Read here (also read the comments for further information). It would seem that an Ohio State global warming advocate scientist, in association with researchers at Michael Mann's Penn State climate group, conducted a study of previous studies on Arctic sea ice. This Ohio State study makes the very vague claim that sea ice loss "appears to be unmatched over at least the last few thousand years,”.
The researchers comments about their study suggests that science and statistical techniques they utilized may be of 'Mannian' nature, which have proven to be black magic, at best.
"When we look carefully at various chemical and biological components of the sediment, and how the sediment is distributed — then, with certain skills and luck, we can reconstruct the conditions at the time the sediment was deposited.”....."They searched for patterns in the proxy data that fit together like pieces of a puzzle."
Any science that is based on "certain" skills and some "luck", while only seeking data that "fit together like pieces of a puzzle" and thus rejecting data that does not conform to the IPCC global warming hypothesis, sounds an awful lot like the discredited hockey-stick style of science.
The Greenland ice cores provide the best evidence of Arctic cooling and warming, which would be an excellent indicator of likely past sea ice conditions. It would appear the Ohio State researchers in choosing their "puzzle pieces" rejected the best data available, the non-conforming ice core data. (click on images to enlarge)
Per the Greenland ice cores, current Arctic temperatures are well within the range of past warming events. In fact, current Arctic warming has not reached the levels of past historical and ancient warming. These images and other historical temperature charts can be found here. Other climate history postings. Modern temperature charts.