Marked increases in atmospheric CO2 concentrations are largely associated with the release of sequestered carbon in fossil fuels. While emissions of green-house gasses (GHG) from cattle have significant global warming potential (GWP), these are biogenic sources and substantially involve carbon in natural cycles, rather than fossil fuel. Cattle utilise human inedible feeds and by-products of human food production to produce nutrient dense foods of great value to humans.
There are marked differences in the chemistry of GHG, with methane having greater radiative forcing effect (34 times) greater than CO2, but a much shorter half-life than CO2 having effect for 12 years v tens of thousands of years. Estimates of the effects of ruminants on global warming have been focussed on the emissions produced, but have not considered the benefits in terms of maintenance of grassland and forest environments, nor considered implications for the food chain or social structures in some regions. These considerations are complex and require deep considerations of sustainability. Fortunately, there is much that can be done to reduce the impacts of cattle production on GHG intensity and overall production. There is potential for the profession to play a positive role in this area of responsibility.