The abatement challenge for Australian Agriculture

Introduction According to the National Greenhouse Gas Inventory (NGGI 2007) the agricultural sector contributes around 16% of national greenhouse gas emissions (Figure 1). The main greenhouse gases emitted from agriculture include methane lost during rumen digestion (enteric) and nitrous oxide lost from nitrogen fertilisers, animal excreta and soils (Figure 1). Agriculture accounts for 60% and 85% of Australia’s total methane and nitrous oxide emissions, respectively (NGGI 2007), both potent greenhouse gases. While most of the methane lost from agricultural systems comes from rumen fermentation (Figure 1), it is estimated that nitrogen fertiliser is responsible for 16% of nitrous oxide emissions from agriculture with 21% derived from nitrogen in animal excreta. The indirect emissions, related to agriculture’s use of transport and stationary energy account for around 11% of national emissions, but are attributed to the stationary energy and transport sectors in Figure 1.