Abstract: Temperature and Clouds

The annual mean air temperature for 2010 over Arctic land areas mirrored 2009, with slightly cooler temperatures than in recent years, although the average temperature for the last decade remained the warmest in the record beginning in 1900 (Fig. A1). The lower values in 2009 and 2010 reflect relatively cold continents in winter. In 2009 there was a coincident circum-Arctic ... decrease in Arctic greenness (see Fig. TE2 in the essay on Vegetation). However, the Arctic in 2011 continues to exhibit area-wide positive temperature anomalies which, together with other indicators discussed in this Report Card, suggest systematic changes since the end of the 20th Century. The past six years have been the warmest such period in the instrumental record for the region poleward of 60°N (SWIPA, 2011). There were notable local manifestations of the recent warming. Beginning on June 30, Barrow in northwesternmost Alaska had a record run of 86 consecutive summer days with minimum temperatures at or above freezing. The previous record, set in 2009, was 68 days. For the sixth consecutive year, the first freeze of autumn in Fairbanks in central Alaska occurred more than two weeks later than its long-term average.

Credit: Arctic Report Card (Richter-Menge, J., M. O. Jeffries and J. E. Overland, Eds.)