Don't agree with me. I made no claim that couldn't be found as easily in a wiki page or in a grade school textbook.
Why don't you just read up a little on the subject before starting to post conjectures about it? At the least it would better inform the questions you ask.
Because a lot of the subject matter is biased with political polemics.
On the other hand, how do you explain 3 million years ago when the earth's temperature was 3 to 4 C degrees warmer than today and the same CO2 concentration at 365 to 410 ppm?