The quantities of greenhouse gases emitted into the atmosphere from su
garcane fields, and their contribution to the total emissions from Aus
tralian agriculture, have never been estimated with any degree of cert
ainty. This review was conducted to collate the available information
on greenhouse gas emissions from the Australian sugarcane crop. Estima
tes were made for the emissions of the 3 major greenhouse gases-carbon
dioxide (CO2), methane (CH4), and nitrous oxide (N2O)-from known or s
uspected sources. Sinks for the sequestration of the gases also have b
een identified. CO2 was found to be emitted during burning of the crop
and from trash-blanketed and bare sugarcane fields. Total emissions f
rom these sources in the 1994 season were estimated at 7.6 Mt CO2-C/ye
ar. However, the sugarcane crop was identified as a major sink for C,
with uptake by the crop in 1994 estimated at 13.4 Mt CO2-C/year. N2O e
manating from sugarcane soils via denitrification following applicatio
n of fertiliser accounted for 45-78% of total gaseous N emissions. Est
imates of N2O emissions from all land under sugarcane in 1994 totalled
4.4 kt N2O-N/year from denitrification with a further 6.3 kt N2O-N em
itted from areas that are still burnt. This review suggests changes in
management procedures that should limit the opportunities for denitri
fication in the soil and thus reduce N2O emissions. Methane evolution
occurs during the smouldering phase, following burning of the crop, wi
th production estimated at 6.7 kt CH4-C/year in 1994. CH4 oxidation in
soil was identified as an important process for removal of atmospheri
c CH4, as were trash-blanketed soils. Although these figures are our b
est estimate of gaseous production from sugarcane fields, there still
remains a degree of uncertainty due to sampling variability and becaus
e of the extrapolation to the entire sugarcane area. However, the coup
ling of new laser techniques with known micrometeorological methods wi
ll allow for a more precise sampling of greenhouse gas emissions over
a larger area. Estimates would thus be more representative, resulting
in a greater degree of confidence being placed in them by the sugar in
dustry.