The agricultural sector (excluding land clearing) contributed around 20 per cent of Australia's
net greenhouse gas emissions in 1996 (Commonwealth of Australia, 1998). The main sources of
these emissions were methane from the digestive systems of cattle and sheep and nitrous oxide
from soils (the latter in part associated with fertiliser use).
Vegetation clearance for agriculture is a further important contributor to Australia's greenhouse
gas emissions. At present the current rate of land clearing for agriculture is in excess of the rate
of revegetation occurring in Australia., implying a net positive contribution to global warming
emissions.