It seems beyond dispute that cows contribute much towards global warming, and that those of us who eat them should hang our heads in shame. As seems so often the case, the truth of the matter is quite different. If cows ate what they should – grass – and lived outside for as much of the year as they can, in a field eating and trampling on grass, then grass would become a carbon sink and sequester the excess carbon in the atmosphere in the soil.
In the latest edition of the Weston A Price journal, Wise Traditions, there is a thought provoking article on cows, grass and carbon.
The journal lists four ways grass eating cows help reduce global warming.
Here is what the article says about grass
Grass, the world’s most widespread crop, is truly amazing. All plants remove carbon from the atmosphere and incorporate it into their structures, but most plants if bitten off regenerate slowly or not at all. Loss of growing leaves is a severe setback. Trees sequester a lot of carbon in their leaves and trunks, but when the tree dies that carbon will mostly be released back into the atmosphere, more quickly in the case of fire.
The growth nodes of grass are at the soil surface. When grass is eaten it is a signal to the plant to send up new leaf growth, resulting in denser turf. The more it is eaten, the faster it grows and the more carbon it captures and stores underground in its roots. As grass is trampled by grazing animals it is pushed underground along with manure and urine where it decomposes and its carbon feeds soil microbes. This property of grass is entirely dependent on the presence of herbivores. Without the nibbling, trampling and fertilization of herbivores, grass fails to function as this massive carbon sink. Grass without grazers dies above ground and loses its carbon back into the air.
Which leads on to the second positive contribution of grass and a herd of grazers. Allan Savory specialises in rebuilding grasslands in deserts. He found that to encourage the grass to re grow in these areas, it needs to be under pressure from grazing animals, who do all that trampling, eating, pissing and pooing that really gets the grass going. Then a predator moves in and the animals move on in a tight group. Without the predators, the grass eaters would spread out over a wider area, making their trampling and so on less intense and less effective. And so herbivores, their predators and grass have evolved together and are mutually dependant. With this combination, grass grows strongly and can recover decimated land.
The third positive effect was discovered by the Marin Carbon Project, initiated by John Wick. Like Allan Savory, he found that taking livestock off pasture to allow it to rest had the reverse effect of what he was hoping for – both the density of the turf and the fertility of the soil went down without the cows.
So he teamed up with a bio-geophysicist with the remarkable name, Whendee Silver, to run a study. Wick spread dairy manure, composted with straw, half inch thick over several large test plots, leaving others nearby as controls. After a year, core samples were taken to measure soil carbon in comparison to the start of the trial. At the end of the year, the carbon in the treated plots had increased by a ton per hectare, and the following year, the carbon in the treated plots increased again.
It seems that carbon behaves like a sponge, making the soil hold three times as much water. And this also meant that the same plot of land could support more cattle.
But perhaps best of all is the fourth method: because the sequestered carbon moves deeper into the soil over time, unless the field is ploughed up, the carbon will stay there and both Wick and Dr Silver have used computer modelling to show that if half of California’s ranchland were treated with this compost, the atmospheric pollution caused by the traffic would be removed from the air and permanently stored.
This would require the soil to stay as pasture – and for us to continue to eat cows that feed on the grass.
Some myths about cows contributing to global warming stem from a paper Livestock’s Long Shadow, a United Nations Food and Agriculture Organization’s publication from 2006. This blames increasing meat consumption for 17% of carbon dioxide contributions to the atmosphere.
And the paper does put this down to the increasing use of grains in animal feeds, grains that need growing, milling and transporting. Grains along with bits of dead animal and goodness knows what else to promote rapid growth.
But if farm animals eat what they are meant to – grass in the case of cows and sheep, with goats, pigs and hens capable of eating virtually anything, this percentage changes considerably.
Then there is the myth that cow pats release methane. Methane is only produced where there is no oxygen, so as cow pats break down, they do not release methane, and the same goes for composted dung.
Now, all ruminants produce methane as a by-product of digestion. Come to that, we humans produce methane as a by-product of our digestion. As do many other animals, with the humble termite winning the prize for methane production. Cow’s methane comes out as a burp. From us humans it enters the atmosphere in a much more potentially humorous way.
It might sound like tapping, but now we know its the termites wee parps.
So bring on the steak!