Switching to renewables will take time. With hydrogen, for example, delivery infrastructure does not exist, and current engines will be obsolete. In the meantime, we need to consume less fossil fuel while conducting business as usual. We’re talking efficiency, which is not a new concept.

Becoming more efficient with fuel is not that hard. Most people could cut their fuel bills – and consequent CO2 emissions – by 10 per cent just by driving more carefully. Going with the flow in traffic, easing off earlier when traffic lights go red, and accelerating a little less aggressively will accomplish that. No capital investment is required.

In 2005, passenger vehicles in Australia consumed 18,144 million litres of fuel. If you mark out a square on the ground with 100-metre sides, you would need to extend it 1.8 kilometres into the air to fill it with that much fuel – and even then a few hundred thousand litres would be lost. Australia’s one-year fuel tank would dwarf the world’s biggest skyscrapers.

If we all drove more efficiently there would still be 180 metres of fuel – mostly carbon – left in the tank at the end of the year.

The Federal Government, derives a 38-cent excise (plus 10 per cent GST) on every one of those 18,144 million litres, and is also the country’s biggest advertiser – but all that lost revenue is hardly an incentive to launch a high-profile marketing campaign targeting fuel efficiency any time soon.

Next step on the road to more efficient motoring is simply using the old car a bit less – say five per cent less. Many could accomplish this just with a bit more planning – getting two things done for the price of one trip, instead of making two trips. National saving: another 90 metres of fuel in the big tank.

Should you upgrade to a better, more fuel-efficient car? That’s debatable. Almost every car company has jumped on the ‘green’ bandwagon, an incomprehensibly hypocritical step, given the business at hand. Around 5000kg of CO2 is emitted in the manufacture of a new car. Just to break even, in terms of carbon footprint, this amount of CO2 would need to be saved via lower fuel consumption, which depending on use could take several years.

Fuel efficiency per se isn’t a good enough reason to buy a new car, but if it is time for you to upgrade for other reasons, perhaps it should weigh heavily on your decision.

What the car industry should be doing, but isn’t, is investing in lightweight vehicle design, because putting a couple of hundred kilos of humanity in a vehicle that weighs two tonnes is fundamentally flawed from an efficiency perspective. What few gains have been made in lightweight vehicle design, via advanced computer modelling and clever use of high-strength steel alloys, plus composites and plastics, are negated by the fact that even small cars are getting bigger and heavier. Just compare the new Corolla to the first Camry, or the new Lancer to the first Magna.

Finally, it’s worth remembering that the average Australian’s carbon footprint has four times more to do with coal-fired electricity than petrol. Efficiency is about total energy use, not just cars.