GREENHOUSE GAS EMISSIONS
Motor vehicles emit greenhouse gases, which contribute to climate change. Not all vehicles have the same impact. In vehicles, the principal greenhouse gas is carbon dioxide (CO2), but vehicles also produce the greenhouse gases nitrous oxide and methane. The vehicle's level of CO2 emissions is linked to the amount of fuel consumed and the type of fuel used.
The road transport sector depends on petroleum based fuels. Growth in the Australian road transport task has led to a corresponding increase in fuel consumption, which in turn, has led to an increase in greenhouse gas emissions from the sector. In 2006, road transport accounted for 12% of Australia's total greenhouse gas emissions. Greenhouse emissions from road transport have been increasing at an average rate of 1.7% per annum since 1990.
The Australian Department of Climate Change maintains Australia's National Greenhouse Accounts which has more information on the emissions of greenhouse gases in Australia.
On the Green Vehicle Guide, a higher Greenhouse Rating means the car produces lower levels of carbon dioxide (CO2). All new vehicle models up to 3.5 tonnes gross vehicle mass sold in Australia are tested to determine both fuel consumption and the level of CO2 emissions emitted. The test produces 3 results for fuel consumption and CO2 emissions - the 'urban', 'extra-urban' and 'combined' values. The combined CO2 emissions value is used to derive the Greenhouse Rating of a vehicle as illustrated in the table below. This information is also displayed on the Fuel Consumption Label attached to the windscreen of new vehicles.