"Bill Otten" wrote:

And we know this HOW David? Papyrus scrolls with CO2 records? Cuneiform rock
carvings describing changing CO2 levels? Monastic lab books full of CO2
experiments? Do you even KNOW how to determine or quantify atmospheric CO2
levels?

bill


Core samples from Greenland, Antarctica, etc. contain trapped samples
of the atmosphere, as well as hints to the climate during those
periods along with other information such as ash from volcanic
eruptions, and so on.

So sorry to hear you failed high-school earth science.