Oldsmobile

I would like to extend my sympathy to those who were somewhat confused by Charles Micallef's self-styled "rather controversial letter" on climate change and cars (April 12).

In pointing out that new cars are not "virgins" - who said they were? - he lists five features which have nothing to do with the age of a car but simply reflect the cast of mind of some - probably a minority - of local drivers. In fact one sees new cars and old carrying some of the paraphernalia he describes, including air conditioners.

Where the writing is not so much controversial as daft is in the matter of CO2. Mr Micallef's "genuine advice" is to fight climate change, even if the methods used may not leave too many of us to enjoy the benefits of stopping climate change. So let us have more CO, benzene and unburnt fuel, providentially and preferentially emitted by old cars, as these substances do not contribute to global warming. From someone who lives in Fgura, the town with the worst air quality in the Republic, this is indeed the unkindest cut of all.

On details, CO2 production by cars is calculated on fuel consumption. As older cars tend to have a higher fuel consumption, their calculated CO2 emissions are higher. In any case the proportion of CO to CO2 from road transport is rather small - some six to seven per cent. So turning the CO from new cars into CO2 is not going to change things much. On the other hand, the removal of most of the CO, benzene and other substances by a catalyser, as well as fine particles by a filter fitted to diesel exhausts, will remove or diminish negative health impacts on the population.

Or one could join the so-called Green Project of the University Students' Council, where we are told that a single tree will absorb as much CO2 as a car driven 45,000km in a year. Now the average European car emits 160g CO2/km which will total 7,200kg (or 7.2t) CO2 net of course. It will take a whopping great tree or very many saplings to absorb that much gas, which has almost 2.0 t. of carbon in it. We could have the Republic covered in trees at that rate. That may be no bad thing, but there well may be no space left to drive cars in.