By January, the freeze is on. The nights are longer, the sun is lower, and the ice covers everything. Global warming or not, it is just cold in the Arctic Basin and ice covers the sea once again. Having said that, the Januaries are getting warmer, slowly and erratically, but undeniably. Compared to the ice average for previous Januaries the trend is down. The ice trend is always down, every month, every season, every year. The curve bounces around a lot, but the mean slope of the January regression is negative: -3.2%/decade. This is not as alarming as the September number (-13%/decade) but it is alarming nonetheless.
Next month will the dead of winter, and in March the sea ice will max out. But the trend is always less and less ice every year, compared to the same month on previous years.
There’s a good article on the Polar Vortex on NSIDC this month…