Animals and methane production

Methane and CO₂were never a problem in the environment. For millions of years both single stomached and ruminant (multi-stomached) animals roamed every continent of the world in vast numbers without disturbing the natural levels of either methane or CO₂. Their numbers possibly far exceeded the populations of domestic animals currently found on the planet. These animals predominantly ate grass, and in doing so maintained a natural and necessary symbiosis between Soil-Plants-Animals.

How it works
The act of grazing, when followed by a prolonged recovery, allows plants to prosper and prolongs the life of a plant. If a plant remains ungrazed after it has reached full recovery it begins to die off. Beyond that point the cell structure begins to change: the leaves and stems begin to lignify or go 'woody', chlorophyll is lost from its cells and the plant changes colour; in the absence of chlorophyll - the element that triggers photosythesis - growth ceases. The plant begins to gradually die of old age.

The ideal time to graze any grass plant is during the 'window of opportunity' that lies between the point of complete recovery and the onset of lignification (just before the upward line begins to arch over in the drawing to the left)

Immediately after being grazed a fully recovered plant enters a natural 'state of shock'. Just as it is not possible to sustain a large volume of above-ground leaf matter (ie a big plant) with a tiny root system, neither is it possible to sustain a large root volume with the seriously depleted post-grazing foliage (little leaf area). During this period the plant undergoes a major root kill-off in order to restore equilibrium. In short, it leaves a large, dead root system in the soil, and of course, those roots are all carbon sequestered from the atmosphere during photosynthesis.

As a plant recovers from the graze it must again rebuild both its root system and its leaf structure, which it does by sequestering further carbon from the atmosphere. During the next graze the animals again consume some of the leaf whilst leaving the roots untouched. The plant again begins to repeat the recovery process, which it does over and over again after every grazing. Over time vast quantities of carbon are captured and transferred below ground by this process.

Digestion is a biological process and as explained, in nature there is a constant movement of CO₂ from the atmosphere into the soil where it is held as organic carbon. In the presence of the correct microbial populations - soil fungi rather than bacteria - the organic carbon is held firmly in the soil as increasing levels of organic matter.

Digestion of grasses also causes a small amount of methane production in ruminants and non-ruminant animals but the amount is so small that it does not pose a an environmental threat to the atmosphere.

Industrial agriculture has now changed that equation somewhat. More than 70% of the world's grain production is now fed to confined animals residing in a vast feedlot like that shown to the right. There is not a blade of grass to be seen or consumed. Many of these animals are not grain eaters by nature. Ruminants such as cattle, sheep and goats are designed by nature to eat high volumes of cellulose such as grass. It is part of their symbiotic relationship with plants.

A damaging by-product of ruminants fed high grain diets is high levels of methane. We really need to address the root cause of the problem here: rather than tax the animals for doing what humans have unreasonably asked them to do we must educate producers and consumers that when properly managed, livestock are integral to the biological process that keeps CO₂ in the soil rather than polluting the atmosphere. The cattle should be back home on the range. Human decision making is the problem here!