Comments perchecreek has made

CO2 levels "never seen..." is incorrect

Meowse,

It may be that the context of the remark by Dr. Naish would qualify the meaning implied by his statement that you've quoted, but to simply imply categorically that contemporary atmospheric CO2 levels are at a level that have never "occurred at a rate we've seen geologically" (emphasis is mine) is incorrect; for, in fact, atmospheric C02 levels have been much, much higher (above 2000ppm).  Of course, it's probably not very reassuring that those levels were associated with a mass extinction.  It would be more correct to say that current C02 levels were not exceeded during the Pleistocene, which seems to be what Dr. Naish meant.

It is also important to emphasize, I believe, that asserting that climate has varied greatly without anthropogenic forcing should in no way be taken to obfuscate the likely significant consequence of such change now.  On 'It was warmer during the Holocene Climatic Optimum'--This period was not global and not like today posted 1 year, 7 months ago 4 Responses