A more accurate way of decribing the cost of petrol

As readers of my blog will be aware, my knowledge of runaway climate change and Australia’s abysmally low fuel excise rates has made me for a long time realise that the two words “petrol” and “expensive” should never be put together in the same sentence (or, more poetically, “never the twain shall meet”).

The fact that one can grammatically use “less cheap” to describe an increasing petrol price is unfortunately not realised by most people even in the environmental movement. I have been using "less cheap" over a decade and the disappearance of the southern winter rain belt in Australia makes me more determined to teach people not to put “expensive” and “petrol” in the same sentence.

This fact, I have come to think, creates a problem with the conventional method of describing the cost of petrol. By the conventional method of measuring by the amount of money for a given volume of petrol, people who have to pay for petrol can always say it is “less expensive” even when as currently petrol has never been so cheap.

What I have thought of doing since petrol’s cheapness began rising and rising is to measure how much one pays for petrol by the amount of petrol for a given sum of money (in Australia's case the number of millilitres of petrol per dollar, written ml/$.

This way:

• when the volume of petrol per dollar increases, one sees it really is getting cheaper (and its emissions of greenhouse gases make it always cheap)
• when the volume per dollar falls as it was earlier this year people with a constant sum of money are less able to produce greenhouse gases and less damage will be done to the climate.

The formula for convertine x cents per litre to y millitres per dollar is:

y = 100000/x

Thus:

• 3349 cpl (a price reasonable for Australia's sensitive environment) equals 29.85ml/$
• 99.9 cpl (a current price in Perth) equal 953.3ml/$.