Climate bulletin - December 2014
Summary of the world's climate in December 2014.
The global average temperature for December 2014 as estimated from the HadCRUT4 data set was 0.63 ± 0.14 °C above the 1961-1990 average. December was one of the ten warmest Decembers on record (uncertainty precluding a more precise ranking than that). Other global temperature data sets maintained by NASA GISS and NOAA NCDC also show that December was a very warm month globally. Sea-surface temperatures (SSTs) in the tropical Pacific were close to (in the far east) or above average in December, but did not exceed El Niño thresholds.
During December, the global average air temperature over land was warmer than the long term average (1.08 ± 0.31 °C). Cooler than average land surface temperatures were recorded in parts of southern and eastern Asia, limited areas of northern Australia, the Iberian Peninsula, South America and north east Canada. Few areas recorded significant cold anomalies: the Antarctic Peninsula reported temperatures below the 2nd percentile. Most land areas were warmer than average. Significant warmth, while not widespread, included parts of the Middle East, the western Pacific islands, parts of Australia, Madagascar, and scattered parts of the Americas. Some western states of the US reported unusually high temperatures for the month and for the country as a whole it was the second warmest December on record.
SSTs were generally warmer than average in December. The global mean SST was 0.45 ± 0.08 °C above the long term average. Unusually warm SSTs were widespread. The eastern North Pacific, western North Atlantic, the Mediterranean and the seas around northern Europe were all much warmer than average. The Indian Ocean and western Tropical Pacific were also unusually warm. Unusually low SSTs were recorded in the central North Pacific, in the North Atlantic (southwest of Iceland), and some areas of the eastern Pacific south of the equator. Other regions of well-below-average SST, such as in the area northeast of New Zealand and in the Tropical Atlantic might also have been significantly cool, but SST estimates in these areas are based only a small number of measurements and so might be less reliable.
Based on data from the National Snow and Ice Data Center, northern hemisphere (Arctic) sea ice extent was 12.5 million square kilometres. December 2014 was nominally the 9th least extensive December on record (2008 and 2009 had similar extents). Southern hemisphere (Antarctic) sea ice extent was 12.38 million square kilometres. December 2014 was nominally the 4th most extensive December on record.