Of course there is doubt. When I talk about the "blessed" period of relative stability, I'm talking about thousands of years, but you presented papers talking about hundreds of years.
You are aware that the periods of greatest animal and plant life had higher CO2 levels than present. Granted that was millions of years ago, but the point still stands.
How many millions of tonnes of CO2 is expelled by a volcano? There are many natural sources of CO2. Even from the sea bed.
As for Mars warming I was speaking to the premise that ice caps melting meant warming. For the past few years, the martian caps have shrank.
Little Ice Age: The little ice age was because the preceding conditions altered the planet's normal atmospheric content. After the conditions returned to normal, the temperatures would return.
You're going to look real silly in about 20 years when everyone is talking about freezing
"I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it." Thomas Jefferson