Devon beef farmer John Sherrell has carried out a carbon audit of his own beef farm at Great Prideaux, Noss Mayo and the Holbeton area. He has discovered that his farm is sequestering (absorbing) much more carbon than it is emitting to the tune of 150 tonnes per year and is therefore carbon negative. How Now Dairy, a dairy farm at Ugborough in Devon, is also carbon negative, and the reality is that most grass based systems that predominate in South Devon are probably fairly close to being carbon neutral or even negative.
The subject of cattle and methane is complex, but essentially in grass based systems, cows are only emitting biogenic methane. Through the biogenic carbon cycle, plants absorb carbon dioxide from the atmosphere and, through photosynthesis, produce carbohydrates such as cellulose that cattle break down, emitting a portion as methane. This methane only persists in the atmosphere for about 12 years and is then converted into water and carbon dioxide. The important part is that this form of carbon dioxide (a recycled flow gas in a natural cycle) is the same carbon that was in the atmosphere, prior to being absorbed by the plant and consumed by the cow, so is essentially recycled, unlike carbon dioxide from fossil fuels (a cumulative stock gas that builds up) that persists for thousands of years in the atmosphere.
Unfortunately, and misleadingly, the current methods of measuring climate change do not differentiate between flow gases and stock gases which results in a very unfair blaming of cattle for climate change, when in fact, they are not always guilty. It is therefore quite possible to eat grass fed beef without contributing to climate change, indeed, you may even be reversing it!
Cattle are a keystone species of the natural world and can bring amazing benefits to biodiversity, but that’s a story for another day!
With grateful thanks to John Sherrell. This article was first published in Holbeton News.