The cattle industry in South Africa and other parts of the world is under attack over its contribution to global warming. This attack is broad-ranging and reaches from the UN to activist community groups concerned about greenhouse gases. Cattle farming has received such a bad press that one cattleman recently told me that his children had come home from university and asked, “How can you live with yourselves, Mom and Dad, for owning all these cattle and causing so much global warming?”
Cattle owners need to publicly address widespread misconceptions about cattle and greenhouse gas emissions. They need to communicate the positive messages – such as the role that free-ranging cattle play in storing carbon. The first misconception is the idea that cattle are breathing out and belching vast quantities of ‘new carbon’ in the form of carbon dioxide and methane.
The anti-cattle lobbyists argue that this ‘new carbon’ is the basis of harmful carbon pollution. How can this be so when every atom of carbon ever emitted by a farm animal – either as carbon dioxide or methane – comes from the atmosphere in the first place?
Think back to basic school biology and science and you will quickly understand this and spot the flaw in the ‘new carbon’ pollution argument. During photosynthesis, plants draw down carbon dioxide and convert it to carbon compounds in the plant. The carbon has gone from a gaseous state in the atmosphere to a solid state in the plant. Cattle eat the plants and the carbon becomes incorporated in the living processes of the animal.
Some of the carbon atoms are incorporated into the physical structure of the animal – about 18% of the dry weight of all mammals is carbon. The critical fact is that this kind of carbon originates from the atmosphere, not from the ground. And when a cow (or sheep or goat) belches, the result is simply a return of carbon to the atmosphere. It is an ever repeating closed loop with no net carbon gain.
It is a natural, organic cycle, powered by solar energy, in which cattle are natural organic components. So why the fuss? Because those calling for a reduction in meat eating in order to save the planet from global warming gases are ignoring the basic facts about the carbon cycle and confusing it with fossil fuel power stations.
Power stations get their carbon from below the earth’s surface (from fossil fuels such as coal, natural gas and oil), burn it and create what is effectively new carbon dioxide in the atmosphere. You can certainly therefore stand at the top of a power station chimney stack and argue that the carbon dioxide coming from the stack is warming the planet. You cannot, however, stand in the veld where cattle or sheep are grazing and draw the same conclusion.
People who want meat eating curtailed are getting power stations and livestock mixed up. They are calculating only the animal output and ignoring the input. This is appalling carbon accounting. Another difference is that the power station can never reuse its waste carbon dioxide, while sheep and cows can. The next mouthful of grass represents a new drawdown of carbon dioxide from the atmosphere.
Far from being part of the carbon emission problem, free-ranging cattle are part of the solution. The grazing relationship between plants and free-ranging animals is one of the few ways to draw down excess carbon dioxide from the atmosphere and store it as carbon in the soil.
Feedlot animals are in a different category because of the added carbon footprint of the fossil fuel used in tilling, seeding and harvesting grain. There is also a fossil fuel component in the production and distribution of fertiliser for grain growing. Finally, fossil fuel is used to transport the grain to the feedlot. We now move onto the methane debate – another myth perpetuated where cows are targeted as the culprits of mass, polluting methane production.
The rumen process
We need to understand the functioning of the ruminant stomach – a place where enteric fermentation takes place in the absence of oxygen – where carbon atoms cannot be chemically changed directly to carbon dioxide molecules because they require the presence of oxygen to do this. Instead, carbon atoms combine with hydrogen atoms to form a methane molecule. This methane is then belched by the cow.
Methane does not, however, have a long life in the atmosphere because two processes happen: The first is that it reacts with atmospheric oxygen. This changes its structure so that the methane molecule disappears and is replaced by carbon dioxide and water. In other words, the carbon atom in the methane molecule reverts to exactly the same form as it was before the process of photosynthesis began.
The formula for this is: CH4 + 2O2 = CO2 + 2H2O + energy released.
The second process that happens is that the methane is consumed as a food source by soil microbes. Microbes in the general environment are efficient at oxidising methane. Yet we are warned of the dangers of methane production by cows, as if it is something bizarre and unusual. Methane is a by-product of anaerobic microbial fermentation in the rumen, powered ultimately by solar energy. Methane production by fossil fuels is an altogether different process.
The fact is that livestock farmers have been widely censured based on misleading information and poorly understood science.
The important message to communicate to the public is not just the fact that free-ranging cattle are carbon neutral but also that they serve as agents to draw down excess carbon dioxide.
In this regard cattle farmers now have a respected scientist on their side; Professor Tim Flannery who holds the Chair in Environmental Sustainability at Macquarie University in Sydney and is the Australian government appointed chief commissioner of the Climate Change Commission. At a recent Australian seminar, Prof Flannery spoke on the topic:
‘Can Red Meat be Green? Experts Debate Sustainable Food Production’. During his talk he emphasised that by using the relationship between plants and animals we can boost the carbon storage capacity of our soil. It is important for all livestock farmers to get this message into the public domain. The food security of the world, environmental sustainability and livelihoods are at stake.
Contact David Mason-Jones on +61 (0) 411 172 328, or email [email protected]. The views expressed in our weekly opinion piece do not necessarily reflect those of Farmer’s Weekly.