Massive Arctic temperature uptrend

The Arctic winter has become 5 degrees warmer in just 30 years.  5 degrees!  (the chart shows the actual temperature; the map shows the anomaly from the 1981 -2000 average)

Mean 925 hPa air temperature north of 67N (Arctic Circle) over 1949-2018 (October – February). Temperature reanalysis from NCEP/NCAR R1. Subplot highlights surface air temperature anomalies averaged from October – February 2018 using a 1981-2010 baseline. (Updated 3/5/2018) (Source)