Wednesday, 1 August 2012
Reducing enteric methane from livestock
This post is based on a presentation by Ed Charmley at the Tennant Creek CFI workshop in July 2012.
Ruminant animals such as cows produce methane (CH4) during the digestion of feed in a process called enteric fermentation. Enteric methane production, particularly from cattle, is the most significant source of greenhouse gas emissions in Australian agriculture.
Research is currently being conducted to identify how much methane cattle produce and potential abatement strategies. There are currently no methodologies approved for the reduction of enteric methane.
Potential methodologies applicable to northern producers are likely to be based around increasing production efficiency, e.g. increased weaning rates, or increasing nutrition to improve the rate of weight gain and reduce lifetime emissions.
Management options to achieve these outcomes might involve different finishing systems, the use of legumes or reducing stocking rates. Improved supplementation is also possible but may be cost prohibitive at least in the short term.
Because enteric methane reduction is an emissions abatement project and not a carbon sequestration project, there are no issues with the permanent (100 year) storage of carbon.
To earn carbon credits under the CFI, activities must be “additional” to business as usual (i.e. not common practice). Given that methane reductions from cattle is associated with productivity gains, which is the aim of most cattle enterprises, deciding what practices are not commonly practiced will require close consideration.
Once the additionality question is answered, methodologies can be developed. These methodologies will need to address the risk of “leakage”. Leakage occurs where reduced emissions inside a project area result in increased emissions elsewhere (e.g. destocking that leads to other cattle producers increasing their supply to meet unchanged market demand). Leakage could be addressed by retaining current turn-off rates using a smaller herd. However, this could be complicated by changes to herd structure.
The more important question is, will producers reduce numbers and engage in the CFI, or decide to turn off more cattle and not bother with carbon credits? This will require consideration of the relative costs and benefits from both options, including the potential for improved land condition under lower stocking rates.
A herd management methodology requires research into tools to set baselines and monitor and audit productivity indicators (rates of reproduction, growth/weight gain and survival. However, given the lack of measurement, mitigation and monitoring technologies, it may be some time before northern cattle producers can claim carbon credits by reducing cattle methane emissions.