[barrkel]

CO2 is 0.04% of atmospheric air by volume. Would it be a highly accurate approximation to say that air has no CO2? Could we then say that it is not possible to have problems with too much CO2 in the atmosphere, since our highly accurate approximation says there isn't any?

The article stands well on its merits. It's not political. It's talking about specific, measurable things with specific measurable effects, and 1% of a large number is still a large number.

[jcromartie]

Molecules in air do not exist on a spectrum from Nitrogen to Oxygen.

[barrkel]

And cells don't exist on a spectrum between male (XY) and female (XX) - leaving aside cells with abnormal numbers of chromosomes.