn tonnes of methane per year. The issue is that cows predigest their food in a pre-stomach, the rumen, with the help of microbes that emit methane. That then gets belched out, accounting for 6.5 per cent of total greenhouse gas emissions. For reference, global aviation only contributes 2.5 per cent.
One oft-suggested option is for us all to eat less dairy and meat. Danone is understandably looking at other options. Breeding more productive cows — which yield more milk for their belch — is an obvious win. Making Daisy and Buttercup more comfortable helps, too: there is evidence that happier bovines make more milk. Adding biochar, seaweed and other molecules to feed is a promising area of study. Recently licensed additive Bovaer claims methane emissions reductions of between 30 and 45 per cent.
Reducing the amount of energy in the feed that never even gets to the cow’s stomach would also be good business for farmers. In one study, cows fed additives not only burped less, but also put on more weight. The implications are well worth some human rumination.
