In Australia, the federal government operates a carbon trading scheme. Outback properties like Kilcowera can be assessed for the amount of carbon the land accumulates over time. A value can be placed on this carbon, and companies can pay farmers to "offset" their carbon emissions. Carbon is measured in ACCU's - Australian Carbon Credit Unit. Kilcowera offsets the carbon produced by a city the size of Wollongong.
More information on Australian Carbon farming can be found here.