Read here. The British ship, HMS Investigator, sailed the Arctic area in the 1850's. The ship was abandoned and then sunk. After 150+ years the sea ice finally retreated enough to allow researchers to find the HMS Investigator, on the bottom of the Arctic Ocean.
Sooooo.....during the 1850's, well before the huge spike in human CO2 emissions, the area north of the Arctic Circle was so free of ice that a wooden ship with sails could easily traverse the area. Simply put, this is irrefutable historical evidence about large scale sea ice melt, which proves that the Arctic has 'been there, done that.'
"Interesting that the ship was lost in 1853, right at the end of the Little Ice Age, and coincidentally just 3 years after the start of the HADCRU global temperature record, from which we are led to believe the earth has warmed about 0.7C. If we are seeing "unprecedented" global temperatures and changes in Arctic sea ice, how did the HMS Investigator get this far north at the end of the Little Ice Age?"