During the recent debates on carbon pricing, the opposition has more closely aligned itself with those that ague that global warming is not man-made. Tony Abbott has even reflected these views in various recent statements, including buying into what is quite possibly the stupidest argument against anthropogenic global warming (AGW) and the carbon price. Abbott said that carbon dioxide is not a proven "environmental villain", which echoes the comments frequently stated by AGW-denialists that carbon dioxide is somehow not a problem because it is "essential to life".
This is quite possibly the stupidest argument against AGW and carbon pricing - there are plenty of other elements and gases that are "essential to life" that are pollutants and are priced and regulated.
Just to take one of them: sulphur. Sulphur is an important trace element that is required by the body for the manufacture of amino acids. It is also a component of many preservatives (particularly in wine). So it could be said that sulphur is essential to life.
However, like carbon, human activity has greatly changed the natural sulphur cycle which has resulted in the atmospheric concentration of sulphur increasing. This has had serious environmental impacts - the most striking of which is acid rain.
To tackle the problem of acid rain governments have used international treaties and a successful emissions trading scheme - sound familiar?
Saying that because carbon dioxide is "essential to life" it can not also be a pollutant is a completely spurious argument, and if we look at the regulation of another element that is also "essential to life", sulphur, we see a similar model to tackling the problem that we have seen proposed for carbon dioxide.