Passenger Cars & Greenhouse Emissions

One of the worst things about the information age is its uncanny knack of giving unprecedented credibility to uninformed opinion. Those who would demonise your car and its perceived contribution as the harbinger of envirogeddon get their airtime, and then some, basically. Whenever the words ‘Kyoto’ and ‘car’ or ‘oil’ coexist in the one enviro-activist’s ill-informed sound bite, the smart money in general news journalism always bets the farm on Kyoto.

A definitive reality check on Greenhouse emissions is embodied in the Federal Government’s National Greenhouse Inventory 2004 (NGI), which is produced by the Department of Environment and Heritage. The report uses the official Kyoto accounting provisions to quantify Australia’s total Greenhouse emission and its predominate sources dating back to 1990. All this can be yours for the princely sum of a Google search and a PDF download (which is one of the really neat things about living in the information age). But be warned: when you open it, cue the Twilight Zone theme music on your MP3 player, because its truths are stranger than any fiction Stephen King could dream up. Try these 2004 Greenhouse emission highlights from left-field:

Passenger cars manage to emit just seven per cent of Australia’s total Greenhouse emissions. That’s right – cars are just one-fourteenth of the Greenhouse problem.

Down Under, cows and sheep fart almost 60 per cent more Greenhouse gas than passenger cars. (For credibility’s sake the official NGI report uses the term ‘enteric fermentation’ rather than ‘fart’, but the cumulative, inelegant rear-end emissions of methane remain unadulterated.) This is despite the drought and the massive decline in livestock numbers over the past 15 years.

Nationally, de-forestation releases more carbon-dioxide into the air than cars do – almost 30 per cent more.

Electricity generation is revealed as the real dark overlord of Australian Greenhouse emission, accounting for more than one-third of total Greenhouse gas production (195.2 million tonnes of carbon dioxide annually) – almost one-third of the problem overall.

Greenhouse emissions from passenger cars make up a little more than half of all transport-related emissions.


Greenhouse is a serious problem, but passenger cars tend to punch well above their weight in the perceived responsibility stakes. Australia’s Greenhouse emissions in 2004 were equivalent to 564.7 million tonnes of carbon-dioxide (CO2). Passenger cars emitted ‘just’ 41.7 million tonnes of CO2-equivalent – comprising just 7.4 per cent of the problem. (All the non-carbon-dioxide Greenhouse emissions – like methane and oxides of nitrogen – are equated to CO2 in the report, so apples can be compared with apples.)

When you add electricity generation (195.2 million tonnes) to the Greenhouse gasses released when coal is mined (21.3 million tonnes) you get a massive 216.5 million tonnes of Greenhouse emissions – 38 per cent of the Greenhouse problem. Coal-fired electricity, formerly touted as ‘clean’, is anything but. Its contribution to Greenhouse is five times greater than the car.

As a nation we love our cars, but it seems we are also having a mad, passionate, caution-to-the-wind affair with our air conditioners, our night lights, dishwashers and an endless supply of hot water.

If the recent past is anything to judge the future by, this disparity is set to become even greater. According to the NGI report, Greenhouse emissions from electricity generation have risen sharply in the past 15 years. In 2004, electricity generation emissions were up 50.8 per cent compared with 1990. In the same time, however, passenger car Greenhouse emissions rose just 18 per cent – in large part thanks to the car industry’s commitment to cleaning up its emissions act.

The blogosphere is knee-deep in Greenhouse-reduction advice, most of it well-intentioned; much of it ill-conceived. If you want to enjoy your motoring and do the right thing, Greenhouse-wise, it’s some comfort to know that the two objectives are not mutually exclusive. The bottom line: if we can cut passenger-car Greenhouse emissions by one-third (by driving hybrids instead of SS Commodores, by walking to work or catching the train, whatever) we will make a 2.5 per cent dent in our national Greenhouse output. However, the same reduction could be achieved simply by reducing our consumption of electricity by just seven per cent – something many of us could do merely by nudging our thermostats up a smidge in summer and down in winter, by turning off lights in unoccupied rooms (and CBD offices), by powering down those unused appliances and by taking shorter showers.

If you really want to make a dent in your Greenhouse emissions, take our quiz below to see which actions are most effective.



…without casting a cloud over your motoring

OPTION 1: Instead of buying a new XR6 Turbo I’ll buy a 2.4-litre four-cylinder Camry.

OPTION 2: I’ll switch my home over from electric hot water to gas.

Analysis: According to the Federal Government’s Green Vehicle Guide data ( in 20,000km of annual motoring the XR6 Turbo will emit 5840kg of CO2, while the Camry will produce less – 4660kg of CO2. Switching to the Camry (you’ll hate it, by the way) will reduce Greenhouse emissions by a significant 1180kg. However, according to the Federal Government’s Australian Greenhouse Office, an average home using electricity to produce hot water emits about four tonnes of CO2 annually. Using gas instead generates only about 1.5 tonnes of CO2.

Verdict: Buy the car of your dreams and convert the hot water to gas. You’ll still produce 1.3 tonnes less CO2 overall.


OPTION 1: I’ll do my bit for the planet and ditch my VZ SS Commodore in favour of a new Toyota Prius.

OPTION 2: I’ll convert my home over to electricity from an accredited renewable energy source.

Analysis: SS Commodores are right up there in CO2 emissions – to the tune of 6.66 tonnes in 20,000km of annual motoring. The Prius is nothing if not diminutive in this respect (and many others, such as size and performance). It pumps out just 2120kg of CO2 in the same distance – a saving of more than four tonnes of CO2. However, this saving does not take into account the six-odd tonnes of CO2 produced as a result of manufacturing the Prius, which basically negates the CO2 emissions benefit for the first 20-something months of ownership. Alternatively, if you switch to electricity from an accredited renewable energy source, the electricity you consume will be carbon-neutral. Most electricity retailers offer power from an accredited renewable source for a small impost. According to AGL, the cost to the average consumer, who uses 6500 kilowatt-hours of electricity annually, will be around $360, or about seven dollars each week – two espressos’ worth. (A 5.5-cent GST-inc. premium is levied upon each kilowatt-hour consumed.) Net carbon saving: more than seven tonnes of CO2.

Verdict: A no brainer. Do your bit for the environment. Keep thrashing the VZ; convert the house to renewable electricity. Net benefit to the environment: 520kg CO2.


OPTION 1: I’ll cycle 28km per week (4km per day) instead of using the car.

OPTION 2: Ill replace all the incandescent light globes in the house with energy-efficient compact fluorescent globes.

Analysis: Cycling 28km per week instead of driving adds up to 1456km annually. If the car you’re leaving behind is a four-cylinder Camry, you’ll save around 340kg of CO2 emissions annually (source: based upon Green Vehicle Guide data). However, according to the Australian Greenhouse Office, the energy used for lighting in an average Australian home generates around 750kg of CO2. It adds switching to compact fluoros will cut greenhouse emissions by 75 per cent, as well as produce the same light output. Net CO2 saving: 560kg.

Verdict: You can change the globes over without raising a sweat. Hell, if you’re in a ‘can-do’ frame of mind (not to mention physical state), do both. You’ll save almost a tonne of CO2, about the same as switching from an XR6 Turbo to a four-cylinder Camry.