https://www.ncei.noaa.gov/news/global-climate-202012
Arctic sea ice extent: The average Arctic sea ice extent for December was 4.54 million square miles, according to analysis by the National Snow and Ice Data Center (NSIDC) based on data from NOAA and NASA.
This value was 8.3 percent smaller than the 1981-2010 average and the third smallest December sea ice extent since records began in 1979. Only Decembers of 2016 and 2017 had a smaller extent. December 2020 marked the 23rd consecutive December with below-average sea ice extent. According to NSIDC, sea ice was below average in the Bering and Barent seas.
Northern Hemisphere snow cover:According to data from NOAA analyzed by the Rutgers Global Snow Lab,
the Northern Hemisphere snow cover extent during December was slightly below average at 110,000 square miles below the 1981-2010 average.
The 2020
Northern Hemisphere land and ocean surface temperature was the
highest in the 141-year record at 2.30°F (1.28°C) above the 20th century average. Meanwhile, the annual Southern Hemisphere land and ocean surface temperature was the fifth highest on record.
Northern Hemisphere snow cover: According to NOAA data analyzed by the
Rutgers Global Snow Lab,
the average annual Northern Hemisphere snow cover extent for 2020 was 9.31 million square miles.
This was the fourth-smallest annual snow cover extent in the 1967-2020 record.