Analysis of greenhouse gas emissions from the average Irish milk production system

Actions to moderate the major emission contributors of enteric fermentation, fertiliser and manure management on farms should not simply move the emissions elsewhere in the system, but actually reduce them. Life cycle assessment methodology was used to provide an objective framework for estimating emissions and to evaluate emission management scenarios with respect to kg CO2 eq emitted per unit of milk produced. An average dairy unit was defined and emissions were compartmentalised to calculate a total emission of 1.50 kg CO2 eq kg−1 (energy corrected milk) yr−1 and 1.3 kg CO2 eq kg−1 yr−1 with economic allocation between milk and meat. Of the total emissions, 49% was enteric fermentation, 21% fertiliser, 13% concentrate feed, 11% dung management and 5% electricity and diesel consumption. Scenario testing indicated that more efficient cows with extensive management could reduce emissions by 14-18%, elimination of non-milking animals could reduce emissions by 14-26% and a combination of both could reduce emissions by 28-33%. It was concluded that the evolution of the Irish dairy sector, driven by the Common Agricultural Policy (CAP), should result in reduced GHG emissions.