[aruanan]

Man is nearly entirely responsible for the increase.

There has been little increase since the 19th century. This interglacial is CO2-poor compared to the rest of geological history. We don't have nearly enough atmospheric CO2. We're only slightly above the amount needed to support plant growth. The largest effect on temperature is between 0 and about 100 ppm. We could triple atmospheric CO2 and have an effect on temperatures that would amount only to tenths of a degree Celsius.

[cogitator]

There has been little increase since the 19th century.

40%.

This interglacial is CO2-poor compared to the rest of geological history.

I really only think it's valid to compare to the Pleistocene. Previous epochs had different climate factors in play. The period prior to the Pleistocene was the Pliocene. From: The Climate of the Pliocene: Simulating Earth's Last Great Warm Period

"The Pliocene epoch covers the period from approximately 5 to 1.8 million years ago and, as such, spanned the period of time during which the Earth transitioned from relatively warm climates to the generally cooler climates of the Pleistocene. This transition included the emergence of the direct ancestors of humankind and contains the beginnings of cyclic Northern Hemisphere glaciation."

We could triple atmospheric CO2 and have an effect on temperatures that would amount only to tenths of a degree Celsius.

Don't know where you're getting your numbers. Most estimates put the direct warming effect of a doubling of CO2 at about 0.8 - 1.0 deg C, with increased atmospheric water vapor adding 2 - 4 deg C on top of that.

(Don't want to disappoint you but I'm calling it a night.)