re: That's the website I usually go to for that info.
"Remember that they've only been measuring this effectively since 1979. I would love to know what the extent was back in the 1930s."
It probably wasn't measurably different than current conditions. But what about 1000 years ago during time of viking exploration. Few argue that it wasn't warmer in the arctic region during that time.
It seems to me one could determine the extent of the warming during that time by looking at small glaciers on small islands in southern part of arctic region [which I assume] could be most affected if arctic ocean ice were to melt.