“Why the CO2 increase is man made (part 1)“. A rare bit of reality pops up unexpectedly on Anthony Watts’ blog. Yes, the increase in atmospheric CO2 is effectively all man-made, says Ferdinand Engelbeen.
Oh, here’s the catch; Engelbeen has left himself an escape hatch for the ensuing denialist assault. The increase in atmospheric CO2 apparently has limited impact on temperature. This is to be discussed later.
So that’s why Anthony offered a bit of “mainstream” perspective. He’s trying to gently steer his readers away from embarrassing attacks on scientific evidence and on to new and more flexible topics.
Wott's Up With That? 
However, many, if not a majority of the posters on Anthony’s blog find the idea that the increase in atmospheric CO2 is caused by humans highly debatable if not down right unbelievable.