In his seminal 1982 book Climate, History, and the Modern World, the renown climatologist Dr. H.H. Lamb revealed that sea ice in the subarctic and Arctic regions was much less extensive during the Medieval Warm Period (9th-13th centuries) compared to today.
Cato Institute atmospheric scientist Ryan Maue looked at high Arctic temperature data going back to 1958 shows that warm spikes are nothing new. An EKG-like pattern is clearly visible in the data, but there is a warming trend. Data before the satellite-era — 1976 — has some problems, so it’s hard to say the current spike is for sure a record. Most of the Arctic warming has come during the winter months, Maue said.