Well, that was an interesting exercise. Gillian Hayman took all our farm data and produced some colourful charts with the Dairy Greenhouse Gas Abatement Strategy calculator. Like most animal-centred farms, the vast majority of our emissions come from the methane burped up by the cows.

Where our greenhouse gases come from

In total, our farm produced 13.3T CO2e per tonne of milk solids in 2010/11 – quite a bit above the average 10.2T CO2e per tonnes of milk solids recorded by the DPI Farm Monitor Project of 2009/10. Why is it so? Ironically, it could well be because our cows eat so much grass rather than grain.

So, what should a dairy farmer do?
According to the authorities:

“Production improvement options and best management practices are most often linked to greenhouse gas emissions reduction. At present, well managed farms have few options to reduce emissions without significant changes to their farming or feeding system…A great deal of research is underway within the Australian dairy industry to decrease the release of methane and nitrous oxide from farming systems.”

In the meantime, we will keep planting trees and be judicious with our fertiliser use.