Arctic sea ice extent in 2020 was nearly average for the last decade.
The chart above shows the record available from Sea Ice Index (SII) since 1989, along with the comparable record from MASIE 2006 to present. It shows 2020 is down 150k km2 (1%) from 2019, and 300k km2 above the low year 2017. In fact 2020 is nearly average for the last decade.
As noted in a previous post, alarms were raised over slower than average Arctic refreezing in October. Those fears were laid to rest firstly when ice extents roared back in November, and then with the Arctic freezing fast in December.
In November, 3.5 Wadhams of sea ice were added during the month. (The metric 1 Wadham = 1 M km2 comes from the professor’s predictions of an ice-free Arctic, meaning less than 1 M km2 extent). In December a further 2.7 Wadhams were added. The last two months more than offset the deficit in October.