They explain …
Arctic sea ice extent during January averaged 13.53 million square kilometers (5.2 million square miles), which is 1.04 million square kilometers (402,000 square miles) below the 1981 to 2010 average. This was the lowest January extent in the satellite record, 90,000 square kilometers (35,000 square miles) below the previous record January low that occurred in 2011. This was largely driven by unusually low ice coverage in the Barents Sea, Kara Sea, and the East Greenland Sea on the Atlantic side, and below average conditions in the Bering Sea and Sea of Okhotsk. Ice conditions were near average in Baffin Bay, the Labrador Sea and Hudson Bay. There was also less ice than usual in the Gulf of St. Lawrence, an important habitat for harp seals.
Yes, January was unusually warm, but this is no seasonal blip, the trend over each and every successive season since 1981 is rather clear. It is of course rather important to not simply consider one point in time, but to look over a period of time at the trend and direction that things are moving in. That clearly reveals that this is all part of that ongoing trend …