Abstract

Human activities have increased the atmospheric concentration of methane by about 140% since pre-industrial times. The accumulation of methane and other ‘greenhouse’ gases is anticipated to cause significant climate changes in the future. Ruminant livestock are the largest producers of methane in Australia and this source constitutes about 12% of the national net emissions. Australia is a signatory to the Kyoto Protocol, which, if it comes into force, requires limiting annual emissions during the period 2008–2012 to 8% over the 1990 value. Australian livestock emissions are projected to increase by 7% by 2010 with total Australian emissions expected to increase by 28–43%. Emissions per unit GDP are higher for the livestock sector than for most other sectors and this may negatively affect the sector if free market emission trading is implemented and no new technologies to reduce emissions cost-effectively are introduced. Using information from the National Greenhouse Gas Inventory, we demonstrate that reductions in emissions per unit product are already occurring in at least one Australian livestock industry and discuss ways to ensure that similar future changes will be recorded. Cautionary notes are made regarding options of grain feeding and more intensive production, which appear to be attractive but may lead to increasing emissions when viewed on a broader basis. The potential for increased animal production with new technologies developed to reduce methane emissions suggests that there may be significant opportunities for the Australian livestock industries arising from the issue of greenhouse gas reductions. Opportunities to establish carbon sinks are also discussed. We suggest that addressing reduction of emissions per hectare rather than per head or per kilo of product results in a strong alignment with the development of more sustainable livestock industries.