Cars chew up juice faster than people

The famous astronomer, the late Carl Sagan, once mused that if there were aliens and they put a probe into orbit around the Earth, the pictures would lead them to conclude that cars are the dominant occupants of our planet.
While Earth’s 700 million cars are outnumbered by 6.5 billion humans, the cars are much hungrier than people.
One litre of petrol contains three times the energy in an average person’s daily food intake. So driving is equivalent to a hundred people pushing your car. Petrol is amazing stuff!
But burning petroleum fuels generates greenhouse gases and with the need to curb climate change, there are pressures to cut emissions.

Furthermore, the worldwide rate of petroleum use, currently at a staggering 84 million barrels per day, is expected to decline over coming decades as we pass “peak oil”.
It would seem like our cars are going to have to go on a diet, and indeed compact fuel efficient cars are now favoured as fuel prices rise.

Australia is one of the most car dependent societies on the planet. According to the Australian Bureau of Statistics, we have more than 11 million cars that collectively travel in excess of 155 billion kilometres each year and burn about 16 billion litres of fuel. Road transport burns a further 13 billion litres of fuel each year.
Biofuels such as ethanol and biodiesel are probably the way of the future. They are really solar energy captured by plants and are in theory carbon neutral.
But modern farming uses enormous amounts of fossil fuels, especially in fertilizer production, so that current biofuel production does generate a lot of greenhouse gas emissions.

In the future we can also expect competition between food and biofuel production for croplands and limited resources like water. Consequently food prices will be driven up by demand for biofuels (see my blog post here).

With such enormous populations of people and cars it will become increasingly difficult to feed them both. Intervention will be required to prevent the wealthy fuelling their cars as poor people across the world are unable to purchase food.
Ideally we will find an alternative energy source for our cars that does not compete with food production. We should seriously consider a CSIRO proposal to establish an Australian biofuel industry based on the harvesting of fast growing drought resistant native trees that can be grown on degraded lands.

For others, a hydrogen economy is the ultimate answer, but that is another story (see my blog post here).

This was originally published in the Fraser Coast Chronicle on 27 March 2007.