in 221785 20070309 124614 Gianna wrote:

As the proportions of atmospheric gases vary over time, the term 'excess' is
subjective. They stated that temperatures, and CO2 levels, have been higher
than they presently are, and that was long before industrialisation etc..

Other sources claim that CO2 today is higher than at any time in the last 600,000 years.
If the person(s) you quote is not disputing that then he must be referring to an earlier
period - in which case how does he know?