Perhaps the data covers such a short period of time, it doesn't really tell you if the current trend is beyond what has been happening since the ice age ended.
Until we could fly over, it was a little hard to get real data on Arctic ice. But at the end of the last ice age, the ice extended down to about southern Iowa, so it's pretty clear it was colder then.
I'm not sure how far back we have good data... (Barbarian checks)
Goes back to the late 70s, and from there at least, it's fallen considerably.