The piste de resistance of BCVA’s sustainability series was UC Davis Professor Frank Mitloehner (@GHGGuru on Twitter). Prof Mitloehner previously served as the chairman of a Global United Nations & Food and Agriculture Organisation (FAO) partnership project to benchmark the environmental footprint of livestock production. His key research quantifies ruminant greenhouse gas emissions and investigates economical ways to make livestock production more environmentally sustainable around the globe. In short, what he doesn’t know about Greenhouse Gases and how they relate to livestock production, isn’t worth knowing.
Cattle are the number one agricultural source of greenhouse gases worldwide and yes globally agriculture makes up almost 20% of all greenhouse gases. Methane from cattle is known to be much shorter lived than Carbon Dioxide but 28 times more potent in warming the atmosphere, however Prof Mitloehner describes the public’s perception regarding cattle and overall greenhouse gas contributions as the “Myth about Methane” with Carbon Dioxide always remaining the most important greenhouse gas without any shadow of doubt.
Whilst any Carbon Dioxide emitted into the atmosphere will remain there certainly for a century whereLivestocas Methane produced today will be broken down in the atmosphere within 10 years. This forms the baseline of the GWP* calculation.
Frank described the bath tub analogy – Carbon Dioxide resembles a full bath with the plug in and the tap continually dripping – No matter how much you reduce Carbon Dioxide emissions, you will still be contributing to the overall Carbon Dioxide content within the atmosphere, whereas Methane resembles the tap running but the plug also being taken out – What Methane is produced today, will be degraded by nature within the atmosphere within a decade.
Citing research from Oxford Universities’s Environmental Change Institute, Prof described how 560 teragrams of Methane is produced by the US each year, but 550 teragrams of Methane are also destroyed within the atmosphere each year, leaving 10 teragrams excess per annum. Importantly this figure is something all in agriculture should seek to reduce whether via dietary manipulation of cows and feed additives. However crucially this figure is vastly different to what is described within media. Knowing the short half-life of Methane within the atmosphere, rather than accusing agriculture of being the problem, livestock farming can be viewed as part of the solution for global greenhouse gas emissions.
With the escalating effects of climate change, that fact has advocates urging the public to eat less beef. They contend it’s an unsustainable diet in a world with a population expected to reach nearly 10 billion by 2050. Prof Mitloehner would contest that “forgoing meat is not the environmental panacea many would have us believe. “As an example – If the entire US were to go vegan for one year, the overall reduction in emissions would be 1%. He states, ‘We cannot eat ourselves out of climate change.’
Cows and other ruminants account for just 4% of all greenhouse gases produced in the United States. Within developed agricultural societies, better breeding, genetics and nutrition have increased the efficiency of livestock production dramatically. In the US in the 1970s, 140 million head of cattle were needed to meet demand. Now, just 90 million head are required. At the same time, those 90 million cattle are producing more meat. “We’re now feeding more people with fewer cattle,”
The global problem
Shrinking livestock’s carbon hoofprint worldwide is a big challenge.
India, for example, has the world’s largest cattle population, but the lowest beef consumption of any country. As a result, cows live longer and emit more Methane over their lifetime. In addition, cows in tropical regions produce less milk and meat, so it takes them longer to get to market.
“If you have hundreds of millions of cattle to achieve a dismal amount of product, then that comes with a high environmental footprint,” Mitloehner said. Hence why researchers at UC Davis have projects in Vietnam, Ethiopia and Burkina Faso to boost livestock productivity through better nutrition. That may be critical going forward as demand for meat is rising in developing countries.
“We expect by 2050 there is going to be a 300 percent increase in beef demand in Asia,”
Whilst not discussed by Prof Mitloehner during the presentation, one of his UC Davis’ s key research areas has been to improve the digestibility of ruminant’s high fibre diets, utilising feed supplements for this purpose. It sounds simple, but finding an affordable and nutritious additive has proved difficult. However, they have succeeded in finding such a supplement by feeding dairy cattle a plant way off the trough menu: seaweed. In addition to reducing Methane output, the seaweed doesn’t make the cows’ milk taste bad. He’s now testing the diet on beef cattle. It could be a relatively inexpensive solution for reducing emissions.
Cows as part of the climate change solution
Besides emitting greenhouse gases, another common criticism of beef production is the land mass cattle occupy. Overgrazing this land can degrade soil health and biodiversity. Yet researchers argue that, managed correctly, cows help restore healthy soils, conserve sensitive species and enhance overall ecological function. Proper cattle grazing management can even help mitigate climate change. Maintaining a healthy root systems isn’t just good for the plants, the longer and denser the roots, the more they can hold atmospheric carbon in the soil.
“Sustainability is keeping everything viable both economically and biologically,”
While sustainable grazing practices won’t eliminate Methane produced by the cows, they can offset it and sequester huge volumes of Carbon Dioxide. Allowing a diversity of native grasses to grow keeps cattle healthy, allows water to infiltrate the soil and develop healthy root systems. The longer and denser the roots, the more carbon they can store in the soil.
“Proper grazing sustains working landscapes that support communities, food production and a healthy environment,”
“There will never be a situation where some major part of our diet will be ruled out,” Mitloehner said. “My job is not to judge people for their eating habits. My job is to look at how we can produce livestock and minimise those environmental impacts that do exist.”
Alasdair Moffett – Synergy Farm Health, Veterinary Surgeon
BVMS, MSc, MRCVS
