Arctic ice cover is a flawed benchmark for AGW claims.

Since the last ice age, the ice cover of the Arctic Ocean varied greatly (but CO2 didn't).  From approximately 8000 to 5000 years ago, when the temperatures were somewhat warmer than today, there was significantly less sea ice in the Arctic Ocean, probably less than 50% of the summer 2007 coverage, which was the absolutely lowest on record. ... Our studies also show that when the ice disappears in one area, it may accumulate in another. ... This is probably due to changes in the prevailing wind systems. This factor has not been sufficiently taken into account when forecasting the imminent disappearance of sea ice in the Arctic Ocean.
Findings by Funder et al of the Danish National Research Foundation for Geogenetics at the University of Copenhagen.
Measurements included study of 500 km of beach ridges and the presence of driftwood species.

More here on wind altering the ice cover.
"The changed wind direction pushes large ice masses away from the Arctic and down along the eastern coast of Greenland".