Watts Up With That? 
July 15, 2010
In part two of Dr. Meier’s post  , he mentioned :
“Examination of several proxy records (e.g., sediment cores) of sea ice indicate ice-free or near ice-free summer conditions for at least some time during the period of 15,000 to 5,000 years ago”
WUWT Reader David Penny astutely noted the implication that Polar Bears must have already survived an ice free Arctic in the not too distant past. According to Wikipedia  :
…the polar bear diverged from the brown bear, Ursus arctos, roughly 150,000 years ago
That must mean it is OK to take Polar Bears of the endangered species list. But the decision to put them on the list never had anything to do with science anyway.
The other implication of Dr. Meier’s statement is that a warmer, ice free Arctic occurred when CO2 levels were less than 290 ppm. This implies that there is no long term correlation between CO2 and Arctic temperatures.
Conversely, there was an ice age during the Ordovician 450 million years ago, when CO2 levels were 10X higher than today
Conclusion: There is no evidence that Arctic warming over the last 30 years has anything to do with CO2. If it were CO2 causing it, we would see warming at both poles.